在Android中将位图转换为棕褐色

Question

有什么办法将位图转换为棕褐色？ 我知道要转换为grayScale是要在ColorMatrix中设置setSaturation。 但是棕褐色呢？

Answer 1

我知道答案，但也许如果一些有其他更好的解决办法..

public Bitmap toSephia(Bitmap bmpOriginal) 
{   
    int width, height, r,g, b, c, gry; 
    height = bmpOriginal.getHeight(); 
    width = bmpOriginal.getWidth(); 
    int depth = 20; 

    Bitmap bmpSephia = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); 
    Canvas canvas = new Canvas(bmpSephia); 
    Paint paint = new Paint(); 
    ColorMatrix cm = new ColorMatrix(); 
    cm.setScale(.3f, .3f, .3f, 1.0f); 
    ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm); 
    paint.setColorFilter(f); 
    canvas.drawBitmap(bmpOriginal, 0, 0, paint); 
    for(int x=0; x < width; x++) { 
     for(int y=0; y < height; y++) { 
      c = bmpOriginal.getPixel(x, y); 

      r = Color.red(c); 
      g = Color.green(c); 
      b = Color.blue(c); 

      gry = (r + g + b)/3; 
      r = g = b = gry; 

      r = r + (depth * 2); 
      g = g + depth; 

      if(r > 255) { 
       r = 255; 
      } 
      if(g > 255) { 
       g = 255; 
      } 
      bmpSephia.setPixel(x, y, Color.rgb(r, g, b)); 
     } 
    }  
    return bmpSephia; 
} 

Answer 2

如果您有图像的情况下，那么你可以使用ColorMartix绘制它的棕褐色。让我描述一下如何使用Drawable来完成这个任务。

public static void setSepiaColorFilter(Drawable drawable) { 
    if (drawable == null) 
    return; 

    final ColorMatrix matrixA = new ColorMatrix(); 
    // making image B&W 
    matrixA.setSaturation(0); 

    final ColorMatrix matrixB = new ColorMatrix(); 
    // applying scales for RGB color values 
    matrixB.setScale(1f, .95f, .82f, 1.0f); 
    matrixA.setConcat(matrixB, matrixA); 

    final ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrixA); 
    drawable.setColorFilter(filter); 
} 

示例项目从Bitbucket移动到GitHub。请检查Release section下载APK二进制文件，无需编译即可测试。

Answer 3

我上the OP's answer提高。与the ColorMatrix method相比，这款产品运行速度快，但产生更好的棕色色调。 （在我看来）

public Bitmap toSepiaNice(Bitmap color) { 
    int red, green, blue, pixel, gry; 
    int height = color.getHeight(); 
    int width = color.getWidth(); 
    int depth = 20; 

    Bitmap sepia = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); 

    int[] pixels = new int[width * height]; 
    color.getPixels(pixels, 0, width, 0, 0, width, height); 
    for (int i = 0; i < pixels.length; i++) { 
     pixel = pixels[i]; 

     red = (pixel >> 16) & 0xFF; 
     green = (pixel >> 8) & 0xFF; 
     blue = pixel & 0xFF; 

     red = green = blue = (red + green + blue)/3; 

     red += (depth * 2); 
     green += depth; 

     if (red > 255) 
      red = 255; 
     if (green > 255) 
      green = 255; 
     pixels[i] = (0xFF << 24) | (red << 16) | (green << 8) | blue; 
    } 
    sepia.setPixels(pixels, 0, width, 0, 0, width, height); 
    return sepia; 
}