Check canvas alignement

1.6.5

- feat: check canvas alignement of the Gp object compare to chosen draw axis

utils.py

@@ -253,24 +253,28 @@ def remapping(value, leftMin, leftMax, rightMin, rightMax):
 
 #### GP funcs
 
-def get_gp_draw_plane(context):
+def get_gp_draw_plane(context, obj=None):
     ''' return tuple with plane coordinate and normal
     of the curent drawing accordign to geometry'''
 
     settings = context.scene.tool_settings
-    orient = settings.gpencil_sculpt.lock_axis#'VIEW', 'AXIS_Y', 'AXIS_X', 'AXIS_Z', 'CURSOR'
-    loc = settings.gpencil_stroke_placement_view3d#'ORIGIN', 'CURSOR', 'SURFACE', 'STROKE'
-    mat = context.object.matrix_world if context.object else None
+    orient = settings.gpencil_sculpt.lock_axis #'VIEW', 'AXIS_Y', 'AXIS_X', 'AXIS_Z', 'CURSOR'
+    loc = settings.gpencil_stroke_placement_view3d #'ORIGIN', 'CURSOR', 'SURFACE', 'STROKE'
+    if obj:
+        mat = obj.matrix_world
+    else:
+        mat = context.object.matrix_world if context.object else None
+
     # -> placement
     if loc == "CURSOR":
         plane_co = context.scene.cursor.location
-    else:#ORIGIN (also on origin if set to 'SURFACE', 'STROKE')
+    
+    else: # ORIGIN (also on origin if set to 'SURFACE', 'STROKE')
         if not context.object:
             plane_co = None
         else:
             plane_co = context.object.matrix_world.to_translation()# context.object.location
 
-
     # -> orientation
     if orient == 'VIEW':
         #only depth is important, no need to get view vector
@@ -294,6 +298,41 @@ def get_gp_draw_plane(context):
     
     return plane_co, plane_no
 
+def check_angle_from_view(obj=None, plane_no=None, context=None):
+    '''Return angle to obj according to chosen drawing axis'''
+    import math
+    from bpy_extras import view3d_utils
+    
+    if not context:
+        context = bpy.context
+
+    if not plane_no:
+        _plane_co, plane_no = get_gp_draw_plane(context, obj=obj)
+    view_direction = view3d_utils.region_2d_to_vector_3d(context.region, context.region_data, (context.region.width/2.0, context.region.height/2.0))
+
+    angle = math.degrees(view_direction.angle(plane_no))
+    
+    # correct angle value when painting from other side (seems a bit off...)
+    if angle > 90:
+        angle = abs(90 - (angle - 90))
+
+    # over angle warning 
+    if angle > 75:
+        return angle, 'ERROR', f"Canvas not aligned at all! (angle: {angle:.2f}°), use Realign GP or change draw axis"
+
+    if angle > 6:
+        return angle, 'ERROR', f'Canvas not aligned! angle: {angle:.2f}°, use Realign GP'
+    
+    if angle > 3: # below 3 is reasonable (camera seem to view induce error !)
+        return angle, 'INFO', f'Canvas almost aligned (angle: {angle:.2f}°)'
+
+    if angle == 0: 
+        return angle, 'INFO', f'Canvas perfectly aligned (angle: {angle:.2f}°)'
+
+    # below 1 consider aligned
+    return angle, 'INFO', f'Canvas alignement seem ok (angle: {angle:.2f}°)'
+    
+
 ## need big update
 def create_gp_palette(gp_data_block,info) :
     palette = gp_data_block.palettes.active