cduck.me
1
2import base64
3import io
4import warnings
5from .missing import MissingModule
6
7
8try:
9 import cairosvg
10except OSError as e:
11 msg = (
12 'Failed to import CairoSVG. '
13 'drawSvg will be unable to output PNG or other raster image formats. '
14 'See https://github.com/cduck/drawSvg#prerequisites for more details.\n'
15 'Original OSError: {}'.format(e)
16 )
17 cairosvg = MissingModule(msg)
18 warnings.warn(msg, RuntimeWarning)
19except ImportError as e:
20 msg = (
21 'CairoSVG will need to be installed to rasterize images: Install with `pip3 install cairosvg`\n'
22 'Original ImportError: {}'.format(e)
23 )
24 cairosvg = MissingModule(msg)
25 warnings.warn(msg, RuntimeWarning)
26
27
28class Raster:
29 def __init__(self, pngData=None, pngFile=None):
30 self.pngData = pngData
31 self.pngFile = pngFile
32 def savePng(self, fname):
33 with open(fname, 'wb') as f:
34 f.write(self.pngData)
35 @staticmethod
36 def fromSvg(svgData):
37 pngData = cairosvg.svg2png(bytestring=svgData)
38 return Raster(pngData)
39 @staticmethod
40 def fromSvgToFile(svgData, outFile):
41 cairosvg.svg2png(bytestring=svgData, write_to=outFile)
42 return Raster(None, pngFile=outFile)
43 def _repr_png_(self):
44 if self.pngData:
45 return self.pngData
46 elif self.pngFile:
47 try:
48 with open(self.pngFile, 'rb') as f:
49 return f.read()
50 except TypeError:
51 pass
52 try:
53 self.pngFile.seek(0)
54 return self.pngFile.read()
55 except io.UnsupportedOperation:
56 pass
57 def asDataUri(self):
58 if self.pngData:
59 data = self.pngData
60 else:
61 try:
62 with open(self.pngFile, 'rb') as f:
63 data = f.read()
64 except TypeError:
65 self.pngFile.seek(0)
66 data = self.pngFile.read()
67 b64 = base64.b64encode(data)
68 return 'data:image/png;base64,' + b64.decode(encoding='ascii')