SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
SkTScopedPtr<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
int startId) {
nextSlot->reset(new SkAdvancedTypefaceMetrics::AdvanceMetric<Data>);
resetRange(nextSlot->get(), startId);
return nextSlot->get();
}
int Random::next(int min, int max)
{
resetRange(min, max);
return m_dist(m_rnd);
}
SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
FontHandle fontHandle,
int num_glyphs,
const uint32_t* subsetGlyphIDs,
uint32_t subsetGlyphIDsLength,
bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data)) {
// Assuming that on average, the ASCII representation of an advance plus
// a space is 8 characters and the ASCII representation of a glyph id is 3
// characters, then the following cut offs for using different range types
// apply:
// The cost of stopping and starting the range is 7 characers
// a. Removing 4 0's or don't care's is a win
// The cost of stopping and starting the range plus a run is 22
// characters
// b. Removing 3 repeating advances is a win
// c. Removing 2 repeating advances and 3 don't cares is a win
// When not currently in a range the cost of a run over a range is 16
// characaters, so:
// d. Removing a leading 0/don't cares is a win because it is omitted
// e. Removing 2 repeating advances is a win
SkTScopedPtr<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> > result;
SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* curRange;
SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* prevRange = NULL;
Data lastAdvance = kInvalidAdvance;
int repeatedAdvances = 0;
int wildCardsInRun = 0;
int trailingWildCards = 0;
uint32_t subsetIndex = 0;
// Limit the loop count to glyph id ranges provided.
int firstIndex = 0;
int lastIndex = num_glyphs;
if (subsetGlyphIDs) {
firstIndex = static_cast<int>(subsetGlyphIDs[0]);
lastIndex =
static_cast<int>(subsetGlyphIDs[subsetGlyphIDsLength - 1]) + 1;
}
curRange = appendRange(&result, firstIndex);
for (int gId = firstIndex; gId <= lastIndex; gId++) {
Data advance = kInvalidAdvance;
if (gId < lastIndex) {
// Get glyph id only when subset is NULL, or the id is in subset.
if (!subsetGlyphIDs ||
(subsetIndex < subsetGlyphIDsLength &&
static_cast<uint32_t>(gId) == subsetGlyphIDs[subsetIndex])) {
SkAssertResult(getAdvance(fontHandle, gId, &advance));
++subsetIndex;
} else {
advance = kDontCareAdvance;
}
}
if (advance == lastAdvance) {
repeatedAdvances++;
trailingWildCards = 0;
} else if (advance == kDontCareAdvance) {
wildCardsInRun++;
trailingWildCards++;
} else if (curRange->fAdvance.count() ==
repeatedAdvances + 1 + wildCardsInRun) { // All in run.
if (lastAdvance == 0) {
resetRange(curRange, gId);
trailingWildCards = 0;
} else if (repeatedAdvances + 1 >= 2 || trailingWildCards >= 4) {
finishRange(curRange, gId - 1,
SkAdvancedTypefaceMetrics::WidthRange::kRun);
prevRange = curRange;
curRange = appendRange(&curRange->fNext, gId);
trailingWildCards = 0;
}
repeatedAdvances = 0;
wildCardsInRun = trailingWildCards;
trailingWildCards = 0;
} else {
if (lastAdvance == 0 &&
repeatedAdvances + 1 + wildCardsInRun >= 4) {
finishRange(curRange,
gId - repeatedAdvances - wildCardsInRun - 2,
SkAdvancedTypefaceMetrics::WidthRange::kRange);
prevRange = curRange;
curRange = appendRange(&curRange->fNext, gId);
trailingWildCards = 0;
} else if (trailingWildCards >= 4 && repeatedAdvances + 1 < 2) {
finishRange(curRange,
gId - trailingWildCards - 1,
SkAdvancedTypefaceMetrics::WidthRange::kRange);
prevRange = curRange;
curRange = appendRange(&curRange->fNext, gId);
trailingWildCards = 0;
} else if (lastAdvance != 0 &&
(repeatedAdvances + 1 >= 3 ||
(repeatedAdvances + 1 >= 2 && wildCardsInRun >= 3))) {
finishRange(curRange,
gId - repeatedAdvances - wildCardsInRun - 2,
SkAdvancedTypefaceMetrics::WidthRange::kRange);
curRange =
appendRange(&curRange->fNext,
gId - repeatedAdvances - wildCardsInRun - 1);
curRange->fAdvance.append(1, &lastAdvance);
finishRange(curRange, gId - 1,
SkAdvancedTypefaceMetrics::WidthRange::kRun);
prevRange = curRange;
curRange = appendRange(&curRange->fNext, gId);
trailingWildCards = 0;
}
repeatedAdvances = 0;
wildCardsInRun = trailingWildCards;
trailingWildCards = 0;
}
curRange->fAdvance.append(1, &advance);
if (advance != kDontCareAdvance) {
lastAdvance = advance;
}
}
if (curRange->fStartId == lastIndex) {
SkASSERT(prevRange);
SkASSERT(prevRange->fNext->fStartId == lastIndex);
prevRange->fNext.reset();
} else {
finishRange(curRange, lastIndex - 1,
SkAdvancedTypefaceMetrics::WidthRange::kRange);
}
return result.release();
}
//----------------------------------------------------------------------------//
// Generation Methods //
//----------------------------------------------------------------------------//
int Random::next()
{
resetRange(0, std::numeric_limits<int>::max());
return m_dist(m_rnd);
}
