It looks like rotation/translation should be easy to do with Affine2D, so I tried using it, but I can't seem to get it to work as expected - here is an example of how I am using it:
import numpy as np from matplotlib.pyplot import * from matplotlib.transforms import Affine2D im = np.random.random((10,10)) tr = Affine2D().rotate_deg(45.) fig = figure() ax = fig.add_subplot(111) ax.imshow(im,transform=tr) fig.canvas.draw() Am I doing something wrong? Thanks! Thomas On Mar 13, 2009, at 5:20 PM, Andrew Straw wrote: > Eric Firing wrote: >> Thomas Robitaille wrote: >>> Hello, >>> >>> I was wondering whether there is a way to rotate a grayscale/ >>> colorscale when using imshow. >>> >>> I have been using PGPLOT (a fortran/c plotting library) for many >>> years >>> now, and the equivalent to imshow is called PGGRAY (or PGIMAG). >>> One of >>> the arguments this function takes is a 6-element array TR which is a >>> transformation matrix. From the PGPLOT documentation: >>> >>> "The transformation matrix TR is used to calculate the world >>> coordinates of the center of the "cell" that represents each array >>> element. The world coordinates of the center of the cell >>> corresponding >>> to array element A(I,J) are given by: >>> X = TR(1) + TR(2)*I + TR(3)*J >>> Y = TR(4) + TR(5)*I + TR(6)*J" >> >> You could do this with the Axes.pcolormesh method. You could start >> with >> an unrotated grid (generated by meshgrid, for example), apply your >> rotation, and use that transformed grid in pcolormesh. Note that >> pcolormesh requires the grid for the cell boundaries, not centers. >> > > It should work with imshow() as well if you can set the affine > component > of the transform to the desired values. Which it looks like you can in > Affine2D(). (The affine matrix is the elements of TR listed above, it > appears.) > > I have not tried to do this, however -- just saying that I think it's > possible. > > -Andrew ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
