Fix path simplification so the path always starts with a MOVETO.

mdboom · mdboom · commit 142dbe288b1f · 2009-10-22T13:43:31.000Z
svn path=/trunk/matplotlib/; revision=7900
diff --git a/lib/matplotlib/path.py b/lib/matplotlib/path.py
@@ -115,6 +115,8 @@ def __init__(self, vertices, codes=None, _interpolation_steps=1):
             codes = np.asarray(codes, self.code_type)
             assert codes.ndim == 1
             assert len(codes) == len(vertices)
+            if len(codes):
+                assert codes[0] == self.MOVETO
 
         assert vertices.ndim == 2
         assert vertices.shape[1] == 2
diff --git a/lib/matplotlib/tests/test_simplification.py b/lib/matplotlib/tests/test_simplification.py
@@ -2,11 +2,10 @@
 import matplotlib
 from matplotlib.testing.decorators import image_comparison, knownfailureif
 import matplotlib.pyplot as plt
-from matplotlib import patches, path
 
 from pylab import *
 import numpy as np
-from matplotlib import patches, path
+from matplotlib import patches, path, transforms
 nan = np.nan
 Path = path.Path
 
@@ -134,6 +133,38 @@ def test_fft_peaks():
 
     assert len(simplified) == 13
 
+def test_start_with_moveto():
+    # Should be entirely clipped away to a single MOVETO
+    data = """
+ZwAAAAku+v9UAQAA+Tj6/z8CAADpQ/r/KAMAANlO+v8QBAAAyVn6//UEAAC6ZPr/2gUAAKpv+v+8
+BgAAm3r6/50HAACLhfr/ewgAAHyQ+v9ZCQAAbZv6/zQKAABepvr/DgsAAE+x+v/lCwAAQLz6/7wM
+AAAxx/r/kA0AACPS+v9jDgAAFN36/zQPAAAF6Pr/AxAAAPfy+v/QEAAA6f36/5wRAADbCPv/ZhIA
+AMwT+/8uEwAAvh77//UTAACwKfv/uRQAAKM0+/98FQAAlT/7/z0WAACHSvv//RYAAHlV+/+7FwAA
+bGD7/3cYAABea/v/MRkAAFF2+//pGQAARIH7/6AaAAA3jPv/VRsAACmX+/8JHAAAHKL7/7ocAAAP
+rfv/ah0AAAO4+/8YHgAA9sL7/8QeAADpzfv/bx8AANzY+/8YIAAA0OP7/78gAADD7vv/ZCEAALf5
++/8IIgAAqwT8/6kiAACeD/z/SiMAAJIa/P/oIwAAhiX8/4QkAAB6MPz/HyUAAG47/P+4JQAAYkb8
+/1AmAABWUfz/5SYAAEpc/P95JwAAPmf8/wsoAAAzcvz/nCgAACd9/P8qKQAAHIj8/7cpAAAQk/z/
+QyoAAAWe/P/MKgAA+aj8/1QrAADus/z/2isAAOO+/P9eLAAA2Mn8/+AsAADM1Pz/YS0AAMHf/P/g
+LQAAtur8/10uAACr9fz/2C4AAKEA/f9SLwAAlgv9/8ovAACLFv3/QDAAAIAh/f+1MAAAdSz9/ycx
+AABrN/3/mDEAAGBC/f8IMgAAVk39/3UyAABLWP3/4TIAAEFj/f9LMwAANm79/7MzAAAsef3/GjQA
+ACKE/f9+NAAAF4/9/+E0AAANmv3/QzUAAAOl/f+iNQAA+a/9/wA2AADvuv3/XDYAAOXF/f+2NgAA
+29D9/w83AADR2/3/ZjcAAMfm/f+7NwAAvfH9/w44AACz/P3/XzgAAKkH/v+vOAAAnxL+//04AACW
+Hf7/SjkAAIwo/v+UOQAAgjP+/905AAB5Pv7/JDoAAG9J/v9pOgAAZVT+/606AABcX/7/7zoAAFJq
+/v8vOwAASXX+/207AAA/gP7/qjsAADaL/v/lOwAALZb+/x48AAAjof7/VTwAABqs/v+LPAAAELf+
+/788AAAHwv7/8TwAAP7M/v8hPQAA9df+/1A9AADr4v7/fT0AAOLt/v+oPQAA2fj+/9E9AADQA///
++T0AAMYO//8fPgAAvRn//0M+AAC0JP//ZT4AAKsv//+GPgAAojr//6U+AACZRf//wj4AAJBQ///d
+PgAAh1v///c+AAB+Zv//Dz8AAHRx//8lPwAAa3z//zk/AABih///TD8AAFmS//9dPwAAUJ3//2w/
+AABHqP//ej8AAD6z//+FPwAANb7//48/AAAsyf//lz8AACPU//+ePwAAGt///6M/AAAR6v//pj8A
+AAj1//+nPwAA/////w=="""
+
+    verts = np.fromstring(data.decode('base64'), dtype='<i4')
+    verts = verts.reshape((len(verts) / 2, 2))
+    path = Path(verts)
+    segs = path.iter_segments(transforms.IdentityTransform, clip=(0.0, 0.0, 100.0, 100.0))
+    segs = list(segs)
+    assert len(segs) == 1
+    assert segs[0][1] == Path.MOVETO
+
 if __name__=='__main__':
     import nose
     nose.runmodule(argv=['-s','--with-doctest'], exit=False)
diff --git a/src/path_converters.h b/src/path_converters.h
@@ -684,9 +684,15 @@ class PathSimplifier : protected EmbeddedQueue<9>
         {
             if (m_origdNorm2 != 0.0)
             {
-                queue_push(agg::path_cmd_line_to, m_nextX, m_nextY);
+                queue_push((m_moveto || m_after_moveto) ?
+                           agg::path_cmd_move_to : agg::path_cmd_line_to,
+                           m_nextX, m_nextY);
+                m_moveto = false;
             }
-            queue_push(agg::path_cmd_line_to, m_lastx, m_lasty);
+            queue_push((m_moveto || m_after_moveto) ?
+                       agg::path_cmd_move_to : agg::path_cmd_line_to,
+                       m_lastx, m_lasty);
+            m_moveto = false;
             queue_push(agg::path_cmd_stop, 0.0, 0.0);
         }
 

Original file line number	Diff line number	Diff line change
`@@ -684,9 +684,15 @@ class PathSimplifier : protected EmbeddedQueue<9>`
`684`	`684`	`{`
`685`	`685`	`if (m_origdNorm2 != 0.0)`
`686`	`686`	`{`
`687`		`- queue_push(agg::path_cmd_line_to, m_nextX, m_nextY);`
	`687`	`+ queue_push((m_moveto \|\| m_after_moveto) ?`
	`688`	`+ agg::path_cmd_move_to : agg::path_cmd_line_to,`
	`689`	`+ m_nextX, m_nextY);`
	`690`	`+ m_moveto = false;`
`688`	`691`	`}`
`689`		`- queue_push(agg::path_cmd_line_to, m_lastx, m_lasty);`
	`692`	`+ queue_push((m_moveto \|\| m_after_moveto) ?`
	`693`	`+ agg::path_cmd_move_to : agg::path_cmd_line_to,`
	`694`	`+ m_lastx, m_lasty);`
	`695`	`+ m_moveto = false;`
`690`	`696`	`queue_push(agg::path_cmd_stop, 0.0, 0.0);`
`691`	`697`	`}`
`692`	`698`