Canvas: Undo & Clear hotkey, brush scales by area, consistent max brush size

[flagman9040]

Description

• add Undo hotkey to canvas
• • default Z key
• add Clear hotkey to canvas
• • default C key

2024-11-20.06_59_08_899.chrome.mp4

---

• Brush size adjustment mode, Area and Radius (new commit removed Radius mode)
• • currently the brush size increase or decrease by 5% (hardcoded) of the maximum allowed Radius of the brush

• • • I'm not sure how gradio determines the maximum brush size

• • • this poses some usability issues especially when dealing with small brush sizes
• • to solve this issue I implemented a new scaling method based on the Area
• • • with the Area method the brush size is increase or decrease by 10% (configurable) in Area allowing for finer adjustment

in my opinion Area mode it's much more usable than Radius mode
as such I have made the Area mode the Default changing old behavior
users who prefer the old method can configure it in settings

I have been testing with Area mode for a while locally and it feels quite natural

Radius

2024-11-20.07_00_34_898.chrome.mp4

Area

2024-11-20.07_01_34_712.chrome.mp4

notice that the Area mode brush size step is much more smoother then Radius

---

Brush size is set to 1/2 diagonal image, beyond the gradio default after the usere uses either the hotkeys or scroll wheel to change the brush size

• see comment below Canvas: Undo & Clear hotkey, brush scales by area, consistent max brush size AUTOMATIC1111/stable-diffusion-webui#16668 (comment)

---

Considering there's no timeline for Gradio 4 or 5
I think implement this relatively trivial function is worth it

---

future potential improvements / discussion

• add hotkey for removeing the image?

• • what key should it use

• in the PR only the factor / step for Area mode is configurable, while the 5% step in Radius model is hardcoded

• should it be made configurable, if so should it share the same setting key as the factor used for Area mode

• • if so it's going to be hard to set a default value
• • or should it use a different setting key

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests