tdesktop/Telegram/SourceFiles/ui/text/text_block.cpp

365 lines
11 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org
Telegram Desktop is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
It 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 General Public License for more details.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#include "ui/text/text_block.h"
// COPIED FROM qtextlayout.cpp AND MODIFIED
namespace {
struct ScriptLine {
ScriptLine() : length(0), textWidth(0) {
}
int32 length;
QFixed textWidth;
};
// All members finished with "_" are internal.
struct LineBreakHelper
{
LineBreakHelper()
: glyphCount(0), maxGlyphs(INT_MAX), currentPosition(0), fontEngine(0), logClusters(0)
{
}
ScriptLine tmpData;
ScriptLine spaceData;
QGlyphLayout glyphs;
int glyphCount;
int maxGlyphs;
int currentPosition;
glyph_t previousGlyph_ = 0;
QFontEngine *previousFontEngine_ = nullptr;
QFixed rightBearing;
QFontEngine *fontEngine;
const unsigned short *logClusters;
inline glyph_t currentGlyph() const
{
Q_ASSERT(currentPosition > 0);
Q_ASSERT(logClusters[currentPosition - 1] < glyphs.numGlyphs);
return glyphs.glyphs[logClusters[currentPosition - 1]];
}
inline void saveCurrentGlyph()
{
if (currentPosition > 0 &&
logClusters[currentPosition - 1] < glyphs.numGlyphs) {
previousGlyph_ = currentGlyph(); // needed to calculate right bearing later
previousFontEngine_ = fontEngine;
} else {
previousGlyph_ = 0;
previousFontEngine_ = nullptr;
}
}
inline void calculateRightBearing(QFontEngine *engine, glyph_t glyph)
{
qreal rb;
engine->getGlyphBearings(glyph, 0, &rb);
// We only care about negative right bearings, so we limit the range
// of the bearing here so that we can assume it's negative in the rest
// of the code, as well ase use QFixed(1) as a sentinel to represent
// the state where we have yet to compute the right bearing.
rightBearing = qMin(QFixed::fromReal(rb), QFixed(0));
}
inline void calculateRightBearing()
{
if (currentPosition > 0 &&
logClusters[currentPosition - 1] < glyphs.numGlyphs) {
calculateRightBearing(fontEngine, currentGlyph());
} else {
rightBearing = 0;
}
}
inline void calculateRightBearingForPreviousGlyph()
{
if (previousGlyph_ > 0) {
calculateRightBearing(previousFontEngine_, previousGlyph_);
} else {
rightBearing = 0;
}
}
// We always calculate the right bearing right before it is needed.
// So we don't need caching / optimizations referred to delayed right bearing calculations.
//static const QFixed RightBearingNotCalculated;
//inline void resetRightBearing()
//{
// rightBearing = RightBearingNotCalculated;
//}
// We express the negative right bearing as an absolute number
// so that it can be applied to the width using addition.
inline QFixed negativeRightBearing() const
{
//if (rightBearing == RightBearingNotCalculated)
// return QFixed(0);
return qAbs(rightBearing);
}
};
//const QFixed LineBreakHelper::RightBearingNotCalculated = QFixed(1);
static inline void addNextCluster(int &pos, int end, ScriptLine &line, int &glyphCount,
const QScriptItem &current, const unsigned short *logClusters,
const QGlyphLayout &glyphs)
{
int glyphPosition = logClusters[pos];
do { // got to the first next cluster
++pos;
++line.length;
} while (pos < end && logClusters[pos] == glyphPosition);
do { // calculate the textWidth for the rest of the current cluster.
