Scaling UDIM images via Image.scale() only scales one tile #117539

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Lewis Toohey · 2024-01-26T11:32:44+01:00

Lewis Toohey commented

2024-01-26 11:32:44 +01:00

System Information
Operating system: Linux-6.5.0-15-generic-x86_64-with-glibc2.38 64 Bits, X11 UI
Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 535.154.05

Blender Version
Broken: version: 4.0.2, branch: blender-v4.0-release, commit date: 2023-12-05 07:41, hash: 9be62e85b727
Worked: (newest version of Blender that worked as expected)

Short description of error
Resizing a UDIM image results in inconsistent image sizes for each tile when saved externally. Only one of the UDIM tiles is saved with the correct size. The others remain at the original size.

Exact steps for others to reproduce the error

Start with a fresh blend file
Go to the Image Editor and create a new image. Name="Untitled". Resolution=1024,1024. Tiled=True.
Add two new tiles (1002, and 1003).
Paint something accross all 3 tiles.
Pack the image (Image->Pack).
Choose Image->Resize. Resize to 512,512.
Choose Image->Save As and save to somewhere in the external file system as a PNG.
Files created will be "Untitled.1001.png", "Untitled.1002.png", "Untitled.1003.png".
Only one of the files will be the correct size (512,512). The other two files will be the original size (1024,1024).

This only affects me because I maintain an addon (SimpleBake) that offers the option to scale the images. As such, this affects my script.

In SimpleBake, instead of choosing Image->Resize, I am executing the equivalent of "bpy.data.images["Untitled"].scale(512,512)". The result is the same. Only one of the UDIM images is saved with the correct size. The other two remain at the original size.

**System Information** Operating system: Linux-6.5.0-15-generic-x86_64-with-glibc2.38 64 Bits, X11 UI Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 535.154.05 **Blender Version** Broken: version: 4.0.2, branch: blender-v4.0-release, commit date: 2023-12-05 07:41, hash: `9be62e85b727` Worked: (newest version of Blender that worked as expected) **Short description of error** Resizing a UDIM image results in inconsistent image sizes for each tile when saved externally. Only one of the UDIM tiles is saved with the correct size. The others remain at the original size. **Exact steps for others to reproduce the error** 1. Start with a fresh blend file 2. Go to the Image Editor and create a new image. Name="Untitled". Resolution=1024,1024. Tiled=True. 3. Add two new tiles (1002, and 1003). 4. Paint something accross all 3 tiles. 5. Pack the image (Image->Pack). 6. Choose Image->Resize. Resize to 512,512. 7. Choose Image->Save As and save to somewhere in the external file system as a PNG. 8. Files created will be "Untitled.1001.png", "Untitled.1002.png", "Untitled.1003.png". 9. Only one of the files will be the correct size (512,512). The other two files will be the original size (1024,1024). This only affects me because I maintain an addon (SimpleBake) that offers the option to scale the images. As such, this affects my script. In SimpleBake, instead of choosing Image->Resize, I am executing the _equivalent of_ "`bpy.data.images["Untitled"].scale(512,512)`". The result is the same. Only one of the UDIM images is saved with the correct size. The other two remain at the original size.

Lewis Toohey added the

labels 2024-01-26 11:32:45 +01:00

Philipp Oeser commented

2024-01-26 14:31:51 +01:00

All image operators work on the active tile, see 9531eb24b3

So I was thinking you just have to do the following before scaling:

bpy.data.images['Untitled'].tiles.active_index = 1

However, this is still resizing only one.

The operator probably relies on a bit more context we have to prepare (via context overrides), will check the details...

All image operators work on the active tile, see 9531eb24b3172d83660649cc0936c05f66aff79b So I was thinking you just have to do the following before scaling: ```python bpy.data.images['Untitled'].tiles.active_index = 1 ``` However, this is still resizing only one. The operator probably relies on a bit more context we have to prepare (via context overrides), will check the details...

Lewis Toohey commented

2024-01-26 14:35:06 +01:00

@lichtwerk Thanks! - but yeah I've already tried this. I expected this to work, but it doesn't:

i=0
ts=len(img.tiles)
print(f"Num of tiles {ts}")
while i < ts:
    print(f"Working on tile {i}")
    img.tiles.active_index = i
    img.scale(sbp.outputwidth, sbp.outputheight)
    i+=1

Once again, only a single tile is resized.

@lichtwerk Thanks! - but yeah I've already tried this. I expected this to work, but it doesn't: ``` i=0 ts=len(img.tiles) print(f"Num of tiles {ts}") while i < ts: print(f"Working on tile {i}") img.tiles.active_index = i img.scale(sbp.outputwidth, sbp.outputheight) i+=1 ``` Once again, only a single tile is resized.

Philipp Oeser commented

2024-01-26 14:36:39 +01:00

Ah, sorry, was misreading the report, so this is not about the operator, but about the function, will check that as well

Lewis Toohey commented

2024-01-26 14:42:24 +01:00

@lichtwerk Amazing, thank you for any help.

Lewis Toohey closed this issue

2024-01-26 14:42:28 +01:00

Blender Bot added

and removed

labels 2024-01-26 14:42:31 +01:00

Lewis Toohey reopened this issue

2024-01-26 14:42:40 +01:00

Blender Bot added

and removed

labels 2024-01-26 14:42:42 +01:00

Lewis Toohey commented

2024-01-26 14:43:05 +01:00

Sorry - clicked the close issue button by mistake!

Philipp Oeser commented

2024-01-26 15:11:32 +01:00

I assume you could just use the operator (but only if your Addon does this from the Image Editor - or at least have the Image Editor available for context, otherwise overwriting the context is hairy since we need an ImageUser and you cant create one from python).

However, we can also tweak the python API (I mean the function) by changing BKE_image_scale a bit.

Not totally sure (yet) if this might have side-effects, but will check further and create a PR for this.

I assume you could just use the operator (but only if your Addon does this from the Image Editor - or at least have the Image Editor available for context, otherwise overwriting the context is hairy since we need an ImageUser and you cant create one from python). However, we can also tweak the python API (I mean the function) by changing `BKE_image_scale` a bit. Not totally sure (yet) if this might have side-effects, but will check further and create a PR for this.

Philipp Oeser added

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Scaling UDIM images via Image.scale() only scales one tile #117539