| /* |
| * Copyright (C) 2018 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS |
| * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
| * THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| #include "BlockFormattingContext.h" |
| |
| #if ENABLE(LAYOUT_FORMATTING_CONTEXT) |
| |
| #include "FormattingContext.h" |
| #include "InlineFormattingState.h" |
| #include "LayoutChildIterator.h" |
| #include "Logging.h" |
| #include <wtf/text/TextStream.h> |
| |
| namespace WebCore { |
| namespace Layout { |
| |
| ContentHeightAndMargin BlockFormattingContext::Geometry::inFlowNonReplacedHeightAndMargin(const Box& layoutBox, UsedHorizontalValues usedHorizontalValues, UsedVerticalValues usedValues) |
| { |
| ASSERT(layoutBox.isInFlow() && !layoutBox.replaced()); |
| ASSERT(layoutBox.isOverflowVisible()); |
| |
| auto compute = [&]() -> ContentHeightAndMargin { |
| |
| // 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' |
| // |
| // If 'margin-top', or 'margin-bottom' are 'auto', their used value is 0. |
| // If 'height' is 'auto', the height depends on whether the element has any block-level children and whether it has padding or borders: |
| // The element's height is the distance from its top content edge to the first applicable of the following: |
| // 1. the bottom edge of the last line box, if the box establishes a inline formatting context with one or more lines |
| // 2. the bottom edge of the bottom (possibly collapsed) margin of its last in-flow child, if the child's bottom margin |
| // does not collapse with the element's bottom margin |
| // 3. the bottom border edge of the last in-flow child whose top margin doesn't collapse with the element's bottom margin |
| // 4. zero, otherwise |
| // Only children in the normal flow are taken into account (i.e., floating boxes and absolutely positioned boxes are ignored, |
| // and relatively positioned boxes are considered without their offset). Note that the child box may be an anonymous block box. |
| |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| auto computedVerticalMargin = Geometry::computedVerticalMargin(layoutBox, usedHorizontalValues); |
| auto nonCollapsedMargin = UsedVerticalMargin::NonCollapsedValues { computedVerticalMargin.before.valueOr(0), computedVerticalMargin.after.valueOr(0) }; |
| auto borderAndPaddingTop = boxGeometry.borderTop() + boxGeometry.paddingTop().valueOr(0); |
| auto height = usedValues.height ? usedValues.height.value() : computedContentHeight(layoutBox); |
| |
| if (height) |
| return { *height, nonCollapsedMargin }; |
| |
| if (!is<Container>(layoutBox) || !downcast<Container>(layoutBox).hasInFlowChild()) |
| return { 0, nonCollapsedMargin }; |
| |
| // 1. the bottom edge of the last line box, if the box establishes a inline formatting context with one or more lines |
| auto& layoutContainer = downcast<Container>(layoutBox); |
| if (layoutContainer.establishesInlineFormattingContext()) { |
| auto& lineBoxes = downcast<InlineFormattingState>(layoutState().establishedFormattingState(layoutContainer)).lineBoxes(); |
| // Even empty containers generate one line. |
| ASSERT(!lineBoxes.isEmpty()); |
| return { lineBoxes.last().logicalBottom() - borderAndPaddingTop, nonCollapsedMargin }; |
| } |
| |
| // 2. the bottom edge of the bottom (possibly collapsed) margin of its last in-flow child, if the child's bottom margin... |
| auto* lastInFlowChild = layoutContainer.lastInFlowChild(); |
| ASSERT(lastInFlowChild); |
| if (!formattingContext().marginCollapse().marginAfterCollapsesWithParentMarginAfter(*lastInFlowChild)) { |
| auto& lastInFlowBoxGeometry = formattingContext().geometryForBox(*lastInFlowChild); |
