TextRunWalker(const TextRun& run, unsigned startingX, const Font* font)
: m_font(font)
, m_startingX(startingX)
, m_offsetX(m_startingX)
, m_run(getTextRun(run))
, m_iterateBackwards(m_run.rtl())
{
// Do not use |run| inside this constructor. Use |m_run| instead.
memset(&m_item, 0, sizeof(m_item));
// We cannot know, ahead of time, how many glyphs a given script run
// will produce. We take a guess that script runs will not produce more
// than twice as many glyphs as there are code points and fallback if
// we find that we are wrong.
m_maxGlyphs = m_run.length() * 2;
createGlyphArrays();
m_item.log_clusters = new unsigned short[m_run.length()];
m_item.face = 0;
m_item.font = allocHarfbuzzFont();
m_item.string = m_run.characters();
m_item.stringLength = m_run.length();
m_item.item.bidiLevel = m_run.rtl();
reset();
}
void shapeGlyphs()
{
for (;;) {
if (HB_ShapeItem(&m_item))
break;
// We overflowed our arrays. Resize and retry.
// HB_ShapeItem fills in m_item.num_glyphs with the needed size.
deleteGlyphArrays();
// The |+ 1| here is a workaround for a bug in Harfbuzz: the Khmer
// shaper (at least) can fail because of insufficient glyph buffers
// and request 0 additional glyphs: throwing us into an infinite
// loop.
createGlyphArrays(m_item.num_glyphs + 1);
}
}
void ComplexTextController::shapeGlyphs()
{
// HB_ShapeItem() resets m_item.num_glyphs. If the previous call to
// HB_ShapeItem() used less space than was available, the capacity of
// the array may be larger than the current value of m_item.num_glyphs.
// So, we need to reset the num_glyphs to the capacity of the array.
m_item.num_glyphs = m_glyphsArrayCapacity;
resetGlyphArrays();
while (!HB_ShapeItem(&m_item)) {
// We overflowed our arrays. Resize and retry.
// HB_ShapeItem fills in m_item.num_glyphs with the needed size.
deleteGlyphArrays();
// The |+ 1| here is a workaround for a bug in Harfbuzz: the Khmer
// shaper (at least) can fail because of insufficient glyph buffers
// and request 0 additional glyphs: throwing us into an infinite
// loop.
createGlyphArrays(m_item.num_glyphs + 1);
}
}
TextRunWalker(const TextRun& run, unsigned startingX, const Font* font)
: m_font(font)
, m_startingX(startingX)
, m_offsetX(m_startingX)
, m_run(getTextRun(run))
, m_iterateBackwards(m_run.rtl())
, m_wordSpacingAdjustment(0)
, m_padding(0)
, m_padError(0)
{
// Do not use |run| inside this constructor. Use |m_run| instead.
memset(&m_item, 0, sizeof(m_item));
// We cannot know, ahead of time, how many glyphs a given script run
// will produce. We take a guess that script runs will not produce more
// than twice as many glyphs as there are code points plus a bit of
// padding and fallback if we find that we are wrong.
createGlyphArrays((m_run.length() + 2) * 2);
m_item.log_clusters = new unsigned short[m_run.length()];
m_item.face = 0;
m_item.font = allocHarfbuzzFont();
m_item.item.bidiLevel = m_run.rtl();
int length = m_run.length();
m_item.stringLength = length;
if (!m_item.item.bidiLevel)
m_item.string = m_run.characters();
else {
// Assume mirrored character is in the same Unicode multilingual plane as the original one.
UChar* string = new UChar[length];
mirrorCharacters(string, m_run.characters(), length);
m_item.string = string;
}
reset();
}
bool expandGlyphArrays()
{
deleteGlyphArrays();
m_maxGlyphs <<= 1;
return createGlyphArrays();
}
