Best effort for pixel perfect icon rendering

[Noisyfox]

This currently requires the toolbar icon to have even size.

Fixes #4328

Before:

After:

Toolbar icons should be noticeably sharper.

[yw4z]

thanks for your efforts on this, i will report results
This problem also appears on popup windows of toolbar. especially on these places

• Emboss > alignment icons
• Emboss > buttons near Style dropdown menu
• Other > Keyboard cheat sheet button
  i guess emboss popup aligns to right of window and bottom of window. icons looks blurry vertically and horizontally

[Noisyfox]

thanks for your efforts on this, i will report results This problem also appears on popup windows of toolbar. especially on these places

• Emboss > alignment icons
• Emboss > buttons near Style dropdown menu
• Other > Keyboard cheat sheet button
  i guess emboss popup aligns to right of window and bottom of window. icons looks blurry vertically and horizontally

Not sure if I could do anything about these.

[Noisyfox]

@yw4z Also I've noticed your comment about icon size using odd numbers #4368 (comment)

Technically you're right but some of the existing code make the assumption that icon sizes are in even numbers and I'm not sure how well it might behave.

If you are planing to use icons with odd numbers, could you try using the binary of this PR and replace with your icons and see if they work well?

[yw4z]

No i didnt changed their resolution to reduce code changes

mostly they have blank 1px line 2 sides
I'm adding all required changes in that commit as a to-do list. still changing things but big part of work is done

[yw4z]

@Noisyfox changing this line to int fixed issue for toolbar popup icons. they are pixel perfect now :)

OrcaSlicer/src/slic3r/GUI/IconManager.cpp

Line 376 in f3b3e92

float offset_y = (line_height - s.y) / 2;

included this to my UI commit

[Noisyfox]

@Noisyfox changing this line to int fixed issue for toolbar popup icons. they are pixel perfect now :)

OrcaSlicer/src/slic3r/GUI/IconManager.cpp

Line 376 in f3b3e92

float offset_y = (line_height - s.y) / 2;

included this to my UI commit

Popups? Did you mean those gizmo panels?

[yw4z]

yes also fixed blur on keyboard cheat sheet button