ableos/sysdata/programs/render_example/src/examples/text.hb

.{memory, log, string} := @use("../../../../libraries/stn/src/lib.hb")
render := @use("../../../../libraries/render/src/lib.hb")

/* expected result: almost-not-trash notepad app
   very jank
   -----------------
   features:
   - basic keys
   - holding support with DAS
   - visible cursor
   - shift key support
*/

psf := @embed("../../../../consolefonts/tamsyn/10x20r.psf")

is_shift_pressed := false
is_ctrl_pressed := false
$initial_delay := 50
$repeat_delay := 7

example := fn(): void {
	screen := render.init(true)
	window := render.new_surface(480, 340)
	font := render.text.font_from_psf2(@bitcast(&psf), false)

	if font == null {
		return
	}

	msg := "sticky note:\n\0"
	msg_len := string.length(msg)

	buf := memory.alloc(u8, 4096)

	bottom := buf + msg_len

	@inline(memory.copy, u8, msg, buf, msg_len)
	cursor := buf + msg_len;

	*cursor = 95
	draw_window(window, font, buf)
	draw_screen(screen, window);
	*cursor = 32

	memory.outb(96, 238)
	memory.outb(96, 238)
	memory.outb(96, 244)

	prev_input := @as(u8, 0xFF)
	current_key := @as(u8, 0)
	holding_timer := 0

	loop {
		input := memory.inb(96)
		if input != prev_input {
			if (input & 0x80) != 0 {
				if (input & 0x7F) == current_key {
					current_key = 0
					holding_timer = 0
				} else if input == 0xAA | input == 0xB6 {
					is_shift_pressed = false
				} else if input == 0x9D {
					is_ctrl_pressed = false
				}
			} else {
				if input == 0x2A | input == 0x36 {
					is_shift_pressed = true
				} else if input == 0x1D {
					is_ctrl_pressed = true
				} else {
					current_key = input
					holding_timer = 1
					cursor = handle_char(map_keys(current_key), cursor, bottom)
				}
			}
			prev_input = input
		}

		if current_key != 0 & holding_timer > 0 {
			holding_timer += 1

			if holding_timer >= initial_delay {
				cursor = handle_char(map_keys(current_key), cursor, bottom)
				holding_timer = initial_delay - repeat_delay
			}
		};
		*cursor = 95
		draw_window(window, font, buf)
		draw_screen(screen, window);
		*cursor = 32

		if holding_timer > 0 & current_key != 0 {
			if (memory.inb(96) & 0x80) != 0 {
				current_key = 0
				holding_timer = 0
			}
		}
	}

	return
}

handle_char := fn(char: u8, cursor: ^u8, bottom: ^u8): ^u8 {
	if char == 0 {
		return cursor
	}
	if is_ctrl_pressed & char == 48 {
		cursor = bottom
	} else if char != 0x8 {
		*cursor = char
		return cursor + 1
	} else if char == 0xA {
		*cursor = 32
		cursor += 1;
		*cursor = 92
		return cursor + 1
	} else if cursor > bottom {
		cursor -= 1;
		*cursor = 32
		return cursor
	}
	return cursor
}

map_keys := fn(scancode: u8): u8 {
	if is_shift_pressed {
		return ps2_table[scancode + 0x40]
	}
	return ps2_table[scancode]
}

ps2_table := [u8].(0x0, 0x1B, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x30, 0x2D, 0x3D, 0x8, 0x9, 0x71, 0x77, 0x65, 0x72, 0x74, 0x79, 0x75, 0x69, 0x6F, 0x70, 0x5B, 0x5D, 0xA, 0x0, 0x61, 0x73, 0x64, 0x66, 0x67, 0x68, 0x6A, 0x6B, 0x6C, 0x3B, 0x27, 0x60, 0x0, 0x5C, 0x7A, 0x78, 0x63, 0x76, 0x62, 0x6E, 0x6D, 0x2C, 0x2E, 0x2F, 0x0, 0x2A, 0x0, 0x20, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1B, 0x21, 0x40, 0x23, 0x24, 0x25, 0x5E, 0x26, 0x2A, 0x28, 0x29, 0x5F, 0x2B, 0x8, 0x9, 0x51, 0x57, 0x45, 0x52, 0x54, 0x59, 0x55, 0x49, 0x4F, 0x50, 0x7B, 0x7D, 0xA, 0x0, 0x41, 0x53, 0x44, 0x46, 0x47, 0x48, 0x4A, 0x4B, 0x4C, 0x3A, 0x22, 0x7E, 0x0, 0x7C, 0x5A, 0x58, 0x43, 0x56, 0x42, 0x4E, 0x4D, 0x3C, 0x3E, 0x3F, 0x0, 0x0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
$padding := 7

draw_window := fn(window: render.Surface, font: render.text.Font, buf: ^u8): void {
	render.clear(window, render.light_yellow)
	line := font.height + font.line_gap + padding - 1
	render.put_rect(window, .(0, 0), .(window.width - 1, window.height - 1), render.black)
	loop if line >= window.height break else {
		render.put_hline(window, line, padding, window.width - padding, render.yellow)
		line += font.height + font.line_gap
	}

	render.put_text(window, font, .(padding, padding), render.black, buf)
}

draw_screen := fn(screen: render.Surface, window: render.Surface): void {
	render.clear(screen, render.light_blue)
	render.put_surface(screen, window, .(100, 100), false)
	render.sync(screen)
}