Add rendering for graphics used externally (e.g., support chat avatar)

Variants of the logo inlcuding specific margins can be generated.
That is needed if the logo is used without the possibility to dynamically
adjust its margins.

.gitignore

@@ -7,3 +7,4 @@ CMakeLists.txt.*
 build*
 .kdev4/
 *.kdev4
+support-chat-avatar.png

render-graphics.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# SPDX-FileCopyrightText: 2023 Melvin Keskin <[email protected]>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+QXMPP_SOURCES=$(dirname "$(readlink -f "${0}")")
+
+echo "*****************************************"
+echo "Rendering graphics"
+echo "*****************************************"
+
+render_support_chat_avatar() {
+    render_svg_with_margin $QXMPP_SOURCES/logo.svg $QXMPP_SOURCES/support-chat-avatar.png 300 300 18
+}
+
+# $1 - $4: see render_svg()
+# $5: margin
+render_svg_with_margin() {
+    output_directory=$(dirname $2)
+    mkdir -p $output_directory
+    tmp_file=$output_directory/rendered_tmp.svg
+    inkscape -o $tmp_file --export-margin=$5 $1
+    render_svg $tmp_file $2 $3 $4
+    rm $tmp_file
+}
+
+# $1: input file
+# $2: output file
+# $3: width
+# $4: height
+render_svg() {
+    inkscape -o $2 -w $3 -h $4 $1 >/dev/null
+    optipng -quiet -o7 $2 >/dev/null
+    advpng -z4 $2 >/dev/null
+    echo "Created "$2
+}
+
+render_support_chat_avatar