🎉 And so it begins

1 files changed, 100 insertions, 0 deletions

diff --git a/src/display.c b/src/display.c
new file mode 100644
index 0000000..b34cbf1
--- /dev/null
+++ b/src/display.c
@@ -0,0 +1,100 @@
+#define _DEFAULT_SOURCE
+#include "display.h"
+
+#include "buffer.h"
+
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#define ESC 0x1b
+
+struct display display_create() {
+
+  struct winsize ws;
+  if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0) {
+    // TODO: if it fails to fetch, do something?
+    return (struct display){
+        .height = 0,
+        .width = 0,
+    };
+  }
+
+  // save old settings
+  struct termios orig_term;
+  tcgetattr(0, &orig_term);
+
+  // set terminal to raw mode
+  struct termios term;
+  cfmakeraw(&term);
+  // non-blocking input
+  // TODO: move to kbd?
+  term.c_cc[VMIN] = 0;
+  term.c_cc[VTIME] = 0;
+
+  tcsetattr(0, TCSADRAIN, &term);
+
+  return (struct display){
+      .orig_term = orig_term,
+      .term = term,
+      .height = ws.ws_row,
+      .width = ws.ws_col,
+  };
+}
+
+void display_destroy(struct display *display) {
+  // reset old terminal mode
+  tcsetattr(0, TCSADRAIN, &display->orig_term);
+}
+
+void putbytes(uint8_t *line_bytes, uint32_t line_length) {
+  fwrite(line_bytes, 1, line_length, stdout);
+}
+
+void putbyte(uint8_t c) { putc(c, stdout); }
+
+void put_ansiparm(int n) {
+  int q = n / 10;
+  if (q != 0) {
+    int r = q / 10;
+    if (r != 0) {
+      putbyte((r % 10) + '0');
+    }
+    putbyte((q % 10) + '0');
+  }
+  putbyte((n % 10) + '0');
+}
+
+void display_move_cursor(struct display *display, uint32_t row, uint32_t col) {
+  putbyte(ESC);
+  putbyte('[');
+  put_ansiparm(row + 1);
+  putbyte(';');
+  put_ansiparm(col + 1);
+  putbyte('H');
+}
+
+void display_clear(struct display *display) {
+  display_move_cursor(display, 0, 0);
+  uint8_t bytes[] = {ESC, '[', 'J'};
+  putbytes(bytes, 3);
+}
+
+void delete_to_eol() {
+  uint8_t bytes[] = {ESC, '[', 'K'};
+  putbytes(bytes, 3);
+}
+
+void display_update(struct display *display, struct render_cmd *cmds,
+                    uint32_t ncmds, uint32_t currow, uint32_t curcol) {
+  for (uint64_t cmdi = 0; cmdi < ncmds; ++cmdi) {
+    struct render_cmd *cmd = &cmds[cmdi];
+    display_move_cursor(display, cmd->row, cmd->col);
+    putbytes(cmd->data, cmd->len);
+    delete_to_eol();
+  }
+
+  display_move_cursor(display, currow, curcol);
+
+  fflush(stdout);
+}