// When the user specifically sets a value for width or height
static void setDimensionFromStyle(css_node_t *node, css_flex_direction_t axis) {
// The parent already computed us a width or height. We just skip it
if (!isUndefined(node->layout.dimensions[dim[axis]])) {
return;
}
// We only run if there's a width or height defined
if (!isDimDefined(node, axis)) {
return;
}
// The dimensions can never be smaller than the padding and border
node->layout.dimensions[dim[axis]] = fmaxf(
boundAxis(node, axis, node->style.dimensions[dim[axis]]),
getPaddingAndBorderAxis(node, axis)
);
}
static void layoutNodeImpl(css_node_t *node, float parentMaxWidth, css_direction_t parentDirection) {
/** START_GENERATED **/
css_direction_t direction = resolveDirection(node, parentDirection);
css_flex_direction_t mainAxis = resolveAxis(getFlexDirection(node), direction);
css_flex_direction_t crossAxis = getCrossFlexDirection(mainAxis, direction);
css_flex_direction_t resolvedRowAxis = resolveAxis(CSS_FLEX_DIRECTION_ROW, direction);
// Handle width and height style attributes
setDimensionFromStyle(node, mainAxis);
setDimensionFromStyle(node, crossAxis);
// Set the resolved resolution in the node's layout
node->layout.direction = direction;
// The position is set by the parent, but we need to complete it with a
// delta composed of the margin and left/top/right/bottom
node->layout.position[leading[mainAxis]] += getLeadingMargin(node, mainAxis) +
getRelativePosition(node, mainAxis);
node->layout.position[trailing[mainAxis]] += getTrailingMargin(node, mainAxis) +
getRelativePosition(node, mainAxis);
node->layout.position[leading[crossAxis]] += getLeadingMargin(node, crossAxis) +
getRelativePosition(node, crossAxis);
node->layout.position[trailing[crossAxis]] += getTrailingMargin(node, crossAxis) +
getRelativePosition(node, crossAxis);
// Inline immutable values from the target node to avoid excessive method
// invocations during the layout calculation.
int childCount = node->children_count;
float paddingAndBorderAxisResolvedRow = getPaddingAndBorderAxis(node, resolvedRowAxis);
if (isMeasureDefined(node)) {
bool isResolvedRowDimDefined = !isUndefined(node->layout.dimensions[dim[resolvedRowAxis]]);
float width = CSS_UNDEFINED;
if (isDimDefined(node, resolvedRowAxis)) {
width = node->style.dimensions[CSS_WIDTH];
} else if (isResolvedRowDimDefined) {
width = node->layout.dimensions[dim[resolvedRowAxis]];
} else {
width = parentMaxWidth -
getMarginAxis(node, resolvedRowAxis);
}
width -= paddingAndBorderAxisResolvedRow;
// We only need to give a dimension for the text if we haven't got any
// for it computed yet. It can either be from the style attribute or because
// the element is flexible.
