sch2fig/: rename Cairo PNG driver from "cairo" to "png"

sch2fig/Makefile

@@ -45,13 +45,13 @@ testref:
 		./$(NAME) test.lib test.sch | fig2dev -L png -m 2 >ref.png
 
 png:
-		./$(NAME) test.lib test.sch -- cairo -o _out.png -s 2
+		./$(NAME) test.lib test.sch -- png -o _out.png -s 2
 		[ ! -r pngref.png ] || \
 		    compare -metric AE pngref.png _out.png _diff.png || \
 		    qiv -t -R -D _diff.png pngref.png _out.png
 
 pngref:
-		./$(NAME) test.lib test.sch -- cairo -o pngref.png -s 2
+		./$(NAME) test.lib test.sch -- png -o pngref.png -s 2
 
 clean::
 		rm -f out.fig _out.png _diff.png

sch2fig/cairo.c

@@ -292,7 +292,7 @@ static void cr_end(void *ctx)
 
 
 const struct gfx_ops cairo_ops = {
-	.name		= "cairo",
+	.name		= "png",
 	// .line	= cr_line,	@@@ later
 	.poly		= layer_poly,
 	.circ		= layer_circ,

sch2fig/main.c

@@ -45,8 +45,8 @@ void usage(const char *name)
 "usage: %s [-r] [file.lib ...] file.sch -- driver_spec\n\n"
 "  FIG driver spec:\n"
 "    fig [-t template.fig] [var=value ...]\n"
-"  Cairo driver spec:\n"
-"    cairo [-o output.png] [-s scale]\n"
+"  Cairo PNG driver spec:\n"
+"    png [-o output.png] [-s scale]\n"
     , name);
 	exit(1);
 }