[librsvg: 7/35] rsvg-convert.1: Give an example of a user stylesheet

[Marge Bot <marge-bot src gnome org>]

commit 3f55f5d1caea01b8b5ba3eb465d7375ee4f3aac9
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Jun 11 13:21:57 2021 -0500

    rsvg-convert.1: Give an example of a user stylesheet
    
    Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/547>

 rsvg-convert.1 | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
---
diff --git a/rsvg-convert.1 b/rsvg-convert.1
index 2eeb43bf..cb3717e4 100644
--- a/rsvg-convert.1
+++ b/rsvg-convert.1
@@ -245,6 +245,63 @@ https://www.rfc-editor.org/info/bcp47
 .RE
 .P
 
+.SS USER STYLESHEET
+
+You can include an extra CSS stylesheet to be used when rendering an SVG document.  The stylesheet
+will have the CSS user origin, while styles declared in the SVG document will have the CSS author
+origin.  This means your extra stylesheet's styles will override or augment the ones in the document, unless 
the document has
+.B !important
+in its styles.
+.P
+.RS
+.B rsvg-convert
+.BI --stylesheet= extra-styles.css
+.I input.svg
+.B >
+.I output.png
+.RE
+.P
+
+For example, if this is
+.IR input.svg :
+.P
+.in +4n
+.EX
+ <svg xmlns="http://www.w3.org/2000/svg"; width="100" height="100">
+   <rect width="200" height="100" fill="white"/>
+
+   <rect class="recolorable" x="10" y="10" width="50" height="50" fill="red"/>
+
+   <text x="10" y="80" font-size="20" fill="currentColor">Hello</text>
+ </svg>
+.EE
+.in
+.P
+And this is
+.IR extra-styles.css :
+.P
+.in +4n
+.EX
+ \.recolorable { fill: blue; }
+
+ * { color: green; }
+.EE
+.in
+.P
+Then the PNG created by the command above will have these elements:
+.IP \(bu 2
+A blue square instead of a red one, because of the selector for the the
+.B recolorable
+class.
+.IP \(bu 2
+Text in green, since a fill with
+.B currentColor
+gets substituted to the value of the
+.B color
+property, and the
+.B *
+selector applies to all elements.
+
 
 .SH OPTIONS
 .TP