Distance measurement

[Graham-sr]

I am trying to measure the distance between 2 points on an image.

The default option seems to be in pixels. However I need it in mm.
I cannot find a way to change the measuring units.
I did stumble upon it on one occasion, but cannot find a way to repeat the option.

Any help would be appreciated.

Regards

[tannerhelland]

Hello @Graham-sr. I apologize that this feature is kind of hidden!

You can change the measurement unit for the measurement tool (and viewport rulers, etc.) in PhotoDemon's status bar:

Also, you may already know this, but "real-world" units like cm or mm rely on the resolution value of the current image (which is the size of the image if it were printed to paper), not the size of the image as it appears "on screen".

You can manually set the current image's resolution value from the Image > Resize menu.

[Graham-sr]

Thanks for your guidance, I was looking in the wrong places ! A second thought – is it possible to change the pointer style when measuring distances ? The default ‘cross’ (called ‘move’ by Windows) tends to obscure the start and end positions that I am trying to measure. I cannot see any way to change this. I need to make fairly precise measurements – I am a stamp collector, measuring small design differences. If this is not currently possible, would you consider making it an option in any later version of PhotoDemon ? Either the ‘normal select’ pointer or the ‘pointing finger’ would seem to be ideal. Regards Graham From: Tanner ***@***.***> Sent: 13 May 2026 02:45 To: tannerhelland/PhotoDemon ***@***.***> Cc: Graham-sr ***@***.***>; Mention ***@***.***> Subject: Re: [tannerhelland/PhotoDemon] Distance measurement (Discussion #772) Hello @Graham-sr <https://github.com/Graham-sr> . I apologize that this feature is kind of hidden! You can change the measurement unit for the measurement tool (and viewport rulers, etc.) in PhotoDemon's status bar: image.png (view on web) <https://github.com/user-attachments/assets/dd974e95-1718-4ca7-a76c-887db6aeceb2> Also, you may already know this, but "real-world" units like cm or mm rely on the resolution value of the current image (which is the size of the image if it were printed to paper), not the size of the image as it appears "on screen". You can manually set the current image's resolution value from the Image > Resize menu. — Reply to this email directly, view it on GitHub <#772 (comment)> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/APWEHX7PU4PCDOQH4F5KC5T42PHRZAVCNFSM6AAAAACYU4EFD2VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTMOBZHA4DENI> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub> . You are receiving this because you were mentioned. <https://github.com/notifications/beacon/APWEHX45CLUFOWHASFVWYW342PHRZBFCNFSM6AAAAACYU4EFD2WGG33NNVSW45C7OR4XAZNRIRUXGY3VONZWS33OINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQBAHNQTJTSMVQXG33OU5WWK3TUNFXW4.gif> Message ID: ***@***.*** ***@***.***> >