bool isRowUndefined = !isDimDefined(node, resolvedRowAxis) && !isResolvedRowDimDefined;
bool isColumnUndefined = !isDimDefined(node, CSS_FLEX_DIRECTION_COLUMN) &&
isUndefined(node->layout.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]]);
// Let's not measure the text if we already know both dimensions
if (isRowUndefined || isColumnUndefined) {
css_dim_t measureDim = node->measure(
node->context,
width
);
if (isRowUndefined) {
node->layout.dimensions[CSS_WIDTH] = measureDim.dimensions[CSS_WIDTH] +
paddingAndBorderAxisResolvedRow;
}
if (isColumnUndefined) {
node->layout.dimensions[CSS_HEIGHT] = measureDim.dimensions[CSS_HEIGHT] +
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_COLUMN);
}
}
if (childCount == 0) {
return;
}
}
bool isNodeFlexWrap = isFlexWrap(node);
css_justify_t justifyContent = node->style.justify_content;
float leadingPaddingAndBorderMain = getLeadingPaddingAndBorder(node, mainAxis);
float leadingPaddingAndBorderCross = getLeadingPaddingAndBorder(node, crossAxis);
float paddingAndBorderAxisMain = getPaddingAndBorderAxis(node, mainAxis);
float paddingAndBorderAxisCross = getPaddingAndBorderAxis(node, crossAxis);
bool isMainDimDefined = !isUndefined(node->layout.dimensions[dim[mainAxis]]);
bool isCrossDimDefined = !isUndefined(node->layout.dimensions[dim[crossAxis]]);
bool isMainRowDirection = isRowDirection(mainAxis);
int i;
int ii;
css_node_t* child;
css_flex_direction_t axis;
css_node_t* firstAbsoluteChild = NULL;
css_node_t* currentAbsoluteChild = NULL;
float definedMainDim = CSS_UNDEFINED;
if (isMainDimDefined) {
definedMainDim = node->layout.dimensions[dim[mainAxis]] - paddingAndBorderAxisMain;
}
// We want to execute the next two loops one per line with flex-wrap
int startLine = 0;
int endLine = 0;
// int nextOffset = 0;
int alreadyComputedNextLayout = 0;
// We aggregate the total dimensions of the container in those two variables
float linesCrossDim = 0;
float linesMainDim = 0;
int linesCount = 0;
while (endLine < childCount) {
// <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;
// Use the line loop to position children in the main axis for as long
// as they are using a simple stacking behaviour. Children that are
// immediately stacked in the initial loop will not be touched again
// in <Loop C>.
bool isSimpleStackMain =
(isMainDimDefined && justifyContent == CSS_JUSTIFY_FLEX_START) ||
(!isMainDimDefined && justifyContent != CSS_JUSTIFY_CENTER);
int firstComplexMain = (isSimpleStackMain ? childCount : startLine);
// Use the initial line loop to position children in the cross axis for
// as long as they are relatively positioned with alignment STRETCH or
// FLEX_START. Children that are immediately stacked in the initial loop
// will not be touched again in <Loop D>.
bool isSimpleStackCross = true;
int firstComplexCross = childCount;
css_node_t* firstFlexChild = NULL;
css_node_t* currentFlexChild = NULL;
float mainDim = leadingPaddingAndBorderMain;
float crossDim = 0;
float maxWidth;
for (i = startLine; i < childCount; ++i) {
child = node->get_child(node->context, i);
child->line_index = linesCount;
child->next_absolute_child = NULL;
child->next_flex_child = NULL;
css_align_t alignItem = getAlignItem(node, child);
// Pre-fill cross axis dimensions when the child is using stretch before
// we call the recursive layout pass
if (alignItem == CSS_ALIGN_STRETCH &&
child->style.position_type == CSS_POSITION_RELATIVE &&
isCrossDimDefined &&
!isDimDefined(child, crossAxis)) {
child->layout.dimensions[dim[crossAxis]] = fmaxf(
boundAxis(child, crossAxis, node->layout.dimensions[dim[crossAxis]] -
paddingAndBorderAxisCross - getMarginAxis(child, crossAxis)),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, crossAxis)
);
} else if (child->style.position_type == CSS_POSITION_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->next_absolute_child = child;
}
currentAbsoluteChild = child;
// Pre-fill dimensions when using absolute position and both offsets for the axis are defined (either both
// left and right or top and bottom).
for (ii = 0; ii < 2; ii++) {
axis = (ii != 0) ? CSS_FLEX_DIRECTION_ROW : CSS_FLEX_DIRECTION_COLUMN;
if (!isUndefined(node->layout.dimensions[dim[axis]]) &&
!isDimDefined(child, axis) &&
isPosDefined(child, leading[axis]) &&
isPosDefined(child, trailing[axis])) {
child->layout.dimensions[dim[axis]] = fmaxf(
boundAxis(child, axis, node->layout.dimensions[dim[axis]] -
getPaddingAndBorderAxis(node, axis) -
getMarginAxis(child, axis) -
getPosition(child, leading[axis]) -
getPosition(child, trailing[axis])),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, axis)
);
}
}
}
float nextContentDim = 0;
// It only makes sense to consider a child flexible if we have a computed
// dimension for the node->
if (isMainDimDefined && isFlex(child)) {
flexibleChildrenCount++;
totalFlexible += child->style.flex;
// Store a private linked list of flexible children so that we can
// efficiently traverse them later.
