Bug#799572: gnome-screenshot hangs indefinitely with blank window when capturing fullscreen, running under compositing window manager

[Klaus Knopper]

Package: gnome-screenshot
Version: 3.16.2-1
Severity: important
Tags: patch upstream


gnome-screenshot runs into an endlees loop when capturing a fullscreen
picture. This may be related to a similar bug in reported for GTK 3.8
described here: https://bugzilla.gnome.org/show_bug.cgi?id=695132

Apparently, this happens especially in scenarios when a compositing
window manager like compiz, unity, or gnome-shell, changes opacity
settings during the "fade effect" of gnome-screenshot, so the final
opacity setting of (default) 0.1, that is checked for in
src/cheese-flash.c, is never reached.

A possible solution could be completely removing the "flash" effect
timer loop. Instead of this, in the patch attached, the final opacity
setting has just been increased to 0.05, which keeps the visual effect
working, but seems to be high enough to circumvent the iopacity setting
rounding effect that triggers the inifinite loop.

-- System Information:
Debian Release: 8.2
  APT prefers stable
  APT policy: (990, 'stable'), (500, 'stable-updates'), (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: i386 (x86_64)

Kernel: Linux 4.2.0-64 (SMP w/2 CPU cores; PREEMPT)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages gnome-screenshot depends on:
ii  dconf-gsettings-backend  0.22.0-1        simple configuration storage syste
ii  libc6                    2.19-20         GNU C Library: Shared libraries
ii  libcairo2                1.14.2-2        Cairo 2D vector graphics library
ii  libcanberra-gtk3-0       0.30-2.1        GTK+ 3.0 helper for playing widget
ii  libcanberra0             0.30-2.1        simple abstract interface for play
ii  libgdk-pixbuf2.0-0       2.31.1-2+deb8u2 GDK Pixbuf library
ii  libglib2.0-0             2.44.1-1.1      GLib library of C routines
ii  libgtk-3-0               3.16.6-1        GTK+ graphical user interface libr
ii  libx11-6                 2:1.6.3-1       X11 client-side library
ii  libxext6                 2:1.3.3-1       X11 miscellaneous extension librar

gnome-screenshot recommends no packages.

gnome-screenshot suggests no packages.

-- no debconf information
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