chromium/third_party/skia/src/core/SkUnPreMultiply.cpp

/*
 * 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 "include/core/SkUnPreMultiply.h"

#include "include/core/SkColorPriv.h"

SkColor SkUnPreMultiply::PMColorToColor(SkPMColor c) { … }

const uint32_t SkUnPreMultiply::gTable[] = …;

#ifdef BUILD_DIVIDE_TABLE
void SkUnPreMultiply_BuildTable() {
    for (unsigned i = 0; i <= 255; i++) {
        uint32_t scale;

        if (0 == i) {
            scale = 0;
        } else {
            scale = ((255 << 24) + (i >> 1)) / i;
        }

        SkDebugf(" 0x%08X,", scale);
        if ((i & 7) == 7) {
            SkDebugf("\n");
        }

        // test the result
        for (int j = 1; j <= i; j++) {
            uint32_t test = (j * scale + (1 << 23)) >> 24;
            uint32_t div = roundf(j * 255.0f / i);
            int diff = SkAbs32(test - div);
            SkASSERT(diff <= 1 && test <= 255);
        }
    }
}
#endif