Clearing grease pencil data/frame/layer using python does not clear viewport #104121

New Issue

Amélie Fondevilla · 2023-01-24T16:43:51+01:00

2023-01-24 16:43:51 +01:00

System Information
Operating system: Linux-5.4.0-137-generic-x86_64-with-glibc2.31 64 Bits
Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.47.03

Blender Version
Broken: version: 3.5.0 Alpha
Worked: never? (doesn't work until 2.83)

Short description of error
When clearing grease pencil data using python API, the strokes are not disappearing in the viewport.
They do disappear when update is sent to viewport (eg. change object mode, attempt to draw stroke, etc.)
The same problem appear when clearing a grease pencil frame or layer.

Exact steps for others to reproduce the error
Open the "New 2D animation" template file.
Draw a stroke.
Open a Python console.
Type C.active_object.data.clear() to clear out data from grease pencil object.
The stroke is still visible in viewport while all data from the object has been removed.

clear_data_update.mp4

**System Information** Operating system: Linux-5.4.0-137-generic-x86_64-with-glibc2.31 64 Bits Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.47.03 **Blender Version** Broken: version: 3.5.0 Alpha Worked: never? (doesn't work until 2.83) **Short description of error** When clearing grease pencil data using python API, the strokes are not disappearing in the viewport. They do disappear when update is sent to viewport (eg. change object mode, attempt to draw stroke, etc.) The same problem appear when clearing a grease pencil frame or layer. **Exact steps for others to reproduce the error** Open the "New 2D animation" template file. Draw a stroke. Open a Python console. Type `C.active_object.data.clear()` to clear out data from grease pencil object. The stroke is still visible in viewport while all data from the object has been removed. [clear_data_update.mp4](https://archive.blender.org/developer/F14193583/clear_data_update.mp4)

Amélie Fondevilla commented

2023-01-24 16:43:51 +01:00

Added subscriber: @amelief

Pratik Borhade commented

2023-01-25 04:32:55 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Pratik Borhade commented

2023-01-25 04:32:58 +01:00

Added subscriber: @PratikPB2123

Antonio Vazquez commented

2023-01-25 10:45:14 +01:00

Added subscriber: @antoniov

Antonio Vazquez commented

2023-01-25 10:45:14 +01:00

I have no idea where the "clear" data API is defined, but for sure this problem is a missing notifier. I guess the solution is find where this clear is done and check if the ID type is ID_GD.

I have no idea where the "clear" data API is defined, but for sure this problem is a missing notifier. I guess the solution is find where this `clear` is done and check if the `ID` type is `ID_GD`.

Amélie Fondevilla commented

2023-01-25 11:32:03 +01:00

So far, I found that the API function is defined in rna_gpencil.c:2726, and is linked to the rna_GPencil_clear C function that is defined in rna_gpencil.c:1118.
This function calls a notifier : WM_main_add_notifier(NC_GPENCIL | ND_DATA | NA_EDITED, NULL); which should in theory re-draw the grease pencil object in the viewport, right ?

I am not sure where to check for the ID type though.

So far, I found that the API function is defined in `rna_gpencil.c:2726`, and is linked to the `rna_GPencil_clear` C function that is defined in `rna_gpencil.c:1118`. This function calls a notifier : `WM_main_add_notifier(NC_GPENCIL | ND_DATA | NA_EDITED, NULL);` which should in theory re-draw the grease pencil object in the viewport, right ? I am not sure where to check for the ID type though.

Antonio Vazquez commented

2023-01-25 12:27:07 +01:00

Try adding DEG_id_tag_update(&gpd->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY); after BKE_gpencil_free_layers(&gpd->layers); in rna_GPencil_clear

Try adding `DEG_id_tag_update(&gpd->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY);` after `BKE_gpencil_free_layers(&gpd->layers);` in `rna_GPencil_clear`

Amélie Fondevilla commented

2023-01-25 12:54:04 +01:00

Yay it works !
Now we only need to make it work for frame/layer clear functions, because they have as only parameter bGPDframe*/ bGPDlayer* which don't have an id field.. (rna_gpencil:1104-1111)

Yay it works ! Now we only need to make it work for frame/layer clear functions, because they have as only parameter `bGPDframe*`/ `bGPDlayer*` which don't have an `id` field.. (`rna_gpencil:1104-1111`)

Antonio Vazquez commented

2023-01-25 16:08:26 +01:00

@amelief Look at rna_GPencil_stroke_remove

You need set this:

  func = RNA_def_function(srna, "remove", "rna_GPencil_stroke_remove");
  RNA_def_function_flag(func, FUNC_USE_SELF_ID);

Then in the called function, just add the ID as parameter.

static void rna_GPencil_frame_clear(ID *id, bGPDframe *frame)

@amelief Look at `rna_GPencil_stroke_remove` You need set this: ``` func = RNA_def_function(srna, "remove", "rna_GPencil_stroke_remove"); RNA_def_function_flag(func, FUNC_USE_SELF_ID); ``` Then in the called function, just add the ID as parameter. `static void rna_GPencil_frame_clear(ID *id, bGPDframe *frame)`

blender-admin commented

2023-01-25 17:00:10 +01:00

This issue was referenced by ef39d85d7c

This issue was referenced by ef39d85d7c94c28e952683c0ddd0f3b7435b8460

Amélie Fondevilla commented

2023-01-26 09:17:14 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Amélie Fondevilla closed this issue

2023-01-26 09:17:14 +01:00

Amélie Fondevilla self-assigned this 2023-01-26 09:17:15 +01:00

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Clearing grease pencil data/frame/layer using python does not clear viewport #104121