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Import latest css-layout

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Summary:
Import latest master from css-layout.

This includes the following pull requests:
https://github.com/facebook/css-layout/pull/192
https://github.com/facebook/css-layout/pull/193
https://github.com/facebook/css-layout/pull/195
https://github.com/facebook/css-layout/pull/196

Reviewed By: javache

Differential Revision: D3411535

fbshipit-source-id: 95bee9bd0282f98f6fafa15335b910b644395ad3
This commit is contained in:
Emil Sjolander
2016-06-13 07:52:14 -07:00
committed by Facebook Github Bot 2
parent 97cfacb5ba
commit 8afcaa36e6
8 changed files with 383 additions and 150 deletions
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295
ReactAndroid/src/main/java/com/facebook/csslayout/LayoutEngine.java
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@@ -7,7 +7,7 @@
*/
// NOTE: this file is auto-copied from https://github.com/facebook/css-layout
// @generated SignedSource<<9165e7546c964b47cb01be9ff8070aa8>>
// @generated SignedSource<<c5a4eadcd6d93bc6d989cba73caa12a7>>
package com.facebook.csslayout;
@@ -24,9 +24,9 @@ import static com.facebook.csslayout.CSSLayout.POSITION_TOP;
* Calculates layouts based on CSS style. See {@link #layoutNode(CSSNode, float, float)}.
*/
public class LayoutEngine {
private static final boolean POSITIVE_FLEX_IS_AUTO = false;
private static final int CSS_FLEX_DIRECTION_COLUMN =
CSSFlexDirection.COLUMN.ordinal();
private static final int CSS_FLEX_DIRECTION_COLUMN_REVERSE =
@@ -80,7 +80,7 @@ public class LayoutEngine {
Spacing.END,
Spacing.END
};
private static boolean isFlexBasisAuto(CSSNode node) {
if (POSITIVE_FLEX_IS_AUTO) {
// All flex values are auto.
@@ -90,7 +90,7 @@ public class LayoutEngine {
return node.style.flex <= 0;
}
}
private static float getFlexGrowFactor(CSSNode node) {
// Flex grow is implied by positive values for flex.
if (node.style.flex > 0) {
@@ -98,7 +98,7 @@ public class LayoutEngine {
}
return 0;
}
private static float getFlexShrinkFactor(CSSNode node) {
if (POSITIVE_FLEX_IS_AUTO) {
// A flex shrink factor of 1 is implied by non-zero values for flex.
@@ -140,7 +140,7 @@ public class LayoutEngine {
return boundValue;
}
private static float boundAxis(CSSNode node, int axis, float value) {
float paddingAndBorderAxis =
node.style.padding.getWithFallback(leadingSpacing[axis], leading[axis]) +
@@ -159,11 +159,11 @@ public class LayoutEngine {
float trailingPos = node.style.position[trailing[axis]];
return Float.isNaN(trailingPos) ? 0 : -trailingPos;
}
private static void setPosition(CSSNode node, CSSDirection direction) {
int mainAxis = resolveAxis(getFlexDirection(node), direction);
int crossAxis = getCrossFlexDirection(mainAxis, direction);
node.layout.position[leading[mainAxis]] = node.style.margin.getWithFallback(leadingSpacing[mainAxis], leading[mainAxis]) +
getRelativePosition(node, mainAxis);
node.layout.position[trailing[mainAxis]] = node.style.margin.getWithFallback(trailingSpacing[mainAxis], trailing[mainAxis]) +
@@ -233,7 +233,7 @@ public class LayoutEngine {
// all dirty nodes at least once. Subsequent visits will be skipped if the input
// parameters don't change.
layoutContext.currentGenerationCount++;
// If the caller didn't specify a height/width, use the dimensions
// specified in the style.
if (Float.isNaN(availableWidth) && node.style.dimensions[DIMENSION_WIDTH] >= 0.0) {
@@ -244,46 +244,92 @@ public class LayoutEngine {
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]));
availableHeight = node.style.dimensions[DIMENSION_HEIGHT] + marginAxisColumn;
}
CSSMeasureMode widthMeasureMode = Float.isNaN(availableWidth) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.EXACTLY;
CSSMeasureMode heightMeasureMode = Float.isNaN(availableHeight) ? CSSMeasureMode.UNDEFINED : CSSMeasureMode.EXACTLY;
if (layoutNodeInternal(layoutContext, node, availableWidth, availableHeight, parentDirection, widthMeasureMode, heightMeasureMode, true, "initial")) {
setPosition(node, node.layout.direction);
}
}
/*package*/ static boolean canUseCachedMeasurement(float availableWidth, float availableHeight,
float marginRow, float marginColumn,
CSSMeasureMode widthMeasureMode, CSSMeasureMode heightMeasureMode,
/*package*/ static boolean canUseCachedMeasurement(
boolean isTextNode,
float availableWidth,
float availableHeight,
float marginRow,
float marginColumn,
CSSMeasureMode widthMeasureMode,
CSSMeasureMode heightMeasureMode,
CSSCachedMeasurement cachedLayout) {
// Is it an exact match?
