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Cleaning up line breaking code.

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* Don't include trailing spacing (as opposed to whitespace) in lineLength
* Modify BiDi interface to require initial bidi layout and linebreaking to happen in one call.
* Code style changes suggested by @kkaefer
This commit is contained in:
Chris Loer
2016-12-14 10:18:37 -08:00
parent f55a6e2b7a
commit f68449aeb8
4 changed files with 72 additions and 79 deletions
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41
src/mbgl/text/glyph_set.cpp
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@@ -48,10 +48,9 @@ const Shaping GlyphSet::getShaping(const std::u16string& logicalInput,
// different from the glyphs that get shown
Shaping shaping(translate.x * 24, translate.y * 24, logicalInput);
ProcessedBiDiText processedText = bidi.processText(logicalInput);
std::vector<std::u16string> reorderedLines =
processedText.applyLineBreaking(determineLineBreaks(logicalInput, spacing, maxWidth));
bidi.processText(logicalInput,
determineLineBreaks(logicalInput, spacing, maxWidth));
shapeLines(shaping, reorderedLines, spacing, lineHeight, horizontalAlign, verticalAlign,
justify, translate);
@@ -84,8 +83,9 @@ void justifyLine(std::vector<PositionedGlyph>& positionedGlyphs,
uint32_t start,
uint32_t end,
float justify) {
if (!justify)
if (!justify) {
return;
}
PositionedGlyph& glyph = positionedGlyphs[end];
auto it = sdfs.find(glyph.glyph);
@@ -105,14 +105,13 @@ float GlyphSet::determineIdeographicLineWidth(const std::u16string& logicalInput
float totalWidth = 0;
// totalWidth doesn't include the last character for magical tuning reasons. This makes the
// algorithm a little
// more agressive about trying to fit the text into fewer lines, taking advantage of the
// tolerance for going a little
// over maxWidth
// algorithm a little more agressive about trying to fit the text into fewer lines, taking
// advantage of the tolerance for going a little over maxWidth
for (uint32_t i = 0; i < logicalInput.size() - 1; i++) {
auto it = sdfs.find(logicalInput[i]);
if (it != sdfs.end())
if (it != sdfs.end()) {
totalWidth += it->second.metrics.advance + spacing;
}
}
int32_t lineCount = std::fmax(1, std::ceil(totalWidth / maxWidth));
@@ -124,14 +123,17 @@ float GlyphSet::determineIdeographicLineWidth(const std::u16string& logicalInput
std::set<int32_t> GlyphSet::determineLineBreaks(const std::u16string& logicalInput,
const float spacing,
float maxWidth) const {
if (!maxWidth)
if (!maxWidth) {
return {};
}
if (logicalInput.empty())
if (logicalInput.empty()) {
return {};
}
if (util::i18n::allowsIdeographicBreaking(logicalInput))
if (util::i18n::allowsIdeographicBreaking(logicalInput)) {
maxWidth = determineIdeographicLineWidth(logicalInput, spacing, maxWidth);
}
std::set<int32_t> lineBreakPoints;
float currentX = 0;
@@ -140,8 +142,9 @@ std::set<int32_t> GlyphSet::determineLineBreaks(const std::u16string& logicalInp
for (uint32_t i = 0; i < logicalInput.size(); i++) {
auto it = sdfs.find(logicalInput[i]);
if (it == sdfs.end())
if (it == sdfs.end()) {
continue;
}
const SDFGlyph& glyph = it->second;
@@ -186,24 +189,28 @@ void GlyphSet::shapeLines(Shaping& shaping,
// Collapse whitespace so it doesn't throw off justification
boost::algorithm::trim_if(line, boost::algorithm::is_any_of(u" \t\n\v\f\r"));
if (line.empty())
if (line.empty()) {
continue;
}
uint32_t lineStartIndex = static_cast<uint32_t>(shaping.positionedGlyphs.size());
for (char16_t chr : line) {
auto it = sdfs.find(chr);
if (it == sdfs.end())
if (it == sdfs.end()) {
continue;
}
const SDFGlyph& glyph = it->second;
shaping.positionedGlyphs.emplace_back(chr, x, y);
x += glyph.metrics.advance + spacing;
}
if (static_cast<uint32_t>(shaping.positionedGlyphs.size()) == lineStartIndex)
if (static_cast<uint32_t>(shaping.positionedGlyphs.size()) == lineStartIndex) {
continue;
}
maxLineLength = util::max(x, maxLineLength);
float lineLength = x - spacing; // Don't count trailing spacing
maxLineLength = util::max(lineLength, maxLineLength);
justifyLine(shaping.positionedGlyphs, sdfs, lineStartIndex,
static_cast<uint32_t>(shaping.positionedGlyphs.size()) - 1, justify);