1 files changed, 44 insertions, 0 deletions
diff --git a/src/user/app/vterm/draw.c b/src/user/app/vterm/draw.c
new file mode 100644
index 0000000..44d3ffe
--- /dev/null
+++ b/src/user/app/vterm/draw.c
@@ -0,0 +1,44 @@
+#include "vterm.h"
+#include <camellia/syscalls.h>
+#include <string.h>
+
+struct framebuf fb;
+handle_t fb_fd;
+struct rect dirty;
+
+
+void dirty_mark(uint32_t x, uint32_t y) {
+	if (dirty.x1 > x) dirty.x1 = x;
+	if (dirty.x2 < x) dirty.x2 = x;
+	if (dirty.y1 > y) dirty.y1 = y;
+	if (dirty.y2 < y) dirty.y2 = y;
+}
+
+void flush(void) {
+	size_t low, high;
+	if (~dirty.x1 == 0) return;
+
+	// still not optimal, copies 80 characters instead of 1
+	low  = fb.pitch * ( dirty.y1    * font.h) + 4 * ( dirty.x1    * font.w);
+	high = fb.pitch * ((dirty.y2+1) * font.h) + 4 * ((dirty.x2+1) * font.w) + 3;
+
+	if (~dirty.y2 == 0) high = fb.len;
+	if (high > fb.len)  high = fb.len;
+
+	while (low < high)
+		low += _syscall_write(fb_fd, fb.b + low, high - low, low, 0);
+
+	dirty.x1 = ~0; dirty.y1 = ~0;
+	dirty.x2 =  0; dirty.y2 =  0;
+}
+
+void scroll(void) {
+	// TODO memmove. this is UD
+	size_t row_len = fb.pitch * font.h;
+	memcpy(fb.b, fb.b + row_len, fb.len - row_len);
+	memset(fb.b + fb.len - row_len, 0, row_len);
+	cursor.y--;
+
+	dirty.x1 =  0; dirty.y1 =  0;
+	dirty.x2 = ~0; dirty.y2 = ~0;
+}