[wxPython-dev] img2py script

[Anthony Tuininga]

On Nov 14, 2007 6:07 PM, Robin Dunn <robin at alldunn.com> wrote:
>
> Anthony Tuininga wrote:
> > Hi everyone. I thought I would ask this question about the img2py
> > script since it seems to me this would be an improvement -- but
> > perhaps I'm missing something. :-)
> >
> > The current script generates fairly ugly code -- which bugs me even
> > though it doesn't matter since its generated. :-) The generated code
> > is also quite lengthy thanks to binary data being encoded with four
> > characters in most cases. Finally the generated code is fairly
> > intrusive in terms of namespace since three methods are generated for
> > each image. My suggestion handles all of these, I believe, but I'd
> > appreciate feedback.
> >
> > A class could be created (wx.PyImage?) that would encompass the
> > routines for getting the data, bitmap and image (see attached) which
> > would clear up the namespace intrusiveness. Then using base64 encoding
> > dramatically reduces the size of the generated script (see attached
> > for an example). The names, case, style, etc. are all subject to
> > change if the concept is accepted, of course.
> >
> > Comments?
>
> In general I like it, although I think I would prefer if the embedded
> images were all instances of the same class, instead of individual
> classes derived from the same base and using classmethods.

I have no objection to using a single class and instances of each as in

class PyImage(object):

    def __init__(self, data):
        self.data = data

    def GetBitmap(self):
        return wx.BitmapFromImage(self.GetImage()

    def GetImage(self):
        data = base64.b64decode(self.data)
        stream = cStringIO.StringIO(data)
        return wx.ImageFromStream(stream)


Checked = PyImage( \
        "iVBORw0KGgoAAAANSUhEUgAAAA0AAAANCAYAAABy6+R8AAAABHNCSVQICAgIfA" \
        "hkiAAAAKlJREFUKJFjlAls+M9AImBhYGBgODYxFi7AyMjEwMQEwczMzAxMTMxw" \
        "momJiUEzrp+BCdkEQhqYmCDKmYjRYLDBCCrHjNBESAMDAwPcNrgmmAarXXZYNc" \
        "DUMDIyompiZoZYbbrVAkPDjYjrDIyMjKg2wUyGAVwaGBlRnAdx0oWAcyjxga4B" \
        "xXnIwXol5BJODWh+QsQDExMzXg0YoQfTjE8DAwMDAyM5aQ8AoE8ebApv5jgAAA" \
        "AASUVORK5CYII=")

I can provide patches if you'd like -- unless you have further
comments or changes or you'd prefer to implement it yourself?

> Using base64 is also a good idea.  IIRC that module wasn't available, or
> at least not part of the standard build, when img2py was first
> conceived.  Have you looked at how much space savings that using zlib is
> buying?  At the beginning when the embedded format was XPM then
> compressing gained us quite a bit in size reduction, but since the
> format has been switched to PNG which is already at least RLE compressed
> it may be possible that the gain is not worth the decompression time.

I did some checking on that. In some instances the compressed data is
smaller but in quite a few cases the compressed data is larger. And if
the image is smaller than 10k, the likelihood of the compressed data
being larger is very high. I'd suggest dropping the compression
entirely. Its also possible that for those few situations you could
have another class PyCompresedImage which changes its GetImage() to
add the zlib.decompress() call -- but I'm not sure its worth the
trouble. Comments?

> --
> Robin Dunn
> Software Craftsman
> http://wxPython.org  Java give you jitters?  Relax with wxPython!
>
>
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