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Baseline support
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Summary:
Added baseline support (see #132)

You have the ability for a custom baseline function (```float(*YGBaselineFunc)(YGNodeRef node);```) to return whatever baseline you want.
Closes facebook/yoga#317

Reviewed By: splhack

Differential Revision: D4385061

Pulled By: emilsjolander

fbshipit-source-id: cb8a59a09237c840fa3e21753ab68239997dab0c
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@woehrl01 @facebook-github-bot
woehrl01 authored and facebook-github-bot committed Jan 6, 2017
1 parent 8d30918 commit b55f22c
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Showing 3 changed files with 113 additions and 14 deletions.
3 changes: 2 additions & 1 deletion YGEnums.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -104,13 +104,14 @@ typedef enum YGExperimentalFeature {
YGExperimentalFeatureWebFlexBasis,
} YGExperimentalFeature;

#define YGAlignCount 5
#define YGAlignCount 6
typedef enum YGAlign {
YGAlignAuto,
YGAlignFlexStart,
YGAlignCenter,
YGAlignFlexEnd,
YGAlignStretch,
YGAlignBaseline,
} YGAlign;

#define YGUnitCount 3
Expand Down
122 changes: 109 additions & 13 deletions Yoga.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -102,6 +102,7 @@ typedef struct YGNode {
struct YGNode *nextChild;

YGMeasureFunc measure;
YGBaselineFunc baseline;
YGPrintFunc print;
void *context;

Expand Down Expand Up @@ -337,6 +338,14 @@ YGMeasureFunc YGNodeGetMeasureFunc(const YGNodeRef node) {
return node->measure;
}

void YGNodeSetBaselineFunc(const YGNodeRef node, YGBaselineFunc baselineFunc) {
node->baseline = baselineFunc;
}

YGBaselineFunc YGNodeGetBaselineFunc(const YGNodeRef node) {
return node->baseline;
}

void YGNodeInsertChild(const YGNodeRef node, const YGNodeRef child, const uint32_t index) {
YG_ASSERT(child->parent == NULL, "Child already has a parent, it must be removed first.");
YG_ASSERT(node->measure == NULL,
Expand Down Expand Up @@ -893,8 +902,8 @@ static float YGNodeLeadingPadding(const YGNodeRef node,
}

return fmaxf(YGValueResolve(YGComputedEdgeValue(node->style.padding, leading[axis], &YGValueZero),
widthSize),
0.0f);
widthSize),
0.0f);
}

static float YGNodeTrailingPadding(const YGNodeRef node,
Expand All @@ -906,8 +915,8 @@ static float YGNodeTrailingPadding(const YGNodeRef node,
}

return fmaxf(YGValueResolve(YGComputedEdgeValue(node->style.padding, trailing[axis], &YGValueZero),
widthSize),
0.0f);
widthSize),
0.0f);
}

static float YGNodeLeadingBorder(const YGNodeRef node, const YGFlexDirection axis) {
Expand Down Expand Up @@ -954,7 +963,12 @@ static inline float YGNodePaddingAndBorderForAxis(const YGNodeRef node,
}

static inline YGAlign YGNodeAlignItem(const YGNodeRef node, const YGNodeRef child) {
return child->style.alignSelf == YGAlignAuto ? node->style.alignItems : child->style.alignSelf;
const YGAlign align =
child->style.alignSelf == YGAlignAuto ? node->style.alignItems : child->style.alignSelf;
if (align == YGAlignBaseline && YGFlexDirectionIsColumn(node->style.flexDirection)) {
return YGAlignFlexStart;
}
return align;
}

static inline YGDirection YGNodeResolveDirection(const YGNodeRef node,
Expand All @@ -966,6 +980,40 @@ static inline YGDirection YGNodeResolveDirection(const YGNodeRef node,
}
}

static float YGBaseline(const YGNodeRef node) {
if (node->baseline != NULL) {
const float baseline = node->baseline(node, node->layout.measuredDimensions[YGDimensionWidth], node->layout.measuredDimensions[YGDimensionHeight]);
YG_ASSERT(!YGFloatIsUndefined(baseline), "Expect custom baseline function to not return NaN")
return baseline;
}

