UI jitter when scrolling #39256

New Issue

Will · 2014-03-19T01:29:42+01:00

Will commented

2014-03-19 01:29:42 +01:00

System Information
Mac OS 10.9, Radeon HD 6870

Blender Version
Broken: (2.7.0, 2014-03-15 16:37, hash 211f08d)

Short description of error
The UI jitters when scrolling. Font size changes (align to view checkbox) and titles move out of step with fields they're attached to.

blender_jitter.mov

**System Information** Mac OS 10.9, Radeon HD 6870 **Blender Version** Broken: (2.7.0, 2014-03-15 16:37, hash 211f08d) **Short description of error** The UI jitters when scrolling. Font size changes (align to view checkbox) and titles move out of step with fields they're attached to. [blender_jitter.mov](https://archive.blender.org/developer/F81772/blender_jitter.mov)

Will commented

2014-03-19 01:29:42 +01:00

Changed status to: 'Open'

Will commented

2014-03-19 01:29:42 +01:00

Added subscriber: @wlesieutre

Bastien Montagne commented

2014-03-19 07:08:37 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2014-03-19 07:08:37 +01:00

Can confirm this on Linux as well…

Bastien Montagne self-assigned this 2014-03-19 07:08:48 +01:00

Bastien Montagne commented

2014-03-19 18:19:56 +01:00

Added subscriber: @brecht

Bastien Montagne commented

2014-03-19 18:19:56 +01:00

DEV NOTES: Ok, so here is the culprit…

Due to float errors and conversion to ints, ui_but_to_pixelrect() sometimes returns a smaller y-height for a given widget when you scroll the view (e.g. typical checkbox will be 20px height in default DPI, but might be set to 19 in some scroll positions).

This is especially noticeable with checkboxes, since the width of the widget is set from its height (to keep it square), but affects all other widgets which use their height to control (part of) their width (also noticeable on e.g. widgets showing an icon).

Now I’m a bit short on ideas here, apart from giving a rectf to draw callbacks (like widget_optionbut & co), and let them make their own cooking to adapt to this case (e.g. checkbox draw could set its box width from rounded height, instead of floored one, etc.).

@brecht, thoughts?

DEV NOTES: Ok, so here is the culprit… Due to float errors and conversion to ints, `ui_but_to_pixelrect()` sometimes returns a smaller y-height for a given widget when you scroll the view (e.g. typical checkbox will be 20px height in default DPI, but might be set to 19 in some scroll positions). This is especially noticeable with checkboxes, since the width of the widget is set from its height (to keep it square), but affects all other widgets which use their height to control (part of) their width (also noticeable on e.g. widgets showing an icon). Now I’m a bit short on ideas here, apart from giving a rectf to draw callbacks (like `widget_optionbut` & co), and let them make their own cooking to adapt to this case (e.g. checkbox draw could set its box width from rounded height, instead of floored one, etc.). @brecht, thoughts?

Bastien Montagne commented

2014-03-19 18:21:15 +01:00

We could also just consider that minor glitch/known limitation… ;)

Brecht Van Lommel commented

2014-04-01 21:09:36 +02:00

This whole pipeline could be cleaned up to avoid the conversions, but if it is just rounding errors, perhaps the button sizes can be made slightly larger? For example instead of 20.0 make it 20.1.

If there's no easy solution I wouldn't consider this a bug though, this has been an issue for as long as I can remember, and a bigger refactor may be the only good solution.

This whole pipeline could be cleaned up to avoid the conversions, but if it is just rounding errors, perhaps the button sizes can be made slightly larger? For example instead of 20.0 make it 20.1. If there's no easy solution I wouldn't consider this a bug though, this has been an issue for as long as I can remember, and a bigger refactor may be the only good solution.

Bastien Montagne commented

2014-04-06 12:56:00 +02:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2014-04-06 12:56:00 +02:00

Bastien Montagne commented

2014-04-06 12:56:00 +02:00

Thanks for the hints, Brecht. I tried with small offsets, and using roundf instead of floorf, but it just displaces the issue to other DPI/zoom values…

So I guess we’ll call it known limitation for now. :/ Thanks for the report, anyway.

Thanks for the hints, Brecht. I tried with small offsets, and using roundf instead of floorf, but it just displaces the issue to other DPI/zoom values… So I guess we’ll call it known limitation for now. :/ Thanks for the report, anyway.

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UI jitter when scrolling #39256