Re: [matplotlib-devel] imshow with PS backend

[JIM M. <ji...@ji...>]

> There are two kinds of images in matplotlib -- AxesImage and
> FigureImage.  By definition, the AxesImage is interpolated to fit into
> the Axes box.  You can control the aspect ratio of the interpolation,
> but it will be interpolated.  FigureImage, on the other hand, performs
> a pixel dump to the postscript canvas at the location you tell it to
> -- see examples/figimage_demo.py.  It should like you are more
> interested in the latter.
I've had a play with FigureImage and I can't see how to make it draw
the image inside the axes, it seems to only draw it in the background.

> If the figure image doesn't work for you, describe your use-case in
> some detail and why neither work and we'll see if we can accommodate
> it.
OK, so imshow does exactly what I want. The only problem is the
resampling. Each pixel represents a value calculated at a point on a
318x301 grid, so in resampling I loose or distort some of the fine
detail. I do not understand why the image need to be resampled when
using a vector based backend. I understand this is necessary for a
raster backend, but surely with a vector backend you can just scale
the image keeping the 318x301 resolution. I know this is possible in
Postscript at least as I've produced the desired output by
amalgamating two files. See

http://jimmacdonald.co.uk/matplotlib/image_CORRECT_ps_hacked.eps

I looked at using pcolor instead, but the postscript files where too
big (~20MB) due to the large number of tiles (this is how I used to do
it in matlab).

JIM
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