Fix issue with some SVG symbols that could not be used in GNS3.

This was due to the height and width values being percentages.

gns3server/controller/node.py

@@ -239,6 +239,7 @@ class Node:
 
     @symbol.setter
     def symbol(self, val):
+
         if val is None:
             val = ":/symbols/computer.svg"
 
@@ -252,8 +253,9 @@ class Node:
         self._symbol = val
         try:
             self._width, self._height, filetype = self._project.controller.symbols.get_size(val)
-        # If symbol is invalid we replace it by default
-        except (ValueError, OSError):
+        except (ValueError, OSError) as e:
+            log.error("Could not write symbol: {}".format(e))
+            # If symbol is invalid we replace it by the default
             self.symbol = ":/symbols/computer.svg"
         if self._label is None:
             # Apply to label user style or default

gns3server/utils/picture.py

@@ -103,10 +103,16 @@ def get_size(data, default_width=0, default_height=0):
         root = tree.getroot()
 
         try:
-            width = _svg_convert_size(root.attrib.get("width", "0"))
-            height = _svg_convert_size(root.attrib.get("height", "0"))
-        except IndexError:
-            raise ValueError("Invalid SVG file")
+            width_attr = root.attrib.get("width", "0")
+            height_attr = root.attrib.get("height", "0")
+            if width_attr.endswith("%") or height_attr.endswith("%"):
+                # check to viewBox attribute if width or height value is a percentage
+                _, _, width_attr, height_attr = root.attrib.get("viewBox").split()
+            else:
+                width = _svg_convert_size(width_attr)
+                height = _svg_convert_size(height_attr)
+        except (AttributeError, IndexError) as e:
+            raise ValueError("Invalid SVG file: {}".format(e))
 
     return width, height, filetype