common/graphic-helpers: adopt lookup_named_color from xpm parser

src/common/gen-color-table.pl

@@ -0,0 +1,80 @@
+#!/usr/bin/perl -w
+
+# Generates xcolor-table.h from X11's rgb.txt
+# Adapted from gdk-pixbuf (LGPL-2.0-or-later)
+
+if (@ARGV != 1) {
+    die "Usage: gen-color-table.pl rgb.txt > xcolor-table.h\n";
+}
+
+open IN, '<', $ARGV[0] or die "Cannot open $ARGV[0]: $!\n";
+
+@colors = ();
+while (<IN>) {
+    next if /^!/;
+    if (!/^\s*([0-9]+)\s+([0-9]+)\s+([0-9]+)\s+(.*\S)\s*$/) {
+	die "Cannot parse line $_";
+    }
+
+    push @colors, [$1, $2, $3, $4];
+}
+
+close IN or die "close IN failed: $!\n";
+
+@colors = sort { lc($a->[3]) cmp lc($b->[3]) } @colors;
+
+$offset = 0;
+
+$date = gmtime;
+
+print <<EOT;
+/* SPDX-License-Identifier: LGPL-2.0-or-later */
+/* xcolor-table.h: Generated by gen-color-table.pl from rgb.txt
+ *
+ *  Date: $date
+ *
+ * Do not edit.
+ */
+static const char color_names[] =
+EOT
+
+for $color (@colors) {
+    $name = $color->[3];
+
+    if ($offset != 0) {
+	print qq(\n);
+    }
+    print qq(	"$name\\0");
+
+    $color->[4] = $offset;
+    $offset += length($name) + 1;
+}
+
+print ";\n\n";
+
+print <<EOT;
+struct xcolor_entry {
+	uint16_t name_offset;
+	uint8_t red;
+	uint8_t green;
+	uint8_t blue;
+};
+
+static const struct xcolor_entry xcolors[] = {
+EOT
+
+$i = 0;
+for $color (@colors) {
+    $red = $color->[0];
+    $green = $color->[1];
+    $blue = $color->[2];
+    $offset = $color->[4];
+
+    if ($i != 0) {
+	print ",\n";
+    }
+    print "	{ $offset, $red, $green, $blue }";
+    $i++;
+}
+
+print "\n};\n";