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This script draws simple SVG images composed of circles, squares, lines, text, etc.

Python, 120 lines
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#!/usr/bin/env python
"""\
SVG.py - Construct/display SVG scenes.

The following code is a lightweight wrapper around SVG files. The metaphor
is to construct a scene, add objects to it, and then write it to a file
to display it.

This program uses ImageMagick to display the SVG files. ImageMagick also 
does a remarkable job of converting SVG files into other formats.
"""

import os
display_prog = 'display' # Command to execute to display images.
      
class Scene:
    def __init__(self,name="svg",height=400,width=400):
        self.name = name
        self.items = []
        self.height = height
        self.width = width
        return

    def add(self,item): self.items.append(item)

    def strarray(self):
        var = ["<?xml version=\"1.0\"?>\n",
               "<svg height=\"%d\" width=\"%d\" >\n" % (self.height,self.width),
               " <g style=\"fill-opacity:1.0; stroke:black;\n",
               "  stroke-width:1;\">\n"]
        for item in self.items: var += item.strarray()            
        var += [" </g>\n</svg>\n"]
        return var

    def write_svg(self,filename=None):
        if filename:
            self.svgname = filename
        else:
            self.svgname = self.name + ".svg"
        file = open(self.svgname,'w')
        file.writelines(self.strarray())
        file.close()
        return

    def display(self,prog=display_prog):
        os.system("%s %s" % (prog,self.svgname))
        return        
        

class Line:
    def __init__(self,start,end):
        self.start = start #xy tuple
        self.end = end     #xy tuple
        return

    def strarray(self):
        return ["  <line x1=\"%d\" y1=\"%d\" x2=\"%d\" y2=\"%d\" />\n" %\
                (self.start[0],self.start[1],self.end[0],self.end[1])]


class Circle:
    def __init__(self,center,radius,color):
        self.center = center #xy tuple
        self.radius = radius #xy tuple
        self.color = color   #rgb tuple in range(0,256)
        return

    def strarray(self):
        return ["  <circle cx=\"%d\" cy=\"%d\" r=\"%d\"\n" %\
                (self.center[0],self.center[1],self.radius),
                "    style=\"fill:%s;\"  />\n" % colorstr(self.color)]

class Rectangle:
    def __init__(self,origin,height,width,color):
        self.origin = origin
        self.height = height
        self.width = width
        self.color = color
        return

    def strarray(self):
        return ["  <rect x=\"%d\" y=\"%d\" height=\"%d\"\n" %\
                (self.origin[0],self.origin[1],self.height),
                "    width=\"%d\" style=\"fill:%s;\" />\n" %\
                (self.width,colorstr(self.color))]

class Text:
    def __init__(self,origin,text,size=24):
        self.origin = origin
        self.text = text
        self.size = size
        return

    def strarray(self):
        return ["  <text x=\"%d\" y=\"%d\" font-size=\"%d\">\n" %\
                (self.origin[0],self.origin[1],self.size),
                "   %s\n" % self.text,
                "  </text>\n"]
        
    
def colorstr(rgb): return "#%x%x%x" % (rgb[0]/16,rgb[1]/16,rgb[2]/16)

def test():
    scene = Scene('test')
    scene.add(Rectangle((100,100),200,200,(0,255,255)))
    scene.add(Line((200,200),(200,300)))
    scene.add(Line((200,200),(300,200)))
    scene.add(Line((200,200),(100,200)))
    scene.add(Line((200,200),(200,100)))
    scene.add(Circle((200,200),30,(0,0,255)))
    scene.add(Circle((200,300),30,(0,255,0)))
    scene.add(Circle((300,200),30,(255,0,0)))
    scene.add(Circle((100,200),30,(255,255,0)))
    scene.add(Circle((200,100),30,(255,0,255)))
    scene.add(Text((50,50),"Testing SVG"))
    scene.write_svg()
    scene.display()
    return

if __name__ == '__main__': test()

The Simple Vector Graphics (SVG) format is an XML-based format for vector graphics. The attached script makes it easy to construct images and add objects to them. This script uses ImageMagick to display the resultant images, but, of course, other display programs would work as well. ImageMagick is also a very good way to convert the resulting SVG images to other (PNG, JPEG, etc.) formats.

4 comments

Andreas Kloss 12 years, 3 months ago  # | flag

SVG = Scalable Vector Graphics, not Simple Vector Graphics. Ok, they may be simple, too, but you can make quite complex things out of them ;)

daviddoria 7 years, 9 months ago  # | flag

Is there a way to change the line thickness?

Dave

Dominic Innocent 5 years, 7 months ago  # | flag

Hi In reply to daviddoria 'yes you can'! You can also change the colour & style of the lines. The problem I fined is that if I close the button pad first then the "test screen" will not close! Have fun. d0m.

Isendrak Skatasmid 4 years, 9 months ago  # | flag

A really cool, though simple thing.

I made an enhanced Version based on this one.

See http://code.activestate.com/recipes/578123-draw-svg-images-in-python-python-recipe-enhanced-v/

This are the Enhancements:

  • Added Polygon and Ellipse Objects
  • Added Line Color and Line Width to Circle, Line and Rectangle Objects
  • Added Fill Color to Text Object

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