ColorTest.cpp File Reference

#include "include/core/SkColor.h"
#include "include/core/SkTypes.h"
#include "include/core/SkUnPreMultiply.h"
#include "include/private/SkColorData.h"
#include "include/private/base/SkCPUTypes.h"
#include "src/base/SkMathPriv.h"
#include "src/base/SkRandom.h"
#include "tests/Test.h"

Go to the source code of this file.

Functions
	DEF_TEST (ColorPremul, reporter)
	DEF_TEST (ColorInterp, reporter)
	DEF_TEST (ColorFastIterp, reporter)

Function Documentation

DEF_TEST() [1/3]

DEF_TEST	(	ColorFastIterp	,
		reporter
	)

Definition at line 61 of file ColorTest.cpp.

                                   {
    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);
    }
}

DEF_TEST() [2/3]

DEF_TEST	(	ColorInterp	,
		reporter
	)

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.

Definition at line 43 of file ColorTest.cpp.

                                {
    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);
 
        if ((false)) {
            REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a0) == dst);
            REPORTER_ASSERT(reporter, SkFourByteInterp(src, dst, a255) == src);
        }
    }
}

DEF_TEST() [3/3]

DEF_TEST	(	ColorPremul	,
		reporter
	)

Definition at line 17 of file ColorTest.cpp.

                                {
    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);
            }
        }
    }
}