Image.save() more heavy than original when using bpy #102421

New Issue

Julien Duroure · 2022-11-11T09:01:22+01:00

Julien Duroure commented

2022-11-11 09:01:22 +01:00

System Information
Operating system: Linux Mint
Graphics card: Nvidia

Blender Version
Broken: after 29a3f43da5
Worked: Before 29a3f43da5

Short description of error
When copying an image with bpy, the newly created is much more heavy than the original

Exact steps for others to reproduce the error

Open the blend file
The original packed image file is around 513 ko
Run script
The created image is around 3.1 Mo

Some notes:

This bug was first discovered using the glTF exporter (see https://github.com/KhronosGroup/glTF-Blender-IO/issues/1787)
I git bisect the commit that cause the issue, but I also needed to cherry-pick the regression fix 4b3315fc98 to get my bisect works in some iteration.

image_size_issue.blend

**System Information** Operating system: Linux Mint Graphics card: Nvidia **Blender Version** Broken: after 29a3f43da5d3 Worked: Before 29a3f43da5d3 **Short description of error** When copying an image with bpy, the newly created is much more heavy than the original **Exact steps for others to reproduce the error** - Open the blend file - The original packed image file is around 513 ko - Run script - The created image is around 3.1 Mo Some notes: - This bug was first discovered using the glTF exporter (see https://github.com/KhronosGroup/glTF-Blender-IO/issues/1787) - I git bisect the commit that cause the issue, but I also needed to cherry-pick the regression fix 4b3315fc98a9 to get my bisect works in some iteration. [image_size_issue.blend](https://archive.blender.org/developer/F13890368/image_size_issue.blend)

Julien Duroure commented

2022-11-11 09:01:22 +01:00

Added subscriber: @JulienDuroure

Omar Emara commented

2022-11-11 10:13:05 +01:00

Added subscribers: @brecht, @OmarEmaraDev

Omar Emara commented

2022-11-11 10:13:05 +01:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Omar Emara commented

2022-11-11 10:13:05 +01:00

I can reproduce, though tagging the module for more information before confirming.

Brecht Van Lommel commented

2022-11-11 18:02:27 +01:00

Changed status from 'Needs Developer To Reproduce' to: 'Confirmed'

Brecht Van Lommel commented

2022-11-11 18:02:27 +01:00

Previously the image save operator would default to JPEG quality 90, and the Python API would use 75. Now that we made them consistent, it's quality 90 for both, leading to bigger file sizes.

That in itself I would not consider a bug, but the issue is that there is currently no API to control the quality.

Previously the image save operator would default to JPEG quality 90, and the Python API would use 75. Now that we made them consistent, it's quality 90 for both, leading to bigger file sizes. That in itself I would not consider a bug, but the issue is that there is currently no API to control the quality.

Brecht Van Lommel commented

2022-11-11 18:20:07 +01:00

I see the glTF add-on already has some code to copy and scale the image datablock, which I think preserves file format settings like quality. But I guess for this case it's packing multiple images into channels of one image, so there is not a single image to copy the file format settings from?

Julien Duroure commented

2022-11-11 18:37:59 +01:00

Exactly.
I made a simple script for this bug report, but for glTF cases, we sometimes need to create images from scratch, packing channels from multiple image source to a single image.

Exactly. I made a simple script for this bug report, but for glTF cases, we sometimes need to create images from scratch, packing channels from multiple image source to a single image.

blender-admin commented

2022-11-14 16:15:28 +01:00

This issue was referenced by 377da3f949

This issue was referenced by 377da3f94934a372c4d57c38595a6224a18d8c5e

blender-admin commented

2022-11-14 17:09:13 +01:00

This issue was referenced by 981245fc6f

This issue was referenced by 981245fc6fc29538e625edf429f926f7a182ddb7

blender-admin commented

2022-11-14 17:09:13 +01:00

This issue was referenced by 5f4afecbf3

This issue was referenced by 5f4afecbf3559a7ddcc2621d1e863a5425859404

Brecht Van Lommel commented

2022-11-14 17:16:59 +01:00

Actually turns out the main problem is that it's saving as PNG despite being set to JPEG. I will fix that, and also add an optional quality parameter to the Image.save() for more control over that.

Actually turns out the main problem is that it's saving as PNG despite being set to JPEG. I will fix that, and also add an optional `quality` parameter to the `Image.save()` for more control over that.

Brecht Van Lommel commented

2022-11-14 17:17:14 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Brecht Van Lommel closed this issue

2022-11-14 17:17:14 +01:00

Brecht Van Lommel self-assigned this 2022-11-14 17:17:14 +01:00

Julien Duroure commented

2022-11-23 15:01:14 +01:00

Thanks Brecht!

Bastien Montagne added this to the Core project 2023-02-09 15:43:10 +01:00

Bastien Montagne removed this from the Core project 2023-02-09 18:19:07 +01:00

Christoph Lendenfeld referenced this issue