add SkAlphaBlend255
git-svn-id: http://skia.googlecode.com/svn/trunk@2426 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/MathTest.cpp b/tests/MathTest.cpp
index 7440dfd..756c68c 100644
--- a/tests/MathTest.cpp
+++ b/tests/MathTest.cpp
@@ -10,40 +10,35 @@
#include "SkMath.h"
#include "SkPoint.h"
#include "SkRandom.h"
+#include "SkColorPriv.h"
-#if 0
-static U8CPU premul_fast(U8CPU a, U8CPU x) {
- return a * x * 32897 >> 23;
+static float float_blend(int src, int dst, float unit) {
+ return dst + (src - dst) * unit;
}
-static U8CPU premul_trunc(U8CPU a, U8CPU x) {
- double result = a * x;
- result /= 255.0;
- return (unsigned)floor(result + 0.0);
-}
+static void test_blend(skiatest::Reporter* reporter) {
+ for (int src = 0; src <= 255; src++) {
+ for (int dst = 0; dst <= 255; dst++) {
+ for (int a = 0; a <= 255; a++) {
+ int r0 = SkAlphaBlend255(src, dst, a);
+ float f1 = float_blend(src, dst, a / 255.f);
+ int r1 = SkScalarRoundToInt(f1);
-static U8CPU premul_round(U8CPU a, U8CPU x) {
- double result = a * x;
- result /= 255.0;
- return (unsigned)floor(result + 0.5);
-}
-
-static void test_premul(skiatest::Reporter* reporter) {
- for (int a = 0; a <= 255; a++) {
- for (int x = 0; x <= 255; x++) {
- unsigned curr_trunc = SkMulDiv255Trunc(a, x);
- unsigned curr_round = SkMulDiv255Round(a, x);
- unsigned fast = premul_fast(a, x);
- unsigned slow_round = premul_round(a, x);
- unsigned slow_trunc = premul_trunc(a, x);
- if (fast != slow || curr != fast) {
- SkDebugf("---- premul(%d %d) curr=%d fast=%d slow=%d\n", a, x,
- curr, fast, slow);
+ if (r0 != r1) {
+ float diff = sk_float_abs(f1 - r1);
+ diff = sk_float_abs(diff - 0.5f);
+ if (diff > (1 / 255.f)) {
+#ifdef SK_DEBUG
+ SkDebugf("src:%d dst:%d a:%d result:%d float:%g\n",
+ src, dst, a, r0, f1);
+#endif
+ REPORTER_ASSERT(reporter, false);
+ }
+ }
}
}
}
}
-#endif
#if defined(SkLONGLONG)
static int symmetric_fixmul(int a, int b) {
@@ -501,7 +496,9 @@
SkDebugf("SinCos: maximum error = %d\n", maxDiff);
#endif
-// test_premul(reporter);
+#ifdef SK_SCALAR_IS_FLOAT
+ test_blend(reporter);
+#endif
}
#include "TestClassDef.h"