contrib/inkscape_tools: better error message on invalid input files

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/contrib/inkscape_tools/src/svg_to_png_and_nit.nit b/contrib/inkscape_tools/src/svg_to_png_and_nit.nit
index f9e690b..abd0912 100644 (file)
--- a/contrib/inkscape_tools/src/svg_to_png_and_nit.nit
+++ b/contrib/inkscape_tools/src/svg_to_png_and_nit.nit
@@ -329,8 +329,10 @@ for drawing in drawings do
        end
        svg_file.close
 
-       assert page_width != -1
-       assert page_height != -1
+       if page_width == -1 or page_height == -1 then
+               stderr.write "Source drawing file '{drawing}' doesn't look like an SVG file\n"
+               exit 1
+       end
 
        # Query Inkscape
        var prog = "inkscape"