add virtuals to optimize composing colorfilters

src/effects/SkTableColorFilter.cpp

 
 #include "SkBitmap.h"
 #include "SkTableColorFilter.h"
 #include "SkColorPriv.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkUnPreMultiply.h"
 #include "SkString.h"
 
 class SkTable_ColorFilter : public SkColorFilter {
@@ skipping 23 matching lines @@
             memcpy(dst, tableB, 256);
             fFlags |= kB_Flag;
         }
     }
 
     virtual ~SkTable_ColorFilter() {
         SkDELETE(fBitmap);
     }
 
     bool asComponentTable(SkBitmap* table) const SK_OVERRIDE;
+    SkColorFilter* newComposed(const SkColorFilter* inner) const SK_OVERRIDE;
 
 #if SK_SUPPORT_GPU
     GrFragmentProcessor* asFragmentProcessor(GrContext* context) const SK_OVERRIDE;
 #endif
 
-    virtual void filterSpan(const SkPMColor src[], int count,
-                            SkPMColor dst[]) const SK_OVERRIDE;
+    void filterSpan(const SkPMColor src[], int count, SkPMColor dst[]) const SK_OVERRIDE;
 
     SK_TO_STRING_OVERRIDE()
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTable_ColorFilter)
 
     enum {
         kA_Flag = 1 << 0,
         kR_Flag = 1 << 1,
         kG_Flag = 1 << 2,
         kB_Flag = 1 << 3,
@@ skipping 41 matching lines @@
     0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7,
     0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
     0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7,
     0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
     0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7,
     0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
     0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7,
     0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF
 };
 
-void SkTable_ColorFilter::filterSpan(const SkPMColor src[], int count,
-                                     SkPMColor dst[]) const {
+void SkTable_ColorFilter::filterSpan(const SkPMColor src[], int count, SkPMColor dst[]) const {
     const uint8_t* table = fStorage;
     const uint8_t* tableA = gIdentityTable;
     const uint8_t* tableR = gIdentityTable;
     const uint8_t* tableG = gIdentityTable;
     const uint8_t* tableB = gIdentityTable;
     if (fFlags & kA_Flag) {
         tableA = table; table += 256;
     }
     if (fFlags & kR_Flag) {
         tableR = table; table += 256;
@@ skipping 143 matching lines @@
                 }
                 bitmapPixels += 256;
             }
             fBitmap = bmp;
         }
         *table = *fBitmap;
     }
     return true;
 }
 
+// Combines the two lookup tables so that making a lookup using res[] has
+// the same effect as making a lookup through inner[] then outer[].
+static void combine_tables(uint8_t res[256], const uint8_t outer[256], const uint8_t inner[256]) {
+    for (int i = 0; i < 256; i++) {
+        res[i] = outer[inner[i]];
+    }
+}
+
+SkColorFilter* SkTable_ColorFilter::newComposed(const SkColorFilter* innerFilter) const {
+    SkBitmap innerBM;
+    if (!innerFilter->asComponentTable(&innerBM)) {
+        return NULL;
+    }
+
+    innerBM.lockPixels();
+    if (NULL == innerBM.getPixels()) {
+        return NULL;
+    }
+
+    const uint8_t* table = fStorage;
+    const uint8_t* tableA = gIdentityTable;
+    const uint8_t* tableR = gIdentityTable;
+    const uint8_t* tableG = gIdentityTable;
+    const uint8_t* tableB = gIdentityTable;
+    if (fFlags & kA_Flag) {
+        tableA = table; table += 256;
+    }
+    if (fFlags & kR_Flag) {
+        tableR = table; table += 256;
+    }
+    if (fFlags & kG_Flag) {
+        tableG = table; table += 256;
+    }
+    if (fFlags & kB_Flag) {
+        tableB = table;
+    }
+
+    uint8_t concatA[256];
+    uint8_t concatR[256];
+    uint8_t concatG[256];
+    uint8_t concatB[256];
+
+    combine_tables(concatA, tableA, innerBM.getAddr8(0, 0));
+    combine_tables(concatR, tableR, innerBM.getAddr8(0, 1));
+    combine_tables(concatG, tableG, innerBM.getAddr8(0, 2));
+    combine_tables(concatB, tableB, innerBM.getAddr8(0, 3));
+
+    return SkTableColorFilter::CreateARGB(concatA, concatR, concatG, concatB);
+}
+
 #if SK_SUPPORT_GPU
 
 #include "GrFragmentProcessor.h"
 #include "GrInvariantOutput.h"
 #include "SkGr.h"
 #include "effects/GrTextureStripAtlas.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/builders/GrGLProgramBuilder.h"
 
 class ColorTableEffect : public GrFragmentProcessor {
@@ skipping 262 matching lines @@
 SkColorFilter* SkTableColorFilter::CreateARGB(const uint8_t tableA[256],
                                               const uint8_t tableR[256],
                                               const uint8_t tableG[256],
                                               const uint8_t tableB[256]) {
     return SkNEW_ARGS(SkTable_ColorFilter, (tableA, tableR, tableG, tableB));
 }
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkTableColorFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkTable_ColorFilter)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END