if (!glyphs.attributes[glyphPosition].dontPrint)
line.textWidth += glyphs.advances[glyphPosition];
++glyphPosition;
} while (glyphPosition < current.num_glyphs && !glyphs.attributes[glyphPosition].clusterStart);
Q_ASSERT((pos == end && glyphPosition == current.num_glyphs) || logClusters[pos] == glyphPosition);
++glyphCount;
}
} // anonymous namespace
class BlockParser {
public:
BlockParser(QTextEngine *e, TextBlock *b, QFixed minResizeWidth, int32 blockFrom, const QString &str)
: block(b), eng(e), str(str) {
parseWords(minResizeWidth, blockFrom);
}
void parseWords(QFixed minResizeWidth, int32 blockFrom) {
LineBreakHelper lbh;
int item = -1;
int newItem = eng->findItem(0);
style::align alignment = eng->option.alignment();
const QCharAttributes *attributes = eng->attributes();
if (!attributes)
return;
int end = 0;
lbh.logClusters = eng->layoutData->logClustersPtr;
block->_words.clear();
int wordStart = lbh.currentPosition;
bool addingEachGrapheme = false;
int lastGraphemeBoundaryPosition = -1;
ScriptLine lastGraphemeBoundaryLine;
while (newItem < eng->layoutData->items.size()) {
if (newItem != item) {
item = newItem;
const QScriptItem &current = eng->layoutData->items[item];
if (!current.num_glyphs) {
eng->shape(item);
attributes = eng->attributes();
if (!attributes)
return;
lbh.logClusters = eng->layoutData->logClustersPtr;
}
lbh.currentPosition = current.position;
end = current.position + eng->length(item);
lbh.glyphs = eng->shapedGlyphs(&current);
QFontEngine *fontEngine = eng->fontEngine(current);
if (lbh.fontEngine != fontEngine) {
lbh.fontEngine = fontEngine;
}
}
const QScriptItem &current = eng->layoutData->items[item];
if (attributes[lbh.currentPosition].whiteSpace) {
while (lbh.currentPosition < end && attributes[lbh.currentPosition].whiteSpace)
addNextCluster(lbh.currentPosition, end, lbh.spaceData, lbh.glyphCount,
current, lbh.logClusters, lbh.glyphs);
if (block->_words.isEmpty()) {
block->_words.push_back(TextWord(wordStart + blockFrom, lbh.tmpData.textWidth, -lbh.negativeRightBearing()));
}
block->_words.back().add_rpadding(lbh.spaceData.textWidth);
block->_width += lbh.spaceData.textWidth;
lbh.spaceData.length = 0;
lbh.spaceData.textWidth = 0;
wordStart = lbh.currentPosition;
addingEachGrapheme = false;
lastGraphemeBoundaryPosition = -1;
lastGraphemeBoundaryLine = ScriptLine();
} else {
do {
addNextCluster(lbh.currentPosition, end, lbh.tmpData, lbh.glyphCount,
current, lbh.logClusters, lbh.glyphs);
if (lbh.currentPosition >= eng->layoutData->string.length()
|| attributes[lbh.currentPosition].whiteSpace
|| isLineBreak(attributes, lbh.currentPosition)) {
lbh.calculateRightBearing();
block->_words.push_back(TextWord(wordStart + blockFrom, lbh.tmpData.textWidth, -lbh.negativeRightBearing()));
block->_width += lbh.tmpData.textWidth;
lbh.tmpData.textWidth = 0;
lbh.tmpData.length = 0;
wordStart = lbh.currentPosition;
break;
} else if (attributes[lbh.currentPosition].graphemeBoundary) {
if (!addingEachGrapheme && lbh.tmpData.textWidth > minResizeWidth) {
if (lastGraphemeBoundaryPosition >= 0) {
lbh.calculateRightBearingForPreviousGlyph();
block->_words.push_back(TextWord(wordStart + blockFrom, -lastGraphemeBoundaryLine.textWidth, -lbh.negativeRightBearing()));
block->_width += lastGraphemeBoundaryLine.textWidth;
lbh.tmpData.textWidth -= lastGraphemeBoundaryLine.textWidth;
lbh.tmpData.length -= lastGraphemeBoundaryLine.length;
wordStart = lastGraphemeBoundaryPosition;
