Use nested template expansions to implement Config8888 conversions.
Review URL: https://codereview.appspot.com/5690068
git-svn-id: http://skia.googlecode.com/svn/trunk@3230 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkConfig8888.cpp b/src/core/SkConfig8888.cpp
new file mode 100644
index 0000000..67a9e41
--- /dev/null
+++ b/src/core/SkConfig8888.cpp
@@ -0,0 +1,257 @@
+#include "SkConfig8888.h"
+
+namespace {
+
+template <int A_IDX, int R_IDX, int G_IDX, int B_IDX>
+inline uint32_t pack_config8888(uint32_t a, uint32_t r,
+ uint32_t g, uint32_t b) {
+#ifdef SK_CPU_LENDIAN
+ return (a << (A_IDX * 8)) | (r << (R_IDX * 8)) |
+ (g << (G_IDX * 8)) | (b << (B_IDX * 8));
+#else
+ return (a << ((3-A_IDX) * 8)) | (r << ((3-R_IDX) * 8)) |
+ (g << ((3-G_IDX) * 8)) | (b << ((3-B_IDX) * 8));
+#endif
+}
+
+template <int A_IDX, int R_IDX, int G_IDX, int B_IDX>
+inline void unpack_config8888(uint32_t color,
+ uint32_t* a, uint32_t* r,
+ uint32_t* g, uint32_t* b) {
+#ifdef SK_CPU_LENDIAN
+ *a = (color >> (A_IDX * 8)) & 0xff;
+ *r = (color >> (R_IDX * 8)) & 0xff;
+ *g = (color >> (G_IDX * 8)) & 0xff;
+ *b = (color >> (B_IDX * 8)) & 0xff;
+#else
+ *a = (color >> ((3 - A_IDX) * 8)) & 0xff;
+ *r = (color >> ((3 - R_IDX) * 8)) & 0xff;
+ *g = (color >> ((3 - G_IDX) * 8)) & 0xff;
+ *b = (color >> ((3 - B_IDX) * 8)) & 0xff;
+#endif
+}
+
+#ifdef SK_CPU_LENDIAN
+ static const int SK_NATIVE_A_IDX = SK_A32_SHIFT / 8;
+ static const int SK_NATIVE_R_IDX = SK_R32_SHIFT / 8;
+ static const int SK_NATIVE_G_IDX = SK_G32_SHIFT / 8;
+ static const int SK_NATIVE_B_IDX = SK_B32_SHIFT / 8;
+#else
+ static const int SK_NATIVE_A_IDX = 3 - (SK_A32_SHIFT / 8);
+ static const int SK_NATIVE_R_IDX = 3 - (SK_R32_SHIFT / 8);
+ static const int SK_NATIVE_G_IDX = 3 - (SK_G32_SHIFT / 8);
+ static const int SK_NATIVE_B_IDX = 3 - (SK_B32_SHIFT / 8);
+#endif
+
+/**
+ * convert_pixel<OUT_CFG, IN_CFG converts a pixel value from one Config8888 to
+ * another. It is implemented by first expanding OUT_CFG to r, g, b, a indices
+ * and an is_premul bool as params to another template function. Then IN_CFG is
+ * expanded via another function call.
+ */
+
+template <bool OUT_PM, int OUT_A_IDX, int OUT_R_IDX, int OUT_G_IDX, int OUT_B_IDX,
+ bool IN_PM, int IN_A_IDX, int IN_R_IDX, int IN_G_IDX, int IN_B_IDX>
+inline uint32_t convert_pixel(uint32_t pixel) {
+ uint32_t a, r, g, b;
+ unpack_config8888<IN_A_IDX, IN_R_IDX, IN_G_IDX, IN_B_IDX>(pixel, &a, &r, &g, &b);
+ if (IN_PM && !OUT_PM) {
+ // We're doing the explicit divide to match WebKit layout
+ // test expectations. We can modify and rebaseline if there
+ // it can be shown that there is a more performant way to
+ // unpremul.
+ if (a) {
+ r = r * 0xff / a;
+ g = g * 0xff / a;
+ b = b * 0xff / a;
+ } else {
+ return 0;
+ }
+ } else if (!IN_PM && OUT_PM) {
+ // This matches WebKit's conversion which we are replacing.
+ // We can consider alternative rounding rules for performance.
