BufferedImage：将所有像素设置为白色，其中alpha = 0

Question

I have a BufferedImage and would like to set all pixels that are fully transparent to be fully-transparent white (rather than transparent blank, or whatever may be in the source file). I can of course loop through the entire image using getRGB and setRGB, but is there some other way that would be much faster?

Answer 1

You can set the pixels like this:

public void setRGB(int startX,
               int startY,
               int w,
               int h,
               int[] rgbArray,
               int offset,
               int scansize)

This method sets an array of integer pixels in the default RGB color model (TYPE_INT_ARGB) and default sRGB color space, into a portion of the image data. Color conversion takes place if the default model does not match the image ColorModel. There are only 8-bits of precision for each color component in the returned data when using this method. With a specified coordinate (x, y) in the this image, the ARGB pixel can be accessed in this way:

 pixel   = rgbArray[offset + (y-startY)*scansize + (x-startX)];

Answer 2

I can't say for sure if it is faster, but take a look at the ColorConvertOp class.

I haven't used it personally, but it might be what you are looking for.