13e812c69a
Consolidate interpolation functions, add new faster more accurate dithering interpolator. git-svn-id: http://skia.googlecode.com/svn/trunk@3072 2bbb7eff-a529-9590-31e7-b0007b416f81
83 lines
2.4 KiB
C++
83 lines
2.4 KiB
C++
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/*
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* Copyright 2011 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "Test.h"
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#include "SkColor.h"
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#include "SkColorPriv.h"
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#include "SkMath.h"
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#include "SkRandom.h"
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#include "SkUnPreMultiply.h"
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static void test_premul(skiatest::Reporter* reporter) {
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for (int a = 0; a <= 255; a++) {
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for (int x = 0; x <= 255; x++) {
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SkColor c0 = SkColorSetARGB(a, x, x, x);
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SkPMColor p0 = SkPreMultiplyColor(c0);
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SkColor c1 = SkUnPreMultiply::PMColorToColor(p0);
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SkPMColor p1 = SkPreMultiplyColor(c1);
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// we can't promise that c0 == c1, since c0 -> p0 is a many to one
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// function, however, we can promise that p0 -> c1 -> p1 : p0 == p1
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REPORTER_ASSERT(reporter, p0 == p1);
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{
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int ax = SkMulDiv255Ceiling(x, a);
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REPORTER_ASSERT(reporter, ax <= a);
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}
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}
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}
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}
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/**
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This test fails: SkFourByteInterp does *not* preserve opaque destinations.
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SkAlpha255To256 implemented as (alpha + 1) is faster than
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(alpha + (alpha >> 7)), but inaccurate, and Skia intends to phase it out.
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*/
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/*
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static void test_interp(skiatest::Reporter* reporter) {
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SkRandom r;
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U8CPU a0 = 0;
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U8CPU a255 = 255;
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for (int i = 0; i < 200; i++) {
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SkColor colorSrc = r.nextU();
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SkColor colorDst = r.nextU();
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SkPMColor src = SkPreMultiplyColor(colorSrc);
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SkPMColor dst = SkPreMultiplyColor(colorDst);
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REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a0) == dst);
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REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a255) == src);
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}
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}
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*/
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static void test_fast_interp(skiatest::Reporter* reporter) {
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SkRandom r;
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U8CPU a0 = 0;
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U8CPU a255 = 255;
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for (int i = 0; i < 200; i++) {
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SkColor colorSrc = r.nextU();
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SkColor colorDst = r.nextU();
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SkPMColor src = SkPreMultiplyColor(colorSrc);
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SkPMColor dst = SkPreMultiplyColor(colorDst);
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REPORTER_ASSERT(reporter, SkFastFourByteInterp(src, dst, a0) == dst);
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REPORTER_ASSERT(reporter, SkFastFourByteInterp(src, dst, a255) == src);
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}
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}
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static void TestColor(skiatest::Reporter* reporter) {
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test_premul(reporter);
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//test_interp(reporter);
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test_fast_interp(reporter);
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}
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#include "TestClassDef.h"
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DEFINE_TESTCLASS("Color", ColorTestClass, TestColor)
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