| auto bottomEdgeOfBottomMargin = lastInFlowBoxGeometry.bottom() + (lastInFlowBoxGeometry.hasCollapsedThroughMargin() ? LayoutUnit() : lastInFlowBoxGeometry.marginAfter()); |
| return { bottomEdgeOfBottomMargin - borderAndPaddingTop, nonCollapsedMargin }; |
| } |
| |
| // 3. the bottom border edge of the last in-flow child whose top margin doesn't collapse with the element's bottom margin |
| auto* inFlowChild = lastInFlowChild; |
| while (inFlowChild && formattingContext().marginCollapse().marginBeforeCollapsesWithParentMarginAfter(*inFlowChild)) |
| inFlowChild = inFlowChild->previousInFlowSibling(); |
| if (inFlowChild) { |
| auto& inFlowDisplayBoxGeometry = formattingContext().geometryForBox(*inFlowChild); |
| return { inFlowDisplayBoxGeometry.top() + inFlowDisplayBoxGeometry.borderBox().height() - borderAndPaddingTop, nonCollapsedMargin }; |
| } |
| |
| // 4. zero, otherwise |
| return { 0, nonCollapsedMargin }; |
| }; |
| |
| auto contentHeightAndMargin = compute(); |
| LOG_WITH_STREAM(FormattingContextLayout, stream << "[Height][Margin] -> inflow non-replaced -> height(" << contentHeightAndMargin.contentHeight << "px) margin(" << contentHeightAndMargin.nonCollapsedMargin.before << "px, " << contentHeightAndMargin.nonCollapsedMargin.after << "px) -> layoutBox(" << &layoutBox << ")"); |
| return contentHeightAndMargin; |
| } |
| |
| ContentWidthAndMargin BlockFormattingContext::Geometry::inFlowNonReplacedWidthAndMargin(const Box& layoutBox, UsedHorizontalValues usedHorizontalValues) const |
| { |
| ASSERT(layoutBox.isInFlow()); |
| |
| auto compute = [&]() { |
| |
| // 10.3.3 Block-level, non-replaced elements in normal flow |
| // |
| // The following constraints must hold among the used values of the other properties: |
| // 'margin-left' + 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' + 'margin-right' = width of containing block |
| // |
| // 1. If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' |
| // (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then |
| // any 'auto' values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero. |
| // |
| // 2. If all of the above have a computed value other than 'auto', the values are said to be "over-constrained" and one of the used values will |
| // have to be different from its computed value. If the 'direction' property of the containing block has the value 'ltr', the specified value |
| // of 'margin-right' is ignored and the value is calculated so as to make the equality true. If the value of 'direction' is 'rtl', |
| // this happens to 'margin-left' instead. |
| // |
| // 3. If there is exactly one value specified as 'auto', its used value follows from the equality. |
| // |
| // 4. If 'width' is set to 'auto', any other 'auto' values become '0' and 'width' follows from the resulting equality. |
| // |
| // 5. If both 'margin-left' and 'margin-right' are 'auto', their used values are equal. This horizontally centers the element with respect to the |
| // edges of the containing block. |
| |
| auto containingBlockWidth = usedHorizontalValues.constraints.width; |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| |
| auto width = usedHorizontalValues.width ? usedHorizontalValues.width : computedContentWidth(layoutBox, containingBlockWidth); |
| auto computedHorizontalMargin = Geometry::computedHorizontalMargin(layoutBox, usedHorizontalValues); |
| UsedHorizontalMargin usedHorizontalMargin; |
| auto borderLeft = boxGeometry.borderLeft(); |
| auto borderRight = boxGeometry.borderRight(); |
| auto paddingLeft = boxGeometry.paddingLeft().valueOr(0); |
| auto paddingRight = boxGeometry.paddingRight().valueOr(0); |
| |
| // #1 |
| if (width) { |
| auto horizontalSpaceForMargin = containingBlockWidth - (computedHorizontalMargin.start.valueOr(0) + borderLeft + paddingLeft + *width + paddingRight + borderRight + computedHorizontalMargin.end.valueOr(0)); |
