> > Could you possibly explain exactly what is going on and how this > structurally differs from the approach that Mike posted? > > In Mike's code, he uses BboxTransformTo using the box he created in > display coords. So this takes a unit square and spits out the box > that I specify when I instantiate the custom patch (using data coords > for x and y and axes coords for w). What is called to actually draw > the box (i.e., when I execute plt.draw())? Is that get_path()? So > basically, whenever MPL wants to draw a patch, does it always call > get_path() and then runs it through whatever is returned from > get_transform() to get the final shape in display coords?
Your understanding is basically right. When plt.draw(or any equivalent) is called, the draw methods of each artists are called. And the draw method of the Patch class, in general, calls the get_path and get_transform, while details can be different. > > So how does this relate to the strategy that you are advocating? Is > _update_patch_transform somehow a synonym for what I described in the > paragraph above? I don't know where that fits into the picture. > Yes, for the Rectangle class, its get_transform method returns a combined transform of patch_transform + default_artist_transform, where the patch_transform is used to transform the unit rectangle to the data coordinate. So, the basic idea is very similar to Mike's implementation, while Mike's should be more efficient as it transforms the unit rectangle directly to the canvas coordinate. > It may be useful to add something to the "Working With Tranformations" > section or the "Transformation Tutorial" about what is minimally > necessary to override for a custom patch. I have been playing around > with MPL for some time now (albeit I don't have much computer > visualization/graphics experience) and still have only a fuzzy idea of > what order things are called in and what the overall > strategy/structure of the system is like. > Well, right now, I guess the source code is your best tutor (which was and still is for me). You may start with the mpatches.Patch that Mike's MyBox inherit from. And any contribution will be greatly appreciated! -JJ > Uri > >> >> -JJ >> >>> Uri >>> >>>> >>>> Mike >>>> >>>> Eric Firing wrote: >>>>> >>>>> Uri Laserson wrote: >>>>> >>>>>> >>>>>> Is it possible to specify a path object that will use different >>>>>> transforms for different vertices? >>>>>> >>>>>> This is again related to plotting a box whose height is specified by >>>>>> data coords, but whose width is a constant in axes coords regardless >>>>>> of scale (so linear and log x-scales would produce a box of the same >>>>>> width). >>>>>> >>>>>> Ideally, I would draw a path like this: >>>>>> 1. the center of the box would be located at x and bottom and top >>>>>> would be y1, y2, all in data coords >>>>>> 2. I would move to (x,y1) at the bottom-center of the box. >>>>>> 3. The x value would now need to be converted to Axes coords, possibly >>>>>> by applying transData + transAxes.inverted >>>>>> 4. I would want to draw a line to (x-0.1, y1) where x is now in axes >>>>>> coords and y is still in data coords. Then up, then right, then down, >>>>>> and then close the polygon. >>>>>> >>>>>> How do I implement this? >>>>>> >>>>> >>>>> I must be missing something, because I still don't see why you can't do >>>>> all this very simply by using a PolyCollection, with the vertices in axes >>>>> coordinates and the offset in data coordinates. >>>>> >>>>> Eric >>>>> >>>>> >>>>>> >>>>>> As I mentioned before, a blended transform would allow me to make the >>>>>> moves i am interested in. However, a change of scale would change the >>>>>> correspondence between data and axes coords, so the axes transform >>>>>> part of the blended axes would have to be recomputed everytime the >>>>>> scale changes based on where the (x,y1) point lands in the axes. Is >>>>>> this correct? >>>>>> >>>>>> Any suggestions are welcome...thanks! >>>>>> >>>>>> Uri >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> Come build with us! The BlackBerry® Developer Conference in SF, CA >>>>> is the only developer event you need to attend this year. Jumpstart your >>>>> developing skills, take BlackBerry mobile applications to market and stay >>>>> ahead of the curve. Join us from November 9-12, 2009. Register >>>>> now! >>>>> http://p.sf.net/sfu/devconf >>>>> _______________________________________________ >>>>> Matplotlib-users mailing list >>>>> Matplotlib-users@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>>>> >>>> >>>> -- >>>> Michael Droettboom >>>> Science Software Branch >>>> Operations and Engineering Division >>>> Space Telescope Science Institute >>>> Operated by AURA for NASA >>>> >>>> >>> >>> >>> >>> -- >>> Uri Laserson >>> PhD Candidate, Biomedical Engineering >>> Harvard Medical School (Genetics) >>> Massachusetts Institute of Technology (Mathematics) >>> phone +1 917 742 8019 >>> laser...@mit.edu >>> >>> ------------------------------------------------------------------------------ >>> Come build with us! The BlackBerry® Developer Conference in SF, CA >>> is the only developer event you need to attend this year. Jumpstart your >>> developing skills, take BlackBerry mobile applications to market and stay >>> ahead of the curve. Join us from November 9-12, 2009. Register now! >>> http://p.sf.net/sfu/devconf >>> _______________________________________________ >>> Matplotlib-users mailing list >>> Matplotlib-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>> >> > > > > -- > Uri Laserson > PhD Candidate, Biomedical Engineering > Harvard Medical School (Genetics) > Massachusetts Institute of Technology (Mathematics) > phone +1 917 742 8019 > laser...@mit.edu > ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. 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