scrolling in xournal leads to bad rendering since update to saucy

[Jany Belluz]

Using KDE as a desktop environment, KWin version:
Qt : 4.8.4
Plate-forme de développement de KDE : 4.11.2
KWin : 4.11.2

With or without compositing, multiple instances of part of the pdf file fill the screen when scrolling through it.

See attached screenshot.

It does not seem to happen when the zoom is so that one entire page is visible on screen.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[cassiodoroVicinetti (artghio)]

This bug affects me only when I scroll down the page.

[Bderenor Caine (dominik-upb)]

This bug affects me as well. Exact same behavior.

[Guenther Palfinger (guenther-palfinger)]

Workaround:

Page Up and Page Down keys (and the equivalent klick on the scroll bar) work. So rendering is OK with Page Down, Page Up and scrolling up (as mentioned by #3).

[joe of loatj (monkeyofasia)]

Same issue here. Can't use page up and down keys as my laptop is closed with the screen facing upwards (Thinkpad X200T) when I'm using the pen on the screen.

Tried installing an older, known working version (from 12.04) but it had the same issue, which suggests it's a deeper issue than just xournal.

[Daniel Franzen (d-franzen)]

I am effected as well.
PageDown key works except when it reaches the bottom of the document. So the last scroll down with buttons messes up the page as well.
I'm using a Thinkpad X201t.
Re-rendering by setting the zoom factor to the exact same value fixes the problem temporarily

[Daniel Franzen (d-franzen)]

The following workaround works for me. It just requests a redraw of the visible area each time after scrolling:

diff -Naur xournal-0.4.7/src/xo-callbacks.c xournal-fixed/src/xo-callbacks.c
--- xournal-0.4.7/src/xo-callbacks.c 2012-07-04 23:02:57.000000000 +0100
+++ xournal-fixed/src/xo-callbacks.c 2013-12-09 22:11:42.545079488 +0000
@@ -2935,6 +2935,11 @@
   double viewport_top, viewport_bottom;
   struct Page *tmppage;

+ GtkAdjustment *v_adj = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(GET_COMPONENT("scrolledwindowMain")));
+ GtkAdjustment *h_adj = gtk_scrolled_window_get_hadjustment(GTK_SCROLLED_WINDOW(GET_COMPONENT("scrolledwindowMain")));
+
+ gnome_canvas_request_redraw(canvas,h_adj->value,v_adj->value,h_adj->value+h_adj->page_size,v_adj->value+v_adj->page_size);
+
   if (!ui.view_continuous) return;

   if (ui.progressive_bg) rescale_bg_pixmaps();

[Martin Ueding (martin-ueding)]

I switched to Awesome WM. The bug does not seem to occur there, so I
cannot say anything about this fix.
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[Martin Ueding (martin-ueding)]

Okay, so I am still using KDE with Awesome WM currently, and the bug occurs there as well. I downloaded the package with `apt-get source` put the patch in there and uploaded it to my “Stable” PPA, here on Launchpad. You can get a patched version from there, if you would like to try.

Daniel, thanks for the patch. I can still see the glitches occur, but they are fixed right away. This one was driving me crazy.

[Guenther Palfinger (guenther-palfinger)]

I tried Martins stable PPA. The package works well for me. Thanks Martin for packaging and Daniel for the patch.

[Martin Ueding (martin-ueding)]

Glad the PPA version works for you. While I put the patch into the
package, I noticed that it did not have anything that `dh_clean` would
use. So I filed yet another bug against the package in the Debian BTS.

Is this bug filed in Debian as well, or does it only affect Ubuntu? I
mean, if it just stays here in this tracker, upstream may never notice
about it.
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[Roberto Natalini (roberto-natalini)]

Martin your PPA version works really very well for me (kubuntu saucy on a fujitsu T902). Xournal is one of my most important tools at work. Many thanks! r

[Martin Ueding (martin-ueding)]

You are welcome. Glad that I could make use of the Debian packaging
skills :-)
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