if (firstFlexChild == NULL) {
firstFlexChild = child;
}
if (currentFlexChild != NULL) {
currentFlexChild->next_flex_child = child;
}
currentFlexChild = 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, which represents
// the smallest possible size for the child, to compute the remaining
// available space.
nextContentDim = getPaddingAndBorderAxis(child, mainAxis) +
getMarginAxis(child, mainAxis);
} else {
maxWidth = CSS_UNDEFINED;
if (!isMainRowDirection) {
if (isDimDefined(node, resolvedRowAxis)) {
maxWidth = node->layout.dimensions[dim[resolvedRowAxis]] -
paddingAndBorderAxisResolvedRow;
} else {
maxWidth = parentMaxWidth -
getMarginAxis(node, resolvedRowAxis) -
paddingAndBorderAxisResolvedRow;
}
}
// This is the main recursive call. We layout non flexible children.
if (alreadyComputedNextLayout == 0) {
layoutNode(child, maxWidth, direction);
}
// Absolute positioned elements do not take part of the layout, so we
// don't use them to compute mainContentDim
if (child->style.position_type == 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 (isNodeFlexWrap &&
isMainDimDefined &&
mainContentDim + nextContentDim > definedMainDim &&
// If there's only one element, then it's bigger than the content
// and needs its own line
i != startLine) {
nonFlexibleChildrenCount--;
alreadyComputedNextLayout = 1;
break;
}
// Disable simple stacking in the main axis for the current line as
// we found a non-trivial child-> The remaining children will be laid out
// in <Loop C>.
if (isSimpleStackMain &&
(child->style.position_type != CSS_POSITION_RELATIVE || isFlex(child))) {
isSimpleStackMain = false;
firstComplexMain = i;
}
// Disable simple stacking in the cross axis for the current line as
// we found a non-trivial child-> The remaining children will be laid out
// in <Loop D>.
if (isSimpleStackCross &&
(child->style.position_type != CSS_POSITION_RELATIVE ||
(alignItem != CSS_ALIGN_STRETCH && alignItem != CSS_ALIGN_FLEX_START) ||
isUndefined(child->layout.dimensions[dim[crossAxis]]))) {
isSimpleStackCross = false;
firstComplexCross = i;
}
if (isSimpleStackMain) {
child->layout.position[pos[mainAxis]] += mainDim;
if (isMainDimDefined) {
setTrailingPosition(node, child, mainAxis);
}
mainDim += getDimWithMargin(child, mainAxis);
crossDim = fmaxf(crossDim, boundAxis(child, crossAxis, getDimWithMargin(child, crossAxis)));
}
if (isSimpleStackCross) {
child->layout.position[pos[crossAxis]] += linesCrossDim + leadingPaddingAndBorderCross;
if (isCrossDimDefined) {
setTrailingPosition(node, child, crossAxis);
}
}
alreadyComputedNextLayout = 0;
mainContentDim += nextContentDim;
endLine = i + 1;
}
// <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;
// The remaining available space that needs to be allocated
float remainingMainDim = 0;
if (isMainDimDefined) {
remainingMainDim = definedMainDim - mainContentDim;
} else {
remainingMainDim = fmaxf(mainContentDim, 0) - mainContentDim;
}
// If there are flexible children in the mix, they are going to fill the
// remaining space
if (flexibleChildrenCount != 0) {
float flexibleMainDim = remainingMainDim / totalFlexible;
float baseMainDim;
float boundMainDim;
// If the flex share of remaining space doesn't meet min/max bounds,
// remove this child from flex calculations.
