Add Perspective Crop tool in photo editor

[rajibando]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.
• I optionally donated to support the Fossify mission.

Feature description

Add a Perspective Correction Tool to the image editor. See this comment for more info.

There is a demand for such an app in the FOSS universe, I can vouch.

Why do you want this feature?

There isn't another app available on the FOSS F-Droid universe, while for programmers of your capability it would have been easy to bridge.

Additional information

GIMP being an Open Source Software under the GNU license, it could be altered and shredded and reused for other users.

Related links:

• https://forum.f-droid.org/t/is-there-an-image-perspective-correction-tool-in-f-droid-repo/29530
• Could a simple standalone image editor with Perspective Correction Tool be possible? #373
• Could a simple standalone image editor with unrestrained Crop Tool be possible? #371

Edit by @naveensingh: Cleaned up the issue.

[Aga-C]

Please rewrite the title to be simpler: "Tool for unrestrained crop with perspective correction".

[tswistak]

I see there's some ruckus about this feature request and some related closed ones, so I just wanted to add, that I'm very for the feature like this. I imagine it should work like in typical scanner apps, e.g. see this video: https://www.youtube.com/watch?v=t0lzIRRNqrg.

So, I can set boundaries of some object, and then it would crop with fixing the perspective. It sounds definitely like a one tool. I think anything more advanced would be an overkill for this app. If needed, for more advanced image editing you have e.g. Krita.

[rajibando]

Dear Mr. Agni,
Let us allow the matter to rest and focus on development instead.
Best wishes,
Rajib

[rajibando]

Dear Mr. Agni C,
While hovering the mouse over the icon, "needs triage", I am greeted with a pop-up that informs: Issue is not yet ready for PR authors to take up
Could you please look into the matter and inform? From my viewpoint the Feature Request is now complete with as much clarity as would have been possible from my end.
I would try to explain aspects that still bother you AFAP from my end.

[naveensingh]

I have edited the title and description of this issue for clarity.

needs triage
Could you please look into the matter and inform?

We keep the needs triage label until it becomes clear if/when/how to implement a feature.

[rajibando]

Dear Mr. Singh,

We keep the needs triage label until it becomes clear if/when/how to implement a feature.

Thank you for explaining the label, needs triage.

I have ... for clarity.

Thank you also for polishing up my primary post by inserting the Related links section at one place to make those links easily noticeable.

I have edited the title and description of this issue for clarity.

I would however request you not to change the subject line. The two tools requested are different, as explained earlier in the body of my post, but you have removed that part too from the said body.

Please restore the following section in my principal post here:

For simple and complete image corrector tool, the said two features are required together. One can't exist without the other, for the app to be self-sufficient.

Unrestrained Crop is planer. Perspective Correction is about correcting spherical, cylindrical, conical or other distortions because of lens or a particular way of holding the camera while clicking a pic.

Once again:

(1) Perspective Correction: This one is to correct spherical, cylindrical, conical and other kinds of distortions arising out of the way the camera is held while clicking a photo, and also from the camera lens itself.

(2) Unrestrained crop: This one is planer correction and chopping off of unnecessary portions.

Please don't edit my posts on my behalf except for polishing up with links, typos, etc. Please allow me my independence to frame my own thoughts and post them. I contemplated very hard to frame my needs within the framework of the exact sciences.

You are of course at liberty to insert your thoughts in your posts here, frame your own ideas and debate and discuss with me on this issue. I would discuss with you the nuances if we together consider that there needs be a discussion.

[tswistak]

Had I been in your shoes, I would have been more careful in using a word with a negative connotation.
A discussion between two mature adults, one definitely elderly :), on an issue can't, and shouldn't, be treated as a ruckus.

Creating three issues instead of one (earlier just one very generic) and ignoring moderators recommendations may not exactly be a ruckus (btw. it's completely normal, non-vulgar word), but I wouldn't call it a normal discussion. I'm not a Fossify member, but as a software developer, I absolutely understand, that feature requests (that are mostly for developers to know what to do) should contain clear and precise description of what should be done and how the new feature should work (use cases, scenarios, expected behaviors etc.). The title should be concise and exact. Also, Fossify has a clear guideline about keeping just one request per one feature request. Creating a second GIMP isn't a single feature request, it's a whole software project. I entered here because I really like the idea of a perspective correction tool, but I also understood that this feature request in the shape you've left it would be rejected as not conforming to the rules. Unrestricted cropping alone wouldn't make any sense in an editor that doesn't have features like cut/copy/paste or layers support, and is meant for simple photo editing, not graphics manipulation like GIMP.

Moreover, I don't know how old you are, and neither do I need to know it. We should all treat ourselves as equal, no matter the age, race, gender, nationality or anything else. And about being careful - you always write "Mr. Agni" while you can easily check (e.g. by hovering over the avatar) that you're writing to a woman.

And here I end this offtopic discussion on my end. It can be hidden as an offtopic, I just wanted to reply to the remark about myself 😉. I'm for this feature request and hope to see it in the app.

To keep this post a bit on topic - this should be possible to be done by doing an affine transformation of an image. I don't know of possibilities of whatever tools are currently used for graphics here, but I think it should have a possibility to define a transformation, at least by transformation matrix (4x4 in this case, because we need a Z-axis row for perspective change). The only problem lays in finding this matrix, but it's possible with a bit of algebra.