cover grid continuously redraws covers

[Frans-Jozef Hendrickx]

while I was experimenting with the grid cover sizes I found that when the grid display tried to show more than 100 covers it would rapidly and randomly redraw them. This seems to happen around 100 covers because I found that resizing the window would toggle this behaviour.

I am using the windows 64 bit 2,2 version Calibre desktop in windows 7. Dual monitor with maximum pixel width of 5820 px.

To reproduce this problem, open a library with more than 100 (121 in mine) covers.
Size the Calibre UI to half the screen.
in the preferences, "look and feel" open the cover grid tab and reduce the cover size until 70-80 covers will show.
Activate the cover grid and test the scrolling, it should work.
Resize the grid by closing the tag and/or detail browsers. Or just resize the window.
The covers will blink rapidly.

I just refined the effect, count the rows and columns (I have 12x8 = 96 covers) they must equal 99 or less. I've opened a cover grid of 33x3 with 2 cm height covers. functions correctly. add another column (34x3 = 102 covers) the redrawing begins. it seems to stabilise but moving the mouse pointer in and out of the grid triggers the redrawing.

it seems to me that there is a limit (the number 99 or indeed a two digit roll-over) I reached that destabilises Calibre but with the ever increasing screen sizes more people will find these limitations.

[Kovid Goyal (kovid)]

Preferences->Look & Feel->Cover Grid->Performance->Number of covers to
keep cached in memory increase that to a number large enough for you.

 status invalid

[Kovid Goyal (kovid)]

Fixed in branch master. The fix will be in the next release. calibre is usually released every Friday.

 status fixreleased