fix Bug 308204, add Visual bbox option

[inkscape.git] / share / extensions / simpletransform.py

diff --git a/share/extensions/simpletransform.py b/share/extensions/simpletransform.py
index c89d771ec57beb99aca70f68cfb2670e890ddbfb..08aa4c55fd6084c47bf22d36618c8a154675f0fb 100644 (file)
--- a/share/extensions/simpletransform.py
+++ b/share/extensions/simpletransform.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 '''
 Copyright (C) 2006 Jean-Francois Barraud, barraud@math.univ-lille1.fr
+Copyright (C) 2010 Alvin Penner, penner@vaxxine.com
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -142,6 +143,44 @@ def roughBBox(path):
                 yMax = max(yMax,pt[1])
     return xmin,xMax,ymin,yMax
 
+def refinedBBox(path):
+    xmin,xMax,ymin,yMax = path[0][0][1][0],path[0][0][1][0],path[0][0][1][1],path[0][0][1][1]
+    for pathcomp in path:
+        for i in range(1, len(pathcomp)):
+            cmin, cmax = cubicExtrema(pathcomp[i-1][1][0], pathcomp[i-1][2][0], pathcomp[i][0][0], pathcomp[i][1][0])
+            xmin = min(xmin, cmin)
+            xMax = max(xMax, cmax)
+            cmin, cmax = cubicExtrema(pathcomp[i-1][1][1], pathcomp[i-1][2][1], pathcomp[i][0][1], pathcomp[i][1][1])
+            ymin = min(ymin, cmin)
+            yMax = max(yMax, cmax)
+    return xmin,xMax,ymin,yMax
+
+def cubicExtrema(y0, y1, y2, y3):
+    cmin = min(y0, y3)
+    cmax = max(y0, y3)
+    d1 = y1 - y0
+    d2 = y2 - y1
+    d3 = y3 - y2
+    if (d1 - 2*d2 + d3):
+        if (d2*d2 > d1*d3):
+            t = (d1 - d2 + math.sqrt(d2*d2 - d1*d3))/(d1 - 2*d2 + d3)
+            if (t > 0) and (t < 1):
+                y = y0*(1-t)*(1-t)*(1-t) + 3*y1*t*(1-t)*(1-t) + 3*y2*t*t*(1-t) + y3*t*t*t
+                cmin = min(cmin, y)
+                cmax = max(cmax, y)
+            t = (d1 - d2 - math.sqrt(d2*d2 - d1*d3))/(d1 - 2*d2 + d3)
+            if (t > 0) and (t < 1):
+                y = y0*(1-t)*(1-t)*(1-t) + 3*y1*t*(1-t)*(1-t) + 3*y2*t*t*(1-t) + y3*t*t*t
+                cmin = min(cmin, y)
+                cmax = max(cmax, y)
+    elif (d3 - d1):
+        t = -d1/(d3 - d1)
+        if (t > 0) and (t < 1):
+            y = y0*(1-t)*(1-t)*(1-t) + 3*y1*t*(1-t)*(1-t) + 3*y2*t*t*(1-t) + y3*t*t*t
+            cmin = min(cmin, y)
+            cmax = max(cmax, y)
+    return cmin, cmax
+
 def computeBBox(aList,mat=[[1,0,0],[0,1,0]]):
     bbox=None
     for node in aList:
@@ -179,7 +218,7 @@ def computeBBox(aList,mat=[[1,0,0],[0,1,0]]):
         if d is not None:
             p = cubicsuperpath.parsePath(d)
             applyTransformToPath(m,p)
-            bbox=boxunion(roughBBox(p),bbox)
+            bbox=boxunion(refinedBBox(p),bbox)
 
         elif node.tag == inkex.addNS('use','svg') or node.tag=='use':
             refid=node.get(inkex.addNS('href','xlink'))