How do I paint a texture stencil onto an object with Python?

I'm trying to paint an image texture onto an object with bpy. I'm not running in background mode, so I can confirm the following:

1. Object is loaded
2. Image texture is loaded and added as a slot on the brush
3. Image texture is set to stencil mode
4. Image texture stencil is aligned with the mesh after some re-jiggering of the viewport (I can confirm this when the command line opens a blender window).

I now want to add strokes that paint the texture stencil onto the object, but having lots of trouble.

No matter what I do, the strokes don't show up on my object. However, I can easily paint the texture on manually. What is going on??

Note -- I tried some simple strokes that cross the viewport -- those didn't work. Now trying various stroke areas. But very confused. The context is correct (it was complaining before about that...)

 def get_override(area_type, region_type): # Find the specified area and region for window in bpy.context.window_manager.windows: screen = window.screen for area in screen.areas: if area.type == area_type: for region in area.regions: if region.type == region_type: override = { 'window': window, 'screen': screen, 'area': area, 'region': region, 'space_data': area.spaces.active, 'blend_data': bpy.context.blend_data, 'scene': bpy.context.scene, 'tool_settings': bpy.context.tool_settings, 'view_layer': bpy.context.view_layer, 'workspace': bpy.context.workspace, 'region_data': area.spaces.active.region_3d if area.type == 'VIEW_3D' else None } return override return None override = get_override( 'VIEW_3D', 'WINDOW') bpy.ops.object.editmode_toggle() bpy.ops.paint.texture_paint_toggle() # Define the strokes to cover the viewport strokes = [] for i in range(10): start_y = 500 + (i * 100) end_y = 500 + (i * 100) strokes.append({ "name": f"stroke{i * 2 + 1}", "mouse": (0, start_y), # Starting point in the viewport "mouse_event": (0, start_y), # Starting point in the viewport "location": (0, 0, 0), # Starting 3D location "pressure": 1.0, "size": 50, "pen_flip": False, "time": 1.0, "x_tilt": 0.0, "y_tilt": 0.0, "is_start": True, }) strokes.append({ "name": f"stroke{i * 2 + 2}", "mouse": (2000, end_y), # Ending point in the viewport "mouse_event": (2000, end_y), # Ending point in the viewport "location": (0, 0, 0), # Ending 3D location "pressure": 1.0, "size": 50, "pen_flip": False, "time": 1.0, "x_tilt": 0.0, "y_tilt": 0.0, "is_start": False, }) with bpy.context.temp_override(window=override['window'], screen=override['screen'], area=override['area'], region=override['region']): # print_context( bpy.context) result = bpy.ops.paint.image_paint(stroke=strokes, mode='NORMAL') 

Here's what I'm trying to do (the painted strokes were done manually):