1412 lines
73 KiB
Java
1412 lines
73 KiB
Java
/**
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* Copyright (c) 2014-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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package com.facebook.csslayout;
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import com.facebook.infer.annotation.Assertions;
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import static com.facebook.csslayout.CSSLayout.DIMENSION_HEIGHT;
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import static com.facebook.csslayout.CSSLayout.DIMENSION_WIDTH;
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import static com.facebook.csslayout.CSSLayout.POSITION_BOTTOM;
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import static com.facebook.csslayout.CSSLayout.POSITION_LEFT;
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import static com.facebook.csslayout.CSSLayout.POSITION_RIGHT;
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import static com.facebook.csslayout.CSSLayout.POSITION_TOP;
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/**
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* Calculates layouts based on CSS style. See {@link #layoutNode(CSSNode, float, float)}.
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*/
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public class LayoutEngine {
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private static final boolean POSITIVE_FLEX_IS_AUTO = false;
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private static final int CSS_FLEX_DIRECTION_COLUMN =
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CSSFlexDirection.COLUMN.ordinal();
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private static final int CSS_FLEX_DIRECTION_COLUMN_REVERSE =
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CSSFlexDirection.COLUMN_REVERSE.ordinal();
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private static final int CSS_FLEX_DIRECTION_ROW =
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CSSFlexDirection.ROW.ordinal();
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private static final int CSS_FLEX_DIRECTION_ROW_REVERSE =
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CSSFlexDirection.ROW_REVERSE.ordinal();
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private static final int CSS_POSITION_RELATIVE = CSSPositionType.RELATIVE.ordinal();
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private static final int CSS_POSITION_ABSOLUTE = CSSPositionType.ABSOLUTE.ordinal();
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private static final int[] leading = {
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POSITION_TOP,
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POSITION_BOTTOM,
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POSITION_LEFT,
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POSITION_RIGHT,
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};
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private static final int[] trailing = {
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POSITION_BOTTOM,
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POSITION_TOP,
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POSITION_RIGHT,
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POSITION_LEFT,
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};
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private static final int[] pos = {
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POSITION_TOP,
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POSITION_BOTTOM,
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POSITION_LEFT,
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POSITION_RIGHT,
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};
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private static final int[] dim = {
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DIMENSION_HEIGHT,
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DIMENSION_HEIGHT,
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DIMENSION_WIDTH,
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DIMENSION_WIDTH,
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};
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private static final int[] leadingSpacing = {
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Spacing.TOP,
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Spacing.BOTTOM,
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Spacing.START,
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Spacing.START
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};
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private static final int[] trailingSpacing = {
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Spacing.BOTTOM,
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Spacing.TOP,
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Spacing.END,
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Spacing.END
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};
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private static boolean isFlexBasisAuto(CSSNode node) {
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if (POSITIVE_FLEX_IS_AUTO) {
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// All flex values are auto.
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return true;
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} else {
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// A flex value > 0 implies a basis of zero.
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return node.style.flex <= 0;
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}
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}
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private static float getFlexGrowFactor(CSSNode node) {
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// Flex grow is implied by positive values for flex.
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if (node.style.flex > 0) {
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return node.style.flex;
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}
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return 0;
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}
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private static float getFlexShrinkFactor(CSSNode node) {
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if (POSITIVE_FLEX_IS_AUTO) {
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// A flex shrink factor of 1 is implied by non-zero values for flex.
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if (node.style.flex != 0) {
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return 1;
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}
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} else {
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// A flex shrink factor of 1 is implied by negative values for flex.
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if (node.style.flex < 0) {
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return 1;
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}
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}
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return 0;
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}
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private static float boundAxisWithinMinAndMax(CSSNode node, int axis, float value) {
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float min = CSSConstants.UNDEFINED;
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float max = CSSConstants.UNDEFINED;
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if (axis == CSS_FLEX_DIRECTION_COLUMN ||
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axis == CSS_FLEX_DIRECTION_COLUMN_REVERSE) {
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min = node.style.minHeight;
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max = node.style.maxHeight;
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} else if (axis == CSS_FLEX_DIRECTION_ROW ||
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axis == CSS_FLEX_DIRECTION_ROW_REVERSE) {
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min = node.style.minWidth;
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max = node.style.maxWidth;
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}
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float boundValue = value;
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if (!Float.isNaN(max) && max >= 0.0 && boundValue > max) {
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boundValue = max;
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}
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if (!Float.isNaN(min) && min >= 0.0 && boundValue < min) {
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boundValue = min;
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}
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return boundValue;
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}
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private static float boundAxis(CSSNode node, int axis, float value) {
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float paddingAndBorderAxis =
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node.style.padding.getWithFallback(leadingSpacing[axis], leading[axis]) +
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node.style.border.getWithFallback(leadingSpacing[axis], leading[axis]) +
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node.style.padding.getWithFallback(trailingSpacing[axis], trailing[axis]) +
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node.style.border.getWithFallback(trailingSpacing[axis], trailing[axis]);
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return Math.max(boundAxisWithinMinAndMax(node, axis, value), paddingAndBorderAxis);
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}
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private static float getRelativePosition(CSSNode node, int axis) {
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float lead = node.style.position[leading[axis]];
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if (!Float.isNaN(lead)) {
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return lead;
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}
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float trailingPos = node.style.position[trailing[axis]];
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return Float.isNaN(trailingPos) ? 0 : -trailingPos;
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}
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private static void setPosition(CSSNode node, CSSDirection direction) {
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int mainAxis = resolveAxis(getFlexDirection(node), direction);
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int crossAxis = getCrossFlexDirection(mainAxis, direction);
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node.layout.position[leading[mainAxis]] = node.style.margin.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) +
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getRelativePosition(node, mainAxis);
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node.layout.position[trailing[mainAxis]] = node.style.margin.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]) +
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getRelativePosition(node, mainAxis);
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node.layout.position[leading[crossAxis]] = node.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) +
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getRelativePosition(node, crossAxis);
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node.layout.position[trailing[crossAxis]] = node.style.margin.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis]) +
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getRelativePosition(node, crossAxis);
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}
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private static int resolveAxis(
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int axis,
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CSSDirection direction) {
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if (direction == CSSDirection.RTL) {
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if (axis == CSS_FLEX_DIRECTION_ROW) {
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return CSS_FLEX_DIRECTION_ROW_REVERSE;
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} else if (axis == CSS_FLEX_DIRECTION_ROW_REVERSE) {
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return CSS_FLEX_DIRECTION_ROW;
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}
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}
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return axis;
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}
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private static CSSDirection resolveDirection(CSSNode node, CSSDirection parentDirection) {
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CSSDirection direction = node.style.direction;
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if (direction == CSSDirection.INHERIT) {
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direction = (parentDirection == null ? CSSDirection.LTR : parentDirection);
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}
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return direction;
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}
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private static int getFlexDirection(CSSNode node) {
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return node.style.flexDirection.ordinal();
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}
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private static int getCrossFlexDirection(
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int axis,
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CSSDirection direction) {
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if (axis == CSS_FLEX_DIRECTION_COLUMN ||
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axis == CSS_FLEX_DIRECTION_COLUMN_REVERSE) {
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return resolveAxis(CSS_FLEX_DIRECTION_ROW, direction);
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} else {
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return CSS_FLEX_DIRECTION_COLUMN;
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}
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}
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private static CSSAlign getAlignItem(CSSNode node, CSSNode child) {
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if (child.style.alignSelf != CSSAlign.AUTO) {
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return child.style.alignSelf;
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}
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return node.style.alignItems;
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}
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private static boolean isMeasureDefined(CSSNode node) {
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return node.isMeasureDefined();
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}
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/*package*/ static void layoutNode(
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CSSLayoutContext layoutContext,
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CSSNode node,
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float availableWidth,
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float availableHeight,
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CSSDirection parentDirection) {
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// Increment the generation count. This will force the recursive routine to visit
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// all dirty nodes at least once. Subsequent visits will be skipped if the input
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// parameters don't change.
