Render image widgets correctly on HiDPI displays when the display's window scale is not equal to 1.

[zane-weissman]

Description

Fixes #761.

This fix applies to high resolution displays (or any display where the user has set the display scale to something other than 100%). For example, imagine you want to render a 16x16 image (in yuck: :image-height 16 :image-width 16) at 2x scale. The resulting image will be 32x32 physical pixels on the display. If your image source has the fidelity (e.g. you have a >32x32 pixel PNG or an SVG), the resulting image should be sharp, but previously, it was being rendered at the logical resolution (16x16) and upscaled to the physical resolution, creating a blurry image.

Usage

No configuration changes. Images will simply be rendered at high resolution if possible.

Showcase

Before and after:

Additional Notes

All of the practical code is taken from src/widgets/systray.rs. Thank you to whoever wrote that code! Also, I am relatively new to Rust, any comments on style etc. are welcome.

Checklist

Please make sure you can check all the boxes that apply to this PR.

• All widgets I've added are correctly documented.
• I added my changes to CHANGELOG.md, if appropriate.
• The documentation in the docs/content/main directory has been adjusted to reflect my changes.
• I used cargo fmt to automatically format all code before committing

[Kynson]

It would be great if this can get merged, currently facing the same problem. (I know the team maybe busy with other stuff, not intended to rush anyone)

Thanks a lot!

[UnnaturalTwilight]

Trying this out on my own fork. Eww fails to load if any images don't have both width and height defined. Most of my config is only defining :image-width and using the default :preserve-aspect-ratio value of true to implicitly define the height.
I'm using fractional scaling on hyprland.

[zane-weissman]

Trying this out on my own fork. Eww fails to load if any images don't have both width and height defined. Most of my config is only defining :image-width and using the default :preserve-aspect-ratio value of true to implicitly define the height. I'm using fractional scaling on hyprland.

Thanks for noticing this - I had image_width and image_height both defined in all my configs. It looks like somehow when image_height was omitted from the yuck config, it was getting passed into the graphics library as 0 and failing a check when the library tried to scale the image to the requested size. I'm not sure why this happened, because I think the default value for image_height should be -1... See line 594 of widget_definitions.rs:

prop(path: as_string, image_width: as_i32 = -1, image_height: as_i32 = -1, preserve_aspect_ratio: as_bool = true, fill_svg: as_string = "") {

Anyways, the fix in 22a970f just sets the image_height and/or image_width to -1 if they're not positive before passing them to gtk::gdk_pixbuf::Pixbuf::from_file_at_scale(). Let me know if it's working for you too!

[UnnaturalTwilight]

It seems to be working. Great job!