SF.net SVN: matplotlib:[6178] trunk/matplotlib

[<ef...@us...>]

Revision: 6178
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=6178&view=rev
Author:   efiring
Date:     2008-10-10 19:43:34 +0000 (Fri, 10 Oct 2008)

Log Message:
-----------
Permit chunking in the backend_agg draw_path() method.
This is experimental, and disabled by default; it can be enabled
by setting the rcParams['agg.path.chunksize'] before a path is
drawn.

Modified Paths:
--------------
    trunk/matplotlib/lib/matplotlib/backends/backend_agg.py
    trunk/matplotlib/lib/matplotlib/rcsetup.py
    trunk/matplotlib/matplotlibrc.template

Modified: trunk/matplotlib/lib/matplotlib/backends/backend_agg.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/backends/backend_agg.py	2008-10-10 16:53:27 UTC (rev 6177)
+++ trunk/matplotlib/lib/matplotlib/backends/backend_agg.py	2008-10-10 19:43:34 UTC (rev 6178)
@@ -62,7 +62,7 @@
         self._renderer = _RendererAgg(int(width), int(height), dpi, debug=False)
         if __debug__: verbose.report('RendererAgg.__init__ _RendererAgg done',
                                      'debug-annoying')
-        self.draw_path = self._renderer.draw_path
+        #self.draw_path = self._renderer.draw_path  # see below
         self.draw_markers = self._renderer.draw_markers
         self.draw_path_collection = self._renderer.draw_path_collection
         self.draw_quad_mesh = self._renderer.draw_quad_mesh
@@ -76,6 +76,28 @@
         if __debug__: verbose.report('RendererAgg.__init__ done',
                                      'debug-annoying')
 
+    def draw_path(self, gc, path, transform, rgbFace=None):
+        nmax = rcParams['agg.path.chunksize'] # here at least for testing
+        npts = path.vertices.shape[0]
+        if nmax > 100 and npts > nmax and path.should_simplify:
+            nch = npy.ceil(npts/float(nmax))
+            chsize = int(npy.ceil(npts/nch))
+            i0 = npy.arange(0, npts, chsize)
+            i1 = npy.zeros_like(i0)
+            i1[:-1] = i0[1:] - 1
+            i1[-1] = npts
+            for ii0, ii1 in zip(i0, i1):
+                v = path.vertices[ii0:ii1,:]
+                c = path.codes
+                if c is not None:
+                    c = c[ii0:ii1]
+                    c[0] = Path.MOVETO # move to end of last chunk
+                p = Path(v, c)
+                self._renderer.draw_path(gc, p, transform, rgbFace)
+        else:
+            self._renderer.draw_path(gc, path, transform, rgbFace)
+
+
     def draw_mathtext(self, gc, x, y, s, prop, angle):
         """
         Draw the math text using matplotlib.mathtext

Modified: trunk/matplotlib/lib/matplotlib/rcsetup.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/rcsetup.py	2008-10-10 16:53:27 UTC (rev 6177)
+++ trunk/matplotlib/lib/matplotlib/rcsetup.py	2008-10-10 19:43:34 UTC (rev 6178)
@@ -488,7 +488,10 @@
     'svg.embed_char_paths' : [True, validate_bool],  # True to save all characters as paths in the SVG
     'plugins.directory' : ['.matplotlib_plugins', str], # where plugin directory is locate
 
-    'path.simplify' : [False, validate_bool]
+    'path.simplify' : [False, validate_bool],
+    'agg.path.chunksize' : [0, validate_int]       # 0 to disable chunking;
+                                                   # recommend about 20000 to
+                                                   # enable. Experimental.
 }
 
 if __name__ == '__main__':

Modified: trunk/matplotlib/matplotlibrc.template
===================================================================
--- trunk/matplotlib/matplotlibrc.template	2008-10-10 16:53:27 UTC (rev 6177)
+++ trunk/matplotlib/matplotlibrc.template	2008-10-10 19:43:34 UTC (rev 6178)
@@ -270,6 +270,16 @@
 ### CONTOUR PLOTS
 #contour.negative_linestyle :  dashed # dashed | solid
 
+### Agg rendering
+### Warning: experimental, 2008/10/10
+#agg.path.chunksize : 0           # 0 to disable; values in the range
+                                  # 10000 to 100000 can improve speed slightly
+                                  # and prevent an Agg rendering failure
+                                  # when plotting very large data sets,
+                                  # especially if they are very gappy.
+                                  # It may cause minor artifacts, though.
+                                  # A value of 20000 is probably a good
+                                  # starting point.
 ### SAVING FIGURES
 #path.simplify : False  # When True, simplify paths in vector backends, such as PDF, PS and SVG
 


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