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layoutContext.currentGenerationCount++;
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CSSMeasureMode widthMeasureMode = CSSMeasureMode.UNDEFINED;
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CSSMeasureMode heightMeasureMode = CSSMeasureMode.UNDEFINED;
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if (!Float.isNaN(availableWidth)) {
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widthMeasureMode = CSSMeasureMode.EXACTLY;
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} else if (node.style.dimensions[DIMENSION_WIDTH] >= 0.0) {
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float marginAxisRow = (node.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
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availableWidth = node.style.dimensions[DIMENSION_WIDTH] + marginAxisRow;
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widthMeasureMode = CSSMeasureMode.EXACTLY;
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} else if (node.style.maxWidth >= 0.0) {
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availableWidth = node.style.maxWidth;
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widthMeasureMode = CSSMeasureMode.AT_MOST;
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}
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if (!Float.isNaN(availableHeight)) {
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heightMeasureMode = CSSMeasureMode.EXACTLY;
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} else if (node.style.dimensions[DIMENSION_HEIGHT] >= 0.0) {
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float marginAxisColumn = (node.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
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availableHeight = node.style.dimensions[DIMENSION_HEIGHT] + marginAxisColumn;
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heightMeasureMode = CSSMeasureMode.EXACTLY;
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} else if (node.style.maxHeight >= 0.0) {
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availableHeight = node.style.maxHeight;
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heightMeasureMode = CSSMeasureMode.AT_MOST;
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}
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if (layoutNodeInternal(layoutContext, node, availableWidth, availableHeight, parentDirection, widthMeasureMode, heightMeasureMode, true, "initial")) {
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setPosition(node, node.layout.direction);
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}
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}
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/*package*/ static boolean canUseCachedMeasurement(
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boolean isTextNode,
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float availableWidth,
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float availableHeight,
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float marginRow,
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float marginColumn,
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CSSMeasureMode widthMeasureMode,
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CSSMeasureMode heightMeasureMode,
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CSSCachedMeasurement cachedLayout) {
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boolean isHeightSame =
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(cachedLayout.heightMeasureMode == CSSMeasureMode.UNDEFINED && heightMeasureMode == CSSMeasureMode.UNDEFINED) ||
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(cachedLayout.heightMeasureMode == heightMeasureMode && FloatUtil.floatsEqual(cachedLayout.availableHeight, availableHeight));
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boolean isWidthSame =
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(cachedLayout.widthMeasureMode == CSSMeasureMode.UNDEFINED && widthMeasureMode == CSSMeasureMode.UNDEFINED) ||
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(cachedLayout.widthMeasureMode == widthMeasureMode && FloatUtil.floatsEqual(cachedLayout.availableWidth, availableWidth));
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if (isHeightSame && isWidthSame) {
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return true;
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}
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boolean isHeightValid =
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(cachedLayout.heightMeasureMode == CSSMeasureMode.UNDEFINED && heightMeasureMode == CSSMeasureMode.AT_MOST && cachedLayout.computedHeight <= (availableHeight - marginColumn)) ||
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(heightMeasureMode == CSSMeasureMode.EXACTLY && FloatUtil.floatsEqual(cachedLayout.computedHeight, availableHeight - marginColumn));
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if (isWidthSame && isHeightValid) {
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return true;
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}
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boolean isWidthValid =
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(cachedLayout.widthMeasureMode == CSSMeasureMode.UNDEFINED && widthMeasureMode == CSSMeasureMode.AT_MOST && cachedLayout.computedWidth <= (availableWidth - marginRow)) ||
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(widthMeasureMode == CSSMeasureMode.EXACTLY && FloatUtil.floatsEqual(cachedLayout.computedWidth, availableWidth - marginRow));
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if (isHeightSame && isWidthValid) {
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return true;
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}
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if (isHeightValid && isWidthValid) {
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return true;
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}
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// We know this to be text so we can apply some more specialized heuristics.
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if (isTextNode) {
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if (isWidthSame) {
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if (heightMeasureMode == CSSMeasureMode.UNDEFINED) {
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// Width is the same and height is not restricted. Re-use cahced value.
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return true;
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}
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if (heightMeasureMode == CSSMeasureMode.AT_MOST &&
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cachedLayout.computedHeight < (availableHeight - marginColumn)) {
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// Width is the same and height restriction is greater than the cached height. Re-use cached value.
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return true;
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}
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// Width is the same but height restriction imposes smaller height than previously measured.
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// Update the cached value to respect the new height restriction.
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cachedLayout.computedHeight = availableHeight - marginColumn;
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return true;
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}
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if (cachedLayout.widthMeasureMode == CSSMeasureMode.UNDEFINED) {
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if (widthMeasureMode == CSSMeasureMode.UNDEFINED ||
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(widthMeasureMode == CSSMeasureMode.AT_MOST &&
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cachedLayout.computedWidth <= (availableWidth - marginRow))) {
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// Previsouly this text was measured with no width restriction, if width is now restricted
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// but to a larger value than the previsouly measured width we can re-use the measurement
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// as we know it will fit.
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return true;
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}
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}
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}
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return false;
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}
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//
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// This is a wrapper around the layoutNodeImpl function. It determines
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// whether the layout request is redundant and can be skipped.
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//
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// Parameters:
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// Input parameters are the same as layoutNodeImpl (see below)
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// Return parameter is true if layout was performed, false if skipped
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//
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private static boolean layoutNodeInternal(
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CSSLayoutContext layoutContext,
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CSSNode node,
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float availableWidth,
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float availableHeight,
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CSSDirection parentDirection,
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CSSMeasureMode widthMeasureMode,
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CSSMeasureMode heightMeasureMode,
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boolean performLayout,
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String reason) {
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CSSLayout layout = node.layout;
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boolean needToVisitNode = (node.isDirty() && layout.generationCount != layoutContext.currentGenerationCount) ||
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layout.lastParentDirection != parentDirection;
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if (needToVisitNode) {
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// Invalidate the cached results.
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layout.nextCachedMeasurementsIndex = 0;
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layout.cachedLayout.widthMeasureMode = null;
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layout.cachedLayout.heightMeasureMode = null;
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}
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CSSCachedMeasurement cachedResults = null;
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// Determine whether the results are already cached. We maintain a separate
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// cache for layouts and measurements. A layout operation modifies the positions
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// and dimensions for nodes in the subtree. The algorithm assumes that each node
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// gets layed out a maximum of one time per tree layout, but multiple measurements
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// may be required to resolve all of the flex dimensions.
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// We handle nodes with measure functions specially here because they are the most
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// expensive to measure, so it's worth avoiding redundant measurements if at all possible.
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if (isMeasureDefined(node)) {
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float marginAxisRow =
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node.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) +
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node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]);
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float marginAxisColumn =
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node.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) +
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node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]);
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// First, try to use the layout cache.
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if (canUseCachedMeasurement(node.isTextNode(), availableWidth, availableHeight, marginAxisRow, marginAxisColumn,
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widthMeasureMode, heightMeasureMode, layout.cachedLayout)) {
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cachedResults = layout.cachedLayout;
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} else {
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// Try to use the measurement cache.
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for (int i = 0; i < layout.nextCachedMeasurementsIndex; i++) {
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if (canUseCachedMeasurement(node.isTextNode(), availableWidth, availableHeight, marginAxisRow, marginAxisColumn,
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widthMeasureMode, heightMeasureMode, layout.cachedMeasurements[i])) {
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cachedResults = layout.cachedMeasurements[i];
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break;
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}
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}
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}
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} else if (performLayout) {
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if (FloatUtil.floatsEqual(layout.cachedLayout.availableWidth, availableWidth) &&
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FloatUtil.floatsEqual(layout.cachedLayout.availableHeight, availableHeight) &&
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layout.cachedLayout.widthMeasureMode == widthMeasureMode &&
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layout.cachedLayout.heightMeasureMode == heightMeasureMode) {
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cachedResults = layout.cachedLayout;
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}
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} else {
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for (int i = 0; i < layout.nextCachedMeasurementsIndex; i++) {
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if (FloatUtil.floatsEqual(layout.cachedMeasurements[i].availableWidth, availableWidth) &&
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FloatUtil.floatsEqual(layout.cachedMeasurements[i].availableHeight, availableHeight) &&
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layout.cachedMeasurements[i].widthMeasureMode == widthMeasureMode &&
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layout.cachedMeasurements[i].heightMeasureMode == heightMeasureMode) {
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cachedResults = layout.cachedMeasurements[i];
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break;
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}
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}
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}
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if (!needToVisitNode && cachedResults != null) {
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layout.measuredDimensions[DIMENSION_WIDTH] = cachedResults.computedWidth;
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layout.measuredDimensions[DIMENSION_HEIGHT] = cachedResults.computedHeight;
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} else {
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layoutNodeImpl(layoutContext, node, availableWidth, availableHeight, parentDirection, widthMeasureMode, heightMeasureMode, performLayout);
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layout.lastParentDirection = parentDirection;
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if (cachedResults == null) {
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if (layout.nextCachedMeasurementsIndex == CSSLayout.MAX_CACHED_RESULT_COUNT) {
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layout.nextCachedMeasurementsIndex = 0;
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}
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CSSCachedMeasurement newCacheEntry = null;
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if (performLayout) {
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// Use the single layout cache entry.
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newCacheEntry = layout.cachedLayout;
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} else {
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// Allocate a new measurement cache entry.
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newCacheEntry = layout.cachedMeasurements[layout.nextCachedMeasurementsIndex];
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if (newCacheEntry == null) {
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newCacheEntry = new CSSCachedMeasurement();
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layout.cachedMeasurements[layout.nextCachedMeasurementsIndex] = newCacheEntry;
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}
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layout.nextCachedMeasurementsIndex++;
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}
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newCacheEntry.availableWidth = availableWidth;
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newCacheEntry.availableHeight = availableHeight;
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newCacheEntry.widthMeasureMode = widthMeasureMode;
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newCacheEntry.heightMeasureMode = heightMeasureMode;
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newCacheEntry.computedWidth = layout.measuredDimensions[DIMENSION_WIDTH];
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newCacheEntry.computedHeight = layout.measuredDimensions[DIMENSION_HEIGHT];
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}
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}
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if (performLayout) {
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node.layout.dimensions[DIMENSION_WIDTH] = node.layout.measuredDimensions[DIMENSION_WIDTH];
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node.layout.dimensions[DIMENSION_HEIGHT] = node.layout.measuredDimensions[DIMENSION_HEIGHT];
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node.markHasNewLayout();
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}
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layout.generationCount = layoutContext.currentGenerationCount;
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return (needToVisitNode || cachedResults == null);
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}
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//
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// This is the main routine that implements a subset of the flexbox layout algorithm
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// described in the W3C CSS documentation: https://www.w3.org/TR/css3-flexbox/.