if (FloatUtil.floatsEqual(cachedLayout.availableWidth, availableWidth) &&
FloatUtil.floatsEqual(cachedLayout.availableHeight, availableHeight) &&
cachedLayout.widthMeasureMode == widthMeasureMode &&
cachedLayout.heightMeasureMode == heightMeasureMode) {
boolean isHeightSame =
(cachedLayout.heightMeasureMode == CSSMeasureMode.UNDEFINED && heightMeasureMode == CSSMeasureMode.UNDEFINED) ||
(cachedLayout.heightMeasureMode == heightMeasureMode && FloatUtil.floatsEqual(cachedLayout.availableHeight, availableHeight));
boolean isWidthSame =
(cachedLayout.widthMeasureMode == CSSMeasureMode.UNDEFINED && widthMeasureMode == CSSMeasureMode.UNDEFINED) ||
(cachedLayout.widthMeasureMode == widthMeasureMode && FloatUtil.floatsEqual(cachedLayout.availableWidth, availableWidth));
if (isHeightSame && isWidthSame) {
return true;
}
// If the width is an exact match, try a fuzzy match on the height.
if (FloatUtil.floatsEqual(cachedLayout.availableWidth, availableWidth) &&
cachedLayout.widthMeasureMode == widthMeasureMode &&
heightMeasureMode == CSSMeasureMode.EXACTLY &&
FloatUtil.floatsEqual(availableHeight - marginColumn, cachedLayout.computedHeight)) {
boolean isHeightValid =
(cachedLayout.heightMeasureMode == CSSMeasureMode.UNDEFINED && heightMeasureMode == CSSMeasureMode.AT_MOST && cachedLayout.computedHeight <= (availableHeight - marginColumn)) ||
(heightMeasureMode == CSSMeasureMode.EXACTLY && FloatUtil.floatsEqual(cachedLayout.computedHeight, availableHeight - marginColumn));
if (isWidthSame && isHeightValid) {
return true;
}
// If the height is an exact match, try a fuzzy match on the width.
if (FloatUtil.floatsEqual(cachedLayout.availableHeight, availableHeight) &&
cachedLayout.heightMeasureMode == heightMeasureMode &&
widthMeasureMode == CSSMeasureMode.EXACTLY &&
FloatUtil.floatsEqual(availableWidth - marginRow, cachedLayout.computedWidth)) {
boolean isWidthValid =
(cachedLayout.widthMeasureMode == CSSMeasureMode.UNDEFINED && widthMeasureMode == CSSMeasureMode.AT_MOST && cachedLayout.computedWidth <= (availableWidth - marginRow)) ||
(widthMeasureMode == CSSMeasureMode.EXACTLY && FloatUtil.floatsEqual(cachedLayout.computedWidth, availableWidth - marginRow));
if (isHeightSame && isWidthValid) {
return true;
}
if (isHeightValid && isWidthValid) {
return true;
}
// We know this to be text so we can apply some more specialized heuristics.
if (isTextNode) {
if (isWidthSame) {
if (heightMeasureMode == CSSMeasureMode.UNDEFINED) {
// Width is the same and height is not restricted. Re-use cahced value.
return true;
}
if (heightMeasureMode == CSSMeasureMode.AT_MOST &&
cachedLayout.computedHeight < (availableHeight - marginColumn)) {
// Width is the same and height restriction is greater than the cached height. Re-use cached value.
return true;
}
// Width is the same but height restriction imposes smaller height than previously measured.
// Update the cached value to respect the new height restriction.
cachedLayout.computedHeight = availableHeight - marginColumn;
return true;
}
if (cachedLayout.widthMeasureMode == CSSMeasureMode.UNDEFINED) {
if (widthMeasureMode == CSSMeasureMode.UNDEFINED ||
(widthMeasureMode == CSSMeasureMode.AT_MOST &&
cachedLayout.computedWidth <= (availableWidth - marginRow))) {
// Previsouly this text was measured with no width restriction, if width is now restricted
// but to a larger value than the previsouly measured width we can re-use the measurement
// as we know it will fit.
return true;
}
}
}
return false;
}
//
// This is a wrapper around the layoutNodeImpl function. It determines
// whether the layout request is redundant and can be skipped.
