| /* |
| * Copyright (C) 2014-2021 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. ``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 |
| * 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 "InlineTextBoxStyle.h" |
| |
| #include "FontCascade.h" |
| #include "HTMLAnchorElement.h" |
| #include "HTMLNames.h" |
| #include "InlineIteratorLine.h" |
| #include "InlineIteratorTextBox.h" |
| #include "LegacyInlineTextBox.h" |
| #include "LegacyRootInlineBox.h" |
| #include "RenderInline.h" |
| #include "TextUnderlineOffset.h" |
| |
| namespace WebCore { |
| |
| static bool isAncestorAndWithinBlock(const RenderInline& ancestor, const RenderObject* child) |
| { |
| const RenderObject* object = child; |
| while (object && (!object->isRenderBlock() || object->isInline())) { |
| if (object == &ancestor) |
| return true; |
| object = object->parent(); |
| } |
| return false; |
| } |
| |
| static void minLogicalTopForTextDecorationLine(const InlineIterator::LineIterator& line, float& minLogicalTop, const RenderElement* decorationRenderer, OptionSet<TextDecorationLine> textDecoration) |
| { |
| for (auto run = line->firstRun(); run; run.traverseNextOnLine()) { |
| if (run->renderer().isOutOfFlowPositioned()) |
| continue; // Positioned placeholders don't affect calculations. |
| |
| if (!(run->style().textDecorationsInEffect() & textDecoration)) |
| continue; // If the text decoration isn't in effect on the child, then it must be outside of |decorationRenderer|'s hierarchy. |
| |
| if (decorationRenderer && decorationRenderer->isRenderInline() && !isAncestorAndWithinBlock(downcast<RenderInline>(*decorationRenderer), &run->renderer())) |
| continue; |
| |
| if (run->isText() || run->style().textDecorationSkipInk() == TextDecorationSkipInk::None) |
| minLogicalTop = std::min<float>(minLogicalTop, run->logicalTop()); |
| } |
| } |
| |
| static void maxLogicalBottomForTextDecorationLine(const InlineIterator::LineIterator& line, float& maxLogicalBottom, const RenderElement* decorationRenderer, OptionSet<TextDecorationLine> textDecoration) |
| { |
| for (auto run = line->firstRun(); run; run.traverseNextOnLine()) { |
| if (run->renderer().isOutOfFlowPositioned()) |
| continue; // Positioned placeholders don't affect calculations. |
| |
| if (!(run->style().textDecorationsInEffect() & textDecoration)) |
| continue; // If the text decoration isn't in effect on the child, then it must be outside of |decorationRenderer|'s hierarchy. |
| |
| if (decorationRenderer && decorationRenderer->isRenderInline() && !isAncestorAndWithinBlock(downcast<RenderInline>(*decorationRenderer), &run->renderer())) |
| continue; |
| |
| if (run->isText() || run->style().textDecorationSkipInk() == TextDecorationSkipInk::None) |
| maxLogicalBottom = std::max<float>(maxLogicalBottom, run->logicalBottom()); |
| } |
| } |
| |
| static const RenderElement* enclosingRendererWithTextDecoration(const RenderText& renderer, OptionSet<TextDecorationLine> textDecoration, bool firstLine) |
| { |
| const RenderElement* current = renderer.parent(); |
| do { |
| if (current->isRenderBlock()) |
| return current; |
| if (!current->isRenderInline() || current->isRubyText()) |
| return nullptr; |
| |
| const RenderStyle& styleToUse = firstLine ? current->firstLineStyle() : current->style(); |
| if (styleToUse.textDecoration() & textDecoration) |
| return current; |
| current = current->parent(); |
| } while (current && (!current->element() || (!is<HTMLAnchorElement>(*current->element()) && !current->element()->hasTagName(HTMLNames::fontTag)))); |
| |
| return current; |
| } |
| |
| float computeUnderlineOffset(TextUnderlinePosition underlinePosition, TextUnderlineOffset underlineOffset, const FontMetrics& fontMetrics, const InlineIterator::TextBoxIterator& textRun, float defaultGap) |
| { |
| // This represents the gap between the baseline and the closest edge of the underline. |
| float gap = std::max<int>(1, std::ceil(defaultGap / 2.0f)); |
| |
| // FIXME: The code for visual overflow detection passes in a null inline text box. This means it is now |
| // broken for the case where auto needs to behave like "under". |
| |
| // According to the specification TextUnderlinePosition::Auto should avoid drawing through glyphs in |
| // scripts where it would not be appropriate (e.g., ideographs). |
| // Strictly speaking this can occur whenever the line contains ideographs |
| // even if it is horizontal, but detecting this has performance implications. For now we only work with |
| // vertical text, since we already determined the baseline type to be ideographic in that |
| // case. |
| |
| auto resolvedUnderlinePosition = underlinePosition; |
| if (resolvedUnderlinePosition == TextUnderlinePosition::Auto && underlineOffset.isAuto()) { |
| if (textRun) |
| resolvedUnderlinePosition = textRun->line()->baselineType() == IdeographicBaseline ? TextUnderlinePosition::Under : TextUnderlinePosition::Auto; |
| else |
| resolvedUnderlinePosition = TextUnderlinePosition::Auto; |
| } |
| |
| switch (resolvedUnderlinePosition) { |
| case TextUnderlinePosition::Auto: |
| if (underlineOffset.isAuto()) |