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//
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// Limitations of this algorithm, compared to the full standard:
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// * Display property is always assumed to be 'flex' except for Text nodes, which
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// are assumed to be 'inline-flex'.
|
|
// * The 'zIndex' property (or any form of z ordering) is not supported. Nodes are
|
|
// stacked in document order.
|
|
// * The 'order' property is not supported. The order of flex items is always defined
|
|
// by document order.
|
|
// * The 'visibility' property is always assumed to be 'visible'. Values of 'collapse'
|
|
// and 'hidden' are not supported.
|
|
// * The 'wrap' property supports only 'nowrap' (which is the default) or 'wrap'. The
|
|
// rarely-used 'wrap-reverse' is not supported.
|
|
// * Rather than allowing arbitrary combinations of flexGrow, flexShrink and
|
|
// flexBasis, this algorithm supports only the three most common combinations:
|
|
// flex: 0 is equiavlent to flex: 0 0 auto
|
|
// flex: n (where n is a positive value) is equivalent to flex: n 1 auto
|
|
// If POSITIVE_FLEX_IS_AUTO is 0, then it is equivalent to flex: n 0 0
|
|
// This is faster because the content doesn't need to be measured, but it's
|
|
// less flexible because the basis is always 0 and can't be overriden with
|
|
// the width/height attributes.
|
|
// flex: -1 (or any negative value) is equivalent to flex: 0 1 auto
|
|
// * Margins cannot be specified as 'auto'. They must be specified in terms of pixel
|
|
// values, and the default value is 0.
|
|
// * The 'baseline' value is not supported for alignItems and alignSelf properties.
|
|
// * Values of width, maxWidth, minWidth, height, maxHeight and minHeight must be
|
|
// specified as pixel values, not as percentages.
|
|
// * There is no support for calculation of dimensions based on intrinsic aspect ratios
|
|
// (e.g. images).
|
|
// * There is no support for forced breaks.
|
|
// * It does not support vertical inline directions (top-to-bottom or bottom-to-top text).
|
|
//
|
|
// Deviations from standard:
|
|
// * Section 4.5 of the spec indicates that all flex items have a default minimum
|
|
// main size. For text blocks, for example, this is the width of the widest word.
|
|
// Calculating the minimum width is expensive, so we forego it and assume a default
|
|
// minimum main size of 0.
|
|
// * Min/Max sizes in the main axis are not honored when resolving flexible lengths.
|
|
// * The spec indicates that the default value for 'flexDirection' is 'row', but
|
|
// the algorithm below assumes a default of 'column'.
|
|
//
|
|
// Input parameters:
|
|
// - node: current node to be sized and layed out
|
|
// - availableWidth & availableHeight: available size to be used for sizing the node
|
|
// or CSS_UNDEFINED if the size is not available; interpretation depends on layout
|
|
// flags
|
|
// - parentDirection: the inline (text) direction within the parent (left-to-right or
|
|
// right-to-left)
|
|
// - widthMeasureMode: indicates the sizing rules for the width (see below for explanation)
|
|
// - heightMeasureMode: indicates the sizing rules for the height (see below for explanation)
|
|
// - performLayout: specifies whether the caller is interested in just the dimensions
|
|
// of the node or it requires the entire node and its subtree to be layed out
|
|
// (with final positions)
|
|
//
|
|
// Details:
|
|
// This routine is called recursively to lay out subtrees of flexbox elements. It uses the
|
|
// information in node.style, which is treated as a read-only input. It is responsible for
|
|
// setting the layout.direction and layout.measured_dimensions fields for the input node as well
|
|
// as the layout.position and layout.line_index fields for its child nodes. The
|
|
// layout.measured_dimensions field includes any border or padding for the node but does
|
|
// not include margins.
|
|
//
|
|
// The spec describes four different layout modes: "fill available", "max content", "min content",
|
|
// and "fit content". Of these, we don't use "min content" because we don't support default
|
|
// minimum main sizes (see above for details). Each of our measure modes maps to a layout mode
|
|
// from the spec (https://www.w3.org/TR/css3-sizing/#terms):
|
|
// - CSS_MEASURE_MODE_UNDEFINED: max content
|
|
// - CSS_MEASURE_MODE_EXACTLY: fill available
|
|
// - CSS_MEASURE_MODE_AT_MOST: fit content
|
|
//
|
|
// When calling layoutNodeImpl and layoutNodeInternal, if the caller passes an available size of
|
|
// undefined then it must also pass a measure mode of CSS_MEASURE_MODE_UNDEFINED in that dimension.
|
|
//
|
|
private static void layoutNodeImpl(
|
|
CSSLayoutContext layoutContext,
|
|
CSSNode node,
|
|
float availableWidth,
|
|
float availableHeight,
|
|
CSSDirection parentDirection,
|
|
CSSMeasureMode widthMeasureMode,
|
|
CSSMeasureMode heightMeasureMode,
|
|
boolean performLayout) {
|
|
|
|
Assertions.assertCondition(Float.isNaN(availableWidth) ? widthMeasureMode == CSSMeasureMode.UNDEFINED : true, "availableWidth is indefinite so widthMeasureMode must be CSSMeasureMode.UNDEFINED");
|
|
Assertions.assertCondition(Float.isNaN(availableHeight) ? heightMeasureMode == CSSMeasureMode.UNDEFINED : true, "availableHeight is indefinite so heightMeasureMode must be CSSMeasureMode.UNDEFINED");
|
|
|
|
float paddingAndBorderAxisRow = ((node.style.padding.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + node.style.border.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW])) + (node.style.padding.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]) + node.style.border.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW])));
|
|
float paddingAndBorderAxisColumn = ((node.style.padding.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + node.style.border.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN])) + (node.style.padding.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]) + node.style.border.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN])));
|
|
float marginAxisRow = (node.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
float marginAxisColumn = (node.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
|
|
// Set the resolved resolution in the node's layout.
|
|
CSSDirection direction = resolveDirection(node, parentDirection);
|
|
node.layout.direction = direction;
|
|
|
|
// For content (text) nodes, determine the dimensions based on the text contents.
|
|
if (isMeasureDefined(node)) {
|
|
float innerWidth = availableWidth - marginAxisRow - paddingAndBorderAxisRow;
|
|
float innerHeight = availableHeight - marginAxisColumn - paddingAndBorderAxisColumn;
|
|
|
|
if (widthMeasureMode == CSSMeasureMode.EXACTLY && heightMeasureMode == CSSMeasureMode.EXACTLY) {
|
|
|
|
// Don't bother sizing the text if both dimensions are already defined.
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, availableWidth - marginAxisRow);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, availableHeight - marginAxisColumn);
|
|
} else if (innerWidth <= 0 || innerHeight <= 0) {
|
|
|
|
// Don't bother sizing the text if there's no horizontal or vertical space.
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, 0);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, 0);
|
|
} else {
|
|
|
|
// Measure the text under the current constraints.
|
|
MeasureOutput measureDim = node.measure(
|
|
|
|
layoutContext.measureOutput,
|
|
innerWidth,
|
|
widthMeasureMode,
|
|
innerHeight,
|
|
heightMeasureMode
|
|
);
|
|
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW,
|
|
(widthMeasureMode == CSSMeasureMode.UNDEFINED || widthMeasureMode == CSSMeasureMode.AT_MOST) ?
|
|
measureDim.width + paddingAndBorderAxisRow :
|
|
availableWidth - marginAxisRow);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN,
|
|
(heightMeasureMode == CSSMeasureMode.UNDEFINED || heightMeasureMode == CSSMeasureMode.AT_MOST) ?
|
|
measureDim.height + paddingAndBorderAxisColumn :
|
|
availableHeight - marginAxisColumn);
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
// For nodes with no children, use the available values if they were provided, or
|
|
// the minimum size as indicated by the padding and border sizes.
|
|
int childCount = node.getChildCount();
|
|
if (childCount == 0) {
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW,
|
|
(widthMeasureMode == CSSMeasureMode.UNDEFINED || widthMeasureMode == CSSMeasureMode.AT_MOST) ?
|
|
paddingAndBorderAxisRow :
|
|
availableWidth - marginAxisRow);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN,
|
|
(heightMeasureMode == CSSMeasureMode.UNDEFINED || heightMeasureMode == CSSMeasureMode.AT_MOST) ?
|
|
paddingAndBorderAxisColumn :
|
|
availableHeight - marginAxisColumn);
|
|
return;
|
|
}
|
|
|
|
// If we're not being asked to perform a full layout, we can handle a number of common
|
|
// cases here without incurring the cost of the remaining function.