YGNodeRef baselineChild = NULL;
for (uint32_t i = 0; i < YGNodeGetChildCount(node); i++) {
const YGNodeRef child = YGNodeGetChild(node, i);
if (child->lineIndex > 0) {
break;
}
if (child->style.positionType == YGPositionTypeAbsolute) {
continue;
}
if (YGNodeAlignItem(node, child) == YGAlignBaseline) {
baselineChild = child;
break;
}

if (baselineChild == NULL) {
baselineChild = child;
}
}

if (baselineChild == NULL) {
return node->layout.measuredDimensions[YGDimensionHeight];
}

const float baseline = YGBaseline(baselineChild);
return baseline + baselineChild->layout.position[YGEdgeTop];
}

static inline YGFlexDirection YGFlexDirectionResolve(const YGFlexDirection flexDirection,
const YGDirection direction) {
if (direction == YGDirectionRTL) {
Expand All @@ -991,6 +1039,24 @@ static inline bool YGNodeIsFlex(const YGNodeRef node) {
(YGNodeStyleGetFlexGrow(node) != 0 || YGNodeStyleGetFlexShrink(node) != 0));
}

static bool YGIsBaselineLayout(const YGNodeRef node) {
if (YGFlexDirectionIsColumn(node->style.flexDirection)) {
return false;
}
if (node->style.alignItems == YGAlignBaseline) {
return true;
}
for (uint32_t i = 0; i < YGNodeGetChildCount(node); i++) {
const YGNodeRef child = YGNodeGetChild(node, i);
if (child->style.positionType == YGPositionTypeRelative &&
child->style.alignSelf == YGAlignBaseline) {
return true;
}
}

return false;
}

static inline float YGNodeDimWithMargin(const YGNodeRef node,
const YGFlexDirection axis,
const float widthSize) {
Expand Down Expand Up @@ -1583,8 +1649,6 @@ static bool YGNodeFixedSizeSetMeasuredDimensions(const YGNodeRef node,
// * Margins cannot be specified as 'auto'. They must be specified in terms of
// pixel
// values, and the default value is 0.
// * The 'baseline' value is not supported for alignItems and alignSelf
// properties.
// * Values of width, maxWidth, minWidth, height, maxHeight and minHeight must
// be
// specified as pixel values, not as percentages.
Expand Down Expand Up @@ -1680,10 +1744,22 @@ static void YGNodelayoutImpl(const YGNodeRef node,
const YGDirection direction = YGNodeResolveDirection(node, parentDirection);
node->layout.direction = direction;

node->layout.padding[YGEdgeStart] = YGNodeLeadingPadding(node, YGFlexDirectionResolve(YGFlexDirectionRow, direction), parentWidth);
node->layout.padding[YGEdgeEnd] = YGNodeTrailingPadding(node, YGFlexDirectionResolve(YGFlexDirectionRow, direction), parentWidth);
node->layout.padding[YGEdgeTop] = YGNodeLeadingPadding(node, YGFlexDirectionResolve(YGFlexDirectionColumn, direction), parentWidth);
node->layout.padding[YGEdgeBottom] = YGNodeTrailingPadding(node, YGFlexDirectionResolve(YGFlexDirectionColumn, direction), parentWidth);
node->layout.padding[YGEdgeStart] =
YGNodeLeadingPadding(node,
YGFlexDirectionResolve(YGFlexDirectionRow, direction),
parentWidth);
node->layout.padding[YGEdgeEnd] =
YGNodeTrailingPadding(node,
YGFlexDirectionResolve(YGFlexDirectionRow, direction),
parentWidth);
node->layout.padding[YGEdgeTop] =
YGNodeLeadingPadding(node,
YGFlexDirectionResolve(YGFlexDirectionColumn, direction),
parentWidth);
node->layout.padding[YGEdgeBottom] =
YGNodeTrailingPadding(node,
YGFlexDirectionResolve(YGFlexDirectionColumn, direction),
parentWidth);

if (node->measure) {
YGNodeWithMeasureFuncSetMeasuredDimensions(
Expand Down Expand Up @@ -2452,7 +2528,8 @@ static void YGNodelayoutImpl(const YGNodeRef node,
}