| if (horizontalSpaceForMargin < 0) |
| usedHorizontalMargin = { computedHorizontalMargin.start.valueOr(0), computedHorizontalMargin.end.valueOr(0) }; |
| } |
| |
| // #2 |
| if (width && computedHorizontalMargin.start && computedHorizontalMargin.end) { |
| if (layoutBox.containingBlock()->style().isLeftToRightDirection()) { |
| usedHorizontalMargin.start = *computedHorizontalMargin.start; |
| usedHorizontalMargin.end = containingBlockWidth - (usedHorizontalMargin.start + borderLeft + paddingLeft + *width + paddingRight + borderRight); |
| } else { |
| usedHorizontalMargin.end = *computedHorizontalMargin.end; |
| usedHorizontalMargin.start = containingBlockWidth - (borderLeft + paddingLeft + *width + paddingRight + borderRight + usedHorizontalMargin.end); |
| } |
| } |
| |
| // #3 |
| if (!computedHorizontalMargin.start && width && computedHorizontalMargin.end) { |
| usedHorizontalMargin.end = *computedHorizontalMargin.end; |
| usedHorizontalMargin.start = containingBlockWidth - (borderLeft + paddingLeft + *width + paddingRight + borderRight + usedHorizontalMargin.end); |
| } else if (computedHorizontalMargin.start && !width && computedHorizontalMargin.end) { |
| usedHorizontalMargin = { *computedHorizontalMargin.start, *computedHorizontalMargin.end }; |
| width = containingBlockWidth - (usedHorizontalMargin.start + borderLeft + paddingLeft + paddingRight + borderRight + usedHorizontalMargin.end); |
| } else if (computedHorizontalMargin.start && width && !computedHorizontalMargin.end) { |
| usedHorizontalMargin.start = *computedHorizontalMargin.start; |
| usedHorizontalMargin.end = containingBlockWidth - (usedHorizontalMargin.start + borderLeft + paddingLeft + *width + paddingRight + borderRight); |
| } |
| |
| // #4 |
| if (!width) { |
| usedHorizontalMargin = { computedHorizontalMargin.start.valueOr(0), computedHorizontalMargin.end.valueOr(0) }; |
| width = containingBlockWidth - (usedHorizontalMargin.start + borderLeft + paddingLeft + paddingRight + borderRight + usedHorizontalMargin.end); |
| } |
| |
| // #5 |
| if (!computedHorizontalMargin.start && !computedHorizontalMargin.end) { |
| auto horizontalSpaceForMargin = containingBlockWidth - (borderLeft + paddingLeft + *width + paddingRight + borderRight); |
| usedHorizontalMargin = { horizontalSpaceForMargin / 2, horizontalSpaceForMargin / 2 }; |
| } |
| |
| ASSERT(width); |
| |
| return ContentWidthAndMargin { *width, usedHorizontalMargin, computedHorizontalMargin }; |
| }; |
| |
| auto contentWidthAndMargin = compute(); |
| LOG_WITH_STREAM(FormattingContextLayout, stream << "[Width][Margin] -> inflow non-replaced -> width(" << contentWidthAndMargin.contentWidth << "px) margin(" << contentWidthAndMargin.usedMargin.start << "px, " << contentWidthAndMargin.usedMargin.end << "px) -> layoutBox(" << &layoutBox << ")"); |
| return contentWidthAndMargin; |
| } |
| |
| ContentWidthAndMargin BlockFormattingContext::Geometry::inFlowReplacedWidthAndMargin(const Box& layoutBox, UsedHorizontalValues usedValues) const |
| { |
| ASSERT(layoutBox.isInFlow() && layoutBox.replaced()); |
| |
| // 10.3.4 Block-level, replaced elements in normal flow |
| // |
| // 1. The used value of 'width' is determined as for inline replaced elements. |
| // 2. Then the rules for non-replaced block-level elements are applied to determine the margins. |
| |
| // #1 |
| usedValues.width = inlineReplacedWidthAndMargin(layoutBox, usedValues).contentWidth; |
| // #2 |
| auto nonReplacedWidthAndMargin = inFlowNonReplacedWidthAndMargin(layoutBox, usedValues); |
| |
| LOG_WITH_STREAM(FormattingContextLayout, stream << "[Width][Margin] -> inflow replaced -> width(" << *usedValues.width << "px) margin(" << nonReplacedWidthAndMargin.usedMargin.start << "px, " << nonReplacedWidthAndMargin.usedMargin.end << "px) -> layoutBox(" << &layoutBox << ")"); |
