Start drawing UI in C

c/main.c

@@ -19,6 +19,11 @@
 #define MOVE_CURSOR_RIGHT       "\x1b[1C"
 #define MOVE_CURSOR_LEFT        "\x1b[1D"
 
+#define MOVE_CURSOR_UP_X          "\x1b[%dA"
+#define MOVE_CURSOR_DOWN_X        "\x1b[%dB"
+#define MOVE_CURSOR_RIGHT_X       "\x1b[%dC"
+#define MOVE_CURSOR_LEFT_X        "\x1b[%dD"
+
 // man console_codes
 
 // Directions
@@ -33,13 +38,13 @@ typedef struct {
 	int number_of_display_lines;
 	int number_of_display_columns;
 	bool resized;
+	bool update_display;
 	bool should_exit;
 	struct termios original_termios;
 } State;
 
 static State state = {0};
 
-
 void sigwinch_handler(int signal)
 {
 	fprintf(stderr, "INFO: received signal \"%s\"\n", strsignal(signal));
@@ -82,6 +87,18 @@ void enable_raw_mode(void)
     }
 }
 
+int draw_ui(void)
+{
+	get_terminal_size();
+
+	printf("%s%s", CLEAR_SCREEN, MOVE_CURSOR_HOME);
+
+	for (int i = 0; i < state.number_of_display_lines; i++) {
+		printf(" ~ \n");
+		printf(MOVE_CURSOR_LEFT_X, state.number_of_display_columns);
+	}
+}
+
 int main(void)
 {
 	// TODO: switch to sigaction
@@ -96,10 +113,18 @@ int main(void)
 	printf(MOVE_CURSOR_HOME);
 	fflush(stdout);
 
-	get_terminal_size(&state);
+	get_terminal_size();
+
+	state.update_display = true;
 
 	char c;
 	while (true) {
+		if (state.update_display) {
+			draw_ui();
+
+			state.update_display = false;
+		}
+
         ssize_t n = read(STDIN_FILENO, &c, 1);
         if (n == -1) continue;
 
@@ -108,14 +133,18 @@ int main(void)
 		switch (c) {
 		case 'h':
 			printf("%s%s", MOVE_CURSOR_LEFT, MOVE_CURSOR_LEFT);
+			state.update_display = true;
 			break;
 		case 'j':
 			printf("%s%s", MOVE_CURSOR_DOWN, MOVE_CURSOR_LEFT);
+			state.update_display = true;
 			break;
 		case 'k':
 			printf("%s%s", MOVE_CURSOR_UP, MOVE_CURSOR_LEFT);
+			state.update_display = true;
 			break;
 		case 'l':
+			state.update_display = true;
 			break;
 		}