window: add hideCursor and showCursor

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

src/Screen.zig

@@ -12,6 +12,10 @@ height: usize = 0,
 
 buf: []Cell = undefined,
 
+cursor_row: usize = 0,
+cursor_col: usize = 0,
+cursor_vis: bool = false,
+
 /// sets each cell to the default cell
 pub fn init(self: *Screen) void {
     for (self.buf, 0..) |_, i| {

src/Window.zig

@@ -63,7 +63,7 @@ pub fn initChild(
 /// writes a cell to the location in the window
 pub fn writeCell(self: Window, col: usize, row: usize, cell: Cell) void {
     if (self.height == 0 or self.width == 0) return;
-    if (self.height < row or self.width < col) return;
+    if (self.height <= row or self.width <= col) return;
     self.screen.writeCell(col + self.x_off, row + self.y_off, cell);
 }
 
@@ -83,6 +83,20 @@ pub fn fill(self: Window, cell: Cell) void {
     }
 }
 
+/// hide the cursor
+pub fn hideCursor(self: Window) void {
+    self.screen.cursor_vis = false;
+}
+
+/// show the cursor at the given coordinates, 0 indexed
+pub fn showCursor(self: Window, col: usize, row: usize) void {
+    if (self.height == 0 or self.width == 0) return;
+    if (self.height <= row or self.width <= col) return;
+    self.screen.cursor_vis = true;
+    self.screen.cursor_row = row + self.y_off;
+    self.screen.cursor_col = col + self.x_off;
+}
+
 test "Window size set" {
     var parent = Window{
         .x_off = 0,

src/vaxis.zig

@@ -370,6 +370,17 @@ pub fn Vaxis(comptime T: type) type {
                 }
                 _ = try tty.write(cell.char.grapheme);
             }
+            if (self.screen.cursor_vis) {
+                try std.fmt.format(
+                    tty.buffered_writer.writer(),
+                    ctlseqs.cup,
+                    .{
+                        self.screen.cursor_row + 1,
+                        self.screen.cursor_col + 1,
+                    },
+                );
+                _ = try tty.write(ctlseqs.show_cursor);
+            }
         }
     };
 }