C++ SkBitmap::getAddr8方法代码示例

// Make either A8 or gray8 bitmap.
static SkBitmap make_bitmap(SkColorType ct) {
    SkBitmap bm;
    switch (ct) {
        case kAlpha_8_SkColorType:
            bm.allocPixels(SkImageInfo::MakeA8(SCALE, SCALE));
            break;
        case kGray_8_SkColorType:
            bm.allocPixels(
                    SkImageInfo::Make(SCALE, SCALE, ct, kOpaque_SkAlphaType));
            break;
        default:
            SkASSERT(false);
            return bm;
    }
    SkAutoLockPixels autoLockPixels(bm);
    uint8_t spectrum[256];
    for (int y = 0; y < 256; ++y) {
        spectrum[y] = y;
    }
    for (int y = 0; y < 128; ++y) {
        // Shift over one byte each scanline.
        memcpy(bm.getAddr8(0, y), &spectrum[y], 128);
    }
    bm.setImmutable();
    return bm;
}

static SkBitmap make_bitmap()
    {
    SkBitmap bm;
    SkColorTable* ctable = new SkColorTable(256);

    SkPMColor* c = ctable->lockColors();
    for (int i = 0; i < 256; i++)
        {
        c[i] = SkPackARGB32(0xFF, i, 0, 0);
        }
    ctable->unlockColors(true);
    bm.setConfig(SkBitmap::kIndex8_Config, 256, 32);
    bm.allocPixels(ctable);
    ctable->unref();

    bm.lockPixels();
    for (int y = 0; y < bm.height(); y++)
        {
        uint8_t* p = bm.getAddr8(0, y);
        for (int x = 0; x < 256; x++)
            {
            p[x] = x;
            }
        }
    bm.unlockPixels();
    return bm;
    }

static SkBitmap make_bitmap() {
    SkBitmap bm;
    SkColorTable* ctable = new SkColorTable(256);

    SkPMColor* c = ctable->lockColors();
    for (int i = 0; i < 256; i++) {
        c[i] = SkPackARGB32(255 - i, 0, 0, 0);
    }
    ctable->unlockColors(true);
    bm.setConfig(SkBitmap::kIndex8_Config, 256, 256);
    bm.allocPixels(ctable);
    ctable->unref();

    bm.lockPixels();
    const float cx = bm.width() * 0.5f;
    const float cy = bm.height() * 0.5f;
    for (int y = 0; y < bm.height(); y++) {
        float dy = y - cy;
        dy *= dy;
        uint8_t* p = bm.getAddr8(0, y);
        for (int x = 0; x < 256; x++) {
            float dx = x - cx;
            dx *= dx;
            float d = (dx + dy) / (cx/2);
            int id = (int)d;
            if (id > 255) {
                id = 255;
            }
            p[x] = id;
        }
    }
    bm.unlockPixels();
    return bm;
}

static SkBitmap make_bitmap() {
    SkPMColor c[256];
    for (int i = 0; i < 256; i++) {
        c[i] = SkPackARGB32(255 - i, 0, 0, 0);
    }

    SkBitmap bm;
    SkColorTable* ctable = new SkColorTable(c, 256);

    bm.allocPixels(SkImageInfo::Make(256, 256, kIndex_8_SkColorType,
                                     kPremul_SkAlphaType),
                   nullptr, ctable);
    ctable->unref();

    bm.lockPixels();
    const float cx = bm.width() * 0.5f;
    const float cy = bm.height() * 0.5f;
    for (int y = 0; y < bm.height(); y++) {
        float dy = y - cy;
        dy *= dy;
        uint8_t* p = bm.getAddr8(0, y);
        for (int x = 0; x < 256; x++) {
            float dx = x - cx;
            dx *= dx;
            float d = (dx + dy) / (cx/2);
            int id = (int)d;
            if (id > 255) {
                id = 255;
            }
            p[x] = id;
        }
    }
    bm.unlockPixels();
    return bm;
}

// https://bug.skia.org/4390
DEF_TEST(ImageFromIndex8Bitmap, r) {
    SkPMColor pmColors[1] = {SkPreMultiplyColor(SK_ColorWHITE)};
    SkBitmap bm;
    SkAutoTUnref<SkColorTable> ctable(
            new SkColorTable(pmColors, SK_ARRAY_COUNT(pmColors)));
    SkImageInfo info =
            SkImageInfo::Make(1, 1, kIndex_8_SkColorType, kPremul_SkAlphaType);
    bm.allocPixels(info, nullptr, ctable);
    SkAutoLockPixels autoLockPixels(bm);
    *bm.getAddr8(0, 0) = 0;
    SkAutoTUnref<SkImage> img(SkImage::NewFromBitmap(bm));
    REPORTER_ASSERT(r, img.get() != nullptr);
}

static SkBitmap make_bitmap() {
    const SkPMColor c[] = { SkPackARGB32(0x80, 0x80, 0, 0) };
    SkColorTable* ctable = new SkColorTable(c, SK_ARRAY_COUNT(c));

