Source/WebCore/layout/FormattingContext.cpp

   1 /*
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   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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  24  */
  25
  26 #include "config.h"
  27 #include "FormattingContext.h"
  28
  29 #if ENABLE(LAYOUT_FORMATTING_CONTEXT)
  30
  31 #include "DisplayBox.h"
  32 #include "LayoutBox.h"
  33 #include "LayoutContainer.h"
  34 #include "LayoutContext.h"
  35 #include "LayoutDescendantIterator.h"
  36 #include "Logging.h"
  37 #include <wtf/IsoMallocInlines.h>
  38 #include <wtf/text/TextStream.h>
  39
  40 namespace WebCore {
  41 namespace Layout {
  42
  43 WTF_MAKE_ISO_ALLOCATED_IMPL(FormattingContext);
  44
  45 FormattingContext::FormattingContext(const Box& formattingContextRoot)
  46     : m_root(makeWeakPtr(formattingContextRoot))
  47 {
  48 }
  49
  50 FormattingContext::~FormattingContext()
  51 {
  52 }
  53
  54 void FormattingContext::computeOutOfFlowHorizontalGeometry(LayoutContext& layoutContext, const Box& layoutBox) const
  55 {
  56     auto compute = [&](std::optional<LayoutUnit> precomputedWidth) {
  57         return Geometry::outOfFlowHorizontalGeometry(layoutContext, *this, layoutBox, precomputedWidth);
  58     };
  59
  60     auto horizontalGeometry = compute({ });
  61     auto containingBlockWidth = layoutContext.displayBoxForLayoutBox(*layoutBox.containingBlock()).contentBoxWidth();
  62
  63     if (auto maxWidth = Geometry::computedValueIfNotAuto(layoutBox.style().logicalMaxWidth(), containingBlockWidth)) {
  64         auto maxHorizontalGeometry = compute(maxWidth);
  65         if (horizontalGeometry.widthAndMargin.width > maxHorizontalGeometry.widthAndMargin.width)
  66             horizontalGeometry = maxHorizontalGeometry;
  67     }
  68
  69     if (auto minWidth = Geometry::computedValueIfNotAuto(layoutBox.style().logicalMinWidth(), containingBlockWidth)) {
  70         auto minHorizontalGeometry = compute(minWidth);
  71         if (horizontalGeometry.widthAndMargin.width < minHorizontalGeometry.widthAndMargin.width)
  72             horizontalGeometry = minHorizontalGeometry;
  73     }
  74
  75     auto& displayBox = layoutContext.displayBoxForLayoutBox(layoutBox);
  76     displayBox.setLeft(horizontalGeometry.left + horizontalGeometry.widthAndMargin.margin.left);
  77     displayBox.setContentBoxWidth(horizontalGeometry.widthAndMargin.width);
  78     displayBox.setHorizontalMargin(horizontalGeometry.widthAndMargin.margin);
  79     displayBox.setHorizontalNonComputedMargin(horizontalGeometry.widthAndMargin.nonComputedMargin);
  80 }
  81
  82 void FormattingContext::computeOutOfFlowVerticalGeometry(const LayoutContext& layoutContext, const Box& layoutBox) const
  83 {
  84     auto compute = [&](std::optional<LayoutUnit> precomputedHeight) {
  85         return Geometry::outOfFlowVerticalGeometry(layoutContext, layoutBox, precomputedHeight);
  86     };
  87
  88     auto verticalGeometry = compute({ });
  89     if (auto maxHeight = Geometry::computedMaxHeight(layoutContext, layoutBox)) {
  90         auto maxVerticalGeometry = compute(maxHeight);
  91         if (verticalGeometry.heightAndMargin.height > maxVerticalGeometry.heightAndMargin.height)
  92             verticalGeometry = maxVerticalGeometry;
  93     }
  94
  95     if (auto minHeight = Geometry::computedMinHeight(layoutContext, layoutBox)) {
  96         auto minVerticalGeometry = compute(minHeight);
  97         if (verticalGeometry.heightAndMargin.height < minVerticalGeometry.heightAndMargin.height)
  98             verticalGeometry = minVerticalGeometry;
  99     }
 100
 101     auto& displayBox = layoutContext.displayBoxForLayoutBox(layoutBox);
