How to change the brightness and contrast of a Pixmap?

feiyuhuahuo

Does QT has functions like opencv functions which can change the brightness and contrast easily?
Like,

img = cv2.imread('sample.png')
img *= 1.2    # this increase the img contrast
img += 30    #  this increase the img brightness

I found some code that using for...loops to change the Qimage pixel one by one. But I think this may be slow.

SGaist

Hi,

AFAIK, no, not like that.

However Qt and OpenCV mixes pretty well so you should be able to use them together without issue.

feiyuhuahuo

Hi， I try to avoid using OpenCV because I want to use as few packages as possible. So how to do it in a Qt way?

SGaist

Well, you will have to reimplement the low-level mathematics yourself for all the operations you want.

Minimizing dependencies is a good goal, getting rid of a library which is optimized for what you want to do might not be the best idea.