    SkBitmap bm;
    bm.allocPixels(SkImageInfo::Make(1, 1, kIndex_8_SkColorType,
                                     kPremul_SkAlphaType),
                   NULL, ctable);
    ctable->unref();

    bm.lockPixels();
    *bm.getAddr8(0, 0) = 0;
    bm.unlockPixels();
    return bm;
}

static SkBitmap make_bitmap() {
    SkBitmap bm;

    SkColorTable* ctable = new SkColorTable(1);
    SkPMColor* c = ctable->lockColors();
    c[0] = SkPackARGB32(0x80, 0x80, 0, 0);
    ctable->unlockColors(true);

    bm.setConfig(SkBitmap::kIndex8_Config, 1, 1);
    bm.allocPixels(ctable);
    ctable->unref();

    bm.lockPixels();
    *bm.getAddr8(0, 0) = 0;
    bm.unlockPixels();
    return bm;
}

static void copyToLCD16(const SkBitmap& src, const SkMask& dst) {
    SkASSERT(SkBitmap::kA8_Config == src.config());
    SkASSERT(SkMask::kLCD16_Format == dst.fFormat);

    const int width = dst.fBounds.width();
    const int height = dst.fBounds.height();
    const uint8_t* srcP = src.getAddr8(0, 0);
    size_t srcRB = src.rowBytes();
    uint16_t* dstP = (uint16_t*)dst.fImage;
    size_t dstRB = dst.fRowBytes;
    for (int y = 0; y < height; ++y) {
        for (int x = 0; x < width; ++x) {
            dstP[x] = a8_to_rgb565(srcP[x]);
        }
        srcP += srcRB;
        dstP = (uint16_t*)((char*)dstP + dstRB);
    }
}

static void pack3xHToLCD32(const SkBitmap& src, const SkMask& dst,
                           const SkMaskGamma::PreBlend& maskPreBlend) {
    SkASSERT(SkBitmap::kA8_Config == src.config());
    SkASSERT(SkMask::kLCD32_Format == dst.fFormat);

    const int width = dst.fBounds.width();
    const int height = dst.fBounds.height();
    SkPMColor* dstP = (SkPMColor*)dst.fImage;
    size_t dstRB = dst.fRowBytes;

    for (int y = 0; y < height; ++y) {
        const uint8_t* srcP = src.getAddr8(0, y);
        for (int x = 0; x < width; ++x) {
            U8CPU r = sk_apply_lut_if<APPLY_PREBLEND>(*srcP++, maskPreBlend.fR);
            U8CPU g = sk_apply_lut_if<APPLY_PREBLEND>(*srcP++, maskPreBlend.fG);
            U8CPU b = sk_apply_lut_if<APPLY_PREBLEND>(*srcP++, maskPreBlend.fB);
            dstP[x] = SkPackARGB32(0xFF, r, g, b);
        }
        dstP = (SkPMColor*)((char*)dstP + dstRB);
    }
}

    void drawBG(SkCanvas* canvas)
    {
        canvas->drawColor(0xFFDDDDDD);
        return;

#if 0
        SkColorTable    ct;
        SkPMColor       colors[] = { SK_ColorRED, SK_ColorBLUE };
        ct.setColors(colors, 2);
        ct.setFlags(ct.getFlags() | SkColorTable::kColorsAreOpaque_Flag);

        SkBitmap        bm;
        bm.setConfig(SkBitmap::kIndex8_Config, 20, 20, 21);
        bm.setColorTable(&ct);
        bm.allocPixels();
        sk_memset16((uint16_t*)bm.getAddr8(0, 0), 0x0001, bm.rowBytes() * bm.height() / 2);
#endif
#if 0
        SkBitmap        bm;
        bm.setConfig(SkBitmap::kRGB_565_Config, 20, 20, 42);
        bm.allocPixels();
        sk_memset32((uint32_t*)bm.getAddr16(0, 0), 0x0000FFFF, bm.rowBytes() * bm.height() / 4);
#endif
#if 1
        SkBitmap        bm;
        bm.setConfig(SkBitmap::kARGB_8888_Config, 20, 20);
        bm.allocPixels();
        sk_memset32((uint32_t*)bm.getAddr32(0, 0), 0xFFDDDDDD, bm.rowBytes() * bm.height() / 4);
#endif

        SkPaint paint;

