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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Test.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkMathPriv.h"
#include "SkRandom.h"
#include "SkUnPreMultiply.h"
static void test_premul(skiatest::Reporter* reporter) {
for (int a = 0; a <= 255; a++) {
for (int x = 0; x <= 255; x++) {
SkColor c0 = SkColorSetARGB(a, x, x, x);
SkPMColor p0 = SkPreMultiplyColor(c0);
SkColor c1 = SkUnPreMultiply::PMColorToColor(p0);
SkPMColor p1 = SkPreMultiplyColor(c1);
// we can't promise that c0 == c1, since c0 -> p0 is a many to one
// function, however, we can promise that p0 -> c1 -> p1 : p0 == p1
REPORTER_ASSERT(reporter, p0 == p1);
{
int ax = SkMulDiv255Ceiling(x, a);
REPORTER_ASSERT(reporter, ax <= a);
}
}
}
}
/**
This test fails: SkFourByteInterp does *not* preserve opaque destinations.
SkAlpha255To256 implemented as (alpha + 1) is faster than
(alpha + (alpha >> 7)), but inaccurate, and Skia intends to phase it out.
*/
/*
static void test_interp(skiatest::Reporter* reporter) {
SkRandom r;
U8CPU a0 = 0;
U8CPU a255 = 255;
for (int i = 0; i < 200; i++) {
SkColor colorSrc = r.nextU();
SkColor colorDst = r.nextU();
SkPMColor src = SkPreMultiplyColor(colorSrc);
SkPMColor dst = SkPreMultiplyColor(colorDst);
REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a0) == dst);
REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a255) == src);
}
}
*/
static void test_fast_interp(skiatest::Reporter* reporter) {
SkRandom r;
U8CPU a0 = 0;
U8CPU a255 = 255;
for (int i = 0; i < 200; i++) {
SkColor colorSrc = r.nextU();
SkColor colorDst = r.nextU();
SkPMColor src = SkPreMultiplyColor(colorSrc);
SkPMColor dst = SkPreMultiplyColor(colorDst);
REPORTER_ASSERT(reporter, SkFastFourByteInterp(src, dst, a0) == dst);
REPORTER_ASSERT(reporter, SkFastFourByteInterp(src, dst, a255) == src);
}
}
static void TestColor(skiatest::Reporter* reporter) {
test_premul(reporter);
//test_interp(reporter);
test_fast_interp(reporter);
}
#include "TestClassDef.h"
DEFINE_TESTCLASS("Color", ColorTestClass, TestColor)
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