From a7c4c98a223f6dd1370f3a7a00e65b8e94f2e742 Mon Sep 17 00:00:00 2001
From: bungeman <bungeman@google.com>
Date: Thu, 28 Aug 2014 11:42:29 -0700
Subject: [PATCH] <third_party/skia> Fix error handling in DirectWrite with
tiny text.
If there is an error while trying to determine the metrics,
we need to bail instead of potentially using uninitialized data.
R=reed@google.com, mtklein@google.com
Author: bungeman@google.com
Review URL: https://codereview.chromium.org/511783003
Change-Id: I03abc22567396b7e174380e10fc0007523355473
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>
---
.../skia/src/ports/SkScalerContext_win_dw.cpp | 86 ++++++++++++-------
.../skia/src/ports/SkScalerContext_win_dw.h | 8 +-
2 files changed, 57 insertions(+), 37 deletions(-)
diff --git a/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.cpp b/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.cpp
index e1fc92fc09c..67a6c4ff1d2 100644
--- a/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.cpp
+++ b/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.cpp
@@ -404,10 +404,10 @@ void SkScalerContext_DW::generateAdvance(SkGlyph* glyph) {
glyph->fAdvanceY = SkScalarToFixed(vecs[0].fY);
}
-void SkScalerContext_DW::getBoundingBox(SkGlyph* glyph,
- DWRITE_RENDERING_MODE renderingMode,
- DWRITE_TEXTURE_TYPE textureType,
- RECT* bbox)
+HRESULT SkScalerContext_DW::getBoundingBox(SkGlyph* glyph,
+ DWRITE_RENDERING_MODE renderingMode,
+ DWRITE_TEXTURE_TYPE textureType,
+ RECT* bbox)
{
//Measure raster size.
fXform.dx = SkFixedToFloat(glyph->getSubXFixed());
@@ -432,50 +432,70 @@ void SkScalerContext_DW::getBoundingBox(SkGlyph* glyph,
run.glyphOffsets = &offset;
SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
- HRVM(fTypeface->fFactory->CreateGlyphRunAnalysis(
- &run,
- 1.0f, // pixelsPerDip,
- &fXform,
- renderingMode,
- fMeasuringMode,
- 0.0f, // baselineOriginX,
- 0.0f, // baselineOriginY,
- &glyphRunAnalysis),
- "Could not create glyph run analysis.");
+ HRM(fTypeface->fFactory->CreateGlyphRunAnalysis(
+ &run,
+ 1.0f, // pixelsPerDip,
+ &fXform,
+ renderingMode,
+ fMeasuringMode,
+ 0.0f, // baselineOriginX,
+ 0.0f, // baselineOriginY,
+ &glyphRunAnalysis),
+ "Could not create glyph run analysis.");
+
+ HRM(glyphRunAnalysis->GetAlphaTextureBounds(textureType, bbox),
+ "Could not get texture bounds.");
+
+ return S_OK;
+}
- HRVM(glyphRunAnalysis->GetAlphaTextureBounds(textureType, bbox),
- "Could not get texture bounds.");
+/** GetAlphaTextureBounds succeeds but sometimes returns empty bounds like
+ * { 0x80000000, 0x80000000, 0x80000000, 0x80000000 }
+ * for small, but not quite zero, sized glyphs.
+ * Only set as non-empty if the returned bounds are non-empty.
+ */
+static bool glyph_check_and_set_bounds(SkGlyph* glyph, const RECT& bbox) {
+ if (bbox.left >= bbox.right || bbox.top >= bbox.bottom) {
+ return false;
+ }
+ glyph->fWidth = SkToU16(bbox.right - bbox.left);
+ glyph->fHeight = SkToU16(bbox.bottom - bbox.top);
+ glyph->fLeft = SkToS16(bbox.left);
+ glyph->fTop = SkToS16(bbox.top);
+ return true;
}
void SkScalerContext_DW::generateMetrics(SkGlyph* glyph) {
glyph->fWidth = 0;
+ glyph->fHeight = 0;
+ glyph->fLeft = 0;
+ glyph->fTop = 0;
this->generateAdvance(glyph);
RECT bbox;
- this->getBoundingBox(glyph, fRenderingMode, fTextureType, &bbox);
+ HRVM(this->getBoundingBox(glyph, fRenderingMode, fTextureType, &bbox),
+ "Requested bounding box could not be determined.");
+
+ if (glyph_check_and_set_bounds(glyph, bbox)) {
+ return;
+ }
// GetAlphaTextureBounds succeeds but returns an empty RECT if there are no
// glyphs of the specified texture type. When this happens, try with the
// alternate texture type.
- if (bbox.left == bbox.right || bbox.top == bbox.bottom) {
- if (DWRITE_TEXTURE_CLEARTYPE_3x1 == fTextureType) {
- this->getBoundingBox(glyph,
- DWRITE_RENDERING_MODE_ALIASED,
- DWRITE_TEXTURE_ALIASED_1x1,
- &bbox);
- if (bbox.left != bbox.right && bbox.top != bbox.bottom) {
- glyph->fForceBW = 1;
- }
+ if (DWRITE_TEXTURE_CLEARTYPE_3x1 == fTextureType) {
+ HRVM(this->getBoundingBox(glyph,
+ DWRITE_RENDERING_MODE_ALIASED,
+ DWRITE_TEXTURE_ALIASED_1x1,
+ &bbox),
+ "Fallback bounding box could not be determined.");
+ if (glyph_check_and_set_bounds(glyph, bbox)) {
+ glyph->fForceBW = 1;
}
- // TODO: handle the case where a request for DWRITE_TEXTURE_ALIASED_1x1
- // fails, and try DWRITE_TEXTURE_CLEARTYPE_3x1.
}
-
- glyph->fWidth = SkToU16(bbox.right - bbox.left);
- glyph->fHeight = SkToU16(bbox.bottom - bbox.top);
- glyph->fLeft = SkToS16(bbox.left);
- glyph->fTop = SkToS16(bbox.top);
+ // TODO: handle the case where a request for DWRITE_TEXTURE_ALIASED_1x1
+ // fails, and try DWRITE_TEXTURE_CLEARTYPE_3x1.
}
void SkScalerContext_DW::generateFontMetrics(SkPaint::FontMetrics* mx,
diff --git a/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.h b/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.h
index 0edd869d05d..3af90a73bb7 100644
--- a/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.h
+++ b/chromium/third_party/skia/src/ports/SkScalerContext_win_dw.h
@@ -38,10 +38,10 @@ private:
DWRITE_RENDERING_MODE renderingMode,
DWRITE_TEXTURE_TYPE textureType);
- void getBoundingBox(SkGlyph* glyph,
- DWRITE_RENDERING_MODE renderingMode,
- DWRITE_TEXTURE_TYPE textureType,
- RECT* bbox);
+ HRESULT getBoundingBox(SkGlyph* glyph,
+ DWRITE_RENDERING_MODE renderingMode,
+ DWRITE_TEXTURE_TYPE textureType,
+ RECT* bbox);
SkTDArray<uint8_t> fBits;
/** The total matrix without the text height scale. */
--
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