Compare Photos with ImageMagick and a KDE Service Menu Action


A Bash quickie from yours truly:

Hope you find it useful.


1 Like

Hi @dmpop, thanks for sharing the script!

I’ve noticed a couple of small typos:

sudo cp resize.desktop /usr/share/kservices5/ServiceMenu/

should be

sudo cp compare.desktop /usr/share/kservices5/ServiceMenus/

If one wants to only compare images side by side without saving an intermediate file, this will resize the result to fit your screen and show it straight away:

IFS=" x" read -r _ w h < <(xrandr | grep -o primary[[:blank:]][[:alnum:]]*)
convert "$1" "$2" +append -filter lanczos -resize "${w}x${h}" show:

You could replace Exec= with that, or if the desktop file does not allow a compound command then just save those two lines to e.g. ~/scripts/compareShow, then chmod +x ~/scripts/compareShow and set Exec=~/scripts/compareShow %F


Fixed. Thank you!

Sorry, don’t want to be pedantic, but also notice “ServiceMenu” ==> “ServiceMenus:slight_smile:

The desktop file doesn’t seem to work on Dolphin for me though. The icon appears for a split second on the task bar and then it just disappears. If I run the script from the command line it words perfectly. Thank you.

I went through the Desktop Entry Specification and used desktop-file-validate to remove all possible errors.

So, to get instant comparison without saving files, put this into

[Desktop Entry]
Name=Compare side-by-side

[Desktop Action compare]
Name=Compare side-by-side
Exec=/home/morgan/scripts/compare-side-by-side %F

Note that you cannot use ~ nor $HOME in Exec= , it must either be an absolute path or relative to any of the folders in $PATH.

Put this into ~/scripts/compare-side-by-side

#!/usr/bin/env bash
IFS=" x" read -r _ w h < <(xrandr | grep -o primary[[:blank:]][[:alnum:]]*)
convert "$1" "$2" +append -filter lanczos -resize "${w}x${h}" show:

Run chmod +x ~/scripts/compare-side-by-side

desktop-file-validate still shows one error:

/usr/share/kservices5/ServiceMenus/compare.desktop: error: key “Actions” is present in group “Desktop Entry”, but the type is “Service” while this key is only valid for type “Application”

I consider that a bug in the specification since the KDE documentation and real-life seem to rely on the action key.

One quick remark: No need to install that file system wide. You can just put it into ~/.local/share/kservices5/ServiceMenu/. You might have to create the directory.

1 Like

Side note: I found it easier to have scripts in ‘open with’ menu rather than in a dolphin/ nautilus/whatever service menu because it allows you to run them from any application such as digikam, darktable, geeqie, etc.

1 Like

If the above isn’t working for you it may be because, like me, you have attached your monitor cable to a connector other than the primary (doh!). The following will work if you can’t be bothered reconnecting cables:

IFS=" x" read -r _ w h < <(xrandr | grep -o current[[:blank:]][[:alnum:]]*[[:blank:]]x[[:blank:]][[:alnum:]]*)

The output of xrandr:
$ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
DVI-D-0 disconnected primary (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DVI-D-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 299mm
1920x1080 60.00*+ 50.00
1680x1050 59.95 …