I have just tried to familiarize myself more with Krita, but this is presenting a stumbling block.. In short:

1. Draw a line
2. It shows up normally
3. Zoom out to check it
4. Display mostly doesn't update -- little rectangle chunks near the cursor do, only.
5. Panning the display causes it to fully update so I can see everything again.

This occurs whenever I am moving the tablet stylus while zooming in/out via keyboard shortcuts. Holding the stylus away from the tablet prevents the problem from occurring -- but of course is rather unnatural for drawing.

I would expect the problem occurs similarly for rotation via keyboard shortcuts, but have not tested that yet.

Zooming via Ctrl+Mdrag works ok. I would prefer to avoid that though as it's really jerky.

Krita: 2.9.9 (with opengl canvas OFF -- turning it on prevents the canvas from being drawn at all ever)
OS: Arch Linux x86_64
KF5: 20150530
Graphics hardware: NVIDIA Corporation G86 [GeForce 8400 GS]
Graphics driver: official nvidia (nvidia-340xx package)

(on a more minor note, it really seems weird that there is no menu item or shortcut to reset canvas rotation. Trying to get back to 0 degrees manually is fiddly. EDIT: Never mind, it's part of 'Canvas Input Settings')

Hi finticemo,

You can press '5' to reset canvas rotation.

kamathraghavendra wrote:Hi finticemo,

You can press '5' to reset canvas rotation.

I can't, actually. But thanks for reminding me that some of the shortcuts are hidden in 'Canvas Input Settings'. Looks like I configured that function as Shift+[ .

The blockiness is because openGL isn't on. The fact that openGL doesn't work can only be blamed on the drivers being broken. I am afraid we can't do much about NVidea drivers not doing as they advertise

TheraHedwig wrote:The blockiness is because openGL isn't on. The fact that openGL doesn't work can only be blamed on the drivers being broken. I am afraid we can't do much about NVidea drivers not doing as they advertise

Is this a known issue with that driver? Because Blender uses OpenGL extensively and works 100% fine, as do various opengl-based games like xmoto, supertux, neverball, and even WebGL in the browser.

I have same issue. It happens often, but I can't say exact steps of reproduction.
AMD Radeon 7700 series, Windows7 64-bit, Krita 2.9.7

Workaround: Alt+Tab and Alt+Tab to repaint everything.

OpenGL is disabled (it is auto-disabled due frequent error "can't compile shader").

dobrokotov wrote:I have same issue. It happens often, but I can't say exact steps of reproduction.

So the steps I described (essentially just 'move the tablet stylus while you press the zoom shortcut key') do not reliably reproduce it for you?

AMD Radeon 7700 series, Windows7 64-bit, Krita 2.9.7

Workaround: Alt+Tab and Alt+Tab to repaint everything.

Yes, that works for me too.. (well, it's Super+R then Super+S for me, but same idea; forcing the window to redraw itself fixes things.)

> So the steps I described (essentially just 'move the tablet stylus while you press the zoom shortcut key') do not reliably reproduce it for you?
No, it starts to happen after I work for about an hour in Krita, on real images with lot of strokes and layers.

Nailed it now, screenshot: http://dobrokot.ru/pics/i2015-12-08__04-50-58_222kb.jpg . Actual image is unaltered, and glitching zoom is repainted when I move cursor-brush over it.

Uhm, guys, it's not really a bug, but rather than we stretch qpainter to it's max. It's why we implemented the OpenGL canvas to begin with.

I can't really say why the drivers are broken, just that Krita uses some really basic functionality that gets overseen really quickly by driver vendors. It's why we've had black screen on Intel devices for a full year.