1 files changed, 110 insertions, 0 deletions
diff --git a/share/extensions/rubberstretch.py b/share/extensions/rubberstretch.py
new file mode 100755
index 0000000..eb1baf9
--- /dev/null
+++ b/share/extensions/rubberstretch.py
@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+# coding=utf-8
+#
+# Copyright (C) 2006 Jean-Francois Barraud, barraud@math.univ-lille1.fr
+#
+# 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
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+"""
+Distorts selected paths, stretching it vertically while squeezing horizontally.
+
+Amount is controlled by ratio parameter.
+
+Curve gives further effect by bunching the surface towards the ends.
+"""
+
+from inkex.utils import X, Y
+from pathmodifier import Diffeo
+import inkex
+
+
+class RubberStretch(Diffeo):
+    """Distort selected paths"""
+
+    ratio = property(lambda self: -(self.options.ratio / 100))
+    curve = property(lambda self: min(self.options.curve / 100, 0.99))
+
+    def add_arguments(self, pars):
+        pars.add_argument("-r", "--ratio", type=float, default=25)
+        pars.add_argument("-c", "--curve", type=float, default=25)
+
+    def applyDiffeo(self, bpt, vects=()):
+        for vect in vects:
+            vect[0] -= bpt[0]
+            vect[1] -= bpt[1]
+            vect[1] *= -1
+        bpt[1] *= -1
+        bx0 = self.bbox.center.x
+        by0 = -self.bbox.center.y
+
+        x, y = (bpt[0] - bx0), (bpt[1] - by0)
+        sx1 = (
+            1
+            + self.curve
+            * (x / (self.bbox.width / 2) + 1)
+            * (x / (self.bbox.width / 2) - 1)
+        ) * 2**self.ratio
+        sy1 = (
+            1
+            + self.curve
+            * (y / (self.bbox.height / 2) + 1)
+            * (y / (self.bbox.height / 2) - 1)
+        ) * 2**self.ratio
+        bpt[0] = bx0 + x * sy1
+        bpt[1] = by0 + y / sx1
+        for vect in vects:
+            dx_dx = sy1
+            dx_dy = (
+                x
+                * 2
+                * self.curve
+                * y
+                / self.bbox.height
+                / self.bbox.height
+                * 2**self.ratio
+            )
+            dy_dx = (
+                -y
+                * 2
+                * self.curve
+                * x
+                / self.bbox.width
+                / self.bbox.width
+                * 2**self.ratio
+                / sx1
+                / sx1
+            )
+            dy_dy = 1 / sx1
+            vect[0] = dx_dx * vect[X] + dx_dy * vect[Y]
+            vect[1] = dy_dx * vect[X] + dy_dy * vect[Y]
+
+        # --spherify
+        # s=((x*x+y*y)/(w*w+h*h))**(-a/2)
+        # bpt[0]=x0+s*x
+        # bpt[1]=y0+s*y
+        # for v in vects:
+        #    dx,dy=v
+        #    v[0]=(1-a/2/(x*x+y*y)*2*x*x)*s*dx+( -a/2/(x*x+y*y)*2*y*x)*s*dy
+        #    v[1]=( -a/2/(x*x+y*y)*2*x*y)*s*dx+(1-a/2/(x*x+y*y)*2*y*y)*s*dy
+
+        for vect in vects:
+            vect[0] += bpt[0]
+            vect[1] += bpt[1]
+            vect[1] *= -1
+        bpt[1] *= -1
+
+
+if __name__ == "__main__":
+    RubberStretch().run()