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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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463
src/Layout.c
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@@ -276,6 +276,10 @@ static bool isFlex(css_node_t *node) {
);
}
static bool isFlexWrap(css_node_t *node) {
return node->style.flex_wrap == CSS_WRAP;
}
static float getDimWithMargin(css_node_t *node, css_flex_direction_t axis) {
return node->layout.dimensions[dim[axis]] +
getMargin(node, leading[axis]) +
@@ -425,97 +429,50 @@ static void layoutNodeImpl(css_node_t *node, float parentMaxWidth) {
}
}
// <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->children_count; ++i) {
css_node_t* child = node->get_child(node->context, i);
// It only makes sense to consider a child flexible if we have a computed
// dimension for the node->
if (!isUndefined(node->layout.dimensions[dim[mainAxis]]) && isFlex(child)) {
flexibleChildrenCount++;
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 += getPaddingAndBorderAxis(child, mainAxis) +
getMarginAxis(child, mainAxis);
} else {
float maxWidth = CSS_UNDEFINED;
if (mainAxis == CSS_FLEX_DIRECTION_ROW) {
// do nothing
} else if (isDimDefined(node, CSS_FLEX_DIRECTION_ROW)) {
maxWidth = node->layout.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] -
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_ROW);
} else {
maxWidth = parentMaxWidth -
getMarginAxis(node, CSS_FLEX_DIRECTION_ROW) -
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_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) == CSS_POSITION_RELATIVE) {
nonFlexibleChildrenCount++;
// At this point we know the final size and margin of the element.
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 = fmaxf(mainContentDim, 0);
float definedMainDim = CSS_UNDEFINED;
if (!isUndefined(node->layout.dimensions[dim[mainAxis]])) {
definedMainDim = node->layout.dimensions[dim[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->children_count) {
// <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->children_count; ++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->children_count; ++i) {
css_node_t* child = node->get_child(node->context, i);
if (isFlex(child)) {
// At this point we know the final size of the element in the main
// dimension
child->layout.dimensions[dim[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 (!isUndefined(node->layout.dimensions[dim[mainAxis]]) && isFlex(child)) {
flexibleChildrenCount++;
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 = CSS_UNDEFINED;
if (mainAxis == CSS_FLEX_DIRECTION_ROW) {
// do nothing
@@ -528,74 +485,234 @@ static void layoutNodeImpl(css_node_t *node, float parentMaxWidth) {
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_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) == CSS_POSITION_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) &&
!isUndefined(node->layout.dimensions[dim[mainAxis]]) &&
mainContentDim + nextContentDim > definedMainDim) {
nextLine = i + 1;
break;
}
nextLine = 0;
mainContentDim += nextContentDim;
endLine = i + 1;
}
// We use justifyContent to figure out how to allocate the remaining
// space available
} else {
css_justify_t justifyContent = getJustifyContent(node);
if (justifyContent == CSS_JUSTIFY_FLEX_START) {
// Do nothing
} else if (justifyContent == CSS_JUSTIFY_CENTER) {
leadingMainDim = remainingMainDim / 2;
} else if (justifyContent == CSS_JUSTIFY_FLEX_END) {
leadingMainDim = remainingMainDim;
} else if (justifyContent == CSS_JUSTIFY_SPACE_BETWEEN) {
remainingMainDim = fmaxf(remainingMainDim, 0);
if (flexibleChildrenCount + nonFlexibleChildrenCount - 1 != 0) {
betweenMainDim = remainingMainDim /
(flexibleChildrenCount + nonFlexibleChildrenCount - 1);
} else {
betweenMainDim = 0;
}
} else if (justifyContent == CSS_JUSTIFY_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, leading[mainAxis]);
for (int i = 0; i < node->children_count; ++i) {
css_node_t* child = node->get_child(node->context, i);
if (getPositionType(child) == CSS_POSITION_ABSOLUTE &&
isPosDefined(child, leading[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).
child->layout.position[pos[mainAxis]] = getPosition(child, leading[mainAxis]) +
getBorder(node, leading[mainAxis]) +
getMargin(child, leading[mainAxis]);
// The remaining available space that needs to be allocated
float remainingMainDim = 0;
if (!isUndefined(node->layout.dimensions[dim[mainAxis]])) {
remainingMainDim = definedMainDim - mainContentDim;
} else {
// 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;
remainingMainDim = fmaxf(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) == CSS_POSITION_RELATIVE) {
// The main dimension is the sum of all the elements dimension plus
// the spacing.
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 = fmaxf(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) {
css_node_t* child = node->get_child(node->context, i);
if (isFlex(child)) {
// At this point we know the final size of the element in the main
// dimension
child->layout.dimensions[dim[mainAxis]] = flexibleMainDim * getFlex(child) +
getPaddingAndBorderAxis(child, mainAxis);
float maxWidth = CSS_UNDEFINED;
if (mainAxis == CSS_FLEX_DIRECTION_ROW) {
// do nothing
} else if (isDimDefined(node, CSS_FLEX_DIRECTION_ROW)) {
maxWidth = node->layout.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] -
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_ROW);
} else {
maxWidth = parentMaxWidth -
getMarginAxis(node, CSS_FLEX_DIRECTION_ROW) -
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_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 {
css_justify_t justifyContent = getJustifyContent(node);
if (justifyContent == CSS_JUSTIFY_FLEX_START) {
// Do nothing
} else if (justifyContent == CSS_JUSTIFY_CENTER) {
leadingMainDim = remainingMainDim / 2;
} else if (justifyContent == CSS_JUSTIFY_FLEX_END) {
leadingMainDim = remainingMainDim;
} else if (justifyContent == CSS_JUSTIFY_SPACE_BETWEEN) {
remainingMainDim = fmaxf(remainingMainDim, 0);
if (flexibleChildrenCount + nonFlexibleChildrenCount - 1 != 0) {
betweenMainDim = remainingMainDim /
(flexibleChildrenCount + nonFlexibleChildrenCount - 1);
} else {
betweenMainDim = 0;
}
} else if (justifyContent == CSS_JUSTIFY_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, leading[mainAxis]);
for (int i = startLine; i < endLine; ++i) {
css_node_t* child = node->get_child(node->context, i);
if (getPositionType(child) == CSS_POSITION_ABSOLUTE &&
isPosDefined(child, leading[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).
