added normalize drawing scale extension

extensions/fablabchemnitz/normalize_drawing_scale/meta.json

@@ -0,0 +1,20 @@
+[
+  {
+    "name": "Normalize Drawing Scale",
+    "id": "fablabchemnitz.de.normalize_drawing_scale",
+    "path": "laser_check",
+    "dependent_extensions": null,
+    "original_name": "Normalize Drawing Scale",
+    "original_id": "fablabchemnitz.de.normalize_drawing_scale",
+    "license": "GNU GPL v3",
+    "license_url": "",
+    "comment": "",
+    "source_url": "https://gitea.fablabchemnitz.de/FabLab_Chemnitz/mightyscape-1.X/src/branch/master/extensions/fablabchemnitz/normalize_drawing_scale",
+    "fork_url": null,
+    "documentation_url": "https://stadtfabrikanten.org/display/IFM/Normale+Drawing+Scale",
+    "inkscape_gallery_url": null,
+    "main_authors": [
+      "github.com/vmario89"
+    ]
+  }
+]

extensions/fablabchemnitz/normalize_drawing_scale/normalize_drawing_scale.inx

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+<?xml version="1.0" encoding="UTF-8"?>
+<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
+    <name>Normalize Drawing Scale</name>
+    <id>fablabchemnitz.de.normalize_drawing_scale</id>
+    <param name="remove_viewbox" type="bool" gui-text="Remove viewBox and set document units to px" gui-description="Removes viewBox attribute from svg:svg. Warning: this disabled the feature to change the document units to anything else than px unit.">false</param>
+    <effect needs-live-preview="false">
+        <object-type>all</object-type>
+        <effects-menu>
+            <submenu name="FabLab Chemnitz">
+				<submenu name="Transformations"/>
+			</submenu>
+        </effects-menu>
+    </effect>
+    <script>
+        <command location="inx" interpreter="python">normalize_drawing_scale.py</command>
+    </script>
+</inkscape-extension>

extensions/fablabchemnitz/normalize_drawing_scale/normalize_drawing_scale.py

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+#!/usr/bin/env python3
+
+import inkex
+from inkex import Transform
+from lxml import etree
+
+class NormalizeDrawingScale(inkex.EffectExtension):
+    
+    def add_arguments(self, pars):
+        pars.add_argument('--remove_viewbox', type=inkex.Boolean, default=True)
+    
+    def effect(self):
+        namedView = self.document.getroot().find(inkex.addNS('namedview', 'sodipodi'))
+        doc_units = namedView.get(inkex.addNS('document-units', 'inkscape'))        
+        docScale = self.svg.scale
+        docWidth = self.svg.uutounit(self.svg.width, doc_units)
+        docHeight = self.svg.uutounit(self.svg.height, doc_units)
+        vxMin, vyMin, vxMax, vyMax = self.svg.get_viewbox()
+        vxTotal = vxMax - vxMin
+        vScaleX = self.svg.unittouu(str(vxTotal / self.svg.width) + doc_units)
+        if round(vScaleX, 5) != 1.0 or self.options.remove_viewbox is True:
+            
+            #set scale to 100% (we adjust viewBox)
+            if self.options.remove_viewbox is False:
+                self.svg.set('viewBox', '0 0 {} {}'.format(docWidth, docHeight))
+            else:
+                self.svg.pop('viewBox')
+                self.document.getroot().set('inkscape:document-units', 'px')
+                self.svg.set('width', docWidth)
+                self.svg.set('height', docHeight)
+
+                namedView.attrib[inkex.addNS('document-units', 'inkscape')] = 'px'
+            translation_matrix = [[1/vScaleX, 0.0, 0.0], [0.0, 1/vScaleX, 0.0]]
+
+            #select each top layer and apply the transformation to scale
+            processed = []
+            for element in self.document.getroot().iter(tag=etree.Element):
+                if element != self.document.getroot():
+                    if element.tag == inkex.addNS('g','svg'):
+                        parent = element.getparent()
+                        if parent.get('inkscape:groupmode') != 'layer' and element.get('inkscape:groupmode') == 'layer':
+                            element.transform = Transform(translation_matrix) * element.composed_transform()
+                            processed.append(element)
+
+            #do the same for all elements which lay on first level and which are not a layer
+            for element in self.document.getroot().getchildren():
+                if isinstance(element, inkex.ShapeElement) and element not in processed:
+                    element.transform = Transform(translation_matrix) * element.composed_transform()
+
+        else:
+            inkex.utils.debug("Nothing to do. Scale is already 100%")
+   
+                             
+if __name__ == '__main__':
+    NormalizeDrawingScale().run()