|
|
if (!performLayout) {
|
|
// If we're being asked to size the content with an at most constraint but there is no available width,
|
|
// the measurement will always be zero.
|
|
if (widthMeasureMode == CSSMeasureMode.AT_MOST && availableWidth <= 0 &&
|
|
heightMeasureMode == CSSMeasureMode.AT_MOST && availableHeight <= 0) {
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, 0);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, 0);
|
|
return;
|
|
}
|
|
|
|
if (widthMeasureMode == CSSMeasureMode.AT_MOST && availableWidth <= 0) {
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, 0);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, Float.isNaN(availableHeight) ? 0 : (availableHeight - marginAxisColumn));
|
|
return;
|
|
}
|
|
|
|
if (heightMeasureMode == CSSMeasureMode.AT_MOST && availableHeight <= 0) {
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, Float.isNaN(availableWidth) ? 0 : (availableWidth - marginAxisRow));
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, 0);
|
|
return;
|
|
}
|
|
|
|
// If we're being asked to use an exact width/height, there's no need to measure the children.
|
|
if (widthMeasureMode == CSSMeasureMode.EXACTLY && heightMeasureMode == CSSMeasureMode.EXACTLY) {
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, availableWidth - marginAxisRow);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, availableHeight - marginAxisColumn);
|
|
return;
|
|
}
|
|
}
|
|
|
|
// STEP 1: CALCULATE VALUES FOR REMAINDER OF ALGORITHM
|
|
int mainAxis = resolveAxis(getFlexDirection(node), direction);
|
|
int crossAxis = getCrossFlexDirection(mainAxis, direction);
|
|
boolean isMainAxisRow = (mainAxis == CSS_FLEX_DIRECTION_ROW || mainAxis == CSS_FLEX_DIRECTION_ROW_REVERSE);
|
|
CSSJustify justifyContent = node.style.justifyContent;
|
|
boolean isNodeFlexWrap = (node.style.flexWrap == CSSWrap.WRAP);
|
|
|
|
CSSNode firstAbsoluteChild = null;
|
|
CSSNode currentAbsoluteChild = null;
|
|
|
|
float leadingPaddingAndBorderMain = (node.style.padding.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + node.style.border.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]));
|
|
float trailingPaddingAndBorderMain = (node.style.padding.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]) + node.style.border.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]));
|
|
float leadingPaddingAndBorderCross = (node.style.padding.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) + node.style.border.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]));
|
|
float paddingAndBorderAxisMain = ((node.style.padding.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + node.style.border.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis])) + (node.style.padding.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]) + node.style.border.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis])));
|
|
float paddingAndBorderAxisCross = ((node.style.padding.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) + node.style.border.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis])) + (node.style.padding.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis]) + node.style.border.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis])));
|
|
|
|
CSSMeasureMode measureModeMainDim = isMainAxisRow ? widthMeasureMode : heightMeasureMode;
|
|
CSSMeasureMode measureModeCrossDim = isMainAxisRow ? heightMeasureMode : widthMeasureMode;
|
|
|
|
// STEP 2: DETERMINE AVAILABLE SIZE IN MAIN AND CROSS DIRECTIONS
|
|
float availableInnerWidth = availableWidth - marginAxisRow - paddingAndBorderAxisRow;
|
|
float availableInnerHeight = availableHeight - marginAxisColumn - paddingAndBorderAxisColumn;
|
|
float availableInnerMainDim = isMainAxisRow ? availableInnerWidth : availableInnerHeight;
|
|
float availableInnerCrossDim = isMainAxisRow ? availableInnerHeight : availableInnerWidth;
|
|
|
|
// STEP 3: DETERMINE FLEX BASIS FOR EACH ITEM
|
|
CSSNode child;
|
|
int i;
|
|
float childWidth;
|
|
float childHeight;
|
|
CSSMeasureMode childWidthMeasureMode;
|
|
CSSMeasureMode childHeightMeasureMode;
|
|
for (i = 0; i < childCount; i++) {
|
|
child = node.getChildAt(i);
|
|
|
|
if (performLayout) {
|
|
// Set the initial position (relative to the parent).
|
|
CSSDirection childDirection = resolveDirection(child, direction);
|
|
setPosition(child, childDirection);
|
|
}
|
|
|
|
// Absolute-positioned children don't participate in flex layout. Add them
|
|
// to a list that we can process later.
|
|
if (child.style.positionType == CSSPositionType.ABSOLUTE) {
|
|
|
|
// Store a private linked list of absolutely positioned children
|
|
// so that we can efficiently traverse them later.
|
|
if (firstAbsoluteChild == null) {
|
|
firstAbsoluteChild = child;
|
|
}
|
|
if (currentAbsoluteChild != null) {
|
|
currentAbsoluteChild.nextChild = child;
|
|
}
|
|
currentAbsoluteChild = child;
|
|
child.nextChild = null;
|
|
} else {
|
|
|
|
if (isMainAxisRow && (child.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0)) {
|
|
|
|
// The width is definite, so use that as the flex basis.
|
|
child.layout.flexBasis = Math.max(child.style.dimensions[DIMENSION_WIDTH], ((child.style.padding.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + child.style.border.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW])) + (child.style.padding.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]) + child.style.border.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]))));
|
|
} else if (!isMainAxisRow && (child.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0)) {
|
|
|
|
// The height is definite, so use that as the flex basis.
|
|
child.layout.flexBasis = Math.max(child.style.dimensions[DIMENSION_HEIGHT], ((child.style.padding.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + child.style.border.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN])) + (child.style.padding.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]) + child.style.border.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]))));
|
|
} else if (!isFlexBasisAuto(child) && !Float.isNaN(availableInnerMainDim)) {
|
|
|
|
// If the basis isn't 'auto', it is assumed to be zero.
|
|
child.layout.flexBasis = Math.max(0, ((child.style.padding.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + child.style.border.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis])) + (child.style.padding.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]) + child.style.border.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]))));
|
|
} else {
|
|
|
|
// Compute the flex basis and hypothetical main size (i.e. the clamped flex basis).
|
|
childWidth = CSSConstants.UNDEFINED;
|
|
childHeight = CSSConstants.UNDEFINED;
|
|
childWidthMeasureMode = CSSMeasureMode.UNDEFINED;
|
|
childHeightMeasureMode = CSSMeasureMode.UNDEFINED;
|
|
|
|
if ((child.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0)) {
|
|
childWidth = child.style.dimensions[DIMENSION_WIDTH] + (child.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + child.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
childWidthMeasureMode = CSSMeasureMode.EXACTLY;
|
|
}
|
|
if ((child.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0)) {
|
|
childHeight = child.style.dimensions[DIMENSION_HEIGHT] + (child.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + child.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
childHeightMeasureMode = CSSMeasureMode.EXACTLY;
|
|
}
|
|
|
|
// According to the spec, if the main size is not definite and the
|
|
// child's inline axis is parallel to the main axis (i.e. it's
|
|
// horizontal), the child should be sized using "UNDEFINED" in
|
|
// the main size. Otherwise use "AT_MOST" in the cross axis.
|
|
if (!isMainAxisRow && Float.isNaN(childWidth) && !Float.isNaN(availableInnerWidth)) {
|
|
childWidth = availableInnerWidth;
|
|
childWidthMeasureMode = CSSMeasureMode.AT_MOST;
|
|
}
|
|
|
|
// The W3C spec doesn't say anything about the 'overflow' property,
|
|
// but all major browsers appear to implement the following logic.
|
|
if (node.style.overflow == CSSOverflow.HIDDEN) {
|
|
if (isMainAxisRow && Float.isNaN(childHeight) && !Float.isNaN(availableInnerHeight)) {
|
|
childHeight = availableInnerHeight;
|
|
childHeightMeasureMode = CSSMeasureMode.AT_MOST;
|
|
}
|
|
}
|
|
|
|
// If child has no defined size in the cross axis and is set to stretch, set the cross
|
|
// axis to be measured exactly with the available inner width
|
|
if (!isMainAxisRow &&
|
|
!Float.isNaN(availableInnerWidth) &&
|
|
!(child.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0) &&
|
|
widthMeasureMode == CSSMeasureMode.EXACTLY &&
|
|
getAlignItem(node, child) == CSSAlign.STRETCH) {
|
|
childWidth = availableInnerWidth;
|
|
childWidthMeasureMode = CSSMeasureMode.EXACTLY;
|
|
}
|
|
if (isMainAxisRow &&
|
|
!Float.isNaN(availableInnerHeight) &&
|
|
!(child.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0) &&
|
|
heightMeasureMode == CSSMeasureMode.EXACTLY &&
|
|
getAlignItem(node, child) == CSSAlign.STRETCH) {
|
|
childHeight = availableInnerHeight;
|
|
childHeightMeasureMode = CSSMeasureMode.EXACTLY;
|
|
}
|
|
|
|
// Measure the child
|
|
layoutNodeInternal(layoutContext, child, childWidth, childHeight, direction, childWidthMeasureMode, childHeightMeasureMode, false, "measure");
|
|
|
|
child.layout.flexBasis = Math.max(isMainAxisRow ? child.layout.measuredDimensions[DIMENSION_WIDTH] : child.layout.measuredDimensions[DIMENSION_HEIGHT], ((child.style.padding.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + child.style.border.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis])) + (child.style.padding.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]) + child.style.border.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]))));
|
|
}
|
|
}
|
|
}
|
|
|
|
// STEP 4: COLLECT FLEX ITEMS INTO FLEX LINES
|
|
|
|
// Indexes of children that represent the first and last items in the line.
