Nodebox Flow Chart Edges

 1from utility_geometry import *
 2
 3def straight_flow_arrow(arg_x,arg_y,target_x,target_y,pointer_size=None,text_string='',back_stroke=0,draw_it=True):
 4    
 5    a = angle(arg_x,arg_y,target_x,target_y)
 6    d = distance(arg_x,arg_y,target_x,target_y)
 7
 8    # A default pointer size based on the length of the line.
 9    if not pointer_size:
10        pointer_size = d*0.10
11
12    # We need some reference points for building the path.
13    line_end_x,line_end_y = coordinates(arg_x,arg_y,d-pointer_size,a)
14    pointer_tip_x,pointer_tip_y = coordinates(arg_x,arg_y,d,a)
15    left_back_x,left_back_y = coordinates(line_end_x,line_end_y,pointer_size,a-90-back_stroke)
16    right_back_x,right_back_y = coordinates(line_end_x,line_end_y,pointer_size,a+90+back_stroke)
17    mid_line_x,mid_line_y = coordinates(arg_x,arg_y,(d-pointer_size)/2.0,a)
18    
19    
20    # Actually generate the Bezier path.
21    beginpath(arg_x,arg_y)
22    lineto(line_end_x,line_end_y)
23    lineto(left_back_x,left_back_y)
24    lineto(pointer_tip_x,pointer_tip_y)
25    lineto(right_back_x,right_back_y)
26    lineto(line_end_x,line_end_y)
27    p = endpath(draw=draw_it)
28    
29    tw = textwidth(text_string,WIDTH-mid_line_x)
30
31    push()
32    align(LEFT)
33    tp = textpath(text_string,mid_line_x+10,mid_line_y-5,width=WIDTH-mid_line_x)
34    pop()
35
36    if draw_it:
37        drawpath(tp)
38
39    return p