disp_mouse_loc.py

#====================================================================
#
#  Display Mouse Location Example
#
#  disp_mouse_loc.py
#
#  Left clicking places a point
#    The mouse's 2D location and distance from the last point are
#    displayed on the bottom left of the 3D View.
#  
#  If you click the mouse within 80 pixels of a point, the point
#  will be relocated to where you just clicked.
# 
#  Tested with Blender 2.78c
#  
#====================================================================

import bpy
import bgl
import blf
from math import sqrt


class Colors:
    red    = 1.0, 0.0, 0.0, 1.0
    green  = 0.0, 1.0, 0.0, 1.0
    white  = 1.0, 1.0, 1.0, 1.0
    yellow = 1.0, 1.0, 0.0, 1.0


print("\n\n\n  Add-on Loaded!\n") # debug


def get_dist_2D(pt1, pt2):
    x1, y1, x2, y2 = pt1[0], pt1[1], pt2[0], pt2[1]
    return sqrt( abs( ((x2-x1)**2) + ((y2-y1)**2) ) )


def draw_font_at_pt(text, pt_co, pt_color):
    font_id = 0
    dpi = 72
    tsize = 24
    bgl.glColor4f(*pt_color)
    blf.position(font_id, pt_co[0], pt_co[1], 0)
    blf.size(font_id, tsize, dpi)
    blf.draw(font_id, text)
    return


def draw_pt_2D(pt_co, pt_color):
    psize = 7
    bgl.glEnable(bgl.GL_BLEND)
    bgl.glPointSize(psize)
    bgl.glColor4f(*pt_color)
    bgl.glBegin(bgl.GL_POINTS)
    bgl.glVertex2f(*pt_co)
    bgl.glEnd()
    return


def draw_callback_px(self, context):
    draw_font_at_pt("Mouse Loc: "+str(self.mouse[0])+', '+str(self.mouse[1]), (70, 64), Colors.green)

    if self.pt_store is not None:
        draw_pt_2D(self.pt_store, Colors.white)
        self.dist_from_click = get_dist_2D(self.pt_store, self.mouse)

    draw_font_at_pt("Dist from point: " + format(self.dist_from_click, '.2f'), (70, 40), Colors.yellow)
    #draw_font_at_pt("Dist from point: " + str(dist_from_click), (70, 40), color_yellow)


class MouseLocDispOperator(bpy.types.Operator):
    """Display the mouse location"""
    bl_idname = "view3d.display_ms_loc"
    bl_label = "Display Mouse Location"

    def modal(self, context, event):
        context.area.tag_redraw()

        if event.type in {'A', 'MIDDLEMOUSE', 'WHEELUPMOUSE', 'WHEELDOWNMOUSE', 
                    'NUMPAD_1', 'NUMPAD_2', 'NUMPAD_3', 'NUMPAD_4', 'NUMPAD_6', 
                    'NUMPAD_7', 'NUMPAD_8', 'NUMPAD_9', 'NUMPAD_5'}:
            return {'PASS_THROUGH'}

        if event.type == 'MOUSEMOVE':
            self.mouse = event.mouse_region_x, event.mouse_region_y

        if event.type == 'LEFTMOUSE' and event.value == 'RELEASE':
            if abs(self.dist_from_click) < 80:
                self.pt_store = event.mouse_region_x, event.mouse_region_y

        if event.type in {'ESC', 'RIGHTMOUSE'}:
            bpy.types.SpaceView3D.draw_handler_remove(self._handle, 'WINDOW')
            return {'CANCELLED'}

        return {'RUNNING_MODAL'}

    def invoke(self, context, event):
        if context.area.type == 'VIEW_3D':
            # the arguments we pass the the callback
            args = (self, context)
            # Add the region OpenGL drawing callback
            # draw in view space with 'POST_VIEW' and 'PRE_VIEW'
            self._handle = bpy.types.SpaceView3D.draw_handler_add(draw_callback_px, 
                        args, 'WINDOW', 'POST_PIXEL')

            self.pt_store = None
            self.mouse = -5000, -5000
            self.dist_from_click = -1.0

            context.window_manager.modal_handler_add(self)
            return {'RUNNING_MODAL'}
        else:
            self.report({'WARNING'}, "View3D not found, cannot run operator")
            return {'CANCELLED'}


def register():
    bpy.utils.register_class(MouseLocDispOperator)

def unregister():
    bpy.utils.unregister_class(MouseLocDispOperator)

if __name__ == "__main__":
    register()