|
|
int startOfLineIndex = 0;
|
|
int endOfLineIndex = 0;
|
|
|
|
// Number of lines.
|
|
int lineCount = 0;
|
|
|
|
// Accumulated cross dimensions of all lines so far.
|
|
float totalLineCrossDim = 0;
|
|
|
|
// Max main dimension of all the lines.
|
|
float maxLineMainDim = 0;
|
|
|
|
while (endOfLineIndex < childCount) {
|
|
|
|
// Number of items on the currently line. May be different than the difference
|
|
// between start and end indicates because we skip over absolute-positioned items.
|
|
int itemsOnLine = 0;
|
|
|
|
// sizeConsumedOnCurrentLine is accumulation of the dimensions and margin
|
|
// of all the children on the current line. This will be used in order to
|
|
// either set the dimensions of the node if none already exist or to compute
|
|
// the remaining space left for the flexible children.
|
|
float sizeConsumedOnCurrentLine = 0;
|
|
|
|
float totalFlexGrowFactors = 0;
|
|
float totalFlexShrinkScaledFactors = 0;
|
|
|
|
i = startOfLineIndex;
|
|
|
|
// Maintain a linked list of the child nodes that can shrink and/or grow.
|
|
CSSNode firstRelativeChild = null;
|
|
CSSNode currentRelativeChild = null;
|
|
|
|
// Add items to the current line until it's full or we run out of items.
|
|
while (i < childCount) {
|
|
child = node.getChildAt(i);
|
|
child.lineIndex = lineCount;
|
|
|
|
if (child.style.positionType != CSSPositionType.ABSOLUTE) {
|
|
float outerFlexBasis = child.layout.flexBasis + (child.style.margin.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + child.style.margin.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]));
|
|
|
|
// If this is a multi-line flow and this item pushes us over the available size, we've
|
|
// hit the end of the current line. Break out of the loop and lay out the current line.
|
|
if (sizeConsumedOnCurrentLine + outerFlexBasis > availableInnerMainDim && isNodeFlexWrap && itemsOnLine > 0) {
|
|
break;
|
|
}
|
|
|
|
sizeConsumedOnCurrentLine += outerFlexBasis;
|
|
itemsOnLine++;
|
|
|
|
if ((child.style.positionType == CSSPositionType.RELATIVE && child.style.flex != 0)) {
|
|
totalFlexGrowFactors += getFlexGrowFactor(child);
|
|
|
|
// Unlike the grow factor, the shrink factor is scaled relative to the child
|
|
// dimension.
|
|
totalFlexShrinkScaledFactors += getFlexShrinkFactor(child) * child.layout.flexBasis;
|
|
}
|
|
|
|
// Store a private linked list of children that need to be layed out.
|
|
if (firstRelativeChild == null) {
|
|
firstRelativeChild = child;
|
|
}
|
|
if (currentRelativeChild != null) {
|
|
currentRelativeChild.nextChild = child;
|
|
}
|
|
currentRelativeChild = child;
|
|
child.nextChild = null;
|
|
}
|
|
|
|
i++;
|
|
endOfLineIndex++;
|
|
}
|
|
|
|
// If we don't need to measure the cross axis, we can skip the entire flex step.
|
|
boolean canSkipFlex = !performLayout && measureModeCrossDim == CSSMeasureMode.EXACTLY;
|
|
|
|
// In order to position the elements in the main axis, we have two
|
|
// controls. The space between the beginning and the first element
|
|
// and the space between each two elements.
|
|
float leadingMainDim = 0;
|
|
float betweenMainDim = 0;
|
|
|
|
// STEP 5: RESOLVING FLEXIBLE LENGTHS ON MAIN AXIS
|
|
// Calculate the remaining available space that needs to be allocated.
|
|
// If the main dimension size isn't known, it is computed based on
|
|
// the line length, so there's no more space left to distribute.
|
|
float remainingFreeSpace = 0;
|
|
if (!Float.isNaN(availableInnerMainDim)) {
|
|
remainingFreeSpace = availableInnerMainDim - sizeConsumedOnCurrentLine;
|
|
} else if (sizeConsumedOnCurrentLine < 0) {
|
|
// availableInnerMainDim is indefinite which means the node is being sized based on its content.
|
|
// sizeConsumedOnCurrentLine is negative which means the node will allocate 0 pixels for
|
|
// its content. Consequently, remainingFreeSpace is 0 - sizeConsumedOnCurrentLine.
|
|
remainingFreeSpace = -sizeConsumedOnCurrentLine;
|
|
}
|
|
|
|
float originalRemainingFreeSpace = remainingFreeSpace;
|
|
float deltaFreeSpace = 0;
|
|
|
|
if (!canSkipFlex) {
|
|
float childFlexBasis;
|
|
float flexShrinkScaledFactor;
|
|
float flexGrowFactor;
|
|
float baseMainSize;
|
|
float boundMainSize;
|
|
|
|
// Do two passes over the flex items to figure out how to distribute the remaining space.
|
|
// The first pass finds the items whose min/max constraints trigger, freezes them at those
|
|
// sizes, and excludes those sizes from the remaining space. The second pass sets the size
|
|
// of each flexible item. It distributes the remaining space amongst the items whose min/max
|
|
// constraints didn't trigger in pass 1. For the other items, it sets their sizes by forcing
|
|
// their min/max constraints to trigger again.
|
|
//
|
|
// This two pass approach for resolving min/max constraints deviates from the spec. The
|
|
// spec (https://www.w3.org/TR/css-flexbox-1/#resolve-flexible-lengths) describes a process
|
|
// that needs to be repeated a variable number of times. The algorithm implemented here
|
|
// won't handle all cases but it was simpler to implement and it mitigates performance
|
|
// concerns because we know exactly how many passes it'll do.
|
|
|
|
// First pass: detect the flex items whose min/max constraints trigger
|
|
float deltaFlexShrinkScaledFactors = 0;
|
|
float deltaFlexGrowFactors = 0;
|
|
currentRelativeChild = firstRelativeChild;
|
|
while (currentRelativeChild != null) {
|
|
childFlexBasis = currentRelativeChild.layout.flexBasis;
|
|
|
|
if (remainingFreeSpace < 0) {
|
|
flexShrinkScaledFactor = getFlexShrinkFactor(currentRelativeChild) * childFlexBasis;
|
|
|
|
// Is this child able to shrink?
|
|
if (flexShrinkScaledFactor != 0) {
|
|
baseMainSize = childFlexBasis +
|
|
remainingFreeSpace / totalFlexShrinkScaledFactors * flexShrinkScaledFactor;
|
|
boundMainSize = boundAxis(currentRelativeChild, mainAxis, baseMainSize);
|
|
if (baseMainSize != boundMainSize) {
|
|
// By excluding this item's size and flex factor from remaining, this item's
|
|
// min/max constraints should also trigger in the second pass resulting in the
|
|
// item's size calculation being identical in the first and second passes.
|
|
deltaFreeSpace -= boundMainSize - childFlexBasis;
|
|
deltaFlexShrinkScaledFactors -= flexShrinkScaledFactor;
|
|
}
|
|
}
|
|
} else if (remainingFreeSpace > 0) {
|
|
flexGrowFactor = getFlexGrowFactor(currentRelativeChild);
|
|
|
|
// Is this child able to grow?
|
|
if (flexGrowFactor != 0) {
|
|
baseMainSize = childFlexBasis +
|
|
remainingFreeSpace / totalFlexGrowFactors * flexGrowFactor;
|
|
boundMainSize = boundAxis(currentRelativeChild, mainAxis, baseMainSize);
|
|
if (baseMainSize != boundMainSize) {
|
|
// By excluding this item's size and flex factor from remaining, this item's
|
|
// min/max constraints should also trigger in the second pass resulting in the
|
|
// item's size calculation being identical in the first and second passes.
|
|
deltaFreeSpace -= boundMainSize - childFlexBasis;
|
|
deltaFlexGrowFactors -= flexGrowFactor;
|
|
}
|
|
}
|
|
}
|
|
|
|
currentRelativeChild = currentRelativeChild.nextChild;
|
|
}
|
|
|
|
totalFlexShrinkScaledFactors += deltaFlexShrinkScaledFactors;
|
|
totalFlexGrowFactors += deltaFlexGrowFactors;
|
|
remainingFreeSpace += deltaFreeSpace;
|
|
|
|
// Second pass: resolve the sizes of the flexible items
|
|
deltaFreeSpace = 0;
|
|
currentRelativeChild = firstRelativeChild;
|
|
while (currentRelativeChild != null) {
|
|
childFlexBasis = currentRelativeChild.layout.flexBasis;
|
|
float updatedMainSize = childFlexBasis;
|
|
|
|
if (remainingFreeSpace < 0) {
|
|
flexShrinkScaledFactor = getFlexShrinkFactor(currentRelativeChild) * childFlexBasis;
|
|
|
|
// Is this child able to shrink?
