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[TextBlob] Fall back to TightRunBounds when the font bounds are empty

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Empty font bounds are likely an indication of a font bug.  As a best
effort, we can use TightRunBounds in this easily detectable case.

Since TightRunBounds only supports kDefault_Positioning currently, the
CL also reinstates handling of kFull_Positioning and
kHorizontal_Positioning (removed in http://crrev.com/858153007).

BUG=507022
R=reed@google.com,bungeman@google.com

Review URL: https://codereview.chromium.org/1399123002
This commit is contained in:
fmalita 2015-10-09 14:46:28 -07:00 committed by Commit bot
parent 8b3eca95ae
commit b0b45d35e4
1 changed files with 45 additions and 7 deletions
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52
src/core/SkTextBlob.cpp
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@ -367,12 +367,44 @@ SkTextBlobBuilder::~SkTextBlobBuilder() {
}
SkRect SkTextBlobBuilder::TightRunBounds(const SkTextBlob::RunRecord& run) {
SkASSERT(SkTextBlob::kDefault_Positioning == run.positioning());
SkRect bounds;
SkPaint paint;
run.font().applyToPaint(&paint);
paint.measureText(run.glyphBuffer(), run.glyphCount() * sizeof(uint16_t), &bounds);
if (SkTextBlob::kDefault_Positioning == run.positioning()) {
paint.measureText(run.glyphBuffer(), run.glyphCount() * sizeof(uint16_t), &bounds);
return bounds.makeOffset(run.offset().x(), run.offset().y());
}
SkAutoSTArray<16, SkRect> glyphBounds(run.glyphCount());
paint.getTextWidths(run.glyphBuffer(),
run.glyphCount() * sizeof(uint16_t),
NULL,
glyphBounds.get());
SkASSERT(SkTextBlob::kFull_Positioning == run.positioning() ||
SkTextBlob::kHorizontal_Positioning == run.positioning());
// kFull_Positioning => [ x, y, x, y... ]
// kHorizontal_Positioning => [ x, x, x... ]
// (const y applied by runBounds.offset(run->offset()) later)
const SkScalar horizontalConstY = 0;
const SkScalar* glyphPosX = run.posBuffer();
const SkScalar* glyphPosY = (run.positioning() == SkTextBlob::kFull_Positioning) ?
glyphPosX + 1 : &horizontalConstY;
const unsigned posXInc = SkTextBlob::ScalarsPerGlyph(run.positioning());
const unsigned posYInc = (run.positioning() == SkTextBlob::kFull_Positioning) ?
posXInc : 0;
bounds.setEmpty();
for (unsigned i = 0; i < run.glyphCount(); ++i) {
bounds.join(glyphBounds[i].makeOffset(*glyphPosX, *glyphPosY));
glyphPosX += posXInc;
glyphPosY += posYInc;
}
SkASSERT((void*)glyphPosX <= SkTextBlob::RunRecord::Next(&run));
SkASSERT(run.positioning() == SkTextBlob::kHorizontal_Positioning ||
(void*)glyphPosY <= SkTextBlob::RunRecord::Next(&run));
return bounds.makeOffset(run.offset().x(), run.offset().y());
}
@ -382,7 +414,16 @@ SkRect SkTextBlobBuilder::ConservativeRunBounds(const SkTextBlob::RunRecord& run
SkASSERT(SkTextBlob::kFull_Positioning == run.positioning() ||
SkTextBlob::kHorizontal_Positioning == run.positioning());
// First, compute the glyph position bbox.
SkPaint paint;
run.font().applyToPaint(&paint);
const SkRect fontBounds = paint.getFontBounds();
if (fontBounds.isEmpty()) {
// Empty font bounds are likely a font bug. TightBounds has a better chance of
// producing useful results in this case.
return TightRunBounds(run);
}
// Compute the glyph position bbox.
SkRect bounds;
switch (run.positioning()) {
case SkTextBlob::kHorizontal_Positioning: {
@ -410,9 +451,6 @@ SkRect SkTextBlobBuilder::ConservativeRunBounds(const SkTextBlob::RunRecord& run
}
// Expand by typeface glyph bounds.
SkPaint paint;
run.font().applyToPaint(&paint);
const SkRect fontBounds = paint.getFontBounds();
bounds.fLeft += fontBounds.left();
bounds.fTop += fontBounds.top();
bounds.fRight += fontBounds.right();