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

3 files changed, 98 insertions, 1 deletions

diff --git a/src/utils/SkNinePatch.cpp b/src/utils/SkNinePatch.cpp
index b8e11fbcaf..3d85edcf93 100644
--- a/src/utils/SkNinePatch.cpp
+++ b/src/utils/SkNinePatch.cpp
@@ -186,7 +186,7 @@ void SkNinePatch::DrawMesh(SkCanvas* canvas, const SkRect& bounds,
     if (numXDivs == 2 && numYDivs <= 2) {
         mesh.fIndices = g3x3Indices;
     } else {
-        int n = fillIndices(indices, numXDivs + 1, numYDivs + 1);
+        SkDEBUGCODE(int n =) fillIndices(indices, numXDivs + 1, numYDivs + 1);
         SkASSERT(n == indexCount);
         mesh.fIndices = indices;
     }
diff --git a/src/utils/SkSfntUtils.cpp b/src/utils/SkSfntUtils.cpp
new file mode 100644
index 0000000000..36f1f97da9
--- /dev/null
+++ b/src/utils/SkSfntUtils.cpp
@@ -0,0 +1,87 @@
+#include "SkEndian.h"
+#include "SkSfntUtils.h"
+
+static uint16_t parse_be16(const uint8_t*& p) {
+    uint16_t value = (p[0] << 8) | p[1];
+    p += 2;
+    return value;
+}
+
+static uint32_t parse_be32(const uint8_t*& p) {
+    uint32_t value = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
+    p += 4;
+    return value;
+}
+
+static Sk64 parse_be64(const uint8_t*& p) {
+    Sk64 value;
+    value.fHi = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
+    value.fLo = (p[4] << 24) | (p[5] << 16) | (p[6] << 8) | p[7];
+    p += 8;
+    return value;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+bool SkSfntUtils::ReadTable_head(SkFontID fontID, SkSfntTable_head* head) {
+    static const uint32_t gTag = SkSetFourByteTag('h', 'e', 'a', 'd');
+    static const ssize_t gSize = 54;
+    
+    uint8_t storage[gSize];
+    ssize_t size = SkFontHost::GetTableData(fontID, gTag, 0, gSize, storage);
+    if (size != gSize) {
+        return false;
+    }
+    
+    const uint8_t* p = storage;
+    head->fVersion = parse_be32(p);
+    head->fRevision = parse_be32(p);
+    head->fCheckSumAdjustment = parse_be32(p);
+    head->fMagicNumber = parse_be32(p);
+    head->fFlags = parse_be16(p);
+    head->fUnitsPerEm = parse_be16(p);
+    head->fDateCreated = parse_be64(p);
+    head->fDateModified = parse_be64(p);
+    head->fXMin = parse_be16(p);
+    head->fXMin = parse_be16(p);
+    head->fXMin = parse_be16(p);
+    head->fXMin = parse_be16(p);
+    head->fMacStyle = parse_be16(p);
+    head->fLowestPPEM = parse_be16(p);
+    head->fFontDirectionHint = parse_be16(p);
+    head->fIndexToLocFormat = parse_be16(p);
+    head->fGlyphDataFormat = parse_be16(p);
+    SkASSERT(p - storage == size);
+    return true;
+}
+
+bool SkSfntUtils::ReadTable_maxp(SkFontID fontID, SkSfntTable_maxp* maxp) {
+    static const uint32_t gTag = SkSetFourByteTag('m', 'a', 'x', 'p');
+    static const ssize_t gSize = 32;
+    
+    uint8_t storage[gSize];
+    ssize_t size = SkFontHost::GetTableData(fontID, gTag, 0, gSize, storage);
+    if (size != gSize) {
+        return false;
+    }
+    
+    const uint8_t* p = storage;
+    maxp->fVersion = parse_be32(p);
+    maxp->fNumGlyphs = parse_be16(p);
+    maxp->fMaxPoints = parse_be16(p);
+    maxp->fMaxContours = parse_be16(p);
+    maxp->fMaxComponentPoints = parse_be16(p);
+    maxp->fMaxComponentContours = parse_be16(p);
+    maxp->fMaxZones = parse_be16(p);
+    maxp->fMaxTwilightPoints = parse_be16(p);
+    maxp->fMaxStorage = parse_be16(p);
+    maxp->fMaxFunctionDefs = parse_be16(p);
+    maxp->fMaxInstructionDefs = parse_be16(p);
+    maxp->fMaxStackElements = parse_be16(p);
+    maxp->fMaxSizeOfInstructions = parse_be16(p);
+    maxp->fMaxComponentElements = parse_be16(p);
+    maxp->fMaxComponentDepth = parse_be16(p);
+    SkASSERT(p - storage == size);
+    return true;
+}
+
diff --git a/src/utils/utils_files.mk b/src/utils/utils_files.mk
new file mode 100644
index 0000000000..a8c9496a86
--- /dev/null
+++ b/src/utils/utils_files.mk
@@ -0,0 +1,10 @@
+SOURCE := \
+	SkCamera.cpp \
+	SkColorMatrix.cpp \
+	SkCullPoints.cpp \
+	SkDumpCanvas.cpp \
+	SkInterpolator.cpp \
+	SkNinePatch.cpp \
+	SkProxyCanvas.cpp \
+	SkSfntUtils.cpp \
+	SkUnitMappers.cpp