4

在 Photoshop 中有几种混合模式,例如:

  • 颜色燃烧
  • 变暗
  • 减轻
  • 覆盖

(更多信息在这里:http ://help.adobe.com/en_US/photoshop/cs/using/WSfd1234e1c4b69f30ea53e41001031ab64-77eba.html )

例如,对于“颜色加深”模式,“查看每个通道中的颜色信息,并通过增加两者之间的对比度使基础颜色变暗以反映混合颜色。与白色混合不会产生任何变化”。

这是我的代码:

Bitmap blendBitmap = BitmapFactory.decodeStream(ctx.getAssets().open(filename));
Canvas canvas = new Canvas(srcBitmap);
canvas.drawBitmap(blendBitmap, 0, 0, null); // ?
p.recycle();
p = null;

例如,是否可以应用 Color Burn 混合模式,而不是简单地将图像绘制在其他图像之上(就像在这个小代码中一样)?

4

1 回答 1

3

这并不困难。

我使用 NDK(因为性能)来处理像素。混合模式的信息非常有用:Photoshop 如何将两张图像混合在一起?

我的最终解决方案是:

#define ChannelBlend_ColorBurn(A, B)  ((uint8_t) ((B == 0) ? B : max(0, (255 - ((255 -  
#define ChannelBlend_Alpha(A, B, O)    ((uint8_t) (O * A + (1 - O) * B))
#define ChannelBlend_AlphaF(A, B, F, O) (ChannelBlend_Alpha(F(A, B), A, O))

typedef struct {
    uint8_t red;
    uint8_t green;
    uint8_t blue;
    uint8_t alpha;
} rgba;

// Blend
JNIEXPORT void 
JNICALL Java_com_package_Filter_jniBlend(JNIEnv* env, jobject obj, jobject bitmapA,
    jobject bitmapB, jobject bitmapOut, jint mode) {

    // Properties
    AndroidBitmapInfo   infoA;
    void*               pixelsA;
    AndroidBitmapInfo   infoB;
    void*               pixelsB;
    AndroidBitmapInfo   infoOut;
    void*               pixelsOut;

    int ret;

    // Get image info
    if ((ret = AndroidBitmap_getInfo(env, bitmapA, &infoA)) < 0 ||
        (ret = AndroidBitmap_getInfo(env, bitmapB, &infoB)) < 0 ||
        (ret = AndroidBitmap_getInfo(env, bitmapOut, &infoOut)) < 0) {
        return;
    }
    // Check image
    if (infoA.format != ANDROID_BITMAP_FORMAT_RGBA_8888 ||
        infoB.format != ANDROID_BITMAP_FORMAT_RGBA_8888 ||
        infoOut.format != ANDROID_BITMAP_FORMAT_RGBA_8888) {
        return;
    }
    // Lock all images
    if ((ret = AndroidBitmap_lockPixels(env, bitmapA, &pixelsA)) < 0 ||
        (ret = AndroidBitmap_lockPixels(env, bitmapB, &pixelsB)) < 0 ||
        (ret = AndroidBitmap_lockPixels(env, bitmapOut, &pixelsOut)) < 0) {
        LOGE("Error! %d", ret);
    }

    int h = infoA.height;
    int w = infoA.width;
    int wh = w * h;

    int n;
    rgba* inputA = (rgba*) pixelsA;
    rgba* inputB = (rgba*) pixelsB;
    rgba* output = (rgba*) pixelsOut;

    rgba pA, pB;

    int x, y;
    for (y = 0; y < h; y++) {
        for (x = 0; x < w; x++) {
            n = y * w + x;

            pA = inputA[n];
            pB = inputB[n];

            float alpha = (float) pB.alpha / 255.0;

            output[n].red = ChannelBlend_AlphaF(pA.red, pB.red, ChannelBlend_ColorBurn, alpha);
            output[n].green = ChannelBlend_AlphaF(pA.green, pB.green, ChannelBlend_ColorBurn, alpha);
            output[n].blue = ChannelBlend_AlphaF(pA.blue, pB.blue, ChannelBlend_ColorBurn, alpha);
        }
    }

    // Unlocks everything
    AndroidBitmap_unlockPixels(env, bitmapA);
    AndroidBitmap_unlockPixels(env, bitmapB);
    AndroidBitmap_unlockPixels(env, bitmapOut);
}

提高性能的小评论:在我为单个像素制作方程式之后,将值存储在某种缓存中以便下次在没有方程式的情况下更快地访问它会很好。

于 2012-11-26T11:19:20.727 回答