| return { *usedValues.width, nonReplacedWidthAndMargin.usedMargin, nonReplacedWidthAndMargin.computedMargin }; |
| } |
| |
| LayoutUnit BlockFormattingContext::Geometry::staticVerticalPosition(const Box& layoutBox, UsedVerticalValues usedVerticalValues) const |
| { |
| // https://www.w3.org/TR/CSS22/visuren.html#block-formatting |
| // In a block formatting context, boxes are laid out one after the other, vertically, beginning at the top of a containing block. |
| // The vertical distance between two sibling boxes is determined by the 'margin' properties. |
| // Vertical margins between adjacent block-level boxes in a block formatting context collapse. |
| if (auto* previousInFlowSibling = layoutBox.previousInFlowSibling()) { |
| auto& previousInFlowBoxGeometry = formattingContext().geometryForBox(*previousInFlowSibling); |
| return previousInFlowBoxGeometry.bottom() + previousInFlowBoxGeometry.marginAfter(); |
| } |
| return usedVerticalValues.constraints.contentBoxTop; |
| } |
| |
| LayoutUnit BlockFormattingContext::Geometry::staticHorizontalPosition(const Box& layoutBox, UsedHorizontalValues usedHorizontalValues) const |
| { |
| // https://www.w3.org/TR/CSS22/visuren.html#block-formatting |
| // In a block formatting context, each box's left outer edge touches the left edge of the containing block (for right-to-left formatting, right edges touch). |
| return usedHorizontalValues.constraints.contentBoxLeft + formattingContext().geometryForBox(layoutBox).marginStart(); |
| } |
| |
| Point BlockFormattingContext::Geometry::staticPosition(const Box& layoutBox, UsedHorizontalValues usedHorizontalValues, UsedVerticalValues usedVerticalValues) const |
| { |
| return { staticHorizontalPosition(layoutBox, usedHorizontalValues), staticVerticalPosition(layoutBox, usedVerticalValues) }; |
| } |
| |
| ContentHeightAndMargin BlockFormattingContext::Geometry::inFlowHeightAndMargin(const Box& layoutBox, UsedHorizontalValues usedHorizontalValues, UsedVerticalValues usedVerticalValues) |
| { |
| ASSERT(layoutBox.isInFlow()); |
| |
| // 10.6.2 Inline replaced elements, block-level replaced elements in normal flow, 'inline-block' |
| // replaced elements in normal flow and floating replaced elements |
| if (layoutBox.replaced()) |
| return inlineReplacedHeightAndMargin(layoutBox, usedHorizontalValues, usedVerticalValues); |
| |
| ContentHeightAndMargin contentHeightAndMargin; |
| // FIXME: Let's special case the table height computation for now -> figure out whether tables fall into the "inFlowNonReplacedHeightAndMargin" category. |
| if (layoutBox.establishesTableFormattingContext()) |
| contentHeightAndMargin = complicatedCases(layoutBox, usedHorizontalValues, usedVerticalValues); |
| else if (layoutBox.isOverflowVisible() && !layoutBox.isDocumentBox()) { |
| // TODO: Figure out the case for the document element. Let's just complicated-case it for now. |
| contentHeightAndMargin = inFlowNonReplacedHeightAndMargin(layoutBox, usedHorizontalValues, usedVerticalValues); |
| } else { |
| // 10.6.6 Complicated cases |
| // Block-level, non-replaced elements in normal flow when 'overflow' does not compute to 'visible' (except if the 'overflow' property's value has been propagated to the viewport). |
| contentHeightAndMargin = complicatedCases(layoutBox, usedHorizontalValues, usedVerticalValues); |
| } |
| |
| auto quirks = formattingContext().quirks(); |
| if (!quirks.needsStretching(layoutBox)) |
| return contentHeightAndMargin; |
| |
| contentHeightAndMargin = quirks.stretchedInFlowHeight(layoutBox, contentHeightAndMargin); |
| |
