Merge lp:~who+dev/inkscape/inkscape-p23 into lp:~inkscape.dev/inkscape/trunk

[Windell Oskay]

Update certain extensions for compatibility with Python 3.

Summary: Change to several of the core python extension files for compatibility with Python 3. These modifications allow them to continue working in python 2.x, without adding dependencies.

Submitted for code review and possible merging.

The changed files are:
inkex.py
bezmisc.py
cspsubdiv.py
simplepath.py
simplestyle.py
simpletransform.py

In addition to these, I would note that ffgeom.py and cubicsuperpath.py work in both Python 2 and 3 without changes. I have not tested other extension files for compatibility.

These changes appear to be non-breaking within Inkscape, as tested via invoking extensions that depend upon these, including flatten, Voronoi pattern (generate from path), and alphabetsoup. I have tested back to Python 2.6 under Inkscape 0.91, and up to Python 3.6 on the command line. While this is neither a formal test procedure nor exhaustive, I have not observed issues or errors due to these changes. If there are formal tests that could identify other issues, I would certainly welcome learning about them.

One coding note that I have is that the function definitions in bezmisc.py required "manually" unpacking the named tuples on their inputs, which adds one line of code to each function. (It could be approached in other ways, but many of those would break extensions that rely upon this.) Someone more expert at python may know of a more elegant approach. I would welcome such suggestions.

I would assert that making the extension environment compatible with Python 3 is a worthwhile goal, even if we are quite some ways away from making Python 3 compatibility an option or requirement. A good near-term goal is that we encourage extension developers to write code that is compatible with both Python 2 and Python 3. The changes in this branch correct several issues that prevent existing extensions (those that call these "core" files) from running under Python 3.

This set of changes in this branch also potentially allows certain Inkscape extensions to be run from the command line without opening the Inkscape GUI (not otherwise possible for verbs) on systems running either Python 2 or 3 as default.

Unmerged revisions

15598. By Windell Oskay on 2017-03-15

changes for compatibility with python 3

=== modified file 'share/extensions/bezmisc.py'
--- share/extensions/bezmisc.py	2016-03-16 09:58:21 +0000
+++ share/extensions/bezmisc.py	2017-03-15 02:08:29 +0000
@@ -18,6 +18,7 @@
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 '''
 
+from __future__ import print_function
 import math, cmath
 
 def rootWrapper(a,b,c,d):
@@ -55,8 +56,9 @@
         return 1.0*(-d/c),
     return ()
 
-def bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))):
+def bezierparameterize(input):
     #parametric bezier
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=input
     x0=bx0
     y0=by0
     cx=3*(bx1-x0)
@@ -69,8 +71,9 @@
     return ax,ay,bx,by,cx,cy,x0,y0
     #ax,ay,bx,by,cx,cy,x0,y0=bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)))
 
-def linebezierintersect(((lx1,ly1),(lx2,ly2)),((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))):
+def linebezierintersect(input):
     #parametric line
+    ((lx1,ly1),(lx2,ly2)),((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=input
     dd=lx1
     cc=lx2-lx1
     bb=ly1
@@ -99,19 +102,23 @@
             retval.append(bezierpointatt(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)),i))
     return retval
 
-def bezierpointatt(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)),t):
+def bezierpointatt(param1,t):
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=param1
     ax,ay,bx,by,cx,cy,x0,y0=bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)))
     x=ax*(t**3)+bx*(t**2)+cx*t+x0
     y=ay*(t**3)+by*(t**2)+cy*t+y0
     return x,y
 
-def bezierslopeatt(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)),t):
+def bezierslopeatt(param1,t):
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=param1
     ax,ay,bx,by,cx,cy,x0,y0=bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)))
     dx=3*ax*(t**2)+2*bx*t+cx
     dy=3*ay*(t**2)+2*by*t+cy
     return dx,dy
 
-def beziertatslope(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)),(dy,dx)):
+def beziertatslope(param1,param2):
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=param1
+    (dy,dx)=param2
     ax,ay,bx,by,cx,cy,x0,y0=bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)))
     #quadratic coefficents of slope formula
     if dx:
@@ -136,9 +143,12 @@
             retval.append(i)
     return retval
 
-def tpoint((x1,y1),(x2,y2),t):
+def tpoint(param1,param2,t):
+    (x1,y1)=param1
+    (x2,y2)=param2
     return x1+t*(x2-x1),y1+t*(y2-y1)
-def beziersplitatt(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)),t):
+def beziersplitatt(param1,t):
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=param1
     m1=tpoint((bx0,by0),(bx1,by1),t)
     m2=tpoint((bx1,by1),(bx2,by2),t)
     m3=tpoint((bx2,by2),(bx3,by3),t)
@@ -167,7 +177,9 @@
 mat-report no. 1992-10, Mathematical Institute, The Technical
 University of Denmark. 
 '''
-def pointdistance((x1,y1),(x2,y2)):
+def pointdistance(point1,point2):
+    (x1,y1)=point1
+    (x2,y2)=point2
     return math.sqrt(((x2 - x1) ** 2) + ((y2 - y1) ** 2))
 def Gravesen_addifclose(b, len, error = 0.001):
     box = 0
@@ -214,13 +226,15 @@
     #print multiplier, endsum, interval, asum, bsum, est1, est0
     return est1
 
