| /* |
| * Copyright (C) 2011 Apple Inc. All rights reserved. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public License |
| * along with this library; see the file COPYING.LIB. If not, write to |
| * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| * |
| */ |
| |
| #include "config.h" |
| #include "RenderCombineText.h" |
| |
| #include "RenderBlock.h" |
| #include "StyleInheritedData.h" |
| #include <wtf/IsoMallocInlines.h> |
| #include <wtf/NeverDestroyed.h> |
| |
| namespace WebCore { |
| |
| WTF_MAKE_ISO_ALLOCATED_IMPL(RenderCombineText); |
| |
| const float textCombineMargin = 1.15f; // Allow em + 15% margin |
| |
| RenderCombineText::RenderCombineText(Text& textNode, const String& string) |
| : RenderText(textNode, string) |
| , m_isCombined(false) |
| , m_needsFontUpdate(false) |
| { |
| } |
| |
| void RenderCombineText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle) |
| { |
| // FIXME: This is pretty hackish. |
| // Only cache a new font style if our old one actually changed. We do this to avoid |
| // clobbering width variants and shrink-to-fit changes, since we won't recombine when |
| // the font doesn't change. |
| if (!oldStyle || oldStyle->fontCascade() != style().fontCascade()) |
| m_combineFontStyle = RenderStyle::clonePtr(style()); |
| |
| RenderText::styleDidChange(diff, oldStyle); |
| |
| if (m_isCombined && selfNeedsLayout()) { |
| // Layouts cause the text to be recombined; therefore, only only un-combine when the style diff causes a layout. |
| RenderText::setRenderedText(originalText()); // This RenderCombineText has been combined once. Restore the original text for the next combineText(). |
| m_isCombined = false; |
| } |
| |
| m_needsFontUpdate = true; |
| combineTextIfNeeded(); |
| } |
| |
| void RenderCombineText::setRenderedText(const String& text) |
| { |
| RenderText::setRenderedText(text); |
| |
| m_needsFontUpdate = true; |
| combineTextIfNeeded(); |
| } |
| |
| float RenderCombineText::width(unsigned from, unsigned length, const FontCascade& font, float xPosition, HashSet<const Font*>* fallbackFonts, GlyphOverflow* glyphOverflow) const |
| { |
| if (m_isCombined) |
| return !length ? 0 : font.size(); |
| |
| return RenderText::width(from, length, font, xPosition, fallbackFonts, glyphOverflow); |
| } |
| |
| Optional<FloatPoint> RenderCombineText::computeTextOrigin(const FloatRect& boxRect) const |
| { |
| if (!m_isCombined) |
| return WTF::nullopt; |
| |
| // Visually center m_combinedTextWidth/Ascent/Descent within boxRect |
| FloatPoint result = boxRect.minXMaxYCorner(); |
| FloatSize combinedTextSize(m_combinedTextWidth, m_combinedTextAscent + m_combinedTextDescent); |
| result.move((boxRect.size().transposedSize() - combinedTextSize) / 2); |
| result.move(0, m_combinedTextAscent); |
| return result; |
| } |
| |
| String RenderCombineText::combinedStringForRendering() const |
| { |
| if (m_isCombined) { |
| auto originalText = this->originalText(); |
| ASSERT(!originalText.isNull()); |
| return originalText; |
| } |
| |
| return { }; |
| } |
| |
| void RenderCombineText::combineTextIfNeeded() |
| { |
| if (!m_needsFontUpdate) |
| return; |
| |
| // An ancestor element may trigger us to lay out again, even when we're already combined. |
| if (m_isCombined) |
| RenderText::setRenderedText(originalText()); |
| |
| m_isCombined = false; |
| m_needsFontUpdate = false; |
| |
| // CSS3 spec says text-combine works only in vertical writing mode. |
| if (style().isHorizontalWritingMode()) |
| return; |
| |
| auto description = originalFont().fontDescription(); |
| float emWidth = description.computedSize() * textCombineMargin; |
