Hello all, I am new to image processing and also in openGL and CoreImage,coreGraphics Libraries. I want to create a basic image editing app with these functionalities. Rotate,crop,resize,scale, along with these filters Black and white,sepia,night vision,colour dithering. What is the best approach openGL or coreGraphics? Any help regarding this would be very much appreciated.
Thanks, Rahul Vyas
Rotate, crop, and scale (“resize” means either crop or scale) are all covered by affine transformations, which you can do in Core Graphics.
The other filters, being color filtering, are completely different, so you should a separate question for each one of those.
I would suggest openGL & GLSL shaders (if iphone supports new OpenGLES 2) instead of coreGraphics & CIKernel. Because CIKernel is VERY limited subset of pixel shaders. For example it does not support: structs, arrays, data dependent IF, For loops which uses variable in test condition and so on... I don't say that CIKernels are bad thing - it is pretty good thing, and it is possible to work around these missing features. But given these VERY big limitations of CIKernels and coreGraphics, I would suggest OpenGL and GLSL pixel shaders,- which have a way more features of C language implemented.
Of course as I've said - if target iPhone supports only OpenGLES 1 - my advice isn't suitable in such case, and you may choose on your own.
EDIT: coreGraphics/CIKernel also doesn't support my beloved preprocessor.
good luck