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Initial implementation of flexWrap

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This commit is contained in:
Christopher Chedeau
2014-12-12 12:03:31 +00:00
parent 28243156e4
commit 10fb645777
12 changed files with 930 additions and 607 deletions
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7
src/java/src/com/facebook/csslayout/CSSNode.java
View File

@@ -287,6 +287,13 @@ public class CSSNode {
}
}
public void setWrap(CSSWrap flexWrap) {
if (!valuesEqual(style.flexWrap, flexWrap)) {
style.flexWrap = flexWrap;
dirty();
}
}
public void setFlex(float flex) {
if (!valuesEqual(style.flex, flex)) {
style.flex = flex;

1
src/java/src/com/facebook/csslayout/CSSStyle.java
View File

@@ -23,6 +23,7 @@ public class CSSStyle {
public CSSAlign alignItems = CSSAlign.STRETCH;
public CSSAlign alignSelf = CSSAlign.AUTO;
public CSSPositionType positionType = CSSPositionType.RELATIVE;
public CSSWrap flexWrap = CSSWrap.NOWRAP;
public float flex;
public float[] margin = new float[4];

14
src/java/src/com/facebook/csslayout/CSSWrap.java Normal file
View File

@@ -0,0 +1,14 @@
/**
* Copyright (c) 2014, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.csslayout;
public enum CSSWrap {
NOWRAP,
WRAP,
}

463
src/java/src/com/facebook/csslayout/LayoutEngine.java
View File

@@ -235,6 +235,10 @@ public class LayoutEngine {
return node.style.justifyContent;
}
private static boolean isFlexWrap(CSSNode node) {
return node.style.flexWrap == CSSWrap.WRAP;
}
private static boolean isFlex(CSSNode node) {
return getPositionType(node) == CSSPositionType.RELATIVE && getFlex(node) > 0;
}
@@ -371,97 +375,50 @@ public class LayoutEngine {
}
}
// <Loop A> Layout non flexible children and count children by type
// mainContentDim is accumulation of the dimensions and margin of all the
// non flexible children. 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 mainContentDim = 0;
// There are three kind of children, non flexible, flexible and absolute.
// We need to know how many there are in order to distribute the space.
int flexibleChildrenCount = 0;
float totalFlexible = 0;
int nonFlexibleChildrenCount = 0;
for (int i = 0; i < node.getChildCount(); ++i) {
CSSNode child = node.getChildAt(i);
// It only makes sense to consider a child flexible if we have a computed
// dimension for the node.
if (!CSSConstants.isUndefined(getLayoutDimension(node, getDim(mainAxis))) && isFlex(child)) {
flexibleChildrenCount++;
totalFlexible = totalFlexible + getFlex(child);
// Even if we don't know its exact size yet, we already know the padding,
// border and margin. We'll use this partial information to compute the
// remaining space.
mainContentDim = mainContentDim + getPaddingAndBorderAxis(child, mainAxis) +
getMarginAxis(child, mainAxis);
} else {
float maxWidth = CSSConstants.UNDEFINED;
if (mainAxis == CSSFlexDirection.ROW) {
// do nothing
} else if (isDimDefined(node, CSSFlexDirection.ROW)) {
maxWidth = getLayoutDimension(node, getDim(CSSFlexDirection.ROW)) -
getPaddingAndBorderAxis(node, CSSFlexDirection.ROW);
} else {
maxWidth = parentMaxWidth -
getMarginAxis(node, CSSFlexDirection.ROW) -
getPaddingAndBorderAxis(node, CSSFlexDirection.ROW);
}
// This is the main recursive call. We layout non flexible children.
layoutNode(child, maxWidth);
// Absolute positioned elements do not take part of the layout, so we
// don't use them to compute mainContentDim
if (getPositionType(child) == CSSPositionType.RELATIVE) {
nonFlexibleChildrenCount++;
// At this point we know the final size and margin of the element.