@@ -303,19 +349,19 @@ public class LayoutEngine {
boolean performLayout,
String reason) {
CSSLayout layout = node.layout;
boolean needToVisitNode = (node.isDirty() && layout.generationCount != layoutContext.currentGenerationCount) ||
layout.lastParentDirection != parentDirection;
if (needToVisitNode) {
// Invalidate the cached results.
layout.nextCachedMeasurementsIndex = 0;
layout.cachedLayout.widthMeasureMode = null;
layout.cachedLayout.heightMeasureMode = null;
}
CSSCachedMeasurement cachedResults = null;
// Determine whether the results are already cached. We maintain a separate
// cache for layouts and measurements. A layout operation modifies the positions
// and dimensions for nodes in the subtree. The algorithm assumes that each node
@@ -329,16 +375,16 @@ public class LayoutEngine {
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]);
node.style.margin.getWithFallback(trailingSpacing[CSS_FLEX_DIRECTION_COLUMN], trailing[CSS_FLEX_DIRECTION_COLUMN]);
// First, try to use the layout cache.
if (canUseCachedMeasurement(availableWidth, availableHeight, marginAxisRow, marginAxisColumn,
if (canUseCachedMeasurement(node.isTextNode(), availableWidth, availableHeight, marginAxisRow, marginAxisColumn,
widthMeasureMode, heightMeasureMode, layout.cachedLayout)) {
cachedResults = layout.cachedLayout;
} else {
// Try to use the measurement cache.
for (int i = 0; i < layout.nextCachedMeasurementsIndex; i++) {
if (canUseCachedMeasurement(availableWidth, availableHeight, marginAxisRow, marginAxisColumn,
if (canUseCachedMeasurement(node.isTextNode(), availableWidth, availableHeight, marginAxisRow, marginAxisColumn,
widthMeasureMode, heightMeasureMode, layout.cachedMeasurements[i])) {
cachedResults = layout.cachedMeasurements[i];
break;
@@ -350,7 +396,7 @@ public class LayoutEngine {
FloatUtil.floatsEqual(layout.cachedLayout.availableHeight, availableHeight) &&
layout.cachedLayout.widthMeasureMode == widthMeasureMode &&
layout.cachedLayout.heightMeasureMode == heightMeasureMode) {
cachedResults = layout.cachedLayout;
}
} else {
@@ -365,15 +411,15 @@ public class LayoutEngine {
}
}
}
if (!needToVisitNode && cachedResults != null) {
layout.measuredDimensions[DIMENSION_WIDTH] = cachedResults.computedWidth;
layout.measuredDimensions[DIMENSION_HEIGHT] = cachedResults.computedHeight;
} else {
layoutNodeImpl(layoutContext, node, availableWidth, availableHeight, parentDirection, widthMeasureMode, heightMeasureMode, performLayout);
layout.lastParentDirection = parentDirection;
if (cachedResults == null) {
if (layout.nextCachedMeasurementsIndex == CSSLayout.MAX_CACHED_RESULT_COUNT) {
layout.nextCachedMeasurementsIndex = 0;
@@ -392,7 +438,7 @@ public class LayoutEngine {
}
layout.nextCachedMeasurementsIndex++;
}
newCacheEntry.availableWidth = availableWidth;
newCacheEntry.availableHeight = availableHeight;
newCacheEntry.widthMeasureMode = widthMeasureMode;
@@ -401,18 +447,18 @@ public class LayoutEngine {
newCacheEntry.computedHeight = layout.measuredDimensions[DIMENSION_HEIGHT];
}
}
if (performLayout) {
node.layout.dimensions[DIMENSION_WIDTH] = node.layout.measuredDimensions[DIMENSION_WIDTH];
node.layout.dimensions[DIMENSION_HEIGHT] = node.layout.measuredDimensions[DIMENSION_HEIGHT];
node.markHasNewLayout();
}
layout.generationCount = layoutContext.currentGenerationCount;
return (needToVisitNode || cachedResults == null);
}
//
// This is the main routine that implements a subset of the flexbox layout algorithm
// described in the W3C CSS documentation: https://www.w3.org/TR/css3-flexbox/.
@@ -449,8 +495,8 @@ public class LayoutEngine {
//
// 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
// 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
@@ -484,7 +530,7 @@ public class LayoutEngine {
// - 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.
//
@@ -501,7 +547,7 @@ public class LayoutEngine {
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]));
@@ -515,7 +561,7 @@ public class LayoutEngine {
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.
