使用Java按行或按像素读写imag文件

Question

I have a specific object with image data. And I want read/write images (in BMP, JPEG and PNG formats) to this object.

Of course, I can read/write image into/from BufferedImage and then copy/paste pixels into/from my object. But, I want to do it more faster without intermediate objects!

How can I perform it over standard Java library or throw other Java library?

PS:
I know pngj library that allow read PNG images by lines. Maybe you know same libraries for BMP, JPEG (or for all of them: BMP, JPEG, PNG)?

Answer 1

If you want to do all the reading by yourself, you can just open the file with a stream and read it into an array, but you would need to work your way through the whole structure of the file (headers etc...) if you are working with compressed formats you'd have to work on that too.

Best would be to use imageio to load/write your files and I don't believe there is a lot of overhead coming from the read/write of your images. Also if you expect to do some heavy work on the images, know that BufferedImages can be hardware accelerated which will improve performance a lot.

Answer 2

Why don't you just have the BufferedImage in your Object ? BufferedImage isn't all that bad. Otherwise, you will need to use something like BufferedImage to convert the image file into pixels, and then read the BufferedImage into something like an int[] array of pixels, but it still requires BufferedImage in the middle, and this would slow things down by adding an extra loop to read over and store the pixels.

Is there a reason why BufferedImage isn't suitable for your purpose?