sob

commit 47706e9bc61a337498f43c7053048932ce617b75
parent 34be376a9445ac7283268a5cdd7c07dee65e576d
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Sun, 12 Oct 2014 22:05:12 +0000

optimize line_draw, reduces flicker in some terminals

Diffstat:
M
sob.c
 | 
32
++++++++++++++++++++++++++++----

1 file changed, 28 insertions(+), 4 deletions(-)
diff --git a/sob.c b/sob.c
@@ -29,6 +29,7 @@ struct line {
 	size_t utfpos;     /* pos in characters */
 	size_t colpos;     /* cursor position (in columns) */
 	size_t collen;     /* total length (in columns) */
+	size_t dirtylen;   /* dirty length (in columns) */
 };
 
 static void   cb_pipe_insert(const char *, size_t);
@@ -66,6 +67,7 @@ static int    pipe_readline(int, int, char *, void (*)(const char *, size_t));
 static int    pipe_cmd(char *[], char *, void (*)(const char *, size_t));
 
 static void   cleanup(void);
+static void   clear(void);
 static void   gettermsize(void);
 static void   handleinput(const unsigned char *, size_t);
 static void   resize(void);
@@ -245,11 +247,22 @@ line_prompt(void)
 static void
 line_draw(void)
 {
-	fprintf(outfp, "\x1b[2J\x1b[H"); /* clear */
-	fflush(outfp);
+	size_t i;
+
+	fprintf(outfp, "\x1b[H"); /* move cursor to (0, 0) */
+	fprintf(outfp, "\x1b[?25l"); /* hide cursor */
+
 	line_prompt();
 	fwrite(line.line, 1, line.bytesiz, outfp);
+
+	/* replace dirty chars with ' ' */
+	if(line.dirtylen > line.collen) {
+		for(i = line.collen; i < line.dirtylen; i++)
+			fputc(' ', outfp);
+	}
 	line_cursor_move(line.colpos);
+	fprintf(outfp, "\x1b[?25h"); /* show cursor */
+	fflush(outfp);
 }
 
 static void
@@ -394,7 +407,6 @@ line_delcharprev(void)
 	line.utfpos--;
 	line.colpos -= col;
 	line.collen -= col;
-
 	line_draw();
 }
 
@@ -691,6 +703,7 @@ sighandler(int signum)
 		isrunning = 0;
 		cleanup();
 	} else if(signum == SIGWINCH) {
+		clear();
 		gettermsize();
 		resize();
 		line_draw();
@@ -710,10 +723,12 @@ setup(void)
 
 	/* set the terminal attributes */
 	tcsetattr(STDIN_FILENO, TCSANOW, &ttystate);
-
 	/* get terminal window size */
 	gettermsize();
 
+	/* clear screen */
+	clear();
+
 	/* signal handling */
 	memset(&sa, 0, sizeof(sa));
 	sa.sa_flags = SA_RESTART;
@@ -754,6 +769,7 @@ handleinput(const unsigned char *input, size_t len)
 	int ismatch = 0;
 	char buf[BUFSIZ];
 
+	line.dirtylen = line.collen;
 	while(p < len && input[p] != '\0') {
 		if(input[p] <= 0x1b) {
 			ismatch = 0;
@@ -838,6 +854,14 @@ usage(void)
 	exit(EXIT_FAILURE);
 }
 
+static void
+clear(void)
+{
+	/* clear screen, move cursor to (0, 0) */
+	fprintf(outfp, "\x1b[2J\x1b[H");
+	fflush(outfp);
+}
+
 int
 main(int argc, char **argv)
 {