force all colorfilters to implement 4f

high-contrast gms differ at most by 1 bit

Bug: skia:
Change-Id: I1308bd105020ea3cd5a30fd3dd322ed134fb5ed5
Reviewed-on: https://skia-review.googlesource.com/15249
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>

1 files changed, 22 insertions, 10 deletions

diff --git a/src/utils/SkShadowUtils.cpp b/src/utils/SkShadowUtils.cpp
index 430ea2c3b1..ebd27e02b9 100644
--- a/src/utils/SkShadowUtils.cpp
+++ b/src/utils/SkShadowUtils.cpp
@@ -10,6 +10,7 @@
 #include "SkColorFilter.h"
 #include "SkColorPriv.h"
 #include "SkPath.h"
+#include "SkPM4f.h"
 #include "SkRandom.h"
 #include "SkResourceCache.h"
 #include "SkShadowTessellator.h"
@@ -36,6 +37,7 @@ public:
     }
 
     void filterSpan(const SkPMColor src[], int count, SkPMColor dst[]) const override;
+    void filterSpan4f(const SkPM4f src[], int count, SkPM4f result[]) const override;
 
 #if SK_SUPPORT_GPU
     sk_sp<GrFragmentProcessor> asFragmentProcessor(GrContext*, SkColorSpace*) const override;
@@ -53,15 +55,18 @@ private:
     typedef SkColorFilter INHERITED;
 };
 
+static inline float eval_gaussian(float x) {
+    float factor = 1 - x;
+    return sk_float_exp(-factor * factor * 4) - 0.018f;
+}
+
 static void build_table() {
     SkDebugf("const uint8_t gByteExpU8Table[256] = {");
     for (int i = 0; i <= 255; ++i) {
         if (!(i % 8)) {
             SkDebugf("\n");
         }
-        SkScalar factor = SK_Scalar1 - i / 255.f;
-        factor = SkScalarExp(-factor * factor * 4) - 0.018f;
-        int v = (int)(factor * 255.9f);
+        int v = (int)(eval_gaussian(i / 255.f) * 256);
         SkDebugf(" 0x%02X,", v);
     }
     SkDebugf("\n};\n");
@@ -71,14 +76,14 @@ const uint8_t gByteExpU8Table[256] = {
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01,
     0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x02,
     0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04,
-    0x04, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x07,
+    0x05, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x07,
     0x07, 0x07, 0x08, 0x08, 0x08, 0x09, 0x09, 0x09,
     0x0A, 0x0A, 0x0B, 0x0B, 0x0B, 0x0C, 0x0C, 0x0D,
     0x0D, 0x0E, 0x0E, 0x0F, 0x0F, 0x10, 0x10, 0x11,
     0x11, 0x12, 0x12, 0x13, 0x14, 0x14, 0x15, 0x15,
     0x16, 0x17, 0x17, 0x18, 0x19, 0x19, 0x1A, 0x1B,
     0x1C, 0x1C, 0x1D, 0x1E, 0x1F, 0x1F, 0x20, 0x21,
-    0x22, 0x23, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
+    0x22, 0x23, 0x24, 0x24, 0x25, 0x26, 0x27, 0x28,
     0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
     0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x38, 0x39,
     0x3A, 0x3B, 0x3C, 0x3D, 0x3F, 0x40, 0x41, 0x42,
@@ -86,15 +91,15 @@ const uint8_t gByteExpU8Table[256] = {
     0x4E, 0x50, 0x51, 0x53, 0x54, 0x55, 0x57, 0x58,
     0x5A, 0x5B, 0x5D, 0x5E, 0x60, 0x61, 0x63, 0x64,
     0x66, 0x68, 0x69, 0x6B, 0x6C, 0x6E, 0x70, 0x71,
-    0x73, 0x74, 0x76, 0x78, 0x79, 0x7B, 0x7D, 0x7E,
+    0x73, 0x75, 0x76, 0x78, 0x79, 0x7B, 0x7D, 0x7F,
     0x80, 0x82, 0x84, 0x85, 0x87, 0x89, 0x8A, 0x8C,
-    0x8E, 0x8F, 0x91, 0x93, 0x95, 0x96, 0x98, 0x9A,
+    0x8E, 0x90, 0x91, 0x93, 0x95, 0x96, 0x98, 0x9A,
     0x9C, 0x9D, 0x9F, 0xA1, 0xA2, 0xA4, 0xA6, 0xA8,
     0xA9, 0xAB, 0xAD, 0xAE, 0xB0, 0xB2, 0xB3, 0xB5,
-    0xB7, 0xB8, 0xBA, 0xBB, 0xBD, 0xBF, 0xC0, 0xC2,
-    0xC3, 0xC5, 0xC6, 0xC8, 0xC9, 0xCB, 0xCC, 0xCE,
+    0xB7, 0xB8, 0xBA, 0xBC, 0xBD, 0xBF, 0xC0, 0xC2,
+    0xC3, 0xC5, 0xC7, 0xC8, 0xCA, 0xCB, 0xCD, 0xCE,
     0xCF, 0xD1, 0xD2, 0xD4, 0xD5, 0xD6, 0xD8, 0xD9,
-    0xDA, 0xDC, 0xDD, 0xDE, 0xDF, 0xE0, 0xE2, 0xE3,
+    0xDA, 0xDC, 0xDD, 0xDE, 0xDF, 0xE1, 0xE2, 0xE3,
     0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB,
     0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF0, 0xF1, 0xF2,
     0xF3, 0xF3, 0xF4, 0xF5, 0xF5, 0xF6, 0xF6, 0xF7,
@@ -114,6 +119,13 @@ void SkGaussianColorFilter::filterSpan(const SkPMColor src[], int count, SkPMCol
     }
 }
 
+void SkGaussianColorFilter::filterSpan4f(const SkPM4f src[], int count, SkPM4f dst[]) const {
+    for (int i = 0; i < count; ++i) {
+        float v = eval_gaussian(src[i].a());
+        dst[i] = SkPM4f::FromPremulRGBA(v, v, v, v);
+    }
+}
+
 sk_sp<SkFlattenable> SkGaussianColorFilter::CreateProc(SkReadBuffer&) {
     return Make();
 }