currentFlexChild = firstFlexChild;
while (currentFlexChild != NULL) {
baseMainDim = flexibleMainDim * currentFlexChild->style.flex +
getPaddingAndBorderAxis(currentFlexChild, mainAxis);
boundMainDim = boundAxis(currentFlexChild, mainAxis, baseMainDim);
if (baseMainDim != boundMainDim) {
remainingMainDim -= boundMainDim;
totalFlexible -= currentFlexChild->style.flex;
}
currentFlexChild = currentFlexChild->next_flex_child;
}
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;
}
currentFlexChild = firstFlexChild;
while (currentFlexChild != NULL) {
// At this point we know the final size of the element in the main
// dimension
currentFlexChild->layout.dimensions[dim[mainAxis]] = boundAxis(currentFlexChild, mainAxis,
flexibleMainDim * currentFlexChild->style.flex +
getPaddingAndBorderAxis(currentFlexChild, mainAxis)
);
maxWidth = CSS_UNDEFINED;
if (isDimDefined(node, resolvedRowAxis)) {
maxWidth = node->layout.dimensions[dim[resolvedRowAxis]] -
paddingAndBorderAxisResolvedRow;
} else if (!isMainRowDirection) {
maxWidth = parentMaxWidth -
getMarginAxis(node, resolvedRowAxis) -
paddingAndBorderAxisResolvedRow;
}
// And we recursively call the layout algorithm for this child
layoutNode(currentFlexChild, maxWidth, direction);
child = currentFlexChild;
currentFlexChild = currentFlexChild->next_flex_child;
child->next_flex_child = NULL;
}
// We use justifyContent to figure out how to allocate the remaining
// space available
} else if (justifyContent != CSS_JUSTIFY_FLEX_START) {
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!
mainDim += leadingMainDim;
for (i = firstComplexMain; i < endLine; ++i) {
child = node->get_child(node->context, i);
if (child->style.position_type == 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]) +
getLeadingBorder(node, mainAxis) +
getLeadingMargin(child, 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;
// Define the trailing position accordingly.
if (isMainDimDefined) {
setTrailingPosition(node, child, mainAxis);
}
// 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 (child->style.position_type == 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, boundAxis(child, crossAxis, getDimWithMargin(child, crossAxis)));
}
}
}
float containerCrossAxis = node->layout.dimensions[dim[crossAxis]];
if (!isCrossDimDefined) {
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
boundAxis(node, crossAxis, crossDim + paddingAndBorderAxisCross),
paddingAndBorderAxisCross
);
}
// <Loop D> Position elements in the cross axis
for (i = firstComplexCross; i < endLine; ++i) {
child = node->get_child(node->context, i);
if (child->style.position_type == 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]) +
getLeadingBorder(node, crossAxis) +
getLeadingMargin(child, 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
if (child->style.position_type == CSS_POSITION_RELATIVE) {
css_align_t alignItem = getAlignItem(node, child);
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(
boundAxis(child, crossAxis, containerCrossAxis -
paddingAndBorderAxisCross - getMarginAxis(child, crossAxis)),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, crossAxis)
);
}
} else if (alignItem != CSS_ALIGN_FLEX_START) {
// The remaining space between the parent dimensions+padding and child
// dimensions+margin.
float remainingCrossDim = containerCrossAxis -
paddingAndBorderAxisCross - 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;
// Define the trailing position accordingly.
if (isCrossDimDefined) {
setTrailingPosition(node, child, crossAxis);
}
}
}
linesCrossDim += crossDim;
linesMainDim = fmaxf(linesMainDim, mainDim);
linesCount += 1;
startLine = endLine;
}
// <Loop E>
//
// Note(prenaux): More than one line, we need to layout the crossAxis
// according to alignContent.
//
// Note that we could probably remove <Loop D> and handle the one line case
// here too, but for the moment this is safer since it won't interfere with
// previously working code.