| bool shouldUpdateFont = false; |
| |
| FontSelector* fontSelector = style().fontCascade().fontSelector(); |
| |
| description.setOrientation(FontOrientation::Horizontal); // We are going to draw combined text horizontally. |
| |
| FontCascade horizontalFont(FontCascadeDescription { description }, style().fontCascade().letterSpacing(), style().fontCascade().wordSpacing()); |
| horizontalFont.update(fontSelector); |
| |
| GlyphOverflow glyphOverflow; |
| glyphOverflow.computeBounds = true; |
| float combinedTextWidth = width(0, text().length(), horizontalFont, 0, nullptr, &glyphOverflow); |
| |
| float bestFitDelta = combinedTextWidth - emWidth; |
| auto bestFitDescription = description; |
| |
| m_isCombined = combinedTextWidth <= emWidth; |
| |
| if (m_isCombined) |
| shouldUpdateFont = m_combineFontStyle->setFontDescription(WTFMove(description)); // Need to change font orientation to horizontal. |
| else { |
| // Need to try compressed glyphs. |
| static const FontWidthVariant widthVariants[] = { FontWidthVariant::HalfWidth, FontWidthVariant::ThirdWidth, FontWidthVariant::QuarterWidth }; |
| for (auto widthVariant : widthVariants) { |
| description.setWidthVariant(widthVariant); // When modifying this, make sure to keep it in sync with FontPlatformData::isForTextCombine()! |
| |
| FontCascade compressedFont(FontCascadeDescription { description }, style().fontCascade().letterSpacing(), style().fontCascade().wordSpacing()); |
| compressedFont.update(fontSelector); |
| |
| glyphOverflow.left = glyphOverflow.top = glyphOverflow.right = glyphOverflow.bottom = 0; |
| float runWidth = RenderText::width(0, text().length(), compressedFont, 0, nullptr, &glyphOverflow); |
| if (runWidth <= emWidth) { |
| combinedTextWidth = runWidth; |
| m_isCombined = true; |
| |
| // Replace my font with the new one. |
| shouldUpdateFont = m_combineFontStyle->setFontDescription(WTFMove(description)); |
| break; |
| } |
| |
| float widthDelta = runWidth - emWidth; |
| if (widthDelta < bestFitDelta) { |
| bestFitDelta = widthDelta; |
| bestFitDescription = description; |
| } |
| } |
| } |
| |
| if (!m_isCombined) { |
| float scaleFactor = std::max(0.4f, emWidth / (emWidth + bestFitDelta)); |
| float originalSize = bestFitDescription.computedSize(); |
| do { |
| float computedSize = originalSize * scaleFactor; |
| bestFitDescription.setComputedSize(computedSize); |
| shouldUpdateFont = m_combineFontStyle->setFontDescription(FontCascadeDescription { bestFitDescription }); |
| |
| FontCascade compressedFont(FontCascadeDescription(bestFitDescription), style().fontCascade().letterSpacing(), style().fontCascade().wordSpacing()); |
| compressedFont.update(fontSelector); |
| |
| glyphOverflow.left = glyphOverflow.top = glyphOverflow.right = glyphOverflow.bottom = 0; |
| float runWidth = RenderText::width(0, text().length(), compressedFont, 0, nullptr, &glyphOverflow); |
| if (runWidth <= emWidth) { |
| combinedTextWidth = runWidth; |
| m_isCombined = true; |
| break; |
| } |
| scaleFactor -= 0.05f; |
| } while (scaleFactor >= 0.4f); |
| } |
| |
| if (shouldUpdateFont) |
| m_combineFontStyle->fontCascade().update(fontSelector); |
| |
| if (m_isCombined) { |
| static NeverDestroyed<String> objectReplacementCharacterString(&objectReplacementCharacter, 1); |
| RenderText::setRenderedText(objectReplacementCharacterString.get()); |
| m_combinedTextWidth = combinedTextWidth; |
| m_combinedTextAscent = glyphOverflow.top; |
| m_combinedTextDescent = glyphOverflow.bottom; |
| m_lineBoxes.dirtyRange(*this, 0, originalText().length(), originalText().length()); |
| setNeedsLayout(); |
| } |
| } |
| |
| } // namespace WebCore |