# drawSvg

This is a Python 3 library for programmatically generating SVG images (vector drawings) and rendering them or displaying them in an iPython notebook.

Most common SVG tags are supported and others can easily be added by writing a small subclass of `DrawableBasicElement` or `DrawableParentElement`.

# Install
drawSvg is available on PyPI:

```
$ pip3 install drawSvg
```

# Examples

### Basic drawing elements
```python
d = draw.Drawing(200, 100, origin='center')

d.append(draw.Lines(-80, -45,
                    70, -49,
                    95, 49,
                    -90, 40,
                    close=False,
            fill='#eeee00',
            stroke='black'))

d.append(draw.Rectangle(0,0,40,50, fill='#1248ff'))
d.append(draw.Circle(-40, -10, 30,
            fill='red', stroke_width=2, stroke='black'))

p = draw.Path(stroke_width=2, stroke='green',
              fill='black', fill_opacity=0.5)
p.M(-30,5)  # Start path at point (-30, 5)
p.l(60,30)  # Draw line to (60, 30)
p.h(-70)    # Draw horizontal line to x=-70
p.Z()       # Draw line to start
d.append(p)

d.append(draw.ArcLine(60,-20,20,60,270,
            stroke='red', stroke_width=5, fill='red', fill_opacity=0.2))
d.append(draw.Arc(60,-20,20,60,270,cw=False,
            stroke='green', stroke_width=3, fill='none'))
d.append(draw.Arc(60,-20,20,270,60,cw=True,
            stroke='blue', stroke_width=1, fill='black', fill_opacity=0.3))

d.setPixelScale(2)  # Set number of pixels per geometry unit
#d.setRenderSize(400,200)  # Alternative to setPixelScale
d.saveSvg('example.svg')
d.savePng('example.png')

# Display in iPython notebook
d.rasterize()  # Display as PNG
d  # Display as SVG
```

![Example output image](https://github.com/cduck/drawSvg/raw/master/example1.png)

### Gradients
```python
d = draw.Drawing(1.5, 0.8, origin='center')

d.draw(draw.Rectangle(-0.75,-0.5,1.5,1, fill='#ddd'))

# Create gradient
gradient = draw.RadialGradient(0,-0.35,0.7*10)
gradient.addStop(0.5/0.7/10, 'green', 1)
gradient.addStop(1/10, 'red', 0)

# Draw a shape to fill with the gradient
p = draw.Path(fill=gradient, stroke='black', stroke_width=0.002)
p.arc(0,-0.35,0.7,30,120)
p.arc(0,-0.35,0.5,120,30,cw=True, includeL=True)
p.Z()
d.append(p)

# Draw another shape to fill with the same gradient
p = draw.Path(fill=gradient, stroke='red', stroke_width=0.002)
p.arc(0,-0.35,0.75,130,160)
p.arc(0,-0.35,0,160,130,cw=True, includeL=True)
p.Z()
d.append(p)

# Another gradient
gradient2 = draw.LinearGradient(0.1,-0.35,0.1+0.6,-0.35+0.2)
gradient2.addStop(0, 'green', 1)
gradient2.addStop(1, 'red', 0)
d.append(draw.Rectangle(0.1,-0.35,0.6,0.2,
                        stroke='black', stroke_width=0.002,
                        fill=gradient2))

# Display
d.setRenderSize(w=600)
d
```

![Example output image](https://github.com/cduck/drawSvg/raw/master/example2.png)

### Duplicate geometry and clip paths
```python
d = draw.Drawing(1.4, 1.4, origin='center')

# Define clip path
clip = draw.ClipPath()
clip.append(draw.Rectangle(-.25,.25-1,1,1))

# Draw a cropped circle
c = draw.Circle(0,0,0.5, stroke_width='0.01', stroke='black',
                         fill_opacity=0.3, clip_path=clip,
                         id='circle')
d.append(c)

# Make a transparent copy, cropped again
g = draw.Group(opacity=0.5, clip_path=clip)
g.append(draw.Use('circle', 0.25,0.1))
d.append(g)

# Display
d.setRenderSize(400)
d.rasterize()
```

![Example output image](https://github.com/cduck/drawSvg/raw/master/example3.png)

### Implementing other SVG tags
```python
# Subclass DrawingBasicElement if it cannot have child nodes
# Subclass DrawingParentElement otherwise
# Subclass DrawingDef if it must go between <def></def> tags in an SVG
class Hyperlink(draw.DrawingParentElement):
    TAG_NAME = 'a'
    def __init__(self, href, target=None, **kwargs):
        # Other init logic...
        # Keyword arguments to super().__init__() correspond to SVG node
        # arguments: stroke_width=5 -> stroke-width="5"
        super().__init__(href=href, target=target, **kwargs)

d = draw.Drawing(1, 1.2, origin='center')

# Create hyperlink
hlink = Hyperlink('https://www.python.org', target='_blank',
                  transform='skewY(-30)')
# Add child elements
hlink.append(draw.Circle(0,0,0.5, fill='green'))
hlink.append(draw.Text('Hyperlink',0.2, 0,0, center=0.6, fill='white'))

# Draw and display
d.append(hlink)
d.setRenderSize(200)
d
```

![Example output image](https://github.com/cduck/drawSvg/blob/master/example4.svg)