//        SkShader* shader = SkShader::CreateBitmapShader(bm, false, SkPaint::kBilinear_FilterType, SkShader::kRepeat_TileMode);
        SkPoint pts[] = { 0, 0, SkIntToScalar(100), SkIntToScalar(0) };
        SkColor colors[] = { SK_ColorBLACK, SK_ColorWHITE };
        SkShader* shader = SkGradientShader::CreateLinear(pts, colors, NULL, 2, SkShader::kMirror_TileMode);
        paint.setShader(shader)->unref();

        canvas->drawPaint(paint);
    }

static SkBitmap make_bitmap() {
    SkPMColor c[256];
    for (int i = 0; i < 256; i++) {
        c[i] = SkPackARGB32(0xFF, i, 0, 0);
    }
    SkColorTable* ctable = new SkColorTable(c, 256);

    SkBitmap bm;
    bm.allocPixels(SkImageInfo::Make(256, 32, kIndex_8_SkColorType, kPremul_SkAlphaType),
                   nullptr, ctable);
    ctable->unref();

    bm.lockPixels();
    for (int y = 0; y < bm.height(); y++) {
        uint8_t* p = bm.getAddr8(0, y);
        for (int x = 0; x < 256; x++) {
            p[x] = x;
        }
    }
    bm.unlockPixels();
    return bm;
}

static SkBitmap indexed_bitmap() {
    SkBitmap n32bitmap;
    n32bitmap.allocN32Pixels(SCALE, SCALE);
    n32bitmap.eraseColor(SK_ColorTRANSPARENT);

    SkCanvas canvas(n32bitmap);
    color_wheel_native(&canvas);
    const SkColor colors[] = {
            SK_ColorTRANSPARENT,
            SK_ColorWHITE,
            SK_ColorBLACK,
            SK_ColorRED,
            SK_ColorGREEN,
            SK_ColorBLUE,
            SK_ColorCYAN,
            SK_ColorMAGENTA,
            SK_ColorYELLOW,
    };
    SkPMColor pmColors[SK_ARRAY_COUNT(colors)];
    for (size_t i = 0; i < SK_ARRAY_COUNT(colors); ++i) {
        pmColors[i] = premultiply_color(colors[i]);
    }
    SkBitmap bm;
    SkAutoTUnref<SkColorTable> ctable(new SkColorTable(pmColors, SK_ARRAY_COUNT(pmColors)));
    SkImageInfo info = SkImageInfo::Make(SCALE, SCALE, kIndex_8_SkColorType,
                                         kPremul_SkAlphaType);
    bm.allocPixels(info, nullptr, ctable);
    SkAutoLockPixels autoLockPixels1(n32bitmap);
    SkAutoLockPixels autoLockPixels2(bm);
    for (int y = 0; y < SCALE; ++y) {
        for (int x = 0; x < SCALE; ++x) {
            SkPMColor c = *n32bitmap.getAddr32(x, y);
            int idx = find(pmColors, SK_ARRAY_COUNT(pmColors), c);
            *bm.getAddr8(x, y) = SkClampMax(idx, SK_ARRAY_COUNT(pmColors) - 1);
        }
    }
    return bm;
}

static bool getColor(const SkBitmap& bitmap, int x, int y, SkColor* c) {
    switch (bitmap.getConfig()) {
        case SkBitmap::kARGB_8888_Config:
            *c = SkUnPreMultiply::PMColorToColor(*bitmap.getAddr32(x, y));
            break;
        case SkBitmap::kRGB_565_Config:
            *c = SkPixel16ToPixel32(*bitmap.getAddr16(x, y));
            break;
        case SkBitmap::kARGB_4444_Config:
            *c = SkUnPreMultiply::PMColorToColor(
                                SkPixel4444ToPixel32(*bitmap.getAddr16(x, y)));
            break;
        case SkBitmap::kIndex8_Config: {
            SkColorTable* ctable = bitmap.getColorTable();
            *c = SkUnPreMultiply::PMColorToColor(
                                            (*ctable)[*bitmap.getAddr8(x, y)]);
            break;
        }
        default:
            return false;
    }
    return true;
}

static SkBitmap make_bitmap() {
    const int N = 1;

    SkPMColor c[N];
    for (int i = 0; i < N; i++) {
        c[i] = SkPackARGB32(0x80, 0x80, 0, 0);
    }
    SkColorTable* ctable = new SkColorTable(c, N);

