Custom icon is not drawn on header / addons prefs panel #48813

New Issue

Sybren A. Stüvel · 2016-07-08T16:53:51+02:00

Sybren A. Stüvel commented

2016-07-08 16:53:51 +02:00

System Information
Kubuntu 16.04, GeForce 8800 GTS 512

Blender Version
Broken: 2.77a and 8bb69b6157

Short description of error
When drawing a button or label with a custom icon on a header or addons panel, the icon isn't shown. Only after forcing a redraw (for example by moving the mouse over the UI element) the icon gets drawn.

Exact steps for others to reproduce the error

Place the attached blend file test_custom_icon.blend and icon in the same folder.
Open the blend file.
Scroll the text editor header such that there is plenty of space on the right-hand side of the header. This is necessary so that you can see the button that will appear here, directly on the first draw.
Run the script.
See the "Render" button without cloud icon.
Move the mouse around over the button.
See the "Render" button appear.

If you go to the properties editor, objects tab, the script also registers a button there, in a custom panel. You can also see that it is drawn without the icon first, but is redrawn when the icon is loaded. My bet is that this redraw trigger doesn't happen for other areas.

**System Information** Kubuntu 16.04, GeForce 8800 GTS 512 **Blender Version** Broken: 2.77a and 8bb69b6157 **Short description of error** When drawing a button or label with a custom icon on a header or addons panel, the icon isn't shown. Only after forcing a redraw (for example by moving the mouse over the UI element) the icon gets drawn. **Exact steps for others to reproduce the error** 1. Place the attached blend file [test_custom_icon.blend](https://archive.blender.org/developer/F320340/test_custom_icon.blend) and icon ![icon-cloud.png](https://archive.blender.org/developer/F320341/icon-cloud.png) in the same folder. 2. Open the blend file. 3. Scroll the text editor header such that there is plenty of space on the right-hand side of the header. This is necessary so that you can see the button that will appear here, directly on the first draw. 3. Run the script. 4. See the "Render" button without cloud icon. 5. Move the mouse around over the button. 6. See the "Render" button appear. If you go to the properties editor, objects tab, the script also registers a button there, in a custom panel. You can also see that it is drawn without the icon first, but is redrawn when the icon is loaded. My bet is that this redraw trigger doesn't happen for other areas.

Sybren A. Stüvel commented

2016-07-08 16:53:51 +02:00

Changed status to: 'Open'

Sybren A. Stüvel commented

2016-07-08 16:53:51 +02:00

Added subscriber: @dr.sybren

Sergey Sharybin commented

2016-07-08 17:39:26 +02:00

Added subscribers: @mont29, @Sergey

Sergey Sharybin commented

2016-07-08 17:39:26 +02:00

@mont29, is it something in your area?

Bastien Montagne commented

2016-07-10 21:31:19 +02:00

Added subscriber: @ideasman42

Bastien Montagne commented

2016-07-10 21:31:19 +02:00

Problem is that those 'custom icons from file' are asynchronously deferred loaded, using 'generic' icon generation job, which generates NC_MATERIAL notifications. Replacing those with NC_WINDOW does fix the issue, question is, do we accept that kind of 'redraw everything' message from icon generation? @ideasman42, what do you think?

Campbell Barton commented

2016-07-11 05:16:04 +02:00

@mont29, right, we can always add global redraw flags to workaround these issues. In this case I don't have a strong opinion,
though IMHO it's quite weak - the more add-ons use generated icons, the more we will redraw everything when they update.

I think we need a more flexible notification system which doesn't depend on hard coded values (making assumptions about whats shown in a region).

Currently a Python script may show any information in the UI, its totally hit-and-miss that the UI is refreshed when they're changed.

We could have design task for this (if someone has time to develop it...) would suggest moving to a publish/subscribe pattern for the notifier system where...

hard coded listener functions are replaced with dynamically registered listeners based on the contents of the region/area.
defining the UI elements automatically subscribes that region to be updated when those values are changed.

How fine-grained we need to be can be chosen later... per-property is possible but overkill. (probably ID & RNA-type is enough).
This way using dynamically generated icons is just a matter of asking to listen for changes to icons - a different kind of listener.

This allows for Python scripts to be able to register to be notified on changes too.

For the 3D-view for eg, it probably doesn't make sense to inspect whats drawn and listen to changes in each object's ID. It could just register a listener for changes to data-types (material, object-object data).
So something similar to the existing system could be done where needed.

@mont29, right, we can always add global redraw flags to workaround these issues. In this case I don't have a strong opinion, though IMHO it's quite weak - the more add-ons use generated icons, the more we will redraw everything when they update. ---- I think we need a more flexible notification system which doesn't depend on hard coded values (making assumptions about whats shown in a region). Currently a Python script may show any information in the UI, its totally hit-and-miss that the UI is refreshed when they're changed. We could have design task for this (if someone has time to develop it...) would suggest moving to a *publish/subscribe* pattern for the notifier system where... - hard coded listener functions are replaced with dynamically registered listeners based on the contents of the region/area. - defining the UI elements automatically *subscribes* that region to be updated when those values are changed. How fine-grained we need to be can be chosen later... per-property is possible but overkill. (probably ID & RNA-type is enough). This way using dynamically generated icons is just a matter of asking to listen for changes to icons - a different kind of listener. This allows for Python scripts to be able to register to be notified on changes too. For the 3D-view for eg, it probably doesn't make sense to inspect whats drawn and listen to changes in each object's ID. It could just register a listener for changes to data-types (material, object-object data). So something similar to the existing system could be done where needed.

Bastien Montagne was assigned by Sergey Sharybin

2016-07-26 17:45:34 +02:00

Sergey Sharybin commented

2016-07-26 17:45:34 +02:00

While notifier is a weak solution it is the only one for now. So either we go this way or consider this a TODO.

Since for now we don't have have much addons who uses this function think it's acceptable to just use notifiers.

While notifier is a weak solution it is the only one for now. So either we go this way or consider this a TODO. Since for now we don't have have much addons who uses this function think it's acceptable to just use notifiers.

Bastien Montagne commented

2016-07-26 17:51:08 +02:00

Yes, agree, for now notifier will do the work.

@ideasman42 your idea sounds nice, imho at this point should be part of the bigger 'workflow' 2.8 topic (as part of custom editors, which will require that kind of thing anyway)…

Yes, agree, for now notifier will do the work. @ideasman42 your idea sounds nice, imho at this point should be part of the bigger 'workflow' 2.8 topic (as part of custom editors, which will require that kind of thing anyway)…

blender-admin commented

2016-07-26 17:55:18 +02:00

This issue was referenced by f3f10e4515

This issue was referenced by f3f10e4515c45925df7dea3b29d2dc73dd097568

Bastien Montagne commented

2016-07-26 17:56:57 +02:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2016-07-26 17:56:57 +02:00

Sybren A. Stüvel commented

2016-07-26 23:20:57 +02:00

Thanks guys!

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Custom icon is not drawn on header / addons prefs panel #48813