From f3e6838b44a5b37ce7664db5b8662e3d02e5f539 Mon Sep 17 00:00:00 2001
From: Freya Murphy <freya@freyacat.org>
Date: Thu, 17 Apr 2025 00:51:46 -0400
Subject: font rending in framebuffer yay!!

---
 kernel/term.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 169 insertions(+)
 create mode 100644 kernel/term.c

(limited to 'kernel/term.c')

diff --git a/kernel/term.c b/kernel/term.c
new file mode 100644
index 0000000..e40e0fe
--- /dev/null
+++ b/kernel/term.c
@@ -0,0 +1,169 @@
+#include "lib/kio.h"
+#include <lib.h>
+#include <comus/term.h>
+#include <comus/asm.h>
+#include <comus/limits.h>
+#include <comus/memory.h>
+#include <comus/drivers/vga.h>
+#include <comus/drivers/uart.h>
+
+// draw function
+static void (*draw_char)(char c, uint16_t x, uint16_t y) = vga_draw_char;
+
+// terminal data
+static char buffer[TERM_MAX_WIDTH * TERM_MAX_HEIGHT];
+static uint16_t buffer_line = UINT16_MAX;
+static uint16_t width = VGA_WIDTH;
+static uint16_t height = VGA_HEIGHT;
+static uint16_t x = 0;
+static uint16_t y = 0;
+
+#define BUFY(y) ((buffer_line + (y)) % TERM_MAX_HEIGHT)
+#define BUFIDX(x,y) ((x) + (BUFY(y) * TERM_MAX_WIDTH))
+
+static void buffer_check(void)
+{
+	if (buffer_line == UINT16_MAX) {
+		buffer_line = 0;
+		memset(buffer, 0, sizeof(buffer));
+	}
+}
+
+static inline bool printable(char c)
+{
+	switch (c) {
+	case '\0':
+	case '\n':
+	case '\t':
+	case '\v':
+	case '\f':
+	case '\r':
+		return false;
+	default:
+		return true;
+	}
+}
+
+static inline void term_move_cur(char c)
+{
+	if (c == '\0')
+		return;
+
+	switch (c) {
+	case '\n':
+		x = 0;
+		y++;
+		break;
+	case '\t':
+		x += 4;
+		break;
+	case '\v':
+	case '\f':
+		y++;
+		break;
+	case '\r':
+		x = 0;
+		break;
+	default:
+		x++;
+	}
+
+	if (x >= width) {
+		x = 0;
+		y++;
+	}
+	if (y >= height) {
+		term_scroll(y - (height - 1));
+		y = height - 1;
+	}
+}
+
+uint16_t term_width(void)
+{
+	return width;
+}
+
+uint16_t term_height(void)
+{
+	return height;
+}
+
+void term_out(char c)
+{
+	term_out_at(c, x, y);
+	term_move_cur(c);
+}
+
+void term_out_at(char c, uint16_t x, uint16_t y)
+{
+	buffer_check();
+
+	if (!printable(c))
+		return;
+
+	buffer[BUFIDX(x, y)] = c;
+	draw_char(c, x, y);
+}
+
+void term_out_str(const char *str)
+{
+	char c;
+	while (c = *(str++), c) {
+		term_out_at(c, x, y);
+		term_move_cur(c);
+	}
+}
+
+void term_out_str_at(const char *str, uint16_t x, uint16_t y)
+{
+	char c;
+	while (c = *(str++), c)
+		term_out_at(c, x, y);
+}
+
+void term_clear(void)
+{
+	for (uint16_t y = 0; y < height; y++)
+		term_clear_line(y);
+}
+
+void term_clear_line(uint16_t line)
+{
+	buffer_check();
+
+	if (line > height)
+		return;
+
+	for (uint16_t x = 0; x < width; x++) {
+		buffer[BUFIDX(x, line)] = 0;
+		draw_char(0, x, line);
+	}
+}
+
+void term_redraw(void)
+{
+	buffer_check();
+
+	for (uint16_t j = 0; j < height; j++) {
+		for (uint16_t i = 0; i < width; i++) {
+			char c = buffer[BUFIDX(i, j)];
+			draw_char(c, i, j);
+		}
+	}
+}
+
+void term_scroll(uint16_t lines)
+{
+	if (!lines)
+		return;
+	buffer_line += lines;
+	term_redraw();
+}
+
+void term_switch_handler(uint16_t w, uint16_t h, void (*fn)(char c, uint16_t x, uint16_t y))
+{
+	draw_char = fn;
+	width = w % TERM_MAX_WIDTH;
+	height = h % TERM_MAX_HEIGHT;
+	term_redraw();
+}
-- 
cgit v1.2.3-freya