cduck.me
1import base64
2import io
3import warnings
4
5from .url_encode import bytes_as_data_uri
6
7try:
8 import cairosvg
9except OSError as e:
10 raise ImportError(
11 'Failed to load CairoSVG. '
12 'drawSvg will be unable to output PNG or other raster image formats. '
13 'See https://github.com/cduck/drawsvg#prerequisites for more details.'
14 ) from e
15except ImportError as e:
16 raise ImportError(
17 'CairoSVG will need to be installed to rasterize images. '
18 'Install with `pip3 install cairosvg`.'
19 ) from e
20
21
22class Raster:
23 def __init__(self, png_data=None, png_file=None):
24 self.png_data = png_data
25 self.png_file = png_file
26 def save_png(self, fname):
27 with open(fname, 'wb') as f:
28 f.write(self.png_data)
29 @staticmethod
30 def from_svg(svg_data):
31 png_data = cairosvg.svg2png(bytestring=svg_data)
32 return Raster(png_data)
33 @staticmethod
34 def from_svg_to_file(svg_data, out_file):
35 cairosvg.svg2png(bytestring=svg_data, write_to=out_file)
36 return Raster(None, png_file=out_file)
37 def _repr_png_(self):
38 if self.png_data:
39 return self.png_data
40 elif self.png_file:
41 try:
42 with open(self.png_file, 'rb') as f:
43 return f.read()
44 except TypeError:
45 pass
46 try:
47 self.png_file.seek(0)
48 return self.png_file.read()
49 except io.UnsupportedOperation:
50 pass
51 def as_data_uri(self):
52 if self.png_data:
53 data = self.png_data
54 else:
55 try:
56 with open(self.png_file, 'rb') as f:
57 data = f.read()
58 except TypeError:
59 self.png_file.seek(0)
60 data = self.png_file.read()
61 return bytes_as_data_uri(data, mime='image/png')