// STEP 8: MULTI-LINE CONTENT ALIGNMENT
if (lineCount > 1 && performLayout && !YGFloatIsUndefined(availableInnerCrossDim)) {
if (performLayout && (lineCount > 1 || YGIsBaselineLayout(node)) &&
!YGFloatIsUndefined(availableInnerCrossDim)) {
const float remainingAlignContentDim = availableInnerCrossDim - totalLineCrossDim;

float crossDimLead = 0;
Expand All @@ -2472,6 +2549,7 @@ static void YGNodelayoutImpl(const YGNodeRef node,
break;
case YGAlignAuto:
case YGAlignFlexStart:
case YGAlignBaseline:
break;
}

Expand All @@ -2482,19 +2560,31 @@ static void YGNodelayoutImpl(const YGNodeRef node,

// compute the line's height and find the endIndex
float lineHeight = 0;
float maxAscentForCurrentLine = 0;
float maxDescentForCurrentLine = 0;
for (ii = startIndex; ii < childCount; ii++) {
const YGNodeRef child = YGNodeListGet(node->children, ii);

if (child->style.positionType == YGPositionTypeRelative) {
if (child->lineIndex != i) {
break;
}

if (YGNodeIsLayoutDimDefined(child, crossAxis)) {
lineHeight = fmaxf(lineHeight,
child->layout.measuredDimensions[dim[crossAxis]] +
YGNodeMarginForAxis(child, crossAxis, availableInnerWidth));
}
if (YGNodeAlignItem(node, child) == YGAlignBaseline) {
const float ascent =
YGBaseline(child) +
YGNodeLeadingMargin(child, YGFlexDirectionColumn, availableInnerWidth);
const float descent =
child->layout.measuredDimensions[YGDimensionHeight] +
YGNodeMarginForAxis(child, YGFlexDirectionColumn, availableInnerWidth) - ascent;
maxAscentForCurrentLine = fmaxf(maxAscentForCurrentLine, ascent);
maxDescentForCurrentLine = fmaxf(maxDescentForCurrentLine, descent);
lineHeight = fmaxf(lineHeight, maxAscentForCurrentLine + maxDescentForCurrentLine);
}
}
}
endIndex = ii;
Expand Down Expand Up @@ -2531,6 +2621,12 @@ static void YGNodelayoutImpl(const YGNodeRef node,
// (auto) crossAxis dimension.
break;
}
case YGAlignBaseline: {
child->layout.position[YGEdgeTop] =
currentLead + maxAscentForCurrentLine - YGBaseline(child) +
YGNodeLeadingPosition(child, YGFlexDirectionColumn, availableInnerCrossDim);
break;
}
case YGAlignAuto:
break;
}
Expand Down
2 changes: 2 additions & 0 deletions Yoga.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@ typedef YGSize (*YGMeasureFunc)(YGNodeRef node,
YGMeasureMode widthMode,
float height,
YGMeasureMode heightMode);
typedef float (*YGBaselineFunc)(YGNodeRef node, const float width, const float height);
typedef void (*YGPrintFunc)(YGNodeRef node);
typedef int (*YGLogger)(YGLogLevel level, const char *format, va_list args);

Expand Down Expand Up @@ -138,6 +139,7 @@ WIN_EXPORT void YGNodeCopyStyle(const YGNodeRef dstNode, const YGNodeRef srcNode

YG_NODE_PROPERTY(void *, Context, context);
YG_NODE_PROPERTY(YGMeasureFunc, MeasureFunc, measureFunc);
YG_NODE_PROPERTY(YGBaselineFunc, BaselineFunc, baselineFunc)
YG_NODE_PROPERTY(YGPrintFunc, PrintFunc, printFunc);
YG_NODE_PROPERTY(bool, HasNewLayout, hasNewLayout);

Expand Down

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