Add option to remove non-scaling-stroke from svg output

pyqtgraph/exporters/SVGExporter.py

@@ -23,7 +23,8 @@ class SVGExporter(Exporter):
             #{'name': 'height', 'type': 'float', 'value': tr.height(), 'limits': (0, None)},
             #{'name': 'viewbox clipping', 'type': 'bool', 'value': True},
             #{'name': 'normalize coordinates', 'type': 'bool', 'value': True},
-            #{'name': 'normalize line width', 'type': 'bool', 'value': True},
+            {'name': 'scaling stroke', 'type': 'bool', 'value': False, 'tip': "If False, strokes are non-scaling, "
+             "which means that they appear the same width on screen regardless of how they are scaled or how the view is zoomed."},
         ])
         #self.params.param('width').sigValueChanged.connect(self.widthChanged)
         #self.params.param('height').sigValueChanged.connect(self.heightChanged)
@@ -49,7 +50,8 @@ class SVGExporter(Exporter):
         ## Qt's SVG generator is not complete. (notably, it lacks clipping)
         ## Instead, we will use Qt to generate SVG for each item independently,
         ## then manually reconstruct the entire document.
-        xml = generateSvg(self.item)
+        options = {ch.name():ch.value() for ch in self.params.children()}
+        xml = generateSvg(self.item, options)
         
         if toBytes:
             return xml.encode('UTF-8')
@@ -69,10 +71,10 @@ xmlHeader = """\
 <desc>Generated with Qt and pyqtgraph</desc>
 """
 
-def generateSvg(item):
+def generateSvg(item, options={}):
     global xmlHeader
     try:
-        node, defs = _generateItemSvg(item)
+        node, defs = _generateItemSvg(item, options=options)
     finally:
         ## reset export mode for all items in the tree
         if isinstance(item, QtGui.QGraphicsScene):
@@ -94,7 +96,7 @@ def generateSvg(item):
     return xmlHeader + defsXml + node.toprettyxml(indent='    ') + "\n</svg>\n"
 
 
-def _generateItemSvg(item, nodes=None, root=None):
+def _generateItemSvg(item, nodes=None, root=None, options={}):
     ## This function is intended to work around some issues with Qt's SVG generator
     ## and SVG in general.
     ## 1) Qt SVG does not implement clipping paths. This is absurd.
@@ -209,18 +211,8 @@ def _generateItemSvg(item, nodes=None, root=None):
 
     ## Get rid of group transformation matrices by applying
     ## transformation to inner coordinates
-    correctCoordinates(g1, defs, item)
+    correctCoordinates(g1, defs, item, options)
     profiler('correct')
-    ## make sure g1 has the transformation matrix
-    #m = (tr.m11(), tr.m12(), tr.m21(), tr.m22(), tr.m31(), tr.m32())
-    #g1.setAttribute('transform', "matrix(%f,%f,%f,%f,%f,%f)" % m)
-    
-    #print "=================",item,"====================="
-    #print g1.toprettyxml(indent="  ", newl='')
-    
-    ## Inkscape does not support non-scaling-stroke (this is SVG 1.2, inkscape supports 1.1)
-    ## So we need to correct anything attempting to use this.
-    #correctStroke(g1, item, root)
     
     ## decide on a name for this item
     baseName = item.__class__.__name__
@@ -239,15 +231,10 @@ def _generateItemSvg(item, nodes=None, root=None):
         ## See if this item clips its children
         if int(item.flags() & item.ItemClipsChildrenToShape) > 0:
             ## Generate svg for just the path
-            #if isinstance(root, QtGui.QGraphicsScene):
-                #path = QtGui.QGraphicsPathItem(item.mapToScene(item.shape()))
-            #else:
-                #path = QtGui.QGraphicsPathItem(root.mapToParent(item.mapToItem(root, item.shape())))
             path = QtGui.QGraphicsPathItem(item.mapToScene(item.shape()))
             item.scene().addItem(path)
             try:
-                #pathNode = _generateItemSvg(path, root=root).getElementsByTagName('path')[0]
-                pathNode = _generateItemSvg(path, root=root)[0].getElementsByTagName('path')[0]
+                pathNode = _generateItemSvg(path, root=root, options=options)[0].getElementsByTagName('path')[0]
                 # assume <defs> for this path is empty.. possibly problematic.
             finally:
                 item.scene().removeItem(path)
@@ -267,17 +254,18 @@ def _generateItemSvg(item, nodes=None, root=None):
     ## Add all child items as sub-elements.
     childs.sort(key=lambda c: c.zValue())
     for ch in childs:
-        csvg = _generateItemSvg(ch, nodes, root)
+        csvg = _generateItemSvg(ch, nodes, root, options=options)
         if csvg is None:
             continue
         cg, cdefs = csvg
         childGroup.appendChild(cg)  ### this isn't quite right--some items draw below their parent (good enough for now)
         defs.extend(cdefs)
-        
+
     profiler('children')
     return g1, defs
 
-def correctCoordinates(node, defs, item):
+
+def correctCoordinates(node, defs, item, options):
     # TODO: correct gradient coordinates inside defs
     
     ## Remove transformation matrices from <g> tags by applying matrix to coordinates inside.
@@ -382,6 +370,10 @@ def correctCoordinates(node, defs, item):
                 w = ((s[0]-s[1])**2).sum()**0.5
                 ch.setAttribute('stroke-width', str(w))
             
+            # Remove non-scaling-stroke if requested
+            if options.get('scaling stroke') is True and ch.getAttribute('vector-effect') == 'non-scaling-stroke':
+                ch.removeAttribute('vector-effect')
+
         if removeTransform:
             grp.removeAttribute('transform')