A example to generate register definition with drawsvg module.

make_reg_svg.py

#!python
# -*- coding: utf-8 -*-

import drawsvg as draw


# Reference: https://github.com/cduck/drawsvg/blob/master/docs/index.md

reg = {
    '31': 'EN',
    '30:29': 'TYPE',
    '28:24': 'SCALE',
    '23:16': 'OPER',
    '15:8': 'SRC',
    '7:0': 'DST',
}

def make_reg():
    gap = 2
    sep_height = 5
    height = 50
    cell_width = 25
    total_width = 32 * cell_width   
    tick_min_y = 10
    d = draw.Drawing(total_width, height, origin=(0, 0))
    # Draw a rectangle
    r = draw.Rectangle(gap, gap, 800-gap*2, height-gap*2, stroke='black', fill='white', stroke_width=2)
    d.append(r)
    for i in range(32):
        d.append(draw.Line(i*cell_width, 0+gap, i*cell_width, sep_height+gap, stroke='black'))
        d.append(draw.Line(i*cell_width, (height-sep_height)-gap, i*cell_width, height-gap, stroke='black'))
        d.append(draw.Text(str(31-i), font_size=10, x=i * cell_width + cell_width/2, y=max(tick_min_y, sep_height+gap), fill='gray', center=True))
    
    for field, name in reg.items():
        if ':' not in field:
            start, end = field, field
        else:
            start, end = field.split(':')
        start = int(start)
        end = int(end)
        d.append(draw.Text(name, 14, x=(31 - (start + end - 1) / 2) * 25, y=(height/2)+gap, fill='black', center=True))
        d.append(draw.Line((31-start)*25, 0+gap, (31-start)*25, height - gap, stroke='black'))
    d.save_svg('example.svg')
    d.save_png('example.png')

if __name__ == '__main__':
    make_reg()