How to highlight portion of Image

Question

Hi
I have a image. i want to highlight the portion of an image. I have the start pixel value,end pixel value and height and width.
I want to highlight the particular area by yellow color and color should be transparent so that highlighted portion can be seen.
What would be the approach.
I tried it with coloring the particular pixel value but i couldnt achieve transparency.
Please provide me piece of code
Any help would be highly appreciated.
thanks

Answer 1

All your tiff images are black and white. Thus, they can't be highlighted since the highlight will result in a color that's not black or white. This problem will extend to all palette based images (ones with an IndexColorModel).
The solution is to turn the palette image into a full RGB one, which you did by using an intermediate image.
Any improvement on this.1) You don't need an intermediate image if ColorModel#getPixelSize() returns >= 24. This will mostly be a memory/garbage collection improvement.
2) You don't need to use TYPE_INT_ARGB for the intermediate image if the original image doesn't have and alpha channel. Instead you can use TYPE_3BYTE_BGR. Again, this would be a memory improvement and the file size may be less since there's no alpha channel.
3) The TIFImageWriter supports several compression schemes. Some of the compression schemes (LZW, JPEG, DEFLATE) offer better file sizes then the default one. When you do a straight call to,
ImageIO.write(newImage, "tif", new File("D:/DocHighlighting/Out.TIF"));you're using the default compression scheme. LZW will offer a smaller file size and the tiff file will be just as portable. JPEG will offer the smallest file size, but more image editing programs will have a trouble opening it and it's a lossy compression. I think DEFLATE is even less portable than JPEG, but it's a lossless compression and will offer a smaller file size than LZW.
Although i tried this way and it worked but new image size is almost 14612KB and original image size was 289KBThat's because it went from black and white (with a specialized black/white compression) to a full colored image. Such is the consequence of introducing more colors. You can decrease the file size a bit by changing the compression type and not introducing an alpha channel if not needed, but for the most part the file size will still be much larger then the black and white one.
If you're really ambitious, you can create an IndexColorModel with 4 colors - black, white, black under highlighting, and white under highlighting - and use that as the color model for your black/white-highlighted images. Then the TIFFImageWriter may very well save the image as palette based, resulting in a significant decrease in the file size.