}
addingEachGrapheme = true;
}
if (addingEachGrapheme) {
lbh.calculateRightBearing();
block->_words.push_back(TextWord(wordStart + blockFrom, -lbh.tmpData.textWidth, -lbh.negativeRightBearing()));
block->_width += lbh.tmpData.textWidth;
lbh.tmpData.textWidth = 0;
lbh.tmpData.length = 0;
wordStart = lbh.currentPosition;
} else {
lastGraphemeBoundaryPosition = lbh.currentPosition;
lastGraphemeBoundaryLine = lbh.tmpData;
lbh.saveCurrentGlyph();
}
}
} while (lbh.currentPosition < end);
}
if (lbh.currentPosition == end)
newItem = item + 1;
}
if (!block->_words.isEmpty()) {
block->_rpadding = block->_words.back().f_rpadding();
block->_width -= block->_rpadding;
block->_words.squeeze();
}
}
bool isLineBreak(const QCharAttributes *attributes, int32 index) {
bool lineBreak = attributes[index].lineBreak;
if (lineBreak && block->lnkIndex() > 0 && index > 0 && str.at(index - 1) == '/') {
return false; // don't break after / in links
}
return lineBreak;
}
private:
TextBlock *block;
QTextEngine *eng;
const QString &str;
};
QFixed ITextBlock::f_rbearing() const {
return (type() == TextBlockTText) ? static_cast<const TextBlock*>(this)->real_f_rbearing() : 0;
}
TextBlock::TextBlock(const style::font &font, const QString &str, QFixed minResizeWidth, uint16 from, uint16 length, uchar flags, uint16 lnkIndex) : ITextBlock(font, str, from, length, flags, lnkIndex) {
_flags |= ((TextBlockTText & 0x0F) << 8);
if (length) {
style::font blockFont = font;
if (!flags && lnkIndex) {
// should use TextStyle lnkFlags somehow... not supported
}
if ((flags & TextBlockFPre) || (flags & TextBlockFCode)) {
blockFont = App::monofont();
if (blockFont->size() != font->size() || blockFont->flags() != font->flags()) {
blockFont = style::font(font->size(), font->flags(), blockFont->family());
}
} else {
if (flags & TextBlockFBold) {
blockFont = blockFont->bold();
} else if (flags & TextBlockFSemibold) {
blockFont = st::semiboldFont;
if (blockFont->size() != font->size() || blockFont->flags() != font->flags()) {
blockFont = style::font(font->size(), font->flags(), blockFont->family());
}
}
if (flags & TextBlockFItalic) blockFont = blockFont->italic();
if (flags & TextBlockFUnderline) blockFont = blockFont->underline();
if (flags & TextBlockFTilde) { // tilde fix in OpenSans
blockFont = st::semiboldFont;
}
}
QString part = str.mid(_from, length);
// Attempt to catch a crash in text processing
SignalHandlers::setCrashAnnotationRef("CrashString", &part);
QStackTextEngine engine(part, blockFont->f);
QTextLayout layout(&engine);
layout.beginLayout();
layout.createLine();
BlockParser parser(&engine, this, minResizeWidth, _from, part);
layout.endLayout();
SignalHandlers::clearCrashAnnotationRef("CrashString");
}
}
EmojiBlock::EmojiBlock(const style::font &font, const QString &str, uint16 from, uint16 length, uchar flags, uint16 lnkIndex, EmojiPtr emoji) : ITextBlock(font, str, from, length, flags, lnkIndex)
, emoji(emoji) {
_flags |= ((TextBlockTEmoji & 0x0F) << 8);
_width = int(st::emojiSize + 2 * st::emojiPadding);
_rpadding = 0;
for (auto i = length; i != 0;) {
auto ch = str[_from + (--i)];
if (ch.unicode() == QChar::Space) {
_rpadding += font->spacew;
} else {
break;
}
}
}
SkipBlock::SkipBlock(const style::font &font, const QString &str, uint16 from, int32 w, int32 h, uint16 lnkIndex) : ITextBlock(font, str, from, 1, 0, lnkIndex), _height(h) {
_flags |= ((TextBlockTSkip & 0x0F) << 8);
_width = w;
}