|
|
if (flexShrinkScaledFactor != 0) {
|
|
updatedMainSize = boundAxis(currentRelativeChild, mainAxis, childFlexBasis +
|
|
remainingFreeSpace / totalFlexShrinkScaledFactors * flexShrinkScaledFactor);
|
|
}
|
|
} else if (remainingFreeSpace > 0) {
|
|
flexGrowFactor = getFlexGrowFactor(currentRelativeChild);
|
|
|
|
// Is this child able to grow?
|
|
if (flexGrowFactor != 0) {
|
|
updatedMainSize = boundAxis(currentRelativeChild, mainAxis, childFlexBasis +
|
|
remainingFreeSpace / totalFlexGrowFactors * flexGrowFactor);
|
|
}
|
|
}
|
|
|
|
deltaFreeSpace -= updatedMainSize - childFlexBasis;
|
|
|
|
if (isMainAxisRow) {
|
|
childWidth = updatedMainSize + (currentRelativeChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + currentRelativeChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
childWidthMeasureMode = CSSMeasureMode.EXACTLY;
|
|
|
|
if (!Float.isNaN(availableInnerCrossDim) &&
|
|
!(currentRelativeChild.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0) &&
|
|
heightMeasureMode == CSSMeasureMode.EXACTLY &&
|
|
getAlignItem(node, currentRelativeChild) == CSSAlign.STRETCH) {
|
|
childHeight = availableInnerCrossDim;
|
|
childHeightMeasureMode = CSSMeasureMode.EXACTLY;
|
|
} else if (!(currentRelativeChild.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0)) {
|
|
childHeight = availableInnerCrossDim;
|
|
childHeightMeasureMode = Float.isNaN(childHeight) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.AT_MOST;
|
|
} else {
|
|
childHeight = currentRelativeChild.style.dimensions[DIMENSION_HEIGHT] + (currentRelativeChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + currentRelativeChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
childHeightMeasureMode = CSSMeasureMode.EXACTLY;
|
|
}
|
|
} else {
|
|
childHeight = updatedMainSize + (currentRelativeChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + currentRelativeChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
childHeightMeasureMode = CSSMeasureMode.EXACTLY;
|
|
|
|
if (!Float.isNaN(availableInnerCrossDim) &&
|
|
!(currentRelativeChild.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0) &&
|
|
widthMeasureMode == CSSMeasureMode.EXACTLY &&
|
|
getAlignItem(node, currentRelativeChild) == CSSAlign.STRETCH) {
|
|
childWidth = availableInnerCrossDim;
|
|
childWidthMeasureMode = CSSMeasureMode.EXACTLY;
|
|
} else if (!(currentRelativeChild.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0)) {
|
|
childWidth = availableInnerCrossDim;
|
|
childWidthMeasureMode = Float.isNaN(childWidth) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.AT_MOST;
|
|
} else {
|
|
childWidth = currentRelativeChild.style.dimensions[DIMENSION_WIDTH] + (currentRelativeChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + currentRelativeChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
childWidthMeasureMode = CSSMeasureMode.EXACTLY;
|
|
}
|
|
}
|
|
|
|
boolean requiresStretchLayout = !(currentRelativeChild.style.dimensions[dim[crossAxis]] >= 0.0) &&
|
|
getAlignItem(node, currentRelativeChild) == CSSAlign.STRETCH;
|
|
|
|
// Recursively call the layout algorithm for this child with the updated main size.
|
|
layoutNodeInternal(layoutContext, currentRelativeChild, childWidth, childHeight, direction, childWidthMeasureMode, childHeightMeasureMode, performLayout && !requiresStretchLayout, "flex");
|
|
|
|
currentRelativeChild = currentRelativeChild.nextChild;
|
|
}
|
|
}
|
|
|
|
remainingFreeSpace = originalRemainingFreeSpace + deltaFreeSpace;
|
|
|
|
// STEP 6: MAIN-AXIS JUSTIFICATION & CROSS-AXIS SIZE DETERMINATION
|
|
|
|
// At this point, all the children have their dimensions set in the main axis.
|
|
// Their dimensions are also set in the cross axis with the exception of items
|
|
// that are aligned "stretch". We need to compute these stretch values and
|
|
// set the final positions.
|
|
|
|
// If we are using "at most" rules in the main axis, we won't distribute
|
|
// any remaining space at this point.
|
|
if (measureModeMainDim == CSSMeasureMode.AT_MOST) {
|
|
remainingFreeSpace = 0;
|
|
}
|
|
|
|
// Use justifyContent to figure out how to allocate the remaining space
|
|
// available in the main axis.
|
|
if (justifyContent != CSSJustify.FLEX_START) {
|
|
if (justifyContent == CSSJustify.CENTER) {
|
|
leadingMainDim = remainingFreeSpace / 2;
|
|
} else if (justifyContent == CSSJustify.FLEX_END) {
|
|
leadingMainDim = remainingFreeSpace;
|
|
} else if (justifyContent == CSSJustify.SPACE_BETWEEN) {
|
|
remainingFreeSpace = Math.max(remainingFreeSpace, 0);
|
|
if (itemsOnLine > 1) {
|
|
betweenMainDim = remainingFreeSpace / (itemsOnLine - 1);
|
|
} else {
|
|
betweenMainDim = 0;
|
|
}
|
|
} else if (justifyContent == CSSJustify.SPACE_AROUND) {
|
|
// Space on the edges is half of the space between elements
|
|
betweenMainDim = remainingFreeSpace / itemsOnLine;
|
|
leadingMainDim = betweenMainDim / 2;
|
|
}
|
|
}
|
|
|
|
float mainDim = leadingPaddingAndBorderMain + leadingMainDim;
|
|
float crossDim = 0;
|
|
|
|
for (i = startOfLineIndex; i < endOfLineIndex; ++i) {
|
|
child = node.getChildAt(i);
|
|
|
|
if (child.style.positionType == CSSPositionType.ABSOLUTE &&
|
|
!Float.isNaN(child.style.position[leading[mainAxis]])) {
|
|
if (performLayout) {
|
|
// In case the child is position absolute and has left/top being
|
|
// defined, we override the position to whatever the user said
|
|
// (and margin/border).
|
|
child.layout.position[pos[mainAxis]] = (Float.isNaN(child.style.position[leading[mainAxis]]) ? 0 : child.style.position[leading[mainAxis]]) +
|
|
node.style.border.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) +
|
|
child.style.margin.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]);
|
|
}
|
|
} else {
|
|
if (performLayout) {
|
|
// If the child is position absolute (without top/left) or relative,
|
|
// we put it at the current accumulated offset.
|
|
child.layout.position[pos[mainAxis]] += mainDim;
|
|
}
|
|
|
|
// Now that we placed the element, we need to update the variables.
|
|
// We need to do that only for relative elements. Absolute elements
|
|
// do not take part in that phase.
|
|
if (child.style.positionType == CSSPositionType.RELATIVE) {
|
|
if (canSkipFlex) {
|
|
// If we skipped the flex step, then we can't rely on the measuredDims because
|
|
// they weren't computed. This means we can't call getDimWithMargin.
|
|
mainDim += betweenMainDim + (child.style.margin.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + child.style.margin.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis])) + child.layout.flexBasis;
|
|
crossDim = availableInnerCrossDim;
|
|
} else {
|
|
// The main dimension is the sum of all the elements dimension plus
|
|
// the spacing.
|
|
mainDim += betweenMainDim + (child.layout.measuredDimensions[dim[mainAxis]] + child.style.margin.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) + child.style.margin.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]));
|
|
|
|
// The cross dimension is the max of the elements dimension since there
|
|
// can only be one element in that cross dimension.
|
|
crossDim = Math.max(crossDim, (child.layout.measuredDimensions[dim[crossAxis]] + child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) + child.style.margin.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis])));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
mainDim += trailingPaddingAndBorderMain;
|
|
|
|
float containerCrossAxis = availableInnerCrossDim;
|
|
if (measureModeCrossDim == CSSMeasureMode.UNDEFINED || measureModeCrossDim == CSSMeasureMode.AT_MOST) {
|
|
// Compute the cross axis from the max cross dimension of the children.
|
|
containerCrossAxis = boundAxis(node, crossAxis, crossDim + paddingAndBorderAxisCross) - paddingAndBorderAxisCross;
|
|
|
|
if (measureModeCrossDim == CSSMeasureMode.AT_MOST) {
|
|
containerCrossAxis = Math.min(containerCrossAxis, availableInnerCrossDim);
|
|
}
|
|
}
|
|
|
|
// If there's no flex wrap, the cross dimension is defined by the container.