-def bezierlengthSimpson(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)), tolerance = 0.001):
+def bezierlengthSimpson(param1, tolerance = 0.001):
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=param1
     global balfax,balfbx,balfcx,balfay,balfby,balfcy
     ax,ay,bx,by,cx,cy,x0,y0=bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)))
     balfax,balfbx,balfcx,balfay,balfby,balfcy = 3*ax,2*bx,cx,3*ay,2*by,cy
     return Simpson(balf, 0.0, 1.0, 4096, tolerance)
 
-def beziertatlength(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)), l = 0.5, tolerance = 0.001):
+def beziertatlength(param1, l = 0.5, tolerance = 0.001):
+    ((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3))=param1
     global balfax,balfbx,balfcx,balfay,balfby,balfcy
     ax,ay,bx,by,cx,cy,x0,y0=bezierparameterize(((bx0,by0),(bx1,by1),(bx2,by2),(bx3,by3)))
     balfax,balfbx,balfcx,balfay,balfby,balfcy = 3*ax,2*bx,cx,3*ay,2*by,cy
@@ -268,7 +282,7 @@
         print s, st
     '''
     for curve in curves:
-        print beziertatlength(curve,0.5)
+        print(beziertatlength(curve,0.5))
 
 
 # vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 fileencoding=utf-8 textwidth=99
 
=== modified file 'share/extensions/cspsubdiv.py'
--- share/extensions/cspsubdiv.py	2011-11-21 20:58:06 +0000
+++ share/extensions/cspsubdiv.py	2017-03-15 02:08:29 +0000
@@ -2,7 +2,8 @@
 from bezmisc import *
 from ffgeom import *
 
-def maxdist(((p0x,p0y),(p1x,p1y),(p2x,p2y),(p3x,p3y))):
+def maxdist(input):
+    ((p0x,p0y),(p1x,p1y),(p2x,p2y),(p3x,p3y))=input
     p0 = Point(p0x,p0y)
     p1 = Point(p1x,p1y)
     p2 = Point(p2x,p2y)
 
=== modified file 'share/extensions/inkex.py'
--- share/extensions/inkex.py	2016-05-26 09:28:23 +0000
+++ share/extensions/inkex.py	2017-03-15 02:08:29 +0000
@@ -98,11 +98,13 @@
          ...
          inkex.errormsg(_("This extension requires two selected paths."))
     """
-    if isinstance(msg, unicode):
-        sys.stderr.write(msg.encode("utf-8") + "\n")
+    if sys.version_info.major == 2:
+        if isinstance(msg, unicode):
+            sys.stderr.write(msg.encode("utf-8") + "\n")
+        else:
+            sys.stderr.write((unicode(msg, "utf-8", errors='replace') + "\n").encode("utf-8"))
     else:
-        sys.stderr.write((unicode(msg, "utf-8", errors='replace') + "\n").encode("utf-8"))
-
+        sys.stderr.write(msg + "\n")
 
 def are_near_relative(a, b, eps):
     return (a-b <= a*eps) and (a-b >= -a*eps)
 
=== modified file 'share/extensions/simplepath.py' (properties changed: -x to +x)
--- share/extensions/simplepath.py	2016-03-16 09:58:21 +0000
+++ share/extensions/simplepath.py	2017-03-15 02:08:29 +0000
@@ -48,7 +48,7 @@
             offset = m.end()
             continue
         #TODO: create new exception
-        raise Exception, 'Invalid path data!'
+        raise Exception('Invalid path data!')
 '''
 pathdefs = {commandfamily:
     [
@@ -86,14 +86,14 @@
     
     while 1:
         try:
-            token, isCommand = lexer.next()
+            token, isCommand = next(lexer)
         except StopIteration:
             break
         params = []
         needParam = True
         if isCommand:
             if not lastCommand and token.upper() != 'M':
-                raise Exception, 'Invalid path, must begin with moveto.'    
+                raise Exception('Invalid path, must begin with moveto.')
             else:                
                 command = token
         else:
@@ -106,16 +106,16 @@
                 else:
                     command = pathdefs[lastCommand.upper()][0].lower()
             else:
-                raise Exception, 'Invalid path, no initial command.'    
+                raise Exception('Invalid path, no initial command.')
         numParams = pathdefs[command.upper()][1]
         while numParams > 0:
             if needParam:
                 try: 
-                    token, isCommand = lexer.next()
+                    token, isCommand = next(lexer)
                     if isCommand:
-                        raise Exception, 'Invalid number of parameters'
+                        raise Exception('Invalid number of parameters')
                 except StopIteration:
-                    raise Exception, 'Unexpected end of path'
+                    raise Exception('Unexpected end of path')
             cast = pathdefs[command.upper()][2][-numParams]
             param = cast(token)
             if command.islower():
 
=== modified file 'share/extensions/simplestyle.py' (properties changed: -x to +x)
--- share/extensions/simplestyle.py	2016-03-16 09:58:21 +0000
+++ share/extensions/simplestyle.py	2017-03-15 02:08:29 +0000
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """
 simplestyle.py
 Two simple functions for working with inline css
@@ -17,7 +18,7 @@
 
 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.
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 """
 
 svgcolors={
 
=== modified file 'share/extensions/simpletransform.py' (properties changed: -x to +x)
--- share/extensions/simpletransform.py	2016-03-16 09:58:21 +0000
+++ share/extensions/simpletransform.py	2017-03-15 02:08:29 +0000
@@ -131,7 +131,7 @@
 def fuseTransform(node):
     if node.get('d')==None:
         #FIXME: how do you raise errors?
-        raise AssertionError, 'can not fuse "transform" of elements that have no "d" attribute'
+        raise AssertionError('can not fuse "transform" of elements that have no "d" attribute')
     t = node.get("transform")
     if t == None:
         return