+ r = SkMulDiv255Ceiling(r, a);
+ g = SkMulDiv255Ceiling(g, a);
+ b = SkMulDiv255Ceiling(b, a);
+ }
+ return pack_config8888<OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX>(a, r, g, b);
+}
+
+template <bool OUT_PM, int OUT_A_IDX, int OUT_R_IDX, int OUT_G_IDX, int OUT_B_IDX, SkCanvas::Config8888 IN_CFG>
+inline uint32_t convert_pixel(uint32_t pixel) {
+ switch(IN_CFG) {
+ case SkCanvas::kNative_Premul_Config8888:
+ return convert_pixel<OUT_PM, OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX,
+ true, SK_NATIVE_A_IDX, SK_NATIVE_R_IDX, SK_NATIVE_G_IDX, SK_NATIVE_B_IDX>(pixel);
+ break;
+ case SkCanvas::kNative_Unpremul_Config8888:
+ return convert_pixel<OUT_PM, OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX,
+ false, SK_NATIVE_A_IDX, SK_NATIVE_R_IDX, SK_NATIVE_G_IDX, SK_NATIVE_B_IDX>(pixel);
+ break;
+ case SkCanvas::kBGRA_Premul_Config8888:
+ return convert_pixel<OUT_PM, OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX,
+ true, 3, 2, 1, 0>(pixel);
+ break;
+ case SkCanvas::kBGRA_Unpremul_Config8888:
+ return convert_pixel<OUT_PM, OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX,
+ false, 3, 2, 1, 0>(pixel);
+ break;
+ case SkCanvas::kRGBA_Premul_Config8888:
+ return convert_pixel<OUT_PM, OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX,
+ true, 3, 0, 1, 2>(pixel);
+ break;
+ case SkCanvas::kRGBA_Unpremul_Config8888:
+ return convert_pixel<OUT_PM, OUT_A_IDX, OUT_R_IDX, OUT_G_IDX, OUT_B_IDX,
+ false, 3, 0, 1, 2>(pixel);
+ break;
+ default:
+ SkDEBUGFAIL("Unexpected config8888");
+ return 0;
+ break;
+ }
+}
+
+template <SkCanvas::Config8888 OUT_CFG, SkCanvas::Config8888 IN_CFG>
+inline uint32_t convert_pixel(uint32_t pixel) {
+ switch(OUT_CFG) {
+ case SkCanvas::kNative_Premul_Config8888:
+ return convert_pixel<true, SK_NATIVE_A_IDX, SK_NATIVE_R_IDX, SK_NATIVE_G_IDX, SK_NATIVE_B_IDX, IN_CFG>(pixel);
+ break;
+ case SkCanvas::kNative_Unpremul_Config8888:
+ return convert_pixel<false, SK_NATIVE_A_IDX, SK_NATIVE_R_IDX, SK_NATIVE_G_IDX, SK_NATIVE_B_IDX, IN_CFG>(pixel);
+ break;
+ case SkCanvas::kBGRA_Premul_Config8888:
+ return convert_pixel<true, 3, 2, 1, 0, IN_CFG>(pixel);
+ break;
+ case SkCanvas::kBGRA_Unpremul_Config8888:
+ return convert_pixel<false, 3, 2, 1, 0, IN_CFG>(pixel);
+ break;
+ case SkCanvas::kRGBA_Premul_Config8888:
+ return convert_pixel<true, 3, 0, 1, 2, IN_CFG>(pixel);
+ break;
+ case SkCanvas::kRGBA_Unpremul_Config8888:
+ return convert_pixel<false, 3, 0, 1, 2, IN_CFG>(pixel);
+ break;
+ default:
+ SkDEBUGFAIL("Unexpected config8888");
+ return 0;
+ break;
+ }
+}
+
+/**
+ * SkConvertConfig8888Pixels has 6 * 6 possible combinations of src and dst
+ * configs. Each is implemented as an instantiation templated function. Two
+ * levels of switch statements are used to select the correct instantiation, one
+ * for the src config and one for the dst config.