    SkBitmap bm;
    bm.setConfig(SkBitmap::kIndex8_Config, 1, 1);
    bm.allocPixels(ctable);
    ctable->unref();

    bm.lockPixels();
    for (int y = 0; y < bm.height(); y++) {
        uint8_t* p = bm.getAddr8(0, y);
        for (int x = 0; x < bm.width(); x++) {
            p[x] = 0;
        }
    }
    bm.unlockPixels();
    return bm;
}

static void pack4xHToLCD16(const SkBitmap& src, const SkMask& dst,
                           const SkMaskGamma::PreBlend& maskPreBlend) {
#define SAMPLES_PER_PIXEL 4
#define LCD_PER_PIXEL 3
    SkASSERT(kAlpha_8_SkColorType == src.colorType());
    SkASSERT(SkMask::kLCD16_Format == dst.fFormat);

    const int sample_width = src.width();
    const int height = src.height();

    uint16_t* dstP = (uint16_t*)dst.fImage;
    size_t dstRB = dst.fRowBytes;
    // An N tap FIR is defined by
    // out[n] = coeff[0]*x[n] + coeff[1]*x[n-1] + ... + coeff[N]*x[n-N]
    // or
    // out[n] = sum(i, 0, N, coeff[i]*x[n-i])

    // The strategy is to use one FIR (different coefficients) for each of r, g, and b.
    // This means using every 4th FIR output value of each FIR and discarding the rest.
    // The FIRs are aligned, and the coefficients reach 5 samples to each side of their 'center'.
    // (For r and b this is technically incorrect, but the coeffs outside round to zero anyway.)

    // These are in some fixed point repesentation.
    // Adding up to more than one simulates ink spread.
    // For implementation reasons, these should never add up to more than two.

    // Coefficients determined by a gausian where 5 samples = 3 std deviations (0x110 'contrast').
    // Calculated using tools/generate_fir_coeff.py
    // With this one almost no fringing is ever seen, but it is imperceptibly blurry.
    // The lcd smoothed text is almost imperceptibly different from gray,
    // but is still sharper on small stems and small rounded corners than gray.
    // This also seems to be about as wide as one can get and only have a three pixel kernel.
    // TODO: caculate these at runtime so parameters can be adjusted (esp contrast).
    static const unsigned int coefficients[LCD_PER_PIXEL][SAMPLES_PER_PIXEL*3] = {
        //The red subpixel is centered inside the first sample (at 1/6 pixel), and is shifted.
        { 0x03, 0x0b, 0x1c, 0x33,  0x40, 0x39, 0x24, 0x10,  0x05, 0x01, 0x00, 0x00, },
        //The green subpixel is centered between two samples (at 1/2 pixel), so is symetric
        { 0x00, 0x02, 0x08, 0x16,  0x2b, 0x3d, 0x3d, 0x2b,  0x16, 0x08, 0x02, 0x00, },
        //The blue subpixel is centered inside the last sample (at 5/6 pixel), and is shifted.
        { 0x00, 0x00, 0x01, 0x05,  0x10, 0x24, 0x39, 0x40,  0x33, 0x1c, 0x0b, 0x03, },
    };

    for (int y = 0; y < height; ++y) {
        const uint8_t* srcP = src.getAddr8(0, y);

        // TODO: this fir filter implementation is straight forward, but slow.
        // It should be possible to make it much faster.
        for (int sample_x = -4, pixel_x = 0; sample_x < sample_width + 4; sample_x += 4, ++pixel_x) {
            int fir[LCD_PER_PIXEL] = { 0 };
            for (int sample_index = SkMax32(0, sample_x - 4), coeff_index = sample_index - (sample_x - 4)
                ; sample_index < SkMin32(sample_x + 8, sample_width)
                ; ++sample_index, ++coeff_index)
            {
                int sample_value = srcP[sample_index];
                for (int subpxl_index = 0; subpxl_index < LCD_PER_PIXEL; ++subpxl_index) {
                    fir[subpxl_index] += coefficients[subpxl_index][coeff_index] * sample_value;
                }
            }
            for (int subpxl_index = 0; subpxl_index < LCD_PER_PIXEL; ++subpxl_index) {
                fir[subpxl_index] /= 0x100;
                fir[subpxl_index] = SkMin32(fir[subpxl_index], 255);
            }

            U8CPU r = sk_apply_lut_if<APPLY_PREBLEND>(fir[0], maskPreBlend.fR);
            U8CPU g = sk_apply_lut_if<APPLY_PREBLEND>(fir[1], maskPreBlend.fG);
            U8CPU b = sk_apply_lut_if<APPLY_PREBLEND>(fir[2], maskPreBlend.fB);
#if SK_SHOW_TEXT_BLIT_COVERAGE
            r = SkMax32(r, 10); g = SkMax32(g, 10); b = SkMax32(b, 10);
#endif
            dstP[pixel_x] = SkPack888ToRGB16(r, g, b);
        }
        dstP = (uint16_t*)((char*)dstP + dstRB);
    }
}