[3d] export all frames from QGIS 3d animations as images

[PeterPetrik]

fix #21300

Now it is possible to export frames of 3d animation as png/jpg/... images. These can be easily merged into .avi (outside QGIS)

[nirvn]

Nice. A few comments:

• spell out FPS , ie frame per second, to make that setting clearer to the average user (you have the space anyways)
• move the width and height unit into the spinbox like it's done in other parts of our UI (eg, save canvas as image dialog)
• while your at it, I'd rename width and height to output width and output height

Very nice to see this feature, thanks!

[nirvn]

Oh and maybe add an hint label below the template line edit to explain the use of #s?

[nyalldawson]

The "#####" placeholder looks very deceptive to me - if I read the code correctly it needs to be present in its entirety, but it looks to users like ## should be allowed for 2 digit frames, ### for 3, etc. (Shouldn't this be supported anyway?)

[nirvn]

+1 on what @nyalldawson raised. The template should handle a varying nb of #s. The more #, the more leading zeroes.

Eg:

• myanim-# would result in myanim-1, ... myanim-10, etc
• myanim-### would result in myanim-001, ... myanim-010, etc

[nirvn]

Actually, on the template front, why don't we use our expression engine instead (like we do for atlas export file names)? We could pass the frame number as a @current_frame variable.

That'd make it better match the UX with other parts of QGIS and be a lot more flexible.

[nirvn]

@total_frame would be useful too for filenames like anim-001-350.png, anim-002-350.png, etc.

[NathanW2]

Ohhhh fancy!!

…

On Sun, Feb 24, 2019 at 4:18 PM Mathieu Pellerin ***@***.***> wrote: @total_frame would be useful too for filenames like anim-001-350.png, anim-002-350.png, etc. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#9244 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAXS3M1AuWdzEDFRPnI9tvNn5mnDYl5aks5vQi6ngaJpZM4bJvIV> .

[PeterPetrik]

@nirvn I have spend several hours on the most difficult problem in the software development world. When thinking about expressions in this field, I ended up with
[% @project_basename %]-[% format_number(@current_frame, 0, 5) %]-[% @total_frames %].png

and compared to
abc#####.png

I sadly concluded that I prefer to stick with the original approach.

Said that, the problem with expressions would be also formatting (0001, 0002), since user would need to insert another function to left-pad it.

[roya0045]

@PeterPetrik What about :
[% @project_basename %]-[% lpad(to_string(@current_frame),length(to_string(@total_frames))) %]-[% @total_frames %].png

[PeterPetrik]

@roya0045 good idea, but I may need to buy a second monitor to be able to see the full text :)

[nirvn]

@PeterPetrik , if you look at the way the filename is handled in the context of atlas, open the layout dialog and pop the atlas panel. It does not use the [% %] expression brackets as the whole string is the expression, which makes things less chaotic (as you are pointing out above).

The default expression there is: 'output_'||@atlas_featurenumber'.

I see no problem in have a default template string here being: '3d_'||@current_frame'.

In terms of how you serve @current_frame, you could either pass on an integer value, or a string with padded 0s (the latter would be friendlier). If someone wants the int value, he/she could do to_int(@current_frame).

[wonder-sk]

@nirvn first I got also excited by the idea to use expressions for the filename template. But then I realized that a default like '3d_'||@current_frame||'.jpg' is quite cumbersome and would need @current_frame to be a string. And it gets more complicated:

• how many leading zeros to use for @current_frame? people get very opinionated about such thing :)
• doing some arithmetic with @current_frame is cumbersome - e.g. lpad(to_int(@current_frame)+100, 5, '0')

It seems to me that while expressions are useful for power users, for an average person who just wants to get animation exported the default filename template would be a bit cryptic wouldn't it? To me it seems that something like 3d-####.jpg is pretty self-explanatory and easy to adjust.

And do we even need fancy expression stuff here? The main point is to export frames and turn them into a video in the next step, so in theory filenames should be quite irrelevant :)

[nirvn]

@wonder-sk ,

• I'm not sure how cumbersome it is, that's a subjective call 😉
• On @current_frame being a string, I don't see this as being a problem; as I was saying, if anyone wants a number, he/she can use to_int(...)
• On the leading zeros issue, IMHO, the default should be as many leading zeros as you need to pad the current frame to match the width of your total frame (i.e., for 30 total frames, it should be 01, 02; for 300 total frames, it should be 001, 002)

That said, this ain't an hill I want to die on 😉 I think it'd be useful, but if you guys have a strong feeling on this issue, go with your favorite implementation method.

[nirvn]

@wonder-sk , @PeterPetrik , BTW, I assume the file extension in the template string determines the image format used to export frames. Is that so? That might be worth separating into its own setting, and presented as a combo box of formats.

[PeterPetrik]

• extension is anything that QImage can export to and not sure how would be possible to create such list easily. Also as a separate combobox it would have more sense in combination with expressions.

• with the expression vs #### discussion, I do not have strong feeling about any implementation, but my preference is for simpler #### form for now (also in respect of the fact that I have had both implementations already implemented and spend several hours yesterday going back and forth :) ).