|
|
if (!isNodeFlexWrap && measureModeCrossDim == CSSMeasureMode.EXACTLY) {
|
|
crossDim = availableInnerCrossDim;
|
|
}
|
|
|
|
// Clamp to the min/max size specified on the container.
|
|
crossDim = boundAxis(node, crossAxis, crossDim + paddingAndBorderAxisCross) - paddingAndBorderAxisCross;
|
|
|
|
// STEP 7: CROSS-AXIS ALIGNMENT
|
|
// We can skip child alignment if we're just measuring the container.
|
|
if (performLayout) {
|
|
for (i = startOfLineIndex; i < endOfLineIndex; ++i) {
|
|
child = node.getChildAt(i);
|
|
|
|
if (child.style.positionType == CSSPositionType.ABSOLUTE) {
|
|
// If the child is absolutely positioned and has a top/left/bottom/right
|
|
// set, override all the previously computed positions to set it correctly.
|
|
if (!Float.isNaN(child.style.position[leading[crossAxis]])) {
|
|
child.layout.position[pos[crossAxis]] = (Float.isNaN(child.style.position[leading[crossAxis]]) ? 0 : child.style.position[leading[crossAxis]]) +
|
|
node.style.border.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) +
|
|
child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]);
|
|
} else {
|
|
child.layout.position[pos[crossAxis]] = leadingPaddingAndBorderCross +
|
|
child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]);
|
|
}
|
|
} else {
|
|
float leadingCrossDim = leadingPaddingAndBorderCross;
|
|
|
|
// For a relative children, we're either using alignItems (parent) or
|
|
// alignSelf (child) in order to determine the position in the cross axis
|
|
CSSAlign alignItem = getAlignItem(node, child);
|
|
|
|
// If the child uses align stretch, we need to lay it out one more time, this time
|
|
// forcing the cross-axis size to be the computed cross size for the current line.
|
|
if (alignItem == CSSAlign.STRETCH) {
|
|
childWidth = child.layout.measuredDimensions[DIMENSION_WIDTH] + (child.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + child.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
childHeight = child.layout.measuredDimensions[DIMENSION_HEIGHT] + (child.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + child.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
boolean isCrossSizeDefinite = false;
|
|
|
|
if (isMainAxisRow) {
|
|
isCrossSizeDefinite = (child.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0);
|
|
childHeight = crossDim;
|
|
} else {
|
|
isCrossSizeDefinite = (child.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0);
|
|
childWidth = crossDim;
|
|
}
|
|
|
|
// If the child defines a definite size for its cross axis, there's no need to stretch.
|
|
if (!isCrossSizeDefinite) {
|
|
childWidthMeasureMode = Float.isNaN(childWidth) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.EXACTLY;
|
|
childHeightMeasureMode = Float.isNaN(childHeight) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.EXACTLY;
|
|
layoutNodeInternal(layoutContext, child, childWidth, childHeight, direction, childWidthMeasureMode, childHeightMeasureMode, true, "stretch");
|
|
}
|
|
} else if (alignItem != CSSAlign.FLEX_START) {
|
|
float remainingCrossDim = containerCrossAxis - (child.layout.measuredDimensions[dim[crossAxis]] + child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) + child.style.margin.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis]));
|
|
|
|
if (alignItem == CSSAlign.CENTER) {
|
|
leadingCrossDim += remainingCrossDim / 2;
|
|
} else { // CSSAlign.FLEX_END
|
|
leadingCrossDim += remainingCrossDim;
|
|
}
|
|
}
|
|
|
|
// And we apply the position
|
|
child.layout.position[pos[crossAxis]] += totalLineCrossDim + leadingCrossDim;
|
|
}
|
|
}
|
|
}
|
|
|
|
totalLineCrossDim += crossDim;
|
|
maxLineMainDim = Math.max(maxLineMainDim, mainDim);
|
|
|
|
// Reset variables for new line.
|
|
lineCount++;
|
|
startOfLineIndex = endOfLineIndex;
|
|
endOfLineIndex = startOfLineIndex;
|
|
}
|
|
|
|
// STEP 8: MULTI-LINE CONTENT ALIGNMENT
|
|
if (lineCount > 1 && performLayout && !Float.isNaN(availableInnerCrossDim)) {
|
|
float remainingAlignContentDim = availableInnerCrossDim - totalLineCrossDim;
|
|
|
|
float crossDimLead = 0;
|
|
float currentLead = leadingPaddingAndBorderCross;
|
|
|
|
CSSAlign alignContent = node.style.alignContent;
|
|
if (alignContent == CSSAlign.FLEX_END) {
|
|
currentLead += remainingAlignContentDim;
|
|
} else if (alignContent == CSSAlign.CENTER) {
|
|
currentLead += remainingAlignContentDim / 2;
|
|
} else if (alignContent == CSSAlign.STRETCH) {
|
|
if (availableInnerCrossDim > totalLineCrossDim) {
|
|
crossDimLead = (remainingAlignContentDim / lineCount);
|
|
}
|
|
}
|
|
|
|
int endIndex = 0;
|
|
for (i = 0; i < lineCount; ++i) {
|
|
int startIndex = endIndex;
|
|
int j;
|
|
|
|
// compute the line's height and find the endIndex
|
|
float lineHeight = 0;
|
|
for (j = startIndex; j < childCount; ++j) {
|
|
child = node.getChildAt(j);
|
|
if (child.style.positionType != CSSPositionType.RELATIVE) {
|
|
continue;
|
|
}
|
|
if (child.lineIndex != i) {
|
|
break;
|
|
}
|
|
if ((child.layout.measuredDimensions[dim[crossAxis]] >= 0.0)) {
|
|
lineHeight = Math.max(lineHeight,
|
|
child.layout.measuredDimensions[dim[crossAxis]] + (child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]) + child.style.margin.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis])));
|
|
}
|
|
}
|
|
endIndex = j;
|
|
lineHeight += crossDimLead;
|
|
|
|
if (performLayout) {
|
|
for (j = startIndex; j < endIndex; ++j) {
|
|
child = node.getChildAt(j);
|
|
if (child.style.positionType != CSSPositionType.RELATIVE) {
|
|
continue;
|
|
}
|
|
|
|
CSSAlign alignContentAlignItem = getAlignItem(node, child);
|
|
if (alignContentAlignItem == CSSAlign.FLEX_START) {
|
|
child.layout.position[pos[crossAxis]] = currentLead + child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]);
|
|
} else if (alignContentAlignItem == CSSAlign.FLEX_END) {
|
|
child.layout.position[pos[crossAxis]] = currentLead + lineHeight - child.style.margin.getWithFallback(trailingSpacing[crossAxis], trailing[crossAxis]) - child.layout.measuredDimensions[dim[crossAxis]];
|
|
} else if (alignContentAlignItem == CSSAlign.CENTER) {
|
|
childHeight = child.layout.measuredDimensions[dim[crossAxis]];
|
|
child.layout.position[pos[crossAxis]] = currentLead + (lineHeight - childHeight) / 2;
|
|
} else if (alignContentAlignItem == CSSAlign.STRETCH) {
|
|
child.layout.position[pos[crossAxis]] = currentLead + child.style.margin.getWithFallback(leadingSpacing[crossAxis], leading[crossAxis]);
|
|
// TODO(prenaux): Correctly set the height of items with indefinite
|
|
// (auto) crossAxis dimension.
|
|
}
|
|
}
|
|
}
|
|
|
|
currentLead += lineHeight;
|
|
}
|
|
}
|
|
|
|
// STEP 9: COMPUTING FINAL DIMENSIONS
|
|
node.layout.measuredDimensions[DIMENSION_WIDTH] = boundAxis(node, CSS_FLEX_DIRECTION_ROW, availableWidth - marginAxisRow);
|
|
node.layout.measuredDimensions[DIMENSION_HEIGHT] = boundAxis(node, CSS_FLEX_DIRECTION_COLUMN, availableHeight - marginAxisColumn);
|
|
|
|
// If the user didn't specify a width or height for the node, set the
|
|
// dimensions based on the children.
|
|
if (measureModeMainDim == CSSMeasureMode.UNDEFINED) {
|
|
// Clamp the size to the min/max size, if specified, and make sure it
|
|
// doesn't go below the padding and border amount.
|
|
node.layout.measuredDimensions[dim[mainAxis]] = boundAxis(node, mainAxis, maxLineMainDim);
|
|
} else if (measureModeMainDim == CSSMeasureMode.AT_MOST) {
|
|
node.layout.measuredDimensions[dim[mainAxis]] = Math.max(
|
|
Math.min(availableInnerMainDim + paddingAndBorderAxisMain,
|
|
boundAxisWithinMinAndMax(node, mainAxis, maxLineMainDim)),
|
|
paddingAndBorderAxisMain);
|
|
}
|
|
|
|
if (measureModeCrossDim == CSSMeasureMode.UNDEFINED) {
|
|
// Clamp the size to the min/max size, if specified, and make sure it
|
|
// doesn't go below the padding and border amount.
