Fix issue where bw bitmask uploaded to gr 565, 8888 glyph cache

Review URL: https://codereview.appspot.com/6498105/



git-svn-id: http://skia.googlecode.com/svn/trunk@5459 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 42 insertions, 14 deletions

diff --git a/src/gpu/SkGrFontScaler.cpp b/src/gpu/SkGrFontScaler.cpp
index 26412f4a35..208e46dfc5 100644
--- a/src/gpu/SkGrFontScaler.cpp
+++ b/src/gpu/SkGrFontScaler.cpp
@@ -110,17 +110,31 @@ bool SkGrFontScaler::getPackedGlyphBounds(GrGlyph::PackedID packed,
 
 }
 
-static void bits_to_bytes(const uint8_t bits[], uint8_t bytes[], int count) {
-    while (count > 0) {
-        unsigned mask = *bits++;
-        for (int i = 7; i >= 0; --i) {
-            *bytes++ = (mask & (1 << i)) ? 0xFF : 0;
-            if (--count == 0) {
-                return;
+namespace {
+// expands each bit in a bitmask to 0 or ~0 of type INT_TYPE. Used to expand a BW glyph mask to
+// A8, RGB565, or RGBA8888.
+template <typename INT_TYPE>
+void expand_bits(INT_TYPE* dst,
+                 const uint8_t* src,
+                 int width,
+                 int height,
+                 int dstRowBytes,
+                 int srcRowBytes) {
+    for (int i = 0; i < height; ++i) {
+        int rowWritesLeft = width;
+        const uint8_t* s = src;
+        INT_TYPE* d = dst;
+        while (rowWritesLeft > 0) {
+            unsigned mask = *s++;
+            for (int i = 7; i >= 0 && rowWritesLeft; --i, --rowWritesLeft) {
+                *d++ = (mask & (1 << i)) ? (INT_TYPE)(~0UL) : 0;
             }
         }
+        dst = reinterpret_cast<INT_TYPE*>(reinterpret_cast<intptr_t>(dst) + dstRowBytes);
+        src += srcRowBytes;
     }
 }
+}
 
 bool SkGrFontScaler::getPackedGlyphImage(GrGlyph::PackedID packed,
                                          int width, int height,
@@ -136,14 +150,28 @@ bool SkGrFontScaler::getPackedGlyphImage(GrGlyph::PackedID packed,
     }
 
     int srcRB = glyph.rowBytes();
-    if (SkMask::kBW_Format == fStrike->getMaskFormat()) {
-        // expand bits to bytes
+    // The windows font host sometimes has BW glyphs in a non-BW strike. So it is important here to
+    // check the glyph's format, not the strike's format, and to be able to convert to any of the
+    // GrMaskFormats.
+    if (SkMask::kBW_Format == glyph.fMaskFormat) {
+        // expand bits to our mask type
         const uint8_t* bits = reinterpret_cast<const uint8_t*>(src);
-        uint8_t* bytes = reinterpret_cast<uint8_t*>(dst);
-        for (int y = 0; y < height; y++) {
-            bits_to_bytes(bits, bytes, width);
-            bits += srcRB;
-            bytes += dstRB;
+        switch (this->getMaskFormat()) {
+            case kA8_GrMaskFormat:{
+                uint8_t* bytes = reinterpret_cast<uint8_t*>(dst);
+                expand_bits(bytes, bits, width, height, dstRB, srcRB);
+                break;
+            }
+            case kA565_GrMaskFormat: {
+                uint16_t* rgb565 = reinterpret_cast<uint16_t*>(dst);
+                expand_bits(rgb565, bits, width, height, dstRB, srcRB);
+                break;
+            }
+            case kA888_GrMaskFormat: {
+                uint32_t* rgba8888 = reinterpret_cast<uint32_t*>(dst);
+                expand_bits(rgba8888, bits, width, height, dstRB, srcRB);
+                break;
+            }
         }
     } else if (srcRB == dstRB) {
         memcpy(dst, src, dstRB * height);