//
// See specs:
// http://www.w3.org/TR/2012/CR-css3-flexbox-20120918/#layout-algorithm
// section 9.4
//
if (linesCount > 1 && isCrossDimDefined) {
float nodeCrossAxisInnerSize = node->layout.dimensions[dim[crossAxis]] -
paddingAndBorderAxisCross;
float remainingAlignContentDim = nodeCrossAxisInnerSize - linesCrossDim;
float crossDimLead = 0;
float currentLead = leadingPaddingAndBorderCross;
css_align_t alignContent = node->style.align_content;
if (alignContent == CSS_ALIGN_FLEX_END) {
currentLead += remainingAlignContentDim;
} else if (alignContent == CSS_ALIGN_CENTER) {
currentLead += remainingAlignContentDim / 2;
} else if (alignContent == CSS_ALIGN_STRETCH) {
if (nodeCrossAxisInnerSize > linesCrossDim) {
crossDimLead = (remainingAlignContentDim / linesCount);
}
}
int endIndex = 0;
for (i = 0; i < linesCount; ++i) {
int startIndex = endIndex;
// compute the line's height and find the endIndex
float lineHeight = 0;
for (ii = startIndex; ii < childCount; ++ii) {
child = node->get_child(node->context, ii);
if (child->style.position_type != CSS_POSITION_RELATIVE) {
continue;
}
if (child->line_index != i) {
break;
}
if (!isUndefined(child->layout.dimensions[dim[crossAxis]])) {
lineHeight = fmaxf(
lineHeight,
child->layout.dimensions[dim[crossAxis]] + getMarginAxis(child, crossAxis)
);
}
}
endIndex = ii;
lineHeight += crossDimLead;
for (ii = startIndex; ii < endIndex; ++ii) {
child = node->get_child(node->context, ii);
if (child->style.position_type != CSS_POSITION_RELATIVE) {
continue;
}
css_align_t alignContentAlignItem = getAlignItem(node, child);
if (alignContentAlignItem == CSS_ALIGN_FLEX_START) {
child->layout.position[pos[crossAxis]] = currentLead + getLeadingMargin(child, crossAxis);
} else if (alignContentAlignItem == CSS_ALIGN_FLEX_END) {
child->layout.position[pos[crossAxis]] = currentLead + lineHeight - getTrailingMargin(child, crossAxis) - child->layout.dimensions[dim[crossAxis]];
} else if (alignContentAlignItem == CSS_ALIGN_CENTER) {
float childHeight = child->layout.dimensions[dim[crossAxis]];
child->layout.position[pos[crossAxis]] = currentLead + (lineHeight - childHeight) / 2;
} else if (alignContentAlignItem == CSS_ALIGN_STRETCH) {
child->layout.position[pos[crossAxis]] = currentLead + getLeadingMargin(child, crossAxis);
// TODO(prenaux): Correctly set the height of items with undefined
// (auto) crossAxis dimension.
}
}
currentLead += lineHeight;
}
}
bool needsMainTrailingPos = false;
bool needsCrossTrailingPos = false;
// 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 (!isMainDimDefined) {
node->layout.dimensions[dim[mainAxis]] = fmaxf(
// We're missing the last padding at this point to get the final
// dimension
boundAxis(node, mainAxis, linesMainDim + getTrailingPaddingAndBorder(node, mainAxis)),
// We can never assign a width smaller than the padding and borders
paddingAndBorderAxisMain
);
if (mainAxis == CSS_FLEX_DIRECTION_ROW_REVERSE ||
mainAxis == CSS_FLEX_DIRECTION_COLUMN_REVERSE) {
needsMainTrailingPos = true;
}
}
if (!isCrossDimDefined) {
node->layout.dimensions[dim[crossAxis]] = 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
boundAxis(node, crossAxis, linesCrossDim + paddingAndBorderAxisCross),
paddingAndBorderAxisCross
);
if (crossAxis == CSS_FLEX_DIRECTION_ROW_REVERSE ||
crossAxis == CSS_FLEX_DIRECTION_COLUMN_REVERSE) {
needsCrossTrailingPos = true;
}
}
// <Loop F> Set trailing position if necessary
if (needsMainTrailingPos || needsCrossTrailingPos) {
for (i = 0; i < childCount; ++i) {
child = node->get_child(node->context, i);
if (needsMainTrailingPos) {
setTrailingPosition(node, child, mainAxis);
}
if (needsCrossTrailingPos) {
setTrailingPosition(node, child, crossAxis);
}
}
}
// <Loop G> Calculate dimensions for absolutely positioned elements
currentAbsoluteChild = firstAbsoluteChild;
while (currentAbsoluteChild != NULL) {
// Pre-fill dimensions when using absolute position and both offsets for
// the axis are defined (either both left and right or top and bottom).