mainContentDim = mainContentDim + getDimWithMargin(child, mainAxis);
}
}
}
// <Loop B> Layout flexible children and allocate empty space
// 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;
float definedMainDim = Math.max(mainContentDim, 0);
float definedMainDim = CSSConstants.UNDEFINED;
if (!CSSConstants.isUndefined(getLayoutDimension(node, getDim(mainAxis)))) {
definedMainDim = getLayoutDimension(node, getDim(mainAxis)) -
getPaddingAndBorderAxis(node, mainAxis);
getPaddingAndBorderAxis(node, mainAxis);
}
// The remaining available space that needs to be allocated
float remainingMainDim = definedMainDim - mainContentDim;
// If there are flexible children in the mix, they are going to fill the
// remaining space
if (flexibleChildrenCount != 0) {
float flexibleMainDim = remainingMainDim / totalFlexible;
// We want to execute the next two loops one per line with flex-wrap
int startLine = 0;
int endLine = 0;
int nextLine = 0;
// We aggregate the total dimensions of the container in those two variables
float linesCrossDim = 0;
float linesMainDim = 0;
while (endLine != node.getChildCount()) {
// <Loop A> Layout non flexible children and count children by type
// The non flexible children can overflow the container, in this case
// we should just assume that there is no space available.
if (flexibleMainDim < 0) {
flexibleMainDim = 0;
}
// We iterate over the full array and only apply the action on flexible
// children. This is faster than actually allocating a new array that
// contains only flexible children.
for (int i = 0; i < node.getChildCount(); ++i) {
// mainContentDim is accumulation of the dimensions and margin of all the
// non flexible children. 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 mainContentDim = 0;
// There are three kind of children, non flexible, flexible and absolute.
// We need to know how many there are in order to distribute the space.
int flexibleChildrenCount = 0;
float totalFlexible = 0;
int nonFlexibleChildrenCount = 0;
for (int i = startLine; i < node.getChildCount(); ++i) {
CSSNode child = node.getChildAt(i);
if (isFlex(child)) {
// At this point we know the final size of the element in the main
// dimension
setLayoutDimension(child, getDim(mainAxis), flexibleMainDim * getFlex(child) +
getPaddingAndBorderAxis(child, mainAxis));
float nextContentDim = 0;
// It only makes sense to consider a child flexible if we have a computed
// dimension for the node.
if (!CSSConstants.isUndefined(getLayoutDimension(node, getDim(mainAxis))) && isFlex(child)) {
flexibleChildrenCount++;
totalFlexible = totalFlexible + getFlex(child);
// Even if we don't know its exact size yet, we already know the padding,
// border and margin. We'll use this partial information to compute the
// remaining space.
nextContentDim = getPaddingAndBorderAxis(child, mainAxis) +
getMarginAxis(child, mainAxis);
} else {
float maxWidth = CSSConstants.UNDEFINED;
if (mainAxis == CSSFlexDirection.ROW) {
// do nothing
@@ -474,74 +431,234 @@ public class LayoutEngine {
getPaddingAndBorderAxis(node, CSSFlexDirection.ROW);
}
// And we recursively call the layout algorithm for this child
layoutNode(child, maxWidth);
// This is the main recursive call. We layout non flexible children.
if (nextLine == 0) {
layoutNode(child, maxWidth);
}
// Absolute positioned elements do not take part of the layout, so we
// don't use them to compute mainContentDim
if (getPositionType(child) == CSSPositionType.RELATIVE) {
nonFlexibleChildrenCount++;
// At this point we know the final size and margin of the element.