 102     displayBox.setTop(verticalGeometry.top + verticalGeometry.heightAndMargin.margin.top);
 103     displayBox.setContentBoxHeight(verticalGeometry.heightAndMargin.height);
 104     ASSERT(!verticalGeometry.heightAndMargin.collapsedMargin);
 105     displayBox.setVerticalMargin(verticalGeometry.heightAndMargin.margin);
 106     displayBox.setVerticalNonCollapsedMargin(verticalGeometry.heightAndMargin.margin);
 107 }
 108
 109 void FormattingContext::computeBorderAndPadding(const LayoutContext& layoutContext, const Box& layoutBox) const
 110 {
 111     auto& displayBox = layoutContext.displayBoxForLayoutBox(layoutBox);
 112     displayBox.setBorder(Geometry::computedBorder(layoutContext, layoutBox));
 113     displayBox.setPadding(Geometry::computedPadding(layoutContext, layoutBox));
 114 }
 115
 116 void FormattingContext::placeInFlowPositionedChildren(const LayoutContext& layoutContext, const Container& container) const
 117 {
 118     // If this container also establishes a formatting context, then positioning already has happend in that the formatting context.
 119     if (container.establishesFormattingContext() && &container != &root())
 120         return;
 121
 122     LOG_WITH_STREAM(FormattingContextLayout, stream << "Start: move in-flow positioned children -> context: " << &layoutContext << " parent: " << &container);
 123     for (auto& layoutBox : childrenOfType<Box>(container)) {
 124         if (!layoutBox.isInFlowPositioned())
 125             continue;
 126         computeInFlowPositionedPosition(layoutContext, layoutBox);
 127     }
 128     LOG_WITH_STREAM(FormattingContextLayout, stream << "End: move in-flow positioned children -> context: " << &layoutContext << " parent: " << &container);
 129 }
 130
 131 void FormattingContext::layoutOutOfFlowDescendants(LayoutContext& layoutContext, const Box& layoutBox) const
 132 {
 133     // Initial containing block by definition is a containing block.
 134     if (!layoutBox.isPositioned() && !layoutBox.isInitialContainingBlock())
 135         return;
 136
 137     if (!is<Container>(layoutBox))
 138         return;
 139
 140     auto& container = downcast<Container>(layoutBox);
 141     if (!container.hasChild())
 142         return;
 143
 144     LOG_WITH_STREAM(FormattingContextLayout, stream << "Start: layout out-of-flow descendants -> context: " << &layoutContext << " root: " << &root());
 145
 146     for (auto& outOfFlowBox : container.outOfFlowDescendants()) {
 147         auto& layoutBox = *outOfFlowBox;
 148
 149         ASSERT(layoutBox.establishesFormattingContext());
 150         auto formattingContext = layoutContext.formattingContext(layoutBox);
 151
 152         computeBorderAndPadding(layoutContext, layoutBox);
 153         computeOutOfFlowHorizontalGeometry(layoutContext, layoutBox);
 154
 155         auto& formattingState = layoutContext.createFormattingStateForFormattingRootIfNeeded(layoutBox);
 156         formattingContext->layout(layoutContext, formattingState);
 157
 158         computeOutOfFlowVerticalGeometry(layoutContext, layoutBox);
 159         layoutOutOfFlowDescendants(layoutContext, layoutBox);
 160     }
 161     LOG_WITH_STREAM(FormattingContextLayout, stream << "End: layout out-of-flow descendants -> context: " << &layoutContext << " root: " << &root());
 162 }
 163
 164 Display::Box FormattingContext::mapBoxToAncestor(const LayoutContext& layoutContext, const Box& layoutBox, const Container& ancestor)
 165 {
 166     ASSERT(layoutBox.isDescendantOf(ancestor));
 167
 168     auto& displayBox = layoutContext.displayBoxForLayoutBox(layoutBox);
 169     auto topLeft = displayBox.topLeft();
 170
 171     auto* containingBlock = layoutBox.containingBlock();
 172     for (; containingBlock && containingBlock != &ancestor; containingBlock = containingBlock->containingBlock())
