[digiKam-users] Digikam Showphoto reescaling: Where to select units?

[Rafael Linux]

I use digikam not only to generate web images, but for print, and when I
reescale a photo many times I need specify metric units, like centimenters.
However, Showphoto don't let me choose any unit, but pixels. There will be
any way to specify units not screen related?

Thank you



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[Gilles Caulier-4]

Hi,

No, it's not implemented, but we have already some entries in bugzilla about this wish.

Gilles Caulier

2018-08-15 21:09 GMT+02:00 Rafael Linux <[hidden email]>:

I use digikam not only to generate web images, but for print, and when I
reescale a photo many times I need specify metric units, like centimenters.
However, Showphoto don't let me choose any unit, but pixels. There will be
any way to specify units not screen related?

Thank you



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Sent from: http://digikam.1695700.n4.nabble.com/digikam-users-f1735189.html

[Remco Viëtor]

On mercredi 15 août 2018 21:09:25 CEST Rafael Linux wrote:
> I use digikam not only to generate web images, but for print, and when I
> reescale a photo many times I need specify metric units, like centimenters.
> However, Showphoto don't let me choose any unit, but pixels. There will be
> any way to specify units not screen related?

In addition to Gilles' reply, keep in mind that an image size in cm also needs
a resolution (in e.g. pixels/cm) to make sense. And that resolution depends on
the final output device. And if the resolution isn't known (yet), you cannot
ask for an output size in anything but pixel size.

Do keep in mind that repeated rescaling of an image (the "many times" above)
will cause quality loss, more than sending the 'wrong' image size to the
printer. (Of course, this is for subsequent rescalings;  if you always start
from a master file to do one rescaling step to your final file, there's no
problem)

Remco

Le 16/08/2018 à 12:08, Remco Viëtor a écrit :

> In addition to Gilles' reply, keep in mind that an image size in cm also needs
> a resolution (in e.g. pixels/cm) to make sense.

I don't understand this. An image have *always* a pixel count in
digikam, what is asked is simply to apply this number of pixel to a cm
size. Of course the result is not necessarily good

but the needed result depends also of the place the lurker is, cm far or
multimeters...

jdd

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[Remco Viëtor]

On jeudi 16 août 2018 12:18:35 CEST [hidden email] wrote:

> Le 16/08/2018 à 12:08, Remco Viëtor a écrit :
> > In addition to Gilles' reply, keep in mind that an image size in cm also
> > needs a resolution (in e.g. pixels/cm) to make sense.
>
> I don't understand this. An image have *always* a pixel count in
> digikam, what is asked is simply to apply this number of pixel to a cm
> size. Of course the result is not necessarily good
>
> but the needed result depends also of the place the lurker is, cm far or
> multimeters...

Of course an image always has a size in pixels. But the question was in the
context of *resizing* an image. If I don't specify a resolution, how does the
program decide what resizing to apply if I specify a size of say 3m × 4m?

Remco

[Rafael Linux]

Thank you Gilles for the info


Remco Viëtor wrote
> In addition to Gilles' reply, keep in mind that an image size in cm also
> needs
> a resolution (in e.g. pixels/cm) to make sense. And that resolution
> depends on
> the final output device. And if the resolution isn't known (yet), you
> cannot
> ask for an output size in anything but pixel size.

Yes, I know. Cause ShowPhoto don't have this option, I need always to open
my photos with GIMP or Krita (despite I don't need to retouch nothing in the
image) to change the print output in centimetres, changing simultaneosly the
image dpi (in attached capture you can see the Krita the powerful reescale
dialog).
<http://digikam.1695700.n4.nabble.com/file/t376179/Krita_image_reescaling.png>


> Do keep in mind that repeated rescaling of an image (the "many times"
> above)
> will cause quality loss, more than sending the 'wrong' image size to the
> printer. (Of course, this is for subsequent rescalings;  if you always
> start
> from a master file to do one rescaling step to your final file, there's no
> problem)
>
> Remco

Sorry, I should told "often" instead "many times". As you say, there will be
a madness to reescale photos previously reescaled.

Anyway, "Restore photography" disposable function of ShowPhoto makes a
EXCELLENT job really.




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