Re: issue with snapshot capture and comparisons using gtk

[Owen Taylor <otaylor redhat com>]

"bharat  tewari" <bharat tewari wipro com> writes:

> sorry if this topic is already brought out but currently i am trying
> to fix the issue in the image snapshot comparisons in the
> gnome-test-tool ( erstwhile gerd) and i have the following
> problem. Before that i will just explain how the gnome-test-tool
> works which will help. First we do a record session where in an
> application ( like nautilus, eog etc.) are started through this tool
> and the tool captures all the events that are generated during the
> recording time. Once you have done that, you can capture window
> snapshots using F5/F6 keys where in you can capture the window. The
> way it does is, it first creates a pixbuf and then copies the
> drawable ( i.e the window data) as gdk_pixbuf_get_from_drawable()
> passing colormap as NULL to this call.

[...]
 
> The snapshots are then compared to find out whether the record and
> the playback has generated the same output.

> Now when i am trying to do the same for a nautilus/eog window which
> loads a png file ( any image file) and i do record and playback,
> most of the times the result is a pass where as when i try to do
> this comparison after resizing the nautilus/eog window which has a
> png loaded, it always fails.

What seems to me to be the obvious first step is to figure out
what the differences are between the two screenshots. Getting
a visual diff between two images should be straightforward
using the GIMP or the 'composite' tool from the ImageMagick
package.

Regards,
                                        Owen