 173         topLeft.moveBy(layoutContext.displayBoxForLayoutBox(*containingBlock).topLeft());
 174
 175     if (!containingBlock) {
 176         ASSERT_NOT_REACHED();
 177         return Display::Box(displayBox);
 178     }
 179
 180     auto mappedDisplayBox = Display::Box(displayBox);
 181     mappedDisplayBox.setTopLeft(topLeft);
 182     return mappedDisplayBox;
 183 }
 184
 185 Position FormattingContext::mapTopLeftToAncestor(const LayoutContext& layoutContext, const Box& layoutBox, const Container& ancestor)
 186 {
 187     ASSERT(layoutBox.isDescendantOf(ancestor));
 188     return mapCoordinateToAncestor(layoutContext, layoutContext.displayBoxForLayoutBox(layoutBox).topLeft(), *layoutBox.containingBlock(), ancestor);
 189 }
 190
 191 Position FormattingContext::mapCoordinateToAncestor(const LayoutContext& layoutContext, Position position, const Container& containingBlock, const Container& ancestor)
 192 {
 193     auto mappedPosition = position;
 194     auto* container = &containingBlock;
 195     for (; container && container != &ancestor; container = container->containingBlock())
 196         mappedPosition.moveBy(layoutContext.displayBoxForLayoutBox(*container).topLeft());
 197
 198     if (!container) {
 199         ASSERT_NOT_REACHED();
 200         return position;
 201     }
 202
 203     return mappedPosition;
 204 }
 205
 206 #ifndef NDEBUG
 207 void FormattingContext::validateGeometryConstraintsAfterLayout(const LayoutContext& layoutContext) const
 208 {
 209     if (!is<Container>(root()))
 210         return;
 211     auto& formattingContextRoot = downcast<Container>(root());
 212     // FIXME: add a descendantsOfType<> flavor that stops at nested formatting contexts
 213     for (auto& layoutBox : descendantsOfType<Box>(formattingContextRoot)) {
 214         if (&layoutBox.formattingContextRoot() != &formattingContextRoot)
 215             continue;
 216         auto& containingBlockDisplayBox = layoutContext.displayBoxForLayoutBox(*layoutBox.containingBlock());
 217         auto& displayBox = layoutContext.displayBoxForLayoutBox(layoutBox);
 218
 219         // 10.3.3 Block-level, non-replaced elements in normal flow
 220         // 10.3.7 Absolutely positioned, non-replaced elements
 221         if ((layoutBox.isBlockLevelBox() || layoutBox.isOutOfFlowPositioned()) && !layoutBox.replaced()) {
 222             // margin-left + border-left-width + padding-left + width + padding-right + border-right-width + margin-right = width of containing block
 223             auto containingBlockWidth = containingBlockDisplayBox.contentBoxWidth();
 224             ASSERT(displayBox.marginLeft() + displayBox.borderLeft() + displayBox.paddingLeft().value_or(0) + displayBox.contentBoxWidth()
 225                 + displayBox.paddingRight().value_or(0) + displayBox.borderRight() + displayBox.marginRight() == containingBlockWidth);
 226         }
 227
 228         // 10.6.4 Absolutely positioned, non-replaced elements
 229         if (layoutBox.isOutOfFlowPositioned() && !layoutBox.replaced()) {
 230             // top + margin-top + border-top-width + padding-top + height + padding-bottom + border-bottom-width + margin-bottom + bottom = height of containing block
 231             auto containingBlockHeight = containingBlockDisplayBox.contentBoxHeight();
 232             ASSERT(displayBox.top() + displayBox.marginTop() + displayBox.borderTop() + displayBox.paddingTop().value_or(0) + displayBox.contentBoxHeight()
 233                 + displayBox.paddingBottom().value_or(0) + displayBox.borderBottom() + displayBox.marginBottom() == containingBlockHeight);
 234         }
 235     }
 236 }
 237 #endif
 238
 239 }
 240 }
 241 #endif