Rectangle Select very slow when bigger images comparing to Gimp instant selection

[grofaty]

I read this complain in http://www.webupd8.org/2015/03/pinta-image-editor-sees-new-stable.html in comment section by one user and tested it now in Pinta 1.7.0.125 and Pinta 1.6 official stable on Ubuntu 14.04.

1. New image 640 x 480.
2. Rectangle Select and try to select as much of the canvas as you can.
Selection is performed instantly. Excellent.

3. New image 2000 x 2000.
4. Repeat step 2.
Selection takes little more then 2 seconds on my laptop (my laptop is few years old).

5. New image 5000 x 5000.
6. Repeat step 2.
Selection takes exactly 12 seconds on my laptop (my laptop is few years old).

Turing tests I have had Terminal window open with top command and I see CPU 3% compiz, CPU 3% xorg at maximum. But at the test of 5000 x 5000 I see "mono" process taken up 98% of CPU and Pinta even got greyed durring process - Ubuntu feature to diagnosis a potential application hang.

Do above tests with Gimp and all of the test are performed instantly even on my old laptop. The user from webupd8.org complained that he is working with big images and Pinta is not really useful to him because of long delay times.

[grofaty (grofaty)]

I have tested little bit more with 5000 x 5000 and I see Rectangle Select is not the only problem. It looks to me that really instant working are Pencil, Erraser and Paintbrush. All shapes like Rectangle, Rounded Recntangle, Line etc have big delay and huge CPU consumption.

[Cameron White (cameronwhite91)]

I've fixed the selection issues in https://github.com/PintaProject/Pinta/commit/b27fc28b

[grofaty (grofaty)]

On Ubuntu 14.04 I have tested 5000 x 5000 Recatngle Selection on 1.7.0.131 and it looks some improvements, but still takes about 10 seconds to make selection. I tested on 1.7.0.132 and there is huge difference it draws selection immediatelly. I think we can mark this problem fixed.

The only little thing about performance is when mouse is moved in my old laptop it takes about half a second to make selection, so seleciton is little bit behind mouse movement. But this is on my old laptop with 5000 x 5000 px that I never use in real life.