| return fontMetrics.ascent() + gap; |
| return fontMetrics.ascent() + underlineOffset.lengthValue(); |
| case TextUnderlinePosition::FromFont: |
| return fontMetrics.ascent() + fontMetrics.underlinePosition() + underlineOffset.lengthOr(0); |
| case TextUnderlinePosition::Under: { |
| ASSERT(textRun); |
| // Position underline relative to the bottom edge of the lowest element's content box. |
| auto line = textRun->line(); |
| auto* decorationRenderer = enclosingRendererWithTextDecoration(textRun->renderer(), TextDecorationLine::Underline, line->isFirst()); |
| |
| float offset; |
| if (textRun->renderer().style().isFlippedLinesWritingMode()) { |
| offset = textRun->logicalTop(); |
| minLogicalTopForTextDecorationLine(line, offset, decorationRenderer, TextDecorationLine::Underline); |
| offset = textRun->logicalTop() - offset; |
| } else { |
| offset = textRun->logicalBottom(); |
| maxLogicalBottomForTextDecorationLine(line, offset, decorationRenderer, TextDecorationLine::Underline); |
| offset -= textRun->logicalBottom(); |
| } |
| auto desiredOffset = textRun->logicalHeight() + gap + std::max(offset, 0.0f) + underlineOffset.lengthOr(0); |
| return std::max<float>(desiredOffset, fontMetrics.ascent()); |
| } |
| } |
| |
| ASSERT_NOT_REACHED(); |
| return fontMetrics.ascent() + gap; |
| } |
| |
| WavyStrokeParameters getWavyStrokeParameters(float fontSize) |
| { |
| WavyStrokeParameters result; |
| // More information is in the WavyStrokeParameters definition. |
| result.controlPointDistance = fontSize * 1.5 / 16; |
| result.step = fontSize / 4.5; |
| return result; |
| } |
| |
| GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const InlineIterator::TextBoxIterator& textRun) |
| { |
| ASSERT(!textRun || textRun->style() == lineStyle); |
| |
| auto decoration = lineStyle.textDecorationsInEffect(); |
| if (decoration.isEmpty()) |
| return GlyphOverflow(); |
| |
| float strokeThickness = lineStyle.textDecorationThickness().resolve(lineStyle.computedFontSize(), lineStyle.fontMetrics()); |
| WavyStrokeParameters wavyStrokeParameters; |
| float wavyOffset = 0; |
| |
| TextDecorationStyle decorationStyle = lineStyle.textDecorationStyle(); |
| float height = lineStyle.fontCascade().fontMetrics().floatHeight(); |
| GlyphOverflow overflowResult; |
| |
| if (decorationStyle == TextDecorationStyle::Wavy) { |
| wavyStrokeParameters = getWavyStrokeParameters(lineStyle.computedFontPixelSize()); |
| wavyOffset = wavyOffsetFromDecoration(); |
| overflowResult.left = strokeThickness; |
| overflowResult.right = strokeThickness; |
| } |
| |
| // These metrics must match where underlines get drawn. |
| // FIXME: Share the code in TextDecorationPainter::paintTextDecoration() so we can just query it for the painted geometry. |
| if (decoration & TextDecorationLine::Underline) { |
| // Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText() |
| int underlineOffset = 1; |
| float textDecorationBaseFontSize = 16; |
| auto defaultGap = lineStyle.computedFontSize() / textDecorationBaseFontSize; |
| underlineOffset += computeUnderlineOffset(lineStyle.textUnderlinePosition(), lineStyle.textUnderlineOffset(), lineStyle.fontMetrics(), textRun, defaultGap); |
| if (decorationStyle == TextDecorationStyle::Wavy) { |
| overflowResult.extendBottom(underlineOffset + wavyOffset + wavyStrokeParameters.controlPointDistance + strokeThickness - height); |
| overflowResult.extendTop(-(underlineOffset + wavyOffset - wavyStrokeParameters.controlPointDistance - strokeThickness)); |
| } else { |
| overflowResult.extendBottom(underlineOffset + strokeThickness - height); |
| overflowResult.extendTop(-underlineOffset); |
| } |
| } |
| if (decoration & TextDecorationLine::Overline) { |
| FloatRect rect(FloatPoint(), FloatSize(1, strokeThickness)); |
| float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(lineStyle.computedFontSize(), lineStyle.fontMetrics()); |
| rect.move(0, autoTextDecorationThickness - strokeThickness - wavyOffset); |
| if (decorationStyle == TextDecorationStyle::Wavy) { |
| FloatBoxExtent wavyExpansion; |
| wavyExpansion.setTop(wavyStrokeParameters.controlPointDistance); |
| wavyExpansion.setBottom(wavyStrokeParameters.controlPointDistance); |
| rect.expand(wavyExpansion); |
| } |
| overflowResult.extendTop(-rect.y()); |
| overflowResult.extendBottom(rect.maxY() - height); |
| } |
| if (decoration & TextDecorationLine::LineThrough) { |
| FloatRect rect(FloatPoint(), FloatSize(1, strokeThickness)); |
| float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(lineStyle.computedFontSize(), lineStyle.fontMetrics()); |
| auto center = 2 * lineStyle.fontMetrics().floatAscent() / 3 + autoTextDecorationThickness / 2; |
| rect.move(0, center - strokeThickness / 2); |
| if (decorationStyle == TextDecorationStyle::Wavy) { |
| FloatBoxExtent wavyExpansion; |
| wavyExpansion.setTop(wavyStrokeParameters.controlPointDistance); |
| wavyExpansion.setBottom(wavyStrokeParameters.controlPointDistance); |
| rect.expand(wavyExpansion); |
| } |
| overflowResult.extendTop(-rect.y()); |
| overflowResult.extendBottom(rect.maxY() - height); |
| } |
| return overflowResult; |
| } |
| |
| } |
