1 files changed, 65 insertions, 12 deletions

diff --git a/skia/ports/SkFontHost_gamma.cpp b/skia/ports/SkFontHost_gamma.cpp
index 28c7051..0b95bce 100644
--- a/skia/ports/SkFontHost_gamma.cpp
+++ b/skia/ports/SkFontHost_gamma.cpp
@@ -1,42 +1,95 @@
-
 #include "SkFontHost.h"
 #include <math.h>
 
+// define this to use pre-compiled tables for gamma. This is slightly faster,
+// and doesn't create any RW global memory, but means we cannot change the
+// gamma at runtime.
+#define USE_PREDEFINED_GAMMA_TABLES
+
+#ifndef USE_PREDEFINED_GAMMA_TABLES
+    // define this if you want to spew out the "C" code for the tables, given
+    // the current values for SK_BLACK_GAMMA and SK_WHITE_GAMMA.
+    #define DUMP_GAMMA_TABLESx
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+
+#ifdef USE_PREDEFINED_GAMMA_TABLES
+
+#include "sk_predefined_gamma.h"
+
+#else   // use writable globals for gamma tables
+
+static bool gGammaIsBuilt;
+static uint8_t gBlackGamma[256], gWhiteGamma[256];
+
+#define SK_BLACK_GAMMA     (1.4f)
+#define SK_WHITE_GAMMA     (1/1.4f)
+
 static void build_power_table(uint8_t table[], float ee)
 {
-//    printf("------ build_power_table %g\n", ee);
+    //    printf("------ build_power_table %g\n", ee);
     for (int i = 0; i < 256; i++)
     {
         float x = i / 255.f;
-     //   printf(" %d %g", i, x);
+        //   printf(" %d %g", i, x);
         x = powf(x, ee);
-     //   printf(" %g", x);
+        //   printf(" %g", x);
         int xx = SkScalarRound(SkFloatToScalar(x * 255));
-     //   printf(" %d\n", xx);
+        //   printf(" %d\n", xx);
         table[i] = SkToU8(xx);
     }
 }
 
-static bool gGammaIsBuilt;
-static uint8_t gBlackGamma[256], gWhiteGamma[256];
+#ifdef DUMP_GAMMA_TABLES
+
+#include "SkString.h"
 
-#define ANDROID_BLACK_GAMMA     (1.4f)
-#define ANDROID_WHITE_GAMMA     (1/1.4f)
+static void dump_a_table(const char name[], const uint8_t table[],
+                         float gamma) {
+    SkDebugf("\n");
+    SkDebugf("\/\/ Gamma table for %g\n", gamma);
+    SkDebugf("static const uint8_t %s[] = {\n", name);
+    for (int y = 0; y < 16; y++) {
+        SkString line, tmp;
+        for (int x = 0; x < 16; x++) {
+            tmp.printf("0x%02X, ", *table++);
+            line.append(tmp);
+        }
+        SkDebugf("    %s\n", line.c_str());
+    }
+    SkDebugf("};\n");
+}
+
+#endif
+
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
 
 void SkFontHost::GetGammaTables(const uint8_t* tables[2])
 {
-    // would be cleaner if these tables were precomputed and just linked in
+#ifndef USE_PREDEFINED_GAMMA_TABLES
     if (!gGammaIsBuilt)
     {
-        build_power_table(gBlackGamma, ANDROID_BLACK_GAMMA);
-        build_power_table(gWhiteGamma, ANDROID_WHITE_GAMMA);
+        build_power_table(gBlackGamma, SK_BLACK_GAMMA);
+        build_power_table(gWhiteGamma, SK_WHITE_GAMMA);
         gGammaIsBuilt = true;
+
+#ifdef DUMP_GAMMA_TABLES
+        dump_a_table("gBlackGamma", gBlackGamma, SK_BLACK_GAMMA);
+        dump_a_table("gWhiteGamma", gWhiteGamma, SK_WHITE_GAMMA);
+#endif
     }
+#endif
     tables[0] = gBlackGamma;
     tables[1] = gWhiteGamma;
 }
 
+// If the luminance is <= this value, then apply the black gamma table
 #define BLACK_GAMMA_THRESHOLD   0x40
+
+// If the luminance is >= this value, then apply the white gamma table
 #define WHITE_GAMMA_THRESHOLD   0xC0
 
 int SkFontHost::ComputeGammaFlag(const SkPaint& paint)