release/scripts/templates/operator_modal_draw.py

   1 import bpy
   2 import bgl
   3 import blf
   4
   5
   6 def draw_callback_px(self, context):
   7     print("mouse points", len(self.mouse_path))
   8
   9     font_id = 0  # XXX, need to find out how best to get this.
  10
  11     # draw some text
  12     blf.position(font_id, 15, 30, 0)
  13     blf.size(font_id, 20, 72)
  14     blf.draw(font_id, "Hello Word " + str(len(self.mouse_path)))
  15
  16     # 50% alpha, 2 pixel width line
  17     bgl.glEnable(bgl.GL_BLEND)
  18     bgl.glColor4f(0.0, 0.0, 0.0, 0.5)
  19     bgl.glLineWidth(2)
  20
  21     bgl.glBegin(bgl.GL_LINE_STRIP)
  22     for x, y in self.mouse_path:
  23         bgl.glVertex2i(x, y)
  24
  25     bgl.glEnd()
  26
  27     # restore opengl defaults
  28     bgl.glLineWidth(1)
  29     bgl.glDisable(bgl.GL_BLEND)
  30     bgl.glColor4f(0.0, 0.0, 0.0, 1.0)
  31
  32
  33 class ModalDrawOperator(bpy.types.Operator):
  34     '''Draw a line with the mouse'''
  35     bl_idname = "view3d.modal_operator"
  36     bl_label = "Simple Modal View3D Operator"
  37
  38     def modal(self, context, event):
  39         context.area.tag_redraw()
  40
  41         if event.type == 'MOUSEMOVE':
  42             self.mouse_path.append((event.mouse_region_x, event.mouse_region_y))
  43
  44         elif event.type == 'LEFTMOUSE':
  45             context.region.callback_remove(self._handle)
  46             return {'FINISHED'}
  47
  48         elif event.type in ('RIGHTMOUSE', 'ESC'):
  49             context.region.callback_remove(self._handle)
  50             return {'CANCELLED'}
  51
  52         return {'RUNNING_MODAL'}
  53
  54     def invoke(self, context, event):
  55         if context.area.type == 'VIEW_3D':
  56             context.window_manager.modal_handler_add(self)
  57
  58             # Add the region OpenGL drawing callback
  59             # draw in view space with 'POST_VIEW' and 'PRE_VIEW'
  60             self._handle = context.region.callback_add(draw_callback_px, (self, context), 'POST_PIXEL')
  61
  62             self.mouse_path = []
  63
  64             return {'RUNNING_MODAL'}
  65         else:
  66             self.report({'WARNING'}, "View3D not found, cannot run operator")
  67             return {'CANCELLED'}
  68
  69
  70 def register():
  71     bpy.utils.register_class(ModalDrawOperator)
  72
  73
  74 def unregister():
  75     bpy.utils.unregister_class(ModalDrawOperator)
  76
  77 if __name__ == "__main__":
  78     register()