child->layout.position[pos[mainAxis]] = getPosition(child, leading[mainAxis]) +
getBorder(node, leading[mainAxis]) +
getMargin(child, leading[mainAxis]);
} else {
// 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 only need to do that for relative elements. Absolute elements
// do not take part in that phase.
if (getPositionType(child) == CSS_POSITION_RELATIVE) {
// The main dimension is the sum of all the elements dimension plus
// the spacing.
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 = fmaxf(crossDim, getDimWithMargin(child, crossAxis));
}
}
float containerMainAxis = node->layout.dimensions[dim[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 (isUndefined(node->layout.dimensions[dim[mainAxis]])) {
containerMainAxis = fmaxf(
// We're missing the last padding at this point to get the final
// dimension
mainDim + getPaddingAndBorder(node, trailing[mainAxis]),
// We can never assign a width smaller than the padding and borders
getPaddingAndBorderAxis(node, mainAxis)
);
}
float containerCrossAxis = node->layout.dimensions[dim[crossAxis]];
if (isUndefined(node->layout.dimensions[dim[crossAxis]])) {
containerCrossAxis = fmaxf(
// 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) {
css_node_t* child = node->get_child(node->context, i);
if (getPositionType(child) == CSS_POSITION_ABSOLUTE &&
isPosDefined(child, leading[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.
child->layout.position[pos[crossAxis]] = getPosition(child, leading[crossAxis]) +
getBorder(node, leading[crossAxis]) +
getMargin(child, leading[crossAxis]);
} else {
float leadingCrossDim = getPaddingAndBorder(node, leading[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) == CSS_POSITION_RELATIVE) {
css_align_t alignItem = getAlignItem(node, child);
if (alignItem == CSS_ALIGN_FLEX_START) {
// Do nothing
} else if (alignItem == CSS_ALIGN_STRETCH) {
// You can only stretch if the dimension has not already been set
// previously.
if (!isDimDefined(child, crossAxis)) {
child->layout.dimensions[dim[crossAxis]] = fmaxf(
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 == CSS_ALIGN_CENTER) {
leadingCrossDim += remainingCrossDim / 2;
} else { // CSS_ALIGN_FLEX_END
leadingCrossDim += remainingCrossDim;
}
}
}
// And we apply the position
child->layout.position[pos[crossAxis]] += linesCrossDim + leadingCrossDim;
}
}
linesCrossDim += crossDim;
linesMainDim = fmaxf(linesMainDim, mainDim);
startLine = endLine;
}
// If the user didn't specify a width or height, and it has not been set
@@ -604,7 +721,7 @@ static void layoutNodeImpl(css_node_t *node, float parentMaxWidth) {
node->layout.dimensions[dim[mainAxis]] = fmaxf(
// We're missing the last padding at this point to get the final
// dimension
mainDim + getPaddingAndBorder(node, trailing[mainAxis]),
linesMainDim + getPaddingAndBorder(node, trailing[mainAxis]),
// We can never assign a width smaller than the padding and borders
getPaddingAndBorderAxis(node, mainAxis)
);
@@ -615,67 +732,11 @@ static void layoutNodeImpl(css_node_t *node, float parentMaxWidth) {
// 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->children_count; ++i) {
css_node_t* child = node->get_child(node->context, i);
if (getPositionType(child) == CSS_POSITION_ABSOLUTE &&
isPosDefined(child, leading[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.
child->layout.position[pos[crossAxis]] = getPosition(child, leading[crossAxis]) +
getBorder(node, leading[crossAxis]) +
getMargin(child, leading[crossAxis]);
} else {
float leadingCrossDim = getPaddingAndBorder(node, leading[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) == CSS_POSITION_RELATIVE) {
css_align_t alignItem = getAlignItem(node, child);
if (alignItem == CSS_ALIGN_FLEX_START) {
// Do nothing
} else if (alignItem == CSS_ALIGN_STRETCH) {
// You can only stretch if the dimension has not already been set
// previously.
if (!isDimDefined(child, crossAxis)) {
child->layout.dimensions[dim[crossAxis]] = fmaxf(
node->layout.dimensions[dim[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 = node->layout.dimensions[dim[crossAxis]] -
getPaddingAndBorderAxis(node, crossAxis) -
getDimWithMargin(child, crossAxis);
if (alignItem == CSS_ALIGN_CENTER) {
leadingCrossDim += remainingCrossDim / 2;
} else { // CSS_ALIGN_FLEX_END
leadingCrossDim += remainingCrossDim;
}
}
}
// And we apply the position
child->layout.position[pos[crossAxis]] += leadingCrossDim;
}
}
// <Loop E> Calculate dimensions for absolutely positioned elements
for (int i = 0; i < node->children_count; ++i) {