On Thu, Jun 19, 2008 at 8:58 AM, Alan G Isaac <[EMAIL PROTECTED]> wrote: > On Thu, 19 Jun 2008, Scott Sinclair apparently wrote: >> canvas = FigureCanvas(fig) > > What is the relationship between a figure and a canvas?
The Figure is the top level matplotlib artist container that contains all the other matplotlib.artist.Artist instances (Axes, Line2D, etc..). Artists don't know anything about output formats (GDK, PS, SVG) but they do know about renderers (matplotlib.backend_bases.RendererBase) which have methods like draw_line, draw_rectangle, and draw_text. The renderer subclasses know the various output languages like postscript or svg. The canvas is the target of the drawing by the renderer, and the canvas puts all the pieces together. The canvas contains a renderer that knows how to draw on the canvas, and it also contains the figure instance to be drawn. The canvas calls fig.draw(renderer) and then the figure instance in turn calls self.figurePatch.draw(renderer) and then the figurePatch, a matplotlib.patches.Rectangle instance, calls renderer.draw_rectangle(graphicscontext, 25, 40) So the renderer doesn't know anything about the matplotlib artist Rectangle, but the Rectangle knows how to tell the renderer to draw itself. This design decouples the functionality to make it possible to change the artists w/o affecting the renderers, so the drawing API is not affected by the matplotlib artist classes. This is covered somewhat in Chapter 10 of the user's guide http://matplotlib.sourceforge.net/users_guide_0.98.0.pdf JDH ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