for (ii = 0; ii < 2; ii++) {
axis = (ii != 0) ? CSS_FLEX_DIRECTION_ROW : CSS_FLEX_DIRECTION_COLUMN;
if (!isUndefined(node->layout.dimensions[dim[axis]]) &&
!isDimDefined(currentAbsoluteChild, axis) &&
isPosDefined(currentAbsoluteChild, leading[axis]) &&
isPosDefined(currentAbsoluteChild, trailing[axis])) {
currentAbsoluteChild->layout.dimensions[dim[axis]] = fmaxf(
boundAxis(currentAbsoluteChild, axis, node->layout.dimensions[dim[axis]] -
getBorderAxis(node, axis) -
getMarginAxis(currentAbsoluteChild, axis) -
getPosition(currentAbsoluteChild, leading[axis]) -
getPosition(currentAbsoluteChild, trailing[axis])
),
// You never want to go smaller than padding
getPaddingAndBorderAxis(currentAbsoluteChild, axis)
);
}
if (isPosDefined(currentAbsoluteChild, trailing[axis]) &&
!isPosDefined(currentAbsoluteChild, leading[axis])) {
currentAbsoluteChild->layout.position[leading[axis]] =
node->layout.dimensions[dim[axis]] -
currentAbsoluteChild->layout.dimensions[dim[axis]] -
getPosition(currentAbsoluteChild, trailing[axis]);
}
}
child = currentAbsoluteChild;
currentAbsoluteChild = currentAbsoluteChild->next_absolute_child;
child->next_absolute_child = NULL;
}
/** END_GENERATED **/
}
static void layoutNodeImpl(css_node_t *node, float parentMaxWidth) {
/** START_GENERATED **/
css_flex_direction_t mainAxis = getFlexDirection(node);
css_flex_direction_t crossAxis = mainAxis == CSS_FLEX_DIRECTION_ROW ?
CSS_FLEX_DIRECTION_COLUMN :
CSS_FLEX_DIRECTION_ROW;
// Handle width and height style attributes
setDimensionFromStyle(node, mainAxis);
setDimensionFromStyle(node, crossAxis);
// The position is set by the parent, but we need to complete it with a
// delta composed of the margin and left/top/right/bottom
node->layout.position[leading[mainAxis]] += getMargin(node, leading[mainAxis]) +
getRelativePosition(node, mainAxis);
node->layout.position[leading[crossAxis]] += getMargin(node, leading[crossAxis]) +
getRelativePosition(node, crossAxis);
if (isMeasureDefined(node)) {
float width = CSS_UNDEFINED;
if (isDimDefined(node, CSS_FLEX_DIRECTION_ROW)) {
width = node->style.dimensions[CSS_WIDTH];
} else if (!isUndefined(node->layout.dimensions[dim[CSS_FLEX_DIRECTION_ROW]])) {
width = node->layout.dimensions[dim[CSS_FLEX_DIRECTION_ROW]];
} else {
width = parentMaxWidth -
getMarginAxis(node, CSS_FLEX_DIRECTION_ROW);
}
width -= getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_ROW);
// We only need to give a dimension for the text if we haven't got any
// for it computed yet. It can either be from the style attribute or because
// the element is flexible.
bool isRowUndefined = !isDimDefined(node, CSS_FLEX_DIRECTION_ROW) &&
isUndefined(node->layout.dimensions[dim[CSS_FLEX_DIRECTION_ROW]]);
bool isColumnUndefined = !isDimDefined(node, CSS_FLEX_DIRECTION_COLUMN) &&
isUndefined(node->layout.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]]);
// Let's not measure the text if we already know both dimensions
if (isRowUndefined || isColumnUndefined) {
css_dim_t measure_dim = node->measure(
node->context,
width
);
if (isRowUndefined) {
node->layout.dimensions[CSS_WIDTH] = measure_dim.dimensions[CSS_WIDTH] +
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_ROW);
}
if (isColumnUndefined) {
node->layout.dimensions[CSS_HEIGHT] = measure_dim.dimensions[CSS_HEIGHT] +
getPaddingAndBorderAxis(node, CSS_FLEX_DIRECTION_COLUMN);
}
}
return;
}
// Pre-fill some dimensions straight from the parent
for (int i = 0; i < node->children_count; ++i) {
css_node_t* child = node->get_child(node->context, i);
// Pre-fill cross axis dimensions when the child is using stretch before
// we call the recursive layout pass
if (getAlignItem(node, child) == CSS_ALIGN_STRETCH &&
getPositionType(child) == CSS_POSITION_RELATIVE &&
!isUndefined(node->layout.dimensions[dim[crossAxis]]) &&
!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 if (getPositionType(child) == CSS_POSITION_ABSOLUTE) {
// Pre-fill dimensions when using absolute position and both offsets for the axis are defined (either both
// left and right or top and bottom).