|
|
node.layout.measuredDimensions[dim[crossAxis]] = boundAxis(node, crossAxis, totalLineCrossDim + paddingAndBorderAxisCross);
|
|
} else if (measureModeCrossDim == CSSMeasureMode.AT_MOST) {
|
|
node.layout.measuredDimensions[dim[crossAxis]] = Math.max(
|
|
Math.min(availableInnerCrossDim + paddingAndBorderAxisCross,
|
|
boundAxisWithinMinAndMax(node, crossAxis, totalLineCrossDim + paddingAndBorderAxisCross)),
|
|
paddingAndBorderAxisCross);
|
|
}
|
|
|
|
// STEP 10: SETTING TRAILING POSITIONS FOR CHILDREN
|
|
if (performLayout) {
|
|
boolean needsMainTrailingPos = false;
|
|
boolean needsCrossTrailingPos = false;
|
|
|
|
if (mainAxis == CSS_FLEX_DIRECTION_ROW_REVERSE ||
|
|
mainAxis == CSS_FLEX_DIRECTION_COLUMN_REVERSE) {
|
|
needsMainTrailingPos = true;
|
|
}
|
|
|
|
if (crossAxis == CSS_FLEX_DIRECTION_ROW_REVERSE ||
|
|
crossAxis == CSS_FLEX_DIRECTION_COLUMN_REVERSE) {
|
|
needsCrossTrailingPos = true;
|
|
}
|
|
|
|
// Set trailing position if necessary.
|
|
if (needsMainTrailingPos || needsCrossTrailingPos) {
|
|
for (i = 0; i < childCount; ++i) {
|
|
child = node.getChildAt(i);
|
|
|
|
if (needsMainTrailingPos) {
|
|
child.layout.position[trailing[mainAxis]] = node.layout.measuredDimensions[dim[mainAxis]] - (child.style.positionType == CSSPositionType.ABSOLUTE ? 0 : child.layout.measuredDimensions[dim[mainAxis]]) - child.layout.position[pos[mainAxis]];
|
|
}
|
|
|
|
if (needsCrossTrailingPos) {
|
|
child.layout.position[trailing[crossAxis]] = node.layout.measuredDimensions[dim[crossAxis]] - (child.style.positionType == CSSPositionType.ABSOLUTE ? 0 : child.layout.measuredDimensions[dim[crossAxis]]) - child.layout.position[pos[crossAxis]];
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// STEP 11: SIZING AND POSITIONING ABSOLUTE CHILDREN
|
|
currentAbsoluteChild = firstAbsoluteChild;
|
|
while (currentAbsoluteChild != null) {
|
|
// Now that we know the bounds of the container, perform layout again on the
|
|
// absolutely-positioned children.
|
|
if (performLayout) {
|
|
|
|
childWidth = CSSConstants.UNDEFINED;
|
|
childHeight = CSSConstants.UNDEFINED;
|
|
|
|
if ((currentAbsoluteChild.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0)) {
|
|
childWidth = currentAbsoluteChild.style.dimensions[DIMENSION_WIDTH] + (currentAbsoluteChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + currentAbsoluteChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
} else {
|
|
// If the child doesn't have a specified width, compute the width based on the left/right offsets if they're defined.
|
|
if (!Float.isNaN(currentAbsoluteChild.style.position[POSITION_LEFT]) && !Float.isNaN(currentAbsoluteChild.style.position[POSITION_RIGHT])) {
|
|
childWidth = node.layout.measuredDimensions[DIMENSION_WIDTH] -
|
|
(node.style.border.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + node.style.border.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW])) -
|
|
(currentAbsoluteChild.style.position[POSITION_LEFT] + currentAbsoluteChild.style.position[POSITION_RIGHT]);
|
|
childWidth = boundAxis(currentAbsoluteChild, CSS_FLEX_DIRECTION_ROW, childWidth);
|
|
}
|
|
}
|
|
|
|
if ((currentAbsoluteChild.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0)) {
|
|
childHeight = currentAbsoluteChild.style.dimensions[DIMENSION_HEIGHT] + (currentAbsoluteChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + currentAbsoluteChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
} else {
|
|
// If the child doesn't have a specified height, compute the height based on the top/bottom offsets if they're defined.
|
|
if (!Float.isNaN(currentAbsoluteChild.style.position[POSITION_TOP]) && !Float.isNaN(currentAbsoluteChild.style.position[POSITION_BOTTOM])) {
|
|
childHeight = node.layout.measuredDimensions[DIMENSION_HEIGHT] -
|
|
(node.style.border.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + node.style.border.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN])) -
|
|
(currentAbsoluteChild.style.position[POSITION_TOP] + currentAbsoluteChild.style.position[POSITION_BOTTOM]);
|
|
childHeight = boundAxis(currentAbsoluteChild, CSS_FLEX_DIRECTION_COLUMN, childHeight);
|
|
}
|
|
}
|
|
|
|
// If we're still missing one or the other dimension, measure the content.
|
|
if (Float.isNaN(childWidth) || Float.isNaN(childHeight)) {
|
|
childWidthMeasureMode = Float.isNaN(childWidth) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.EXACTLY;
|
|
childHeightMeasureMode = Float.isNaN(childHeight) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.EXACTLY;
|
|
|
|
// According to the spec, if the main size is not definite and the
|
|
// child's inline axis is parallel to the main axis (i.e. it's
|
|
// horizontal), the child should be sized using "UNDEFINED" in
|
|
// the main size. Otherwise use "AT_MOST" in the cross axis.
|
|
if (!isMainAxisRow && Float.isNaN(childWidth) && !Float.isNaN(availableInnerWidth)) {
|
|
childWidth = availableInnerWidth;
|
|
childWidthMeasureMode = CSSMeasureMode.AT_MOST;
|
|
}
|
|
|
|
// The W3C spec doesn't say anything about the 'overflow' property,
|
|
// but all major browsers appear to implement the following logic.
|
|
if (node.style.overflow == CSSOverflow.HIDDEN) {
|
|
if (isMainAxisRow && Float.isNaN(childHeight) && !Float.isNaN(availableInnerHeight)) {
|
|
childHeight = availableInnerHeight;
|
|
childHeightMeasureMode = CSSMeasureMode.AT_MOST;
|
|
}
|
|
}
|
|
|
|
layoutNodeInternal(layoutContext, currentAbsoluteChild, childWidth, childHeight, direction, childWidthMeasureMode, childHeightMeasureMode, false, "abs-measure");
|
|
childWidth = currentAbsoluteChild.layout.measuredDimensions[DIMENSION_WIDTH] + (currentAbsoluteChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_ROW], leading[CSS_FLEX_DIRECTION_ROW]) + currentAbsoluteChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_ROW], trailing[CSS_FLEX_DIRECTION_ROW]));
|
|
childHeight = currentAbsoluteChild.layout.measuredDimensions[DIMENSION_HEIGHT] + (currentAbsoluteChild.style.margin.getWithFallback(leadingSpacing[CSS_FLEX_DIRECTION_COLUMN], leading[CSS_FLEX_DIRECTION_COLUMN]) + currentAbsoluteChild.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]));
|
|
}
|
|
|
|
layoutNodeInternal(layoutContext, currentAbsoluteChild, childWidth, childHeight, direction, CSSMeasureMode.EXACTLY, CSSMeasureMode.EXACTLY, true, "abs-layout");
|
|
|
|
if (!Float.isNaN(currentAbsoluteChild.style.position[trailing[CSS_FLEX_DIRECTION_ROW]]) &&
|
|
!!Float.isNaN(currentAbsoluteChild.style.position[leading[CSS_FLEX_DIRECTION_ROW]])) {
|
|
currentAbsoluteChild.layout.position[leading[CSS_FLEX_DIRECTION_ROW]] =
|
|
node.layout.measuredDimensions[dim[CSS_FLEX_DIRECTION_ROW]] -
|
|
currentAbsoluteChild.layout.measuredDimensions[dim[CSS_FLEX_DIRECTION_ROW]] -
|
|
(Float.isNaN(currentAbsoluteChild.style.position[trailing[CSS_FLEX_DIRECTION_ROW]]) ? 0 : currentAbsoluteChild.style.position[trailing[CSS_FLEX_DIRECTION_ROW]]);
|
|
}
|
|
|
|
if (!Float.isNaN(currentAbsoluteChild.style.position[trailing[CSS_FLEX_DIRECTION_COLUMN]]) &&
|
|
!!Float.isNaN(currentAbsoluteChild.style.position[leading[CSS_FLEX_DIRECTION_COLUMN]])) {
|
|
currentAbsoluteChild.layout.position[leading[CSS_FLEX_DIRECTION_COLUMN]] =
|
|
node.layout.measuredDimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] -
|
|
currentAbsoluteChild.layout.measuredDimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] -
|
|
(Float.isNaN(currentAbsoluteChild.style.position[trailing[CSS_FLEX_DIRECTION_COLUMN]]) ? 0 : currentAbsoluteChild.style.position[trailing[CSS_FLEX_DIRECTION_COLUMN]]);
|
|
}
|
|
}
|
|
|
|
currentAbsoluteChild = currentAbsoluteChild.nextChild;
|
|
}
|
|
}
|
|
}
|