Bitmap.setPixels在Android下扭曲颜色

Question

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I need to get an image from my phone`s camera. I use formula to convert from YUV to RGB. Then I put RGB into IntBuffer. Then I copy pixels from IntBuffer into Bitmap. This way gives correct result. But I need to use not an IntBuffer but a common array of int[]. In this case function bitmap.setPixels produces uncorrect results . Colors are wrong. The first image is correct. The second image is a result of int[].

Android 4.1.1 HTC Desire X

    @Override
public void onPreviewFrame(byte[] data, Camera camera) {
    Size previewSize = parameters.getPreviewSize();
    int imageWidth = previewSize.width;
    int imageHeight = previewSize.height;

     if(toggleButton1.isChecked())
     {  
         if(ck==0)   
         {  

              Bitmap preview_bitmap = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);
              Bitmap preview_bitmap2 = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);

             final byte alpha = (byte) 255;
             int numPixels = imageWidth*imageHeight;

             IntBuffer intBuffer = IntBuffer.allocate(imageWidth*imageHeight);
             intBuffer.position(0);

             int buff[]= new int[imageWidth*imageHeight];

             int i=0;
             for (int y = 0; y < imageHeight; y++) {     
                for (int x = 0; x < imageWidth; x++) {   
                     int Y = data[y*imageWidth + x] & 0xff;

                     int xby2 = x/2;
                     int yby2 = y/2;
                     float U = (float)(data[numPixels + 2*xby2 + yby2*imageWidth] & 0xff) - 128.0f;
                     float V = (float)(data[numPixels + 2*xby2 + 1 + yby2*imageWidth] & 0xff) - 128.0f;
                     // Do the YUV -> RGB conversion
                     float Yf = 1.164f*((float)Y) - 16.0f;
                     int R = (int)(Yf + 1.596f*V);
                     int G = (int)(Yf - 0.813f*V - 0.391f*U);
                     int B = (int)(Yf            + 2.018f*U);

                     R = R < 0 ? 0 : R > 255 ? 255 : R;
                     G = G < 0 ? 0 : G > 255 ? 255 : G;
                     B = B < 0 ? 0 : B > 255 ? 255 : B;


                     intBuffer.put(alpha*16777216 + R*65536 + G*256 + B);
                     buff[i]=     (alpha*16777216 + R*65536 + G*256 + B);


                     i++;     
                 }
             }

            intBuffer.flip();

            preview_bitmap.copyPixelsFromBuffer(intBuffer); 
            preview_bitmap2.setPixels(buff,0,imageWidth,0,0,imageWidth,imageHeight);

            //imageView1.setImageBitmap(preview_bitmap);
            //imageView2.setImageBitmap(preview_bitmap2);

            save_SDcard(preview_bitmap,"pic1.jpg");
            save_SDcard(preview_bitmap2,"pic2.jpg");
             ck++;
         }
     }               
}

Answer 1

this is the simple code i used to swap the red and blue channels when i had a similar issue

for (int i = 0; i < totalPixels; ++i) {
    // The alpha and green channels' positions are preserved while the red and blue are swapped
    pixelsBuffer[i] = ((pixelsBuffer[i] & 0xff00ff00)) | ((pixelsBuffer[i] & 0x000000ff) << 16) | ((pixelsBuffer[i] & 0x00ff0000) >> 16);
} 

Answer 2

You can use an int[], then just use IntBuffer.wrap to create an IntBuffer reference without allocating new memory. Bitmap.copyPixelsFromBuffer() copies the raw pixels without modifying them, setPixels is doing alpha multiplication, and possibly format conversion (by all appearances there is some kind of ARGB/BGRA conversion going on.

Try these adjustments to continue to use copyPixelsFromBuffer() along with your int[]:

@Override
public void onPreviewFrame(byte[] data, Camera camera) {
    Size previewSize = parameters.getPreviewSize();
    int imageWidth = previewSize.width;
    int imageHeight = previewSize.height;

     if(toggleButton1.isChecked())
     {  
         if(ck==0)   
         {  

              Bitmap preview_bitmap = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);
              Bitmap preview_bitmap2 = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);

             final byte alpha = (byte) 255;
             int numPixels = imageWidth*imageHeight;
             int buff[]= new int[numPixels];

             int i=0;
             for (int y = 0; y < imageHeight; y++) {     
                for (int x = 0; x < imageWidth; x++) {   
                     int Y = data[y*imageWidth + x] & 0xff;

                     int xby2 = x/2;
                     int yby2 = y/2;
                     float U = (float)(data[numPixels + 2*xby2 + yby2*imageWidth] & 0xff) - 128.0f;
                     float V = (float)(data[numPixels + 2*xby2 + 1 + yby2*imageWidth] & 0xff) - 128.0f;
                     // Do the YUV -> RGB conversion
                     float Yf = 1.164f*((float)Y) - 16.0f;
                     int R = (int)(Yf + 1.596f*V);
                     int G = (int)(Yf - 0.813f*V - 0.391f*U);
                     int B = (int)(Yf            + 2.018f*U);

                     R = R < 0 ? 0 : R > 255 ? 255 : R;
                     G = G < 0 ? 0 : G > 255 ? 255 : G;
                     B = B < 0 ? 0 : B > 255 ? 255 : B;

                     // better implementation than multiplying
                     buff[i] = Color.argb(alpha,R,G,B);
                     i++;     
                 }
             }

            // just wrap your buff
            IntBuffer intBuffer = IntBuffer.wrap(buff);

            preview_bitmap.copyPixelsFromBuffer(intBuffer); 
            preview_bitmap2.setPixels(buff,0,imageWidth,0,0,imageWidth,imageHeight);

            //imageView1.setImageBitmap(preview_bitmap);
            //imageView2.setImageBitmap(preview_bitmap2);

            save_SDcard(preview_bitmap,"pic1.jpg");
            save_SDcard(preview_bitmap2,"pic2.jpg");
             ck++;
         }
     }               
}