nextContentDim = getDimWithMargin(child, mainAxis);
}
}
// The element we are about to add would make us go to the next line
if (isFlexWrap(node) &&
!CSSConstants.isUndefined(getLayoutDimension(node, getDim(mainAxis))) &&
mainContentDim + nextContentDim > definedMainDim) {
nextLine = i + 1;
break;
}
nextLine = 0;
mainContentDim = mainContentDim + nextContentDim;
endLine = i + 1;
}
// We use justifyContent to figure out how to allocate the remaining
// space available
} else {
CSSJustify justifyContent = getJustifyContent(node);
if (justifyContent == CSSJustify.FLEX_START) {
// Do nothing
} else if (justifyContent == CSSJustify.CENTER) {
leadingMainDim = remainingMainDim / 2;
} else if (justifyContent == CSSJustify.FLEX_END) {
leadingMainDim = remainingMainDim;
} else if (justifyContent == CSSJustify.SPACE_BETWEEN) {
remainingMainDim = Math.max(remainingMainDim, 0);
if (flexibleChildrenCount + nonFlexibleChildrenCount - 1 != 0) {
betweenMainDim = remainingMainDim /
(flexibleChildrenCount + nonFlexibleChildrenCount - 1);
} else {
betweenMainDim = 0;
}
} else if (justifyContent == CSSJustify.SPACE_AROUND) {
// Space on the edges is half of the space between elements
betweenMainDim = remainingMainDim /
(flexibleChildrenCount + nonFlexibleChildrenCount);
leadingMainDim = betweenMainDim / 2;
}
}
// <Loop B> Layout flexible children and allocate empty space
// <Loop C> Position elements in the main axis and compute dimensions
// 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;
// At this point, all the children have their dimensions set. We need to
// find their position. In order to do that, we accumulate data in
// variables that are also useful to compute the total dimensions of the
// container!
float crossDim = 0;
float mainDim = leadingMainDim +
getPaddingAndBorder(node, getLeading(mainAxis));
for (int i = 0; i < node.getChildCount(); ++i) {
CSSNode child = node.getChildAt(i);
if (getPositionType(child) == CSSPositionType.ABSOLUTE &&
isPosDefined(child, getLeading(mainAxis))) {
// 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).
setLayoutPosition(child, getPos(mainAxis), getPosition(child, getLeading(mainAxis)) +
getBorder(node, getLeading(mainAxis)) +
getMargin(child, getLeading(mainAxis)));
// The remaining available space that needs to be allocated
float remainingMainDim = 0;
if (!CSSConstants.isUndefined(getLayoutDimension(node, getDim(mainAxis)))) {
remainingMainDim = definedMainDim - mainContentDim;
} else {
// If the child is position absolute (without top/left) or relative,
// we put it at the current accumulated offset.
setLayoutPosition(child, getPos(mainAxis), getLayoutPosition(child, getPos(mainAxis)) + mainDim);
remainingMainDim = Math.max(mainContentDim, 0) - mainContentDim;
}
// Now that we placed the element, we need to update the variables
// We only need to do that for relative elements. Absolute elements
// do not take part in that phase.
if (getPositionType(child) == CSSPositionType.RELATIVE) {
// The main dimension is the sum of all the elements dimension plus
// the spacing.
mainDim = mainDim + betweenMainDim + getDimWithMargin(child, 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, getDimWithMargin(child, crossAxis));
// If there are flexible children in the mix, they are going to fill the
// remaining space
if (flexibleChildrenCount != 0) {
float flexibleMainDim = remainingMainDim / totalFlexible;
// The non flexible children can overflow the container, in this case
// we should just assume that there is no space available.
if (flexibleMainDim < 0) {
flexibleMainDim = 0;
}
// We iterate over the full array and only apply the action on flexible
// children. This is faster than actually allocating a new array that
// contains only flexible children.
