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Improve SkScalerContext_GDI::generateCharToGlyph for non-BMP code points.

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Sometimes, when ScriptShape is presented with a surrogate pair which does
not map to a glyph, it returns two space glyphs instead of .notdef (0).
Detect this class of issues and handle appropriately.



git-svn-id: http://skia.googlecode.com/svn/trunk@11660 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
bungeman@google.com 2013-10-08 21:32:15 +00:00
parent dac4a1d518
commit 27f74aab32
2 changed files with 27 additions and 11 deletions
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4
include/utils/win/SkHRESULT.h
View File

@ -38,6 +38,7 @@ The HR variants will return the HRESULT when FAILED.
The HRB variants will return false when FAILED.
The HRN variants will return NULL when FAILED.
The HRV variants will simply return when FAILED.
The HRZ variants will return 0 when FAILED.
*/
#define HR(ex) HR_GENERAL(ex, NULL, _hr)
#define HRM(ex, msg) HR_GENERAL(ex, msg, _hr)
@ -50,5 +51,8 @@ The HRV variants will simply return when FAILED.
#define HRV(ex) HR_GENERAL(ex, NULL, )
#define HRVM(ex, msg) HR_GENERAL(ex, msg, )
#define HRZ(ex) HR_GENERAL(ex, NULL, 0)
#define HRZM(ex, msg) HR_GENERAL(ex, msg, 0)
//@}
#endif

34
src/ports/SkFontHost_win.cpp
View File

@ -14,6 +14,7 @@
#include "SkFontDescriptor.h"
#include "SkFontHost.h"
#include "SkGlyph.h"
#include "SkHRESULT.h"
#include "SkMaskGamma.h"
#include "SkOTTable_maxp.h"
#include "SkOTTable_name.h"
@ -849,18 +850,29 @@ uint16_t SkScalerContext_GDI::generateCharToGlyph(SkUnichar utf32) {
}
} else {
// Use uniscribe to detemine glyph index for non-BMP characters.
// Need to add extra item to SCRIPT_ITEM to work around a bug in older
// windows versions. https://bugzilla.mozilla.org/show_bug.cgi?id=366643
SCRIPT_ITEM si[2 + 1];
int items;
SkAssertResult(
SUCCEEDED(ScriptItemize(utf16, 2, 2, NULL, NULL, si, &items)));
static const int numWCHAR = 2;
static const int maxItems = 2;
// MSDN states that this can be NULL, but some things don't work then.
SCRIPT_CONTROL sc = { 0 };
// Add extra item to SCRIPT_ITEM to work around a bug (now documented).
// https://bugzilla.mozilla.org/show_bug.cgi?id=366643
SCRIPT_ITEM si[maxItems + 1];
int numItems;
HRZM(ScriptItemize(utf16, numWCHAR, maxItems, &sc, NULL, si, &numItems),
"Could not itemize character.");
WORD log[2];
SCRIPT_VISATTR vsa;
int glyphs;
SkAssertResult(SUCCEEDED(ScriptShape(
fDDC, &fSC, utf16, 2, 1, &si[0].a, &index, log, &vsa, &glyphs)));
// Sometimes ScriptShape cannot find a glyph for a non-BMP and returns 2 space glyphs.
static const int maxGlyphs = 2;
SCRIPT_VISATTR vsa[maxGlyphs];
WORD outGlyphs[maxGlyphs];
WORD logClust[numWCHAR];
int numGlyphs;
HRZM(ScriptShape(fDDC, &fSC, utf16, numWCHAR, maxGlyphs, &si[0].a,
outGlyphs, logClust, vsa, &numGlyphs),
"Could not shape character.");
if (1 == numGlyphs) {
index = outGlyphs[0];
}
}
return index;
}