C++ SkBitmap::getAddr16方法代码示例

// returns true and set color if the bitmap can be drawn as a single color
// (for efficiency)
static bool canUseColorShader(const SkBitmap& bm, SkColor* color) {
    if (1 != bm.width() || 1 != bm.height()) {
        return false;
    }

    SkAutoLockPixels alp(bm);
    if (!bm.readyToDraw()) {
        return false;
    }

    switch (bm.config()) {
        case SkBitmap::kARGB_8888_Config:
            *color = SkUnPreMultiply::PMColorToColor(*bm.getAddr32(0, 0));
            return true;
        case SkBitmap::kRGB_565_Config:
            *color = SkPixel16ToColor(*bm.getAddr16(0, 0));
            return true;
        case SkBitmap::kIndex8_Config:
            *color = SkUnPreMultiply::PMColorToColor(bm.getIndex8Color(0, 0));
            return true;
        default: // just skip the other configs for now
            break;
    }
    return false;
}

// returns true and set color if the bitmap can be drawn as a single color
// (for efficiency)
static bool can_use_color_shader(const SkBitmap& bm, SkColor* color) {
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    // HWUI does not support color shaders (see b/22390304)
    return false;
#endif

    if (1 != bm.width() || 1 != bm.height()) {
        return false;
    }

    SkAutoLockPixels alp(bm);
    if (!bm.readyToDraw()) {
        return false;
    }

    switch (bm.colorType()) {
        case kN32_SkColorType:
            *color = SkUnPreMultiply::PMColorToColor(*bm.getAddr32(0, 0));
            return true;
        case kRGB_565_SkColorType:
            *color = SkPixel16ToColor(*bm.getAddr16(0, 0));
            return true;
        case kIndex_8_SkColorType:
            *color = SkUnPreMultiply::PMColorToColor(bm.getIndex8Color(0, 0));
            return true;
        default: // just skip the other configs for now
            break;
    }
    return false;
}

static uint16_t get_argb4444_neighbor_avg_color(const SkBitmap& bitmap,
                                                int xOrig, int yOrig) {
    uint8_t count = 0;
    uint8_t r = 0;
    uint8_t g = 0;
    uint8_t b = 0;

    for (int y = yOrig - 1; y <= yOrig + 1; y++) {
        if (y < 0 || y >= bitmap.height()) {
            continue;
        }
        uint16_t* src = bitmap.getAddr16(0, y);
        for (int x = xOrig - 1; x <= xOrig + 1; x++) {
            if (x < 0 || x >= bitmap.width()) {
                continue;
            }
            if ((SkGetPackedA4444(src[x]) & 0x0F) != SK_AlphaTRANSPARENT) {
                uint16_t color = remove_alpha_argb4444(src[x]);
                r += SkGetPackedR4444(color);
                g += SkGetPackedG4444(color);
                b += SkGetPackedB4444(color);
                count++;
            }
        }
    }

    if (count == 0) {
        return SkPackARGB4444(SK_AlphaOPAQUE & 0x0F, 0, 0, 0);
    } else {
        return SkPackARGB4444(SK_AlphaOPAQUE & 0x0F,
                                   r / count, g / count, b / count);
    }
}

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 void check_for_nonwhite(const SkBitmap& bm, int alpha) {
    if (bm.config() != SkBitmap::kRGB_565_Config) {
        return;
    }

    for (int y = 0; y < bm.height(); y++) {
        for (int x = 0; x < bm.width(); x++) {
            uint16_t c = *bm.getAddr16(x, y);
            if (c != 0xFFFF) {
                SkDebugf("------ nonwhite alpha=%x [%d %d] %x\n", alpha, x, y, c);
                return;
            }
        }
    }
}

static SkBitmap make_argb4444_gradient() {
    SkBitmap bitmap;
    init_bitmap(kARGB_4444_SkColorType, &bitmap);
    uint8_t rowColor = 0;
    for (int y = 0; y < SLIDE_SIZE; y++) {
        uint16_t* dst = bitmap.getAddr16(0, y);
        for (int x = 0; x < SLIDE_SIZE; x++) {
            dst[x] = SkPackARGB4444(rowColor, rowColor,
                                    rowColor, rowColor);
        }
        if (y % PIXEL_SIZE_4444 == PIXEL_SIZE_4444 - 1) {
            rowColor++;
        }
    }
    return bitmap;
}

    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 unpremultiply_bitmap(const SkBitmap& bitmap,
                                     const SkIRect& srcRect) {
    SkBitmap outBitmap;
    outBitmap.allocPixels(bitmap.info().makeWH(srcRect.width(), srcRect.height()));
    int dstRow = 0;

    SkAutoLockPixels outBitmapPixelLock(outBitmap);
    SkAutoLockPixels bitmapPixelLock(bitmap);
    switch (bitmap.colorType()) {
        case kARGB_4444_SkColorType: {
            for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
                uint16_t* dst = outBitmap.getAddr16(0, dstRow);
                uint16_t* src = bitmap.getAddr16(0, y);
                for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
                    uint8_t a = SkGetPackedA4444(src[x]);
                    // It is necessary to average the color component of
                    // transparent pixels with their surrounding neighbors
                    // since the PDF renderer may separately re-sample the
                    // alpha and color channels when the image is not
                    // displayed at its native resolution. Since an alpha of
                    // zero gives no information about the color component,
                    // the pathological case is a white image with sharp
                    // transparency bounds - the color channel goes to black,
                    // and the should-be-transparent pixels are rendered
                    // as grey because of the separate soft mask and color
                    // resizing.
                    if (a == (SK_AlphaTRANSPARENT & 0x0F)) {
                        *dst = get_argb4444_neighbor_avg_color(bitmap, x, y);
                    } else {
                        *dst = remove_alpha_argb4444(src[x]);
                    }
                    dst++;
                }
                dstRow++;
            }
            break;
        }
        case kN32_SkColorType: {
            for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
                uint32_t* dst = outBitmap.getAddr32(0, dstRow);
                uint32_t* src = bitmap.getAddr32(0, y);
                for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
                    uint8_t a = SkGetPackedA32(src[x]);
                    if (a == SK_AlphaTRANSPARENT) {
                        *dst = get_argb8888_neighbor_avg_color(bitmap, x, y);
                    } else {
                        *dst = remove_alpha_argb8888(src[x]);
                    }
                    dst++;
                }
                dstRow++;
            }
            break;
        }
        default:
            SkASSERT(false);
    }

    outBitmap.setImmutable();

    return outBitmap;
}