1 #include "Test.h"
2 #include "SkColor.h"
3 #include "SkUnPreMultiply.h"
4
test_premul(skiatest::Reporter * reporter)5 static void test_premul(skiatest::Reporter* reporter) {
6 for (int a = 0; a <= 255; a++) {
7 for (int x = 0; x <= 255; x++) {
8 SkColor c0 = SkColorSetARGB(a, x, x, x);
9 SkPMColor p0 = SkPreMultiplyColor(c0);
10
11 SkColor c1 = SkUnPreMultiply::PMColorToColor(p0);
12 SkPMColor p1 = SkPreMultiplyColor(c1);
13
14 // we can't promise that c0 == c1, since c0 -> p0 is a many to one
15 // function, however, we can promise that p0 -> c1 -> p1 : p0 == p1
16 REPORTER_ASSERT(reporter, p0 == p1);
17
18 {
19 int ax = SkMulDiv255Ceiling(x, a);
20 REPORTER_ASSERT(reporter, ax <= a);
21 }
22 }
23 }
24 }
25
26
TestColor(skiatest::Reporter * reporter)27 static void TestColor(skiatest::Reporter* reporter) {
28 test_premul(reporter);
29 }
30
31 #include "TestClassDef.h"
32 DEFINE_TESTCLASS("Color", ColorTestClass, TestColor)
33