svg-flatten: Make view box log output more readable

svg-flatten/src/svg_doc.cpp

@@ -54,7 +54,7 @@ bool gerbolyze::SVGDocument::load(istream &in) {
     /* Set up the document's viewport transform */
     istringstream vb_stream(root_elem.attribute("viewBox").value());
     vb_stream >> vb_x >> vb_y >> vb_w >> vb_h;
-    cerr << "loaded viewbox: " << vb_x << ", " << vb_y << ", " << vb_w << ", " << vb_h << endl;
+    cerr << "SVG document viewbox: origin=" << vb_x << "," << vb_y << ", size=" << vb_w << "," << vb_h << endl;
 
     page_w = usvg_double_attr(root_elem, "width");
     page_h = usvg_double_attr(root_elem, "height");