+ */
+
+template <SkCanvas::Config8888 DST_CFG, SkCanvas::Config8888 SRC_CFG>
+inline void convert_config8888(uint32_t* dstPixels,
+ size_t dstRowBytes,
+ const uint32_t* srcPixels,
+ size_t srcRowBytes,
+ int width,
+ int height) {
+ intptr_t dstPix = reinterpret_cast<intptr_t>(dstPixels);
+ intptr_t srcPix = reinterpret_cast<intptr_t>(srcPixels);
+
+ for (int y = 0; y < height; ++y) {
+ srcPixels = reinterpret_cast<const uint32_t*>(srcPix);
+ dstPixels = reinterpret_cast<uint32_t*>(dstPix);
+ for (int x = 0; x < width; ++x) {
+ dstPixels[x] = convert_pixel<DST_CFG, SRC_CFG>(srcPixels[x]);
+ }
+ dstPix += dstRowBytes;
+ srcPix += srcRowBytes;
+ }
+}
+
+template <SkCanvas::Config8888 SRC_CFG>
+inline void convert_config8888(uint32_t* dstPixels,
+ size_t dstRowBytes,
+ SkCanvas::Config8888 dstConfig,
+ const uint32_t* srcPixels,
+ size_t srcRowBytes,
+ int width,
+ int height) {
+ switch(dstConfig) {
+ case SkCanvas::kNative_Premul_Config8888:
+ convert_config8888<SkCanvas::kNative_Premul_Config8888, SRC_CFG>(dstPixels, dstRowBytes, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kNative_Unpremul_Config8888:
+ convert_config8888<SkCanvas::kNative_Unpremul_Config8888, SRC_CFG>(dstPixels, dstRowBytes, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kBGRA_Premul_Config8888:
+ convert_config8888<SkCanvas::kBGRA_Premul_Config8888, SRC_CFG>(dstPixels, dstRowBytes, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kBGRA_Unpremul_Config8888:
+ convert_config8888<SkCanvas::kBGRA_Unpremul_Config8888, SRC_CFG>(dstPixels, dstRowBytes, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kRGBA_Premul_Config8888:
+ convert_config8888<SkCanvas::kRGBA_Premul_Config8888, SRC_CFG>(dstPixels, dstRowBytes, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kRGBA_Unpremul_Config8888:
+ convert_config8888<SkCanvas::kRGBA_Unpremul_Config8888, SRC_CFG>(dstPixels, dstRowBytes, srcPixels, srcRowBytes, width, height);
+ break;
+ default:
+ SkDEBUGFAIL("Unexpected config8888");
+ break;
+ }
+}
+
+}
+
+void SkConvertConfig8888Pixels(uint32_t* dstPixels,
+ size_t dstRowBytes,
+ SkCanvas::Config8888 dstConfig,
+ const uint32_t* srcPixels,
+ size_t srcRowBytes,
+ SkCanvas::Config8888 srcConfig,
+ int width,
+ int height) {
+ if (srcConfig == dstConfig) {
+ if (srcPixels == dstPixels) {
+ return;
+ }
+ if (dstRowBytes == srcRowBytes &&
+ 4U * width == srcRowBytes) {
+ memcpy(dstPixels, srcPixels, srcRowBytes * height);
+ return;
+ } else {
+ intptr_t srcPix = reinterpret_cast<intptr_t>(srcPixels);
+ intptr_t dstPix = reinterpret_cast<intptr_t>(dstPixels);
+ for (int y = 0; y < height; ++y) {
+ srcPixels = reinterpret_cast<const uint32_t*>(srcPix);
+ dstPixels = reinterpret_cast<uint32_t*>(dstPix);
+ memcpy(dstPixels, srcPixels, 4 * width);
+ srcPix += srcRowBytes;
+ dstPix += dstRowBytes;
+ }
+ return;
+ }
+ }
+ switch(srcConfig) {
+ case SkCanvas::kNative_Premul_Config8888:
+ convert_config8888<SkCanvas::kNative_Premul_Config8888>(dstPixels, dstRowBytes, dstConfig, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kNative_Unpremul_Config8888:
+ convert_config8888<SkCanvas::kNative_Unpremul_Config8888>(dstPixels, dstRowBytes, dstConfig, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kBGRA_Premul_Config8888:
+ convert_config8888<SkCanvas::kBGRA_Premul_Config8888>(dstPixels, dstRowBytes, dstConfig, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kBGRA_Unpremul_Config8888:
+ convert_config8888<SkCanvas::kBGRA_Unpremul_Config8888>(dstPixels, dstRowBytes, dstConfig, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kRGBA_Premul_Config8888:
+ convert_config8888<SkCanvas::kRGBA_Premul_Config8888>(dstPixels, dstRowBytes, dstConfig, srcPixels, srcRowBytes, width, height);
+ break;
+ case SkCanvas::kRGBA_Unpremul_Config8888:
+ convert_config8888<SkCanvas::kRGBA_Unpremul_Config8888>(dstPixels, dstRowBytes, dstConfig, srcPixels, srcRowBytes, width, height);
+ break;
+ default:
+ SkDEBUGFAIL("Unexpected config8888");
+ break;
+ }
+}