Fast zooming (Ctrl+Mouse wheels) doesn't work.

[arhiv6]

In Qucs at fast zooming (using Ctrl + Mouse wheel) is not working properly. If you change the zoom is not fast - it works fine. But if you zoom in quickly, the scale is reset to the initial value - that is it does not work. Tested on Ubuntu15.10 32 and 64bits, version 0.0.18 and 0.0.19. Video: https://youtu.be/yOsCOftvIBM

[in3otd]

I have tried to reproduce the issue (Slackware 32 b, Qucs 0.0.19), but I did not see this problem. Do you see a similar behavior also with panning (just the mouse wheel and Shift+Mouse wheel)?

[arhiv6]

Mouse wheel and Shift+Mouse wheel working normal.

[andresmmera]

I've noticed that behaviour some time ago... but in the end I can live with it so I've never reported it :-) Here i'm using Ubuntu 14.04 LTS 64b

[in3otd]

ok... can you try to insert a line

qDebug() << delta;

here and recompile, looking then at the numbers printed on the terminal while zooming, just to check if some strange step value is passed to the routine. I always get just 60 or -60.

[andresmmera]

Uhm,... I've followed your instructions and after doing some random fast zooming (CTRL+Wheel) I can see many 60 and -60, but also 120, -120 and -180

[andresmmera]

I can confirm that it shows (-60, 60) when you scroll slowly. However, as soon as you scroll faster, the effect described above arises and the log shows some 120 and 180.

[andresmmera]

I've reduced the zooming step by replacing "int delta = Event->delta() >> 1; " by "double delta = Event->delta()*0.7;" at line 1881 and it seems to work here...

[in3otd]

thanks; could you please try changing the lines here to

if(delta < 0) Scaling = 1/1.1;
else Scaling = 1.1;

and check whether the zoom issue is gone

[andresmmera]

Yep, this way the problem disappeared too :-)

[in3otd]

just saw your new comment: looking at the code I think that the multiples of 60 returned by the wheel event are causing the zoom to actually reverse direction. Just taking the sign as suggested above should be enough, I don't think a fast(er) zoom is really needed in practice.

[andresmmera]

Of course, a faster zoom is not needed at all. It was kinda quick 'patch'...

[in3otd]

well, I think we can keep the faster zoom feature at little cost and this will also accomodate any mouse returning less than 120 for the wheel delta(). Please try #499 and check how it works there.

[guitorri]

The fix is merged in both, develop and release-0.0.19.