Today I read a thread at the wxPython user group about someone who was looking for a math equation editor that used Latex formulas: http://groups.google.com/group/wxpython-users/browse_thread/thread/33be14898871c5fa
Chris Barker suggested using the Matplotlib package and the Aggdraw_for_wx package. He provided a demo app that rendered and displayed a math equation. I've filled out his code with the abilities to save the rendered image to a PNG file and also to also crop the image to just the minimum that's needed using the PIL (Python Imaging Library) package. I put in the equation some fancy math symbols to show off its output at an arbitrary 300 dpi.
If PIL is not installed on your system then the output image simply won't get cropped. You'll have to do that yourself with any of a multitude of third-party image or graphics editors such as Photoshop, the GIMP or HyperSnap-DX, etc., etc.
I've got to admit that I know nothing about Matplotlib, yet I was able to guess how to create some common symbols. I suppose that if I actually read its manual I'd figure out how to draw all the Greek and special math symbols. But, no matter. Here's the demo code:
1 #!/usr/bin/env python
2
3 """
4 Test of embedding matplotlib, and using it to render a mathematical equation.
5
6 Original demo by Chris Barker 2010-12-15
7 Ergonomic, cropping and file saving additions by Ray Pasco 2010-12-15
8
9 Tested using :
10
11 Windows 6.1.7600 [ Win7 64-bit running on an AMD CPU ]
12 Python 2.6.5 (r265:79096, Mar 19 2010, 21:48:26) [MSC v.1500 32 bit (Intel)]
13 Wx 2.8.11.0
14 Matplotlib 1.0.0
15 PIL 1.1.7
16 """
17
18 import time
19
20 import wx
21
22 # These imports take an incredibly long time. [ ~1.8 seconds ]
23 # Let the user know this is normal and expected.
24 print '\n---- Importing Matplotlib and Related Modules...'
25 start = time.clock() # measure the import time
26 #
27 import matplotlib
28 matplotlib.use( 'WXAgg' ) # AggDraw for wxPython.
29 import matplotlib.figure
30 import matplotlib.backends.backend_wxagg
31 #
32 end = time.clock()
33 print ' Import Time =', end-start, 'seconds'
34
35 #------------------------------------------------------------------------------
36
37 class MathPanel( wx.Panel ) :
38 """
39 The MathPanel is a very simple panel with just and MPL figure on it,
40 it will automatically render text in the middle of the figure
41 """
42
43 def __init__( self, parent ) :
44
45 wx.Panel.__init__( self, parent=parent, size=(500, 200) )
46
47 #-----
48
49 # initialize matplotlib stuff.
50 #
51 # To make all new figure backgrounds be initialized to white
52 # edit the file [ \Lib\site-packages\matplotlib\mpl-data\matplotlibrc ]
53 # Find line [ figure.facecolor : 0.75 ] in section [ ### FIGURE ] and change it to
54 # [ figure.facecolor : 1.00 ]. Who would want a gray background color by default !?
55 #
56 # Create the "figure" and set its background color to white.
57 self.figure = matplotlib.figure.Figure( None, facecolor='white' )
58 self.canvas = matplotlib.backends.backend_wxagg.FigureCanvasWxAgg( \
59 self, -1, self.figure )
60
61 self._SetSize()
62 self.Bind( wx.EVT_SIZE, self._SetSize )
63
64 self.TeX = ''
65 self.font_size = 20
66 self.RenderEquation()
67
68 #end __init__
69
70 #----------------------------------
71
72 def SetTeX( self, str ) :
73
74 self.TeX = '$%s$' % (str)
75 self.RenderEquation()
76
77 #----------------------------------
78
79 def RenderEquation( self ) :
80
81 self.renderError = False # Can save to file only if False
82
83 try :
84 self.figure.clear()
85 self.figure.text( 0.05, 0.5, self.TeX, size=self.font_size )
86 self.canvas.draw()
87
88 except matplotlib.pyparsing.ParseFatalException :
89
90 self.renderError = True # Don't save the Tex error message to a file !
91 self.figure.clear()
92 self.figure.text( 0.05, 0.5, 'Parsing Error in MathTeX', size=self.font_size )
93 self.canvas.draw()
94
95 #end try
96
97 #end def
98
99 #----------------------------------
100
101 def _SetSize( self, evt=None ) :
102
103 pixels = self.GetSize()
104 self.SetSize( pixels )
105 self.canvas.SetSize( pixels )
106
107 dpi = self.figure.get_dpi()
108 self.figure.set_size_inches( float( pixels[0] ) / dpi,
109 float( pixels[1] ) / dpi )
110 #end def
111
112 #------------------------------------------------------------------------------
113
114 class MathFrame( wx.Frame ) :
115
116 def __init__( self ) :
117
118 wx.Frame.__init__( self, None, -1, pos=(10, 10),
119 title='Matplotlib Math EquationRenderer Test' )
120 self.ClientSize = (800, 275)
121
122 # Frames need an initial panel to provide tab traversal and
123 # cross-platform background color capabilities.
