[Digikam-users] Main window 100% not pixel per pixel

[Samuel Gilbert]

Hello,

Here is the requested info and some tests I did to try to figure out what is 
going on :

Version 1.3.0
Using KDE Development Platform 4.4.5 (KDE 4.4.5)
ArchLinux package : digikam 1.3.0-1

I don't know if it's relevant, but Kipi-plugins are also version 1.3.0.

The problem occurs regardless of the image type.  It occurs with all the 
photos I tried :

Canon Rebel XT JPEG
Canon Rebel XT RAW (CR2 files)
JP2 files generated with digiKam's RAW import tool
Nikon D90 JPEG
Nikon D90 RAW (NEF files)

I have some PNG files that are scans of photos taken with my old 35mm Camera.  
The problem does not occur with those files.  It also does not occur with the 
JPEG files generated by my WebCam.

I noticed that the files for with the zoom works correctly do not have any kind 
of metadata tags (EXIF, IPCT, etc...).  Could it be that digiKam uses 
something in the tags to figure out what is a 100% zoom?  If that is the case, 
what does 100% mean?

I did the following test to check if digikam is using the image DPI info :

I selected 50% zoom in the main windows with a JPEG file generated by my Canan 
Rebl XT.  The image has 3456 pixels by 2304 for which the X and Y resolution 
is 72 with the resolution unit set to "Inch".  On screen, the display size is 
167mm by 112mm.  Once converted to inches, we get 6.57480315 by 
4.40944882.  This mean that we have 3456 for 6.57480315 inches at 50% zoom.

3456 px / 6.57480315 inch / 2 (to account for 50% zoom) = 262.82155687

This does not match the image's DPI.  I also verified that Xorg had the correct 
monitor size prior to the test checking the screen dimensions reported by 
xdpyinfo against the physical display size measured with a ruler.

In the EXIF tags of the image used for the test, there is also the focal plane 
resolution.  Resolution is 3954.23 by 3958.76 with unit set to "inch".  Given 
the image size, this gives a sensor size of 0.874000753623 by 0.582000424375 
inches.  That may be, but I don't understand how it's related to the size of 
the image on screen when a zoom of 100% is selected.

Is there something else I should check?

Samuel

On 2010-07-16 Friday 02:02:09 Gilles Caulier wrote:
> Which digiKam version ?
> 
> Which image type ?
> 
> Try digiKam 1.3.0
> 
> Gilles Caulier
> 
> Le 16 juillet 2010 07:16, Samuel Gilbert
> 
> <samuel.gilbert at usherbrooke.ca> a écrit :
> > Hello,
> > 
> >  I was wondering if there is a reason why the image isn't displayed pixel
> > per pixel when I select 100% in the main window.  If I open the image in
> > the editor or in another viewer, selecting a zoom of 100% results in the
> > image being displayed pixel per pixel.  Is this behavior a bug, or is
> > there something I'm missing?
> > 
> > Samuel
> > _______________________________________________
> > Digikam-users mailing list
> > Digikam-users at kde.org
> > https://mail.kde.org/mailman/listinfo/digikam-users
> 
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