for (int i = startLine; i < endLine; ++i) {
CSSNode child = node.getChildAt(i);
if (isFlex(child)) {
// At this point we know the final size of the element in the main
// dimension
setLayoutDimension(child, getDim(mainAxis), flexibleMainDim * getFlex(child) +
getPaddingAndBorderAxis(child, mainAxis));
float maxWidth = CSSConstants.UNDEFINED;
if (mainAxis == CSSFlexDirection.ROW) {
// do nothing
} else if (isDimDefined(node, CSSFlexDirection.ROW)) {
maxWidth = getLayoutDimension(node, getDim(CSSFlexDirection.ROW)) -
getPaddingAndBorderAxis(node, CSSFlexDirection.ROW);
} else {
maxWidth = parentMaxWidth -
getMarginAxis(node, CSSFlexDirection.ROW) -
getPaddingAndBorderAxis(node, CSSFlexDirection.ROW);
}
// And we recursively call the layout algorithm for this child
layoutNode(child, maxWidth);
}
}
// We use justifyContent to figure out how to allocate the remaining
// space available
} else {
CSSJustify justifyContent = getJustifyContent(node);
if (justifyContent == CSSJustify.FLEX_START) {
// Do nothing
} else if (justifyContent == CSSJustify.CENTER) {
leadingMainDim = remainingMainDim / 2;
} else if (justifyContent == CSSJustify.FLEX_END) {
leadingMainDim = remainingMainDim;
} else if (justifyContent == CSSJustify.SPACE_BETWEEN) {
remainingMainDim = Math.max(remainingMainDim, 0);
if (flexibleChildrenCount + nonFlexibleChildrenCount - 1 != 0) {
betweenMainDim = remainingMainDim /
(flexibleChildrenCount + nonFlexibleChildrenCount - 1);
} else {
betweenMainDim = 0;
}
} else if (justifyContent == CSSJustify.SPACE_AROUND) {
// Space on the edges is half of the space between elements
betweenMainDim = remainingMainDim /
(flexibleChildrenCount + nonFlexibleChildrenCount);
leadingMainDim = betweenMainDim / 2;
}
}
// <Loop C> Position elements in the main axis and compute dimensions
// At this point, all the children have their dimensions set. We need to
// find their position. In order to do that, we accumulate data in
// variables that are also useful to compute the total dimensions of the
// container!
float crossDim = 0;
float mainDim = leadingMainDim +
getPaddingAndBorder(node, getLeading(mainAxis));
for (int i = startLine; i < endLine; ++i) {
CSSNode child = node.getChildAt(i);
if (getPositionType(child) == CSSPositionType.ABSOLUTE &&
isPosDefined(child, getLeading(mainAxis))) {
// 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).
setLayoutPosition(child, getPos(mainAxis), getPosition(child, getLeading(mainAxis)) +
getBorder(node, getLeading(mainAxis)) +
getMargin(child, getLeading(mainAxis)));
} else {
// If the child is position absolute (without top/left) or relative,
// we put it at the current accumulated offset.
setLayoutPosition(child, getPos(mainAxis), getLayoutPosition(child, getPos(mainAxis)) + mainDim);
}
// Now that we placed the element, we need to update the variables
// We only need to do that for relative elements. Absolute elements
// do not take part in that phase.
if (getPositionType(child) == CSSPositionType.RELATIVE) {
// The main dimension is the sum of all the elements dimension plus
// the spacing.
mainDim = mainDim + betweenMainDim + getDimWithMargin(child, 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, getDimWithMargin(child, crossAxis));
}
}
float containerMainAxis = getLayoutDimension(node, getDim(mainAxis));
// If the user didn't specify a width or height, and it has not been set
// by the container, then we set it via the children.