@@ -547,7 +593,7 @@ public class LayoutEngine {
measureDim.height + paddingAndBorderAxisColumn :
availableHeight - marginAxisColumn);
}
return;
}
@@ -577,7 +623,7 @@ public class LayoutEngine {
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));
@@ -589,7 +635,7 @@ public class LayoutEngine {
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);
@@ -613,7 +659,7 @@ public class LayoutEngine {
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;
@@ -638,7 +684,7 @@ public class LayoutEngine {
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) {
@@ -654,27 +700,27 @@ public class LayoutEngine {
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;
@@ -683,7 +729,7 @@ public class LayoutEngine {
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
@@ -702,23 +748,42 @@ public class LayoutEngine {
}
}
// 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;
@@ -726,7 +791,7 @@ public class LayoutEngine {
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;
@@ -753,7 +818,7 @@ public class LayoutEngine {
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) {
@@ -765,7 +830,7 @@ public class LayoutEngine {
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;
@@ -781,11 +846,11 @@ public class LayoutEngine {
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;
@@ -808,7 +873,7 @@ public class LayoutEngine {
// its content. Consequently, remainingFreeSpace is 0 - sizeConsumedOnCurrentLine.
remainingFreeSpace = -sizeConsumedOnCurrentLine;
}
float originalRemainingFreeSpace = remainingFreeSpace;
float deltaFreeSpace = 0;
@@ -818,20 +883,20 @@ public class LayoutEngine {
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.
// 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;
@@ -841,7 +906,7 @@ public class LayoutEngine {
if (remainingFreeSpace < 0) {
flexShrinkScaledFactor = getFlexShrinkFactor(currentRelativeChild) * childFlexBasis;
// Is this child able to shrink?
if (flexShrinkScaledFactor != 0) {
baseMainSize = childFlexBasis +
@@ -872,14 +937,14 @@ public class LayoutEngine {
}
}
}
currentRelativeChild = currentRelativeChild.nextChild;
}
totalFlexShrinkScaledFactors += deltaFlexShrinkScaledFactors;
totalFlexGrowFactors += deltaFlexGrowFactors;
remainingFreeSpace += deltaFreeSpace;
// Second pass: resolve the sizes of the flexible items
deltaFreeSpace = 0;
currentRelativeChild = firstRelativeChild;
@@ -889,7 +954,7 @@ public class LayoutEngine {
if (remainingFreeSpace < 0) {
flexShrinkScaledFactor = getFlexShrinkFactor(currentRelativeChild) * childFlexBasis;
// Is this child able to shrink?
if (flexShrinkScaledFactor != 0) {
updatedMainSize = boundAxis(currentRelativeChild, mainAxis, childFlexBasis +
@@ -904,14 +969,20 @@ public class LayoutEngine {
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 (!(currentRelativeChild.style.dimensions[dim[CSS_FLEX_DIRECTION_COLUMN]] >= 0.0)) {
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 {
@@ -921,8 +992,14 @@ public class LayoutEngine {
} 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 (!(currentRelativeChild.style.dimensions[dim[CSS_FLEX_DIRECTION_ROW]] >= 0.0)) {
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 {
@@ -930,7 +1007,7 @@ public class LayoutEngine {
childWidthMeasureMode = CSSMeasureMode.EXACTLY;
}
}
boolean requiresStretchLayout = !(currentRelativeChild.style.dimensions[dim[crossAxis]] >= 0.0) &&
getAlignItem(node, currentRelativeChild) == CSSAlign.STRETCH;
@@ -940,7 +1017,7 @@ public class LayoutEngine {
currentRelativeChild = currentRelativeChild.nextChild;
}
}
remainingFreeSpace = originalRemainingFreeSpace + deltaFreeSpace;
// STEP 6: MAIN-AXIS JUSTIFICATION & CROSS-AXIS SIZE DETERMINATION
@@ -999,7 +1076,7 @@ public class LayoutEngine {
// 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.
@@ -1013,7 +1090,7 @@ public class LayoutEngine {
// 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])));
@@ -1023,12 +1100,12 @@ public class LayoutEngine {
}
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);
}
@@ -1065,14 +1142,14 @@ public class LayoutEngine {
// 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;
@@ -1080,7 +1157,7 @@ public class LayoutEngine {
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;
@@ -1207,7 +1284,7 @@ public class LayoutEngine {
boundAxisWithinMinAndMax(node, crossAxis, totalLineCrossDim + paddingAndBorderAxisCross)),
paddingAndBorderAxisCross);
}
// STEP 10: SETTING TRAILING POSITIONS FOR CHILDREN
if (performLayout) {
boolean needsMainTrailingPos = false;
@@ -1238,7 +1315,7 @@ public class LayoutEngine {
}
}
}
// STEP 11: SIZING AND POSITIONING ABSOLUTE CHILDREN
currentAbsoluteChild = firstAbsoluteChild;
while (currentAbsoluteChild != null) {
@@ -1260,7 +1337,7 @@ public class LayoutEngine {
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 {
@@ -1277,7 +1354,7 @@ public class LayoutEngine {
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
@@ -1300,9 +1377,9 @@ public class LayoutEngine {
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]] =
@@ -1310,7 +1387,7 @@ public class LayoutEngine {
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]] =