135 lines
4.9 KiB
C++
135 lines
4.9 KiB
C++
/**
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* Copyright (c) 2014-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include "YGNode.h"
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#include "Yoga-internal.h"
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// This struct is an helper model to hold the data for step 4 of flexbox
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// algo, which is collecting the flex items in a line.
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//
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// - itemsOnLine: Number of items which can fit in a line considering the
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// available Inner dimension, the flex items computed flexbasis and their
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// margin. It may be different than the difference between start and end
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// indicates because we skip over absolute-positioned items.
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//
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// - sizeConsumedOnCurrentLine: It is accumulation of the dimensions and margin
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// of all the children on the current line. This will be used in order to either
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// set the dimensions of the node if none already exist or to compute the
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// remaining space left for the flexible children.
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//
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// - totalFlexGrowFactors: total flex grow factors of flex items which are to be
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// layed in the current line
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//
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// - totalFlexShrinkFactors: total flex shrink factors of flex items which are
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// to be layed in the current line
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//
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// - endOfLineIndex: Its the end index of the last flex item which was examined
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// and it may or may not be part of the current line(as it may be absolutely
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// positioned or inculding it may have caused to overshoot availableInnerDim)
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//
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// - relativeChildren: Maintain a vector of the child nodes that can shrink
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// and/or grow.
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struct YGCollectFlexItemsRowValues {
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uint32_t itemsOnLine;
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float sizeConsumedOnCurrentLine;
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float totalFlexGrowFactors;
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float totalFlexShrinkScaledFactors;
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float endOfLineIndex;
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std::vector<YGNodeRef> relativeChildren;
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float remainingFreeSpace;
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// The size of the mainDim for the row after considering size, padding, margin
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// and border of flex items. This is used to calculate maxLineDim after going
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// through all the rows to decide on the main axis size of parent.
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float mainDim;
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// The size of the crossDim for the row after considering size, padding,
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// margin and border of flex items. Used for calculating containers crossSize.
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float crossDim;
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};
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bool YGValueEqual(const YGValue a, const YGValue b);
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// This custom float equality function returns true if either absolute
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// difference between two floats is less than 0.0001f or both are undefined.
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bool YGFloatsEqual(const float a, const float b);
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// We need custom max function, since we want that, if one argument is
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// YGUndefined then the max funtion should return the other argument as the max
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// value. We wouldn't have needed a custom max function if YGUndefined was NAN
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// as fmax has the same behaviour, but with NAN we cannot use `-ffast-math`
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// compiler flag.
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float YGFloatMax(const float a, const float b);
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// We need custom min function, since we want that, if one argument is
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// YGUndefined then the min funtion should return the other argument as the min
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// value. We wouldn't have needed a custom min function if YGUndefined was NAN
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// as fmin has the same behaviour, but with NAN we cannot use `-ffast-math`
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// compiler flag.
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float YGFloatMin(const float a, const float b);
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// This custom float comparision function compares the array of float with
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// YGFloatsEqual, as the default float comparision operator will not work(Look
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// at the comments of YGFloatsEqual function).
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template <std::size_t size>
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bool YGFloatArrayEqual(
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const std::array<float, size>& val1,
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const std::array<float, size>& val2) {
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bool areEqual = true;
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for (std::size_t i = 0; i < size && areEqual; ++i) {
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areEqual = YGFloatsEqual(val1[i], val2[i]);
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}
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return areEqual;
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}
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YGFlexDirection YGFlexDirectionCross(
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const YGFlexDirection flexDirection,
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const YGDirection direction);
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inline bool YGFlexDirectionIsRow(const YGFlexDirection flexDirection) {
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return flexDirection == YGFlexDirectionRow ||
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flexDirection == YGFlexDirectionRowReverse;
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}
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inline float YGResolveValue(const YGValue value, const float parentSize) {
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switch (value.unit) {
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case YGUnitUndefined:
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case YGUnitAuto:
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return YGUndefined;
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case YGUnitPoint:
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return value.value;
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case YGUnitPercent:
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return value.value * parentSize * 0.01;
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}
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return YGUndefined;
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}
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inline bool YGFlexDirectionIsColumn(const YGFlexDirection flexDirection) {
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return flexDirection == YGFlexDirectionColumn ||
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flexDirection == YGFlexDirectionColumnReverse;
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}
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inline YGFlexDirection YGResolveFlexDirection(
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const YGFlexDirection flexDirection,
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const YGDirection direction) {
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if (direction == YGDirectionRTL) {
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if (flexDirection == YGFlexDirectionRow) {
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return YGFlexDirectionRowReverse;
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} else if (flexDirection == YGFlexDirectionRowReverse) {
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return YGFlexDirectionRow;
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}
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}
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return flexDirection;
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}
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static inline float YGResolveValueMargin(
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const YGValue value,
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const float parentSize) {
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return value.unit == YGUnitAuto ? 0 : YGResolveValue(value, parentSize);
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}
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