if (CSSConstants.isUndefined(getLayoutDimension(node, getDim(mainAxis)))) {
containerMainAxis = Math.max(
// We're missing the last padding at this point to get the final
// dimension
mainDim + getPaddingAndBorder(node, getTrailing(mainAxis)),
// We can never assign a width smaller than the padding and borders
getPaddingAndBorderAxis(node, mainAxis)
);
}
float containerCrossAxis = getLayoutDimension(node, getDim(crossAxis));
if (CSSConstants.isUndefined(getLayoutDimension(node, getDim(crossAxis)))) {
containerCrossAxis = Math.max(
// For the cross dim, we add both sides at the end because the value
// is aggregate via a max function. Intermediate negative values
// can mess this computation otherwise
crossDim + getPaddingAndBorderAxis(node, crossAxis),
getPaddingAndBorderAxis(node, crossAxis)
);
}
// <Loop D> Position elements in the cross axis
for (int i = startLine; i < endLine; ++i) {
CSSNode child = node.getChildAt(i);
if (getPositionType(child) == CSSPositionType.ABSOLUTE &&
isPosDefined(child, getLeading(crossAxis))) {
// In case the child is absolutely positionned and has a
// top/left/bottom/right being set, we override all the previously
// computed positions to set it correctly.
setLayoutPosition(child, getPos(crossAxis), getPosition(child, getLeading(crossAxis)) +
getBorder(node, getLeading(crossAxis)) +
getMargin(child, getLeading(crossAxis)));
} else {
float leadingCrossDim = getPaddingAndBorder(node, getLeading(crossAxis));
// For a relative children, we're either using alignItems (parent) or
// alignSelf (child) in order to determine the position in the cross axis
if (getPositionType(child) == CSSPositionType.RELATIVE) {
CSSAlign alignItem = getAlignItem(node, child);
if (alignItem == CSSAlign.FLEX_START) {
// Do nothing
} else if (alignItem == CSSAlign.STRETCH) {
// You can only stretch if the dimension has not already been set
// previously.
if (!isDimDefined(child, crossAxis)) {
setLayoutDimension(child, getDim(crossAxis), Math.max(
containerCrossAxis -
getPaddingAndBorderAxis(node, crossAxis) -
getMarginAxis(child, crossAxis),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, crossAxis)
));
}
} else {
// The remaining space between the parent dimensions+padding and child
// dimensions+margin.
float remainingCrossDim = containerCrossAxis -
getPaddingAndBorderAxis(node, crossAxis) -
getDimWithMargin(child, crossAxis);
if (alignItem == CSSAlign.CENTER) {
leadingCrossDim = leadingCrossDim + remainingCrossDim / 2;
} else { // CSSAlign.FLEX_END
leadingCrossDim = leadingCrossDim + remainingCrossDim;
}
}
}
// And we apply the position
setLayoutPosition(child, getPos(crossAxis), getLayoutPosition(child, getPos(crossAxis)) + linesCrossDim + leadingCrossDim);
}
}
linesCrossDim = linesCrossDim + crossDim;
linesMainDim = Math.max(linesMainDim, mainDim);
startLine = endLine;
}
// If the user didn't specify a width or height, and it has not been set
@@ -550,7 +667,7 @@ public class LayoutEngine {
setLayoutDimension(node, getDim(mainAxis), Math.max(
// We're missing the last padding at this point to get the final
// dimension
mainDim + getPaddingAndBorder(node, getTrailing(mainAxis)),
linesMainDim + getPaddingAndBorder(node, getTrailing(mainAxis)),
// We can never assign a width smaller than the padding and borders
getPaddingAndBorderAxis(node, mainAxis)
));
@@ -561,67 +678,11 @@ public class LayoutEngine {
// For the cross dim, we add both sides at the end because the value
// is aggregate via a max function. Intermediate negative values
// can mess this computation otherwise
crossDim + getPaddingAndBorderAxis(node, crossAxis),
linesCrossDim + getPaddingAndBorderAxis(node, crossAxis),
getPaddingAndBorderAxis(node, crossAxis)
));
}
// <Loop D> Position elements in the cross axis
for (int i = 0; i < node.getChildCount(); ++i) {
CSSNode child = node.getChildAt(i);
if (getPositionType(child) == CSSPositionType.ABSOLUTE &&
isPosDefined(child, getLeading(crossAxis))) {
// In case the child is absolutely positionned and has a
// top/left/bottom/right being set, we override all the previously
// computed positions to set it correctly.
