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