124 frmPanel = wx.Panel( self )
125
126 #-----
127
128 self.math_panel = MathPanel( frmPanel )
129
130 self.input_box = wx.TextCtrl( frmPanel, size=(500, -1) )
131 self.input_box.Font = wx.Font( 10,
132 wx.FONTFAMILY_TELETYPE,
133 wx.FONTSTYLE_NORMAL,
134 wx.FONTWEIGHT_NORMAL )
135 self.input_box.Bind( wx.EVT_TEXT, self.OnText )
136
137 # Set a default equation. Show some fancy math symbols.
138 equation = r'Goober = {\min(\int\ (\ {\delta{(\ \pi{}*\frac{\sum(\ a+\O\o\l\S\P\L\{b\}\ )\ } {( c-d )}})}\ )}'
139 self.input_box.Value = equation
140
141 label_stTxt = wx.StaticText( frmPanel, label='Type some TeX here :' )
142
143 saveBtn = wx.Button( frmPanel, label='Save Equation to File' )
144 saveBtn.Bind( wx.EVT_LEFT_DOWN, self.OnSaveToFileBtn )
145
146 exitBtn = wx.Button( frmPanel, label='Exit' )
147 exitBtn.Bind( wx.EVT_LEFT_DOWN, self.OnExit )
148
149 #----- Layout
150
151 frmPnl_vertSzr = wx.BoxSizer( wx.VERTICAL )
152
153 frmPnl_vertSzr.Add( label_stTxt, proportion=0, flag=wx.TOP|wx.LEFT, border=5 )
154 frmPnl_vertSzr.Add( self.input_box, proportion=0, flag=wx.GROW|wx.ALL, border=5 )
155 frmPnl_vertSzr.Add( self.math_panel, proportion=1, flag=wx.GROW )
156 frmPnl_vertSzr.Add( saveBtn, proportion=0,
157 flag=wx.ALIGN_CENTER|wx.BOTTOM|wx.TOP, border=10 )
158 frmPnl_vertSzr.Add( exitBtn, proportion=0,
159 flag=wx.ALIGN_CENTER|wx.BOTTOM, border=10 )
160
161 frmPanel.SetSizerAndFit( frmPnl_vertSzr )
162
163 #end __init__
164
165 #----------------------------------
166
167 def OnText( self, evt ) :
168
169 self.math_panel.SetTeX( self.input_box.Value )
170
171 #----------------------------------
172
173 def OnExit( self, evt ) :
174
175 self.Close()
176
177 #----------------------------------
178
179 def OnSaveToFileBtn( self, event ) :
180
181 if not self.math_panel.renderError :
182
183 filename = 'Rendered_Equation.png'
184 self.math_panel.figure.savefig( filename, dpi=300 )
185 print '\n---- Equation Graphic Saved to File [ %s ]' % filename
186
187 # See if the PIL package is installed.
188 pilIsInstalled = True
189 try :
190 # Try to crop the image to its near-minimum extent.
191 import Image # PIL (Python Image Library)
192 import ImageChops # Image Channel Operations library
193 import ImageStat # Image Statistics library
194 import ImageOps # Various whole image operations.
195
196 except :
197 pilIsInstalled = False # Image will not get auto-cropped.
198 #end try
199
200 if pilIsInstalled : # Auto-crop the image.
201 pilImg = Image.open( filename )
202
203 # Find the ordinates of the minimally enclosing bounding box.
204 #
205 # Create a simplified and inverted version of the original image to examine.
206 invertedImage = ImageChops.invert( pilImg.convert( 'L' ) ) # BG must be black to examine.
207
208 # Get the bounding box's ordinates. Works on any image with a black background.
209 box = invertedImage.getbbox() pilImg = pilImg.crop( box )
210
211 # Add back a thin border padding. This is arbitrary, but seems reasonable.
212 pilImg = ImageOps.expand( pilImg, border=10, fill=(255, 255, 255) )
213
214 # Save the image to a disk file. Only PNG and TIFF formats are non-destructive.
215 pilImg.save( filename )
216 print ' Cropped Equation Graphic Saved'
217
218 #end if
219
220 else :
221 print '\n---- Tex Rendering Error: Figure Image NOT SAVED to a File.'
222 #end if
223
224 #end def
225
226 #end MathFrame class
227
228 #==============================================================================
229
230 if __name__ == '__main__' :
231
232 # What packages are installed ?
233 import os, sys, platform
234 print
235 if os.name == 'nt' :
236 print 'Windows ', platform.win32_ver()[1]
237 else :
238 print 'Platform ', platform.system()
239 #end if
240 print 'Python ', sys.version
241
242 addon_pkgs = [ ('Wx ', 'wx.VERSION_STRING'),
243 ('Matplotlib', 'matplotlib.__version__'), ]
244
245 try :
246 import Image # Doesn't need to be installed.
247 pilStr = 'PIL '
248 pilAddonStr = 'Image.VERSION'
249 addon_pkgs.append( (pilStr , pilAddonStr) )
250 except :
251 pass
252 #end try
253
254 for addonStr, attribute in addon_pkgs :
255 try :
256 print addonStr, eval( attribute )
257 except NameError :
258 print
259 #end try
260 #end for
261 print
262
263 #----
264
265 app = wx.App( redirect=False )
266 appFrame = MathFrame().Show()
267 app.MainLoop()
268
269 #end if
Here is the file graphic reduced in size by a factor of 3 :