for (int ii = 0; ii < 2; ii++) {
css_flex_direction_t axis = (ii != 0) ? CSS_FLEX_DIRECTION_ROW : CSS_FLEX_DIRECTION_COLUMN;
if (!isUndefined(node->layout.dimensions[dim[axis]]) &&
!isDimDefined(child, axis) &&
isPosDefined(child, leading[axis]) &&
isPosDefined(child, trailing[axis])) {
child->layout.dimensions[dim[axis]] = fmaxf(
node->layout.dimensions[dim[axis]] -
getPaddingAndBorderAxis(node, axis) -
getMarginAxis(child, axis) -
getPosition(child, leading[axis]) -
getPosition(child, trailing[axis]),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, axis)
);
}
}
}
}
float definedMainDim = CSS_UNDEFINED;
if (!isUndefined(node->layout.dimensions[dim[mainAxis]])) {
definedMainDim = node->layout.dimensions[dim[mainAxis]] -
getPaddingAndBorderAxis(node, mainAxis);
}
// 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
// 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);
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
} 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.
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;
}
// <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;
// The remaining available space that needs to be allocated
float remainingMainDim = 0;
if (!isUndefined(node->layout.dimensions[dim[mainAxis]])) {
remainingMainDim = definedMainDim - mainContentDim;
} else {
remainingMainDim = fmaxf(mainContentDim, 0) - mainContentDim;
}
// 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
// by the container, then we set it via the children.
if (isUndefined(node->layout.dimensions[dim[mainAxis]])) {
node->layout.dimensions[dim[mainAxis]] = fmaxf(
// We're missing the last padding at this point to get the final
// dimension
linesMainDim + getPaddingAndBorder(node, trailing[mainAxis]),
// We can never assign a width smaller than the padding and borders
getPaddingAndBorderAxis(node, mainAxis)
);
}
if (isUndefined(node->layout.dimensions[dim[crossAxis]])) {
node->layout.dimensions[dim[crossAxis]] = 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
linesCrossDim + getPaddingAndBorderAxis(node, crossAxis),
getPaddingAndBorderAxis(node, crossAxis)
);
}
// <Loop E> Calculate dimensions for absolutely positioned elements
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) {
// Pre-fill dimensions when using absolute position and both offsets for the axis are defined (either both
// left and right or top and bottom).
for (int ii = 0; ii < 2; ii++) {
css_flex_direction_t axis = (ii != 0) ? CSS_FLEX_DIRECTION_ROW : CSS_FLEX_DIRECTION_COLUMN;
if (!isUndefined(node->layout.dimensions[dim[axis]]) &&
!isDimDefined(child, axis) &&
isPosDefined(child, leading[axis]) &&
isPosDefined(child, trailing[axis])) {
child->layout.dimensions[dim[axis]] = fmaxf(
node->layout.dimensions[dim[axis]] -
getPaddingAndBorderAxis(node, axis) -
getMarginAxis(child, axis) -
getPosition(child, leading[axis]) -
getPosition(child, trailing[axis]),
// You never want to go smaller than padding
getPaddingAndBorderAxis(child, axis)
);
}
}
for (int ii = 0; ii < 2; ii++) {
css_flex_direction_t axis = (ii != 0) ? CSS_FLEX_DIRECTION_ROW : CSS_FLEX_DIRECTION_COLUMN;
if (isPosDefined(child, trailing[axis]) &&
!isPosDefined(child, leading[axis])) {
child->layout.position[leading[axis]] =
node->layout.dimensions[dim[axis]] -
child->layout.dimensions[dim[axis]] -
getPosition(child, trailing[axis]);
}
}
}
}
/** END_GENERATED **/
}