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#include <mbgl/text/glyph_set.hpp>
#include <mbgl/platform/log.hpp>
#include <mbgl/math/minmax.hpp>
#include <mbgl/util/i18n.hpp>
#include <mbgl/text/bidi.hpp>
#include <cassert>
namespace mbgl {
void GlyphSet::insert(uint32_t id, SDFGlyph&& glyph) {
auto it = sdfs.find(id);
if (it == sdfs.end()) {
// Glyph doesn't exist yet.
sdfs.emplace(id, std::move(glyph));
} else if (it->second.metrics == glyph.metrics) {
if (it->second.bitmap != glyph.bitmap) {
// The actual bitmap was updated; this is unsupported.
Log::Warning(Event::Glyph, "Modified glyph changed bitmap represenation");
}
// At least try to update it in case it's currently unsused.
// If it is already used; we won't attempt to update the glyph atlas texture.
it->second.bitmap = std::move(glyph.bitmap);
} else {
// The metrics were updated; this is unsupported.
Log::Warning(Event::Glyph, "Modified glyph has different metrics");
return;
}
}
const std::map<uint32_t, SDFGlyph> &GlyphSet::getSDFs() const {
return sdfs;
}
const Shaping GlyphSet::getShaping(const std::u16string &string, const WritingDirection writingDirection, const float maxWidth,
const float lineHeight, const float horizontalAlign,
const float verticalAlign, const float justify,
const float spacing, const Point<float> &translate) const {
Shaping shaping(translate.x * 24, translate.y * 24, string);
// the y offset *should* be part of the font metadata
const int32_t yOffset = -17;
float x = 0;
const float y = yOffset;
// Loop through all characters of this label and shape.
for (char16_t chr : string) {
auto it = sdfs.find(chr);
if (it != sdfs.end()) {
shaping.positionedGlyphs.emplace_back(chr, x, y);
x += it->second.metrics.advance + spacing;
}
}
if (shaping.positionedGlyphs.empty())
return shaping;
lineWrap(shaping, lineHeight, maxWidth, horizontalAlign, verticalAlign, justify, translate,
util::i18n::allowsIdeographicBreaking(string), writingDirection);
return shaping;
}
void align(Shaping &shaping, const float justify, const float horizontalAlign,
const float verticalAlign, const uint32_t maxLineLength, const float lineHeight,
const uint32_t line, const Point<float> &translate) {
const float shiftX = (justify - horizontalAlign) * maxLineLength + ::round(translate.x * 24/* one em */);
const float shiftY = (-verticalAlign * (line + 1) + 0.5) * lineHeight + ::round(translate.y * 24/* one em */);
for (auto& glyph : shaping.positionedGlyphs) {
glyph.x += shiftX;
glyph.y += shiftY;
}
}
void justifyLine(std::vector<PositionedGlyph> &positionedGlyphs, const std::map<uint32_t, SDFGlyph> &sdfs, uint32_t start,
uint32_t end, float justify) {
PositionedGlyph &glyph = positionedGlyphs[end];
auto it = sdfs.find(glyph.glyph);
if (it != sdfs.end()) {
const uint32_t lastAdvance = it->second.metrics.advance;
const float lineIndent = float(glyph.x + lastAdvance) * justify;
for (uint32_t j = start; j <= end; j++) {
positionedGlyphs[j].x -= lineIndent;
}
}
}
void GlyphSet::lineWrap(Shaping &shaping, const float lineHeight, float maxWidth,
const float horizontalAlign, const float verticalAlign,
const float justify, const Point<float> &translate,
bool useBalancedIdeographicBreaking, const WritingDirection writingDirection) const {
float lineFeedOffset = writingDirection == WritingDirection::RightToLeft ? -lineHeight : lineHeight;
uint32_t lastSafeBreak = 0;
uint32_t lengthBeforeCurrentLine = 0;
uint32_t lineStartIndex = 0;
uint32_t line = 0;
uint32_t maxLineLength = 0;
std::vector<PositionedGlyph> &positionedGlyphs = shaping.positionedGlyphs;
if (maxWidth) {
if (useBalancedIdeographicBreaking) {
auto lastPositionedGlyph = positionedGlyphs[positionedGlyphs.size() - 1];
uint32_t estimatedLineCount = std::fmax(1, std::ceil(lastPositionedGlyph.x / maxWidth));
maxWidth = lastPositionedGlyph.x / estimatedLineCount;
}
for (uint32_t i = 0; i < positionedGlyphs.size(); i++) {
PositionedGlyph &shape = positionedGlyphs[i];
shape.x -= lengthBeforeCurrentLine;
shape.y += lineFeedOffset * line;
if (shape.x > maxWidth && lastSafeBreak > 0) {
uint32_t lineLength = positionedGlyphs[lastSafeBreak + 1].x;
maxLineLength = util::max(lineLength, maxLineLength);
for (uint32_t k = lastSafeBreak + 1; k <= i; k++) {
positionedGlyphs[k].y += lineFeedOffset;
positionedGlyphs[k].x -= lineLength;
}
if (justify) {
// Collapse invisible characters.
uint32_t breakGlyph = positionedGlyphs[lastSafeBreak].glyph;
uint32_t lineEnd = lastSafeBreak;
if (util::i18n::isVisible(breakGlyph)) {
lineEnd--;
}
justifyLine(positionedGlyphs, sdfs, lineStartIndex, lineEnd, justify);
}
lineStartIndex = lastSafeBreak + 1;
lastSafeBreak = 0;
lengthBeforeCurrentLine += lineLength;
line++;
}
// Ideographic characters, spaces, and word-breaking punctuation that often appear without surrounding spaces.
if (useBalancedIdeographicBreaking
|| util::i18n::allowsWordBreaking(shape.glyph)
|| util::i18n::allowsIdeographicBreaking(shape.glyph)) {
lastSafeBreak = i;
}
}
}
const PositionedGlyph& lastPositionedGlyph = positionedGlyphs.back();
const auto lastGlyphIt = sdfs.find(lastPositionedGlyph.glyph);
assert(lastGlyphIt != sdfs.end());
const uint32_t lastLineLength = lastPositionedGlyph.x + lastGlyphIt->second.metrics.advance;
maxLineLength = std::max(maxLineLength, lastLineLength);
const uint32_t height = (line + 1) * lineHeight;
justifyLine(positionedGlyphs, sdfs, lineStartIndex, uint32_t(positionedGlyphs.size()) - 1, justify);
align(shaping, justify, horizontalAlign, verticalAlign, maxLineLength, lineHeight, line, translate);
// Calculate the bounding box
shaping.top += -verticalAlign * height;
shaping.bottom = shaping.top + height;
shaping.left += -horizontalAlign * maxLineLength;
shaping.right = shaping.left + maxLineLength;
}
} // end namespace mbgl
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