Check terminal size.

Sprite 1.7

Author: ibara

README.md

@@ -6,7 +6,8 @@ You can use it to create and share pixel art.
 By default, sprite sets up a 16x16 pixel canvas.
 If you'd like the larger 32x32 pixel canvas,
 start sprite with the -e flag.
-It is the responsibility of the user to ensure the terminal is properly sized.
+If your terminal is not large enough to fit the 32x32 canvas,
+it will use the 16x16 canvas instead.
 
 Requirements
 ------------

sprite.1

@@ -33,15 +33,13 @@ You can use it to create and share pixel art.
 The options are as follows:
 .Bl -tag -width Ds
 .It Fl e
-Use an extended canvas of 32x32 pixels instead of the default 16x16 pixels.
+Use an extended canvas of 32x32 pixels instead of the default 16x16 pixels,
+if the terminal is large enough to support the larger canvas.
 .El
 .Sh AUTHORS
 .Nm
 was written by
 .An Brian Callahan Aq Mt bcallah@openbsd.org .
 .Sh CAVEATS
-It is the responsibility of the user to ensure the terminal is properly
-sized.
-.Pp
 Console aspect ratio may not match user expectations.
 PNG export creates standard square pixels.

sprite.c

@@ -169,7 +169,7 @@ color_panel(void)
 static void
 scrinit(void)
 {
-	int i;
+	int i, x, y;
 
 	if (has_colors() == FALSE) {
 		endwin();
@@ -179,6 +179,14 @@ scrinit(void)
 	start_color();
 	init_colors();
 
+	getmaxyx(stdscr, y, x);
+	if (y < 39 || x < 90)
+		extended = 0;
+	if (y < 23 || x < 74) {
+		endwin();
+		errx(1, "terminal too small!");
+	}
+
 	move(3, 31);
 
 	addch(ACS_ULCORNER);
@@ -392,7 +400,7 @@ file_save(int y, int x)
 	noecho();
 
 	if ((fp = fopen(buf, "w+")) == NULL) {
-		move(21, 31);
+		move(21 + (extended ? 16 : 0), 31);
 		printw("Error: could not open %s for writing", buf);
 		goto out;
 	}