add SkSfntUtils to parse some known truetype tables

add comments and cleanup to count_tables in SkFontHost_tables.cpp
fix transparency bug in gifs
use (alpha+1) for blending in srcover mode, to ensure opaque results



git-svn-id: http://skia.googlecode.com/svn/trunk@155 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 52 insertions, 0 deletions

diff --git a/include/utils/SkSfntUtils.h b/include/utils/SkSfntUtils.h
new file mode 100644
index 0000000000..1d8f74e83b
--- /dev/null
+++ b/include/utils/SkSfntUtils.h
@@ -0,0 +1,52 @@
+
+#ifndef SkSfntUtils_DEFINED
+#define SkSfntUtils_DEFINED
+
+#include "SkFontHost.h"
+
+struct SkSfntTable_head {
+    SkFixed     fVersion;
+    SkFixed     fRevision;
+    uint32_t    fCheckSumAdjustment;
+    uint32_t    fMagicNumber;
+    uint16_t    fFlags;
+    uint16_t    fUnitsPerEm;
+    Sk64        fDateCreated;
+    Sk64        fDateModified;
+    int16_t     fXMin;
+    int16_t     fYMin;
+    int16_t     fXMax;
+    int16_t     fYMax;
+    uint16_t    fMacStyle;
+    uint16_t    fLowestPPEM;
+    int16_t     fFontDirectionHint;
+    int16_t     fIndexToLocFormat;
+    int16_t     fGlyphDataFormat;
+};
+
+struct SkSfntTable_maxp {
+    SkFixed     fVersion;
+    uint16_t    fNumGlyphs;
+    uint16_t    fMaxPoints;
+    uint16_t    fMaxContours;
+    uint16_t    fMaxComponentPoints;
+    uint16_t    fMaxComponentContours;
+    uint16_t    fMaxZones;
+    uint16_t    fMaxTwilightPoints;
+    uint16_t    fMaxStorage;
+    uint16_t    fMaxFunctionDefs;
+    uint16_t    fMaxInstructionDefs;
+    uint16_t    fMaxStackElements;
+    uint16_t    fMaxSizeOfInstructions;
+    uint16_t    fMaxComponentElements;
+    uint16_t    fMaxComponentDepth;
+};
+
+class SkSfntUtils {
+public:
+    static bool ReadTable_head(SkFontID, SkSfntTable_head*);
+    static bool ReadTable_maxp(SkFontID, SkSfntTable_maxp*);
+};
+
+#endif
+