setLayoutPosition(child, getPos(crossAxis), getPosition(child, getLeading(crossAxis)) +
getBorder(node, getLeading(crossAxis)) +
getMargin(child, getLeading(crossAxis)));
} else {
float leadingCrossDim = getPaddingAndBorder(node, getLeading(crossAxis));
// For a relative children, we're either using alignItems (parent) or
// alignSelf (child) in order to determine the position in the cross axis
if (getPositionType(child) == CSSPositionType.RELATIVE) {
CSSAlign alignItem = getAlignItem(node, child);
if (alignItem == CSSAlign.FLEX_START) {
// Do nothing
} else if (alignItem == CSSAlign.STRETCH) {
// You can only stretch if the dimension has not already been set
// previously.
if (!isDimDefined(child, crossAxis)) {
setLayoutDimension(child, getDim(crossAxis), Math.max(
getLayoutDimension(node, getDim(crossAxis)) -
getPaddingAndBorderAxis(node, crossAxis) -
getMarginAxis(child, crossAxis),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, crossAxis)
));
}
} else {
// The remaining space between the parent dimensions+padding and child
// dimensions+margin.
float remainingCrossDim = getLayoutDimension(node, getDim(crossAxis)) -
getPaddingAndBorderAxis(node, crossAxis) -
getDimWithMargin(child, crossAxis);
if (alignItem == CSSAlign.CENTER) {
leadingCrossDim = leadingCrossDim + remainingCrossDim / 2;
} else { // CSSAlign.FLEX_END
leadingCrossDim = leadingCrossDim + remainingCrossDim;
}
}
}
// And we apply the position
setLayoutPosition(child, getPos(crossAxis), getLayoutPosition(child, getPos(crossAxis)) + leadingCrossDim);
}
}
// <Loop E> Calculate dimensions for absolutely positioned elements
for (int i = 0; i < node.getChildCount(); ++i) {

55
src/java/tests/com/facebook/csslayout/LayoutEngineTest.java
View File

@@ -3931,5 +3931,60 @@ public class LayoutEngineTest {
test("should layout with children of a contain with left", root_node, root_layout);
}
@Test
public void testCase93()
{
TestCSSNode root_node = new TestCSSNode();
{
TestCSSNode node_0 = root_node;
node_0.style.flexDirection = CSSFlexDirection.ROW;
node_0.style.flexWrap = CSSWrap.WRAP;
node_0.style.width = 100;
addChildren(node_0, 3);
{
TestCSSNode node_1;
node_1 = node_0.getChildAt(0);
node_1.style.width = 40;
node_1.style.height = 10;
node_1 = node_0.getChildAt(1);
node_1.style.width = 40;
node_1.style.height = 10;
node_1 = node_0.getChildAt(2);
node_1.style.width = 40;
node_1.style.height = 10;
}
}
TestCSSNode root_layout = new TestCSSNode();
{
TestCSSNode node_0 = root_layout;
node_0.layout.y = 0;
node_0.layout.x = 0;
node_0.layout.width = 100;
node_0.layout.height = 20;
addChildren(node_0, 3);
{
TestCSSNode node_1;
node_1 = node_0.getChildAt(0);
node_1.layout.y = 0;
node_1.layout.x = 0;
node_1.layout.width = 40;
node_1.layout.height = 10;
node_1 = node_0.getChildAt(1);
node_1.layout.y = 0;
node_1.layout.x = 40;
node_1.layout.width = 40;
node_1.layout.height = 10;
node_1 = node_0.getChildAt(2);
node_1.layout.y = 10;
node_1.layout.x = 0;
node_1.layout.width = 40;
node_1.layout.height = 10;
}
}
test("should layout flex-wrap", root_node, root_layout);
}
/** END_GENERATED **/
}