1 /*
2 * Copyright 2011 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkColor.h"
9 #include "SkColorData.h"
10 #include "SkColorPriv.h"
11 #include "SkMathPriv.h"
12 #include "SkRandom.h"
13 #include "SkTypes.h"
14 #include "SkUnPreMultiply.h"
15 #include "Test.h"
16
17 #define GetPackedR16As32(packed) (SkGetPackedR16(dc) << (8 - SK_R16_BITS))
18 #define GetPackedG16As32(packed) (SkGetPackedG16(dc) << (8 - SK_G16_BITS))
19 #define GetPackedB16As32(packed) (SkGetPackedB16(dc) << (8 - SK_B16_BITS))
20
test_premul(skiatest::Reporter * reporter)21 static inline void test_premul(skiatest::Reporter* reporter) {
22 for (int a = 0; a <= 255; a++) {
23 for (int x = 0; x <= 255; x++) {
24 SkColor c0 = SkColorSetARGB(a, x, x, x);
25 SkPMColor p0 = SkPreMultiplyColor(c0);
26
27 SkColor c1 = SkUnPreMultiply::PMColorToColor(p0);
28 SkPMColor p1 = SkPreMultiplyColor(c1);
29
30 // we can't promise that c0 == c1, since c0 -> p0 is a many to one
31 // function, however, we can promise that p0 -> c1 -> p1 : p0 == p1
32 REPORTER_ASSERT(reporter, p0 == p1);
33
34 {
35 int ax = SkMulDiv255Ceiling(x, a);
36 REPORTER_ASSERT(reporter, ax <= a);
37 }
38 }
39 }
40 }
41
42 /**
43 This test fails: SkFourByteInterp does *not* preserve opaque destinations.
44 SkAlpha255To256 implemented as (alpha + 1) is faster than
45 (alpha + (alpha >> 7)), but inaccurate, and Skia intends to phase it out.
46 */
47 /*
48 static void test_interp(skiatest::Reporter* reporter) {
49 SkRandom r;
50
51 U8CPU a0 = 0;
52 U8CPU a255 = 255;
53 for (int i = 0; i < 200; i++) {
54 SkColor colorSrc = r.nextU();
55 SkColor colorDst = r.nextU();
56 SkPMColor src = SkPreMultiplyColor(colorSrc);
57 SkPMColor dst = SkPreMultiplyColor(colorDst);
58
59 REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a0) == dst);
60 REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a255) == src);
61 }
62 }
63 */
64
test_fast_interp(skiatest::Reporter * reporter)65 static inline void test_fast_interp(skiatest::Reporter* reporter) {
66 SkRandom r;
67
68 U8CPU a0 = 0;
69 U8CPU a255 = 255;
70 for (int i = 0; i < 200; i++) {
71 SkColor colorSrc = r.nextU();
72 SkColor colorDst = r.nextU();
73 SkPMColor src = SkPreMultiplyColor(colorSrc);
74 SkPMColor dst = SkPreMultiplyColor(colorDst);
75
76 REPORTER_ASSERT(reporter, SkFastFourByteInterp(src, dst, a0) == dst);
77 REPORTER_ASSERT(reporter, SkFastFourByteInterp(src, dst, a255) == src);
78 }
79 }
80
DEF_TEST(Color,reporter)81 DEF_TEST(Color, reporter) {
82 test_premul(reporter);
83 //test_interp(reporter);
84 test_fast_interp(reporter);
85 //test_565blend();
86 }
87