Bug 140493

Summary:	Allow to change DPI-info metadata
Product:	[Applications] digikam	Reporter:	MaxiPunkt <maxantispam>
Component:	Plugin-Generic-MetadataEdit	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	REPORTED ---
Severity:	wishlist	CC:	caulier.gilles
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	Mandriva RPMs
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description MaxiPunkt 2007-01-23 13:43:26 UTC

Version:           0.1.2 (using KDE KDE 3.5.4)
Installed from:    Mandriva RPMs
OS:                Linux

Many graphic-formats (i.e. JPG, TIF, PNG) are able to hold information aobut DPI-settings, which is useful for defining printout-sizes of images, i.e. when doing a 1:1 print of a scanned images.

Newest SVN-version of GwenView i.e. now is able to use it, see:
http://bugs.kde.org/show_bug.cgi?id=129948

An option to "tweak" DPI-information in graphic-files would be very useful.

Comment 1 Angelo Naselli 2007-01-24 22:07:19 UTC

Gilles, I know it is not related to exif tag, but can we add something like that into that plugin or something like?

Comment 2 caulier.gilles 2007-10-03 16:51:53 UTC

Angelo,

If i'm not too wrong Exif tags below are what you want to use :

0x011a  XResolution  rational64u  IFD0    
==> The number of pixels per <ResolutionUnit> in the <ImageWidth> direction. When the image resolution is unknown, 72 [dpi] is designated.

0x011b  YResolution  rational64u  IFD0  
==> The number of pixels per <ResolutionUnit> in the <ImageLength> direction. The same value as <XResolution> is designated.

0x0128  ResolutionUnit  int16u  IFD0  1 = None;2 = inches;3 = cm
==> The unit for measuring <XResolution> and <YResolution>. The same unit is used for both <XResolution> and <YResolution>. If the image resolution is unknown, 2 (inches) is designated.

If we use these tags, if will be very easy to adjust values with libkexiv2...

Gilles


Adding/set DPI info require to rewrite whole image. This information is not on Exif/Iptc

Comment 3 Angelo Naselli 2007-10-03 17:34:10 UTC

exif data should be the keys you can find into
http://bugs.kde.org/show_bug.cgi?id=129948#c35 IIRC.
I'd like to have it for printwizard, but in my case i need it as read only :)
 
About this bug report:
All the graphic images (at least most of) have dpi info inside
the file itself. But Qt/KDE api don't allow to manage them well,
on jpeg for instance in gwenview i used Aurelien's interface.
Into bug #12994 reporter added a lot of links concerning documents
for some kind of images. There you can find in which bytes are
those info. 

HTH,
	Angelo

Comment 4 Angelo Naselli 2007-10-03 17:35:25 UTC

Bug #129948 i meant :)