| LOG_WITH_STREAM(FormattingContextLayout, stream << "[Height][Margin] -> inflow non-replaced -> streched to viewport -> height(" << contentHeightAndMargin.contentHeight << "px) margin(" << contentHeightAndMargin.nonCollapsedMargin.before << "px, " << contentHeightAndMargin.nonCollapsedMargin.after << "px) -> layoutBox(" << &layoutBox << ")"); |
| return contentHeightAndMargin; |
| } |
| |
| ContentWidthAndMargin BlockFormattingContext::Geometry::inFlowWidthAndMargin(const Box& layoutBox, UsedHorizontalValues usedHorizontalValues) |
| { |
| ASSERT(layoutBox.isInFlow()); |
| |
| if (!layoutBox.replaced()) { |
| if (layoutBox.establishesTableFormattingContext()) { |
| // This is a special table "fit-content size" behavior handling. Not in the spec though. |
| // Table returns its final width as min/max. Use this final width value to computed horizontal margins etc. |
| usedHorizontalValues.width = shrinkToFitWidth(layoutBox, usedHorizontalValues.constraints.width); |
| } |
| return inFlowNonReplacedWidthAndMargin(layoutBox, usedHorizontalValues); |
| } |
| return inFlowReplacedWidthAndMargin(layoutBox, usedHorizontalValues); |
| } |
| |
| FormattingContext::IntrinsicWidthConstraints BlockFormattingContext::Geometry::intrinsicWidthConstraints(const Box& layoutBox) |
| { |
| auto fixedMarginBorderAndPadding = [&](auto& layoutBox) { |
| auto& style = layoutBox.style(); |
| return fixedValue(style.marginStart()).valueOr(0) |
| + LayoutUnit { style.borderLeftWidth() } |
| + fixedValue(style.paddingLeft()).valueOr(0) |
| + fixedValue(style.paddingRight()).valueOr(0) |
| + LayoutUnit { style.borderRightWidth() } |
| + fixedValue(style.marginEnd()).valueOr(0); |
| }; |
| |
| auto computedIntrinsicWidthConstraints = [&]() -> IntrinsicWidthConstraints { |
| auto& style = layoutBox.style(); |
| if (auto width = fixedValue(style.logicalWidth())) |
| return { *width, *width }; |
| |
| // Minimum/maximum width can't be depending on the containing block's width. |
| if (!style.logicalWidth().isAuto()) |
| return { }; |
| |
| if (auto* replaced = layoutBox.replaced()) { |
| if (replaced->hasIntrinsicWidth()) { |
| auto replacedWidth = replaced->intrinsicWidth(); |
| return { replacedWidth, replacedWidth }; |
| } |
| return { }; |
| } |
| |
| if (layoutBox.establishesFormattingContext() && is<Container>(layoutBox)) |
| return LayoutContext::createFormattingContext(downcast<Container>(layoutBox), layoutState())->computedIntrinsicWidthConstraints(); |
| |
| if (!is<Container>(layoutBox) || !downcast<Container>(layoutBox).hasInFlowOrFloatingChild()) |
| return { }; |
| |
| auto intrinsicWidthConstraints = IntrinsicWidthConstraints { }; |
| auto& formattingState = layoutState().formattingStateForBox(layoutBox); |
| for (auto& child : childrenOfType<Box>(downcast<Container>(layoutBox))) { |
| if (child.isOutOfFlowPositioned()) |
| continue; |
| auto childIntrinsicWidthConstraints = formattingState.intrinsicWidthConstraintsForBox(child); |
| ASSERT(childIntrinsicWidthConstraints); |
| |
| // FIXME Check for box-sizing: border-box; |
| auto marginBorderAndPadding = fixedMarginBorderAndPadding(child); |
| intrinsicWidthConstraints.minimum = std::max(intrinsicWidthConstraints.minimum, childIntrinsicWidthConstraints->minimum + marginBorderAndPadding); |
| intrinsicWidthConstraints.maximum = std::max(intrinsicWidthConstraints.maximum, childIntrinsicWidthConstraints->maximum + marginBorderAndPadding); |
| } |
| return intrinsicWidthConstraints; |
| }; |
| // FIXME Check for box-sizing: border-box; |
| auto intrinsicWidthConstraints = constrainByMinMaxWidth(layoutBox, computedIntrinsicWidthConstraints()); |
| intrinsicWidthConstraints.expand(fixedMarginBorderAndPadding(layoutBox)); |
| return intrinsicWidthConstraints; |
| } |
| |
| } |
| } |
| |
| #endif |
