Adding a more efficient drawing code.

Thanks Mihail Zenkov <mihail.zenkov@gmail.com> for giving the hint!

diff --git a/config.def.h b/config.def.h
index 684adf7..8732ca3 100644 (file)
--- a/config.def.h
+++ b/config.def.h
@@ -9,10 +9,13 @@ static char font[] = "Liberation Mono:pixelsize=12:antialias=false:autohint=fals
 static int borderpx = 2;
 static char shell[] = "/bin/sh";
 
-/* double-click timeout (in milliseconds) between clicks for selection */
+/* timeouts (in milliseconds) */
 static unsigned int doubleclicktimeout = 300;
 static unsigned int tripleclicktimeout = 600;
 
+/* frames per second st should at maximum draw to the screen */
+static unsigned int framespersecond = 60;
+
 /* TERM value */
 static char termname[] = "st-256color";
 

diff --git a/st.c b/st.c
index 8206001..f4b419e 100644 (file)
--- a/st.c
+++ b/st.c
@@ -3166,10 +3166,12 @@ void
 run(void) {
        XEvent ev;
        fd_set rfd;
-       int xfd = XConnectionNumber(xw.dpy), i;
-       struct timeval drawtimeout, *tv = NULL;
+       int xfd = XConnectionNumber(xw.dpy);
+       struct timeval drawtimeout, *tv = NULL, now, last;
 
-       for(i = 0;; i++) {
+       gettimeofday(&last, NULL);
+
+       for(;;) {
                FD_ZERO(&rfd);
                FD_SET(cmdfd, &rfd);
                FD_SET(xfd, &rfd);
@@ -3179,35 +3181,44 @@ run(void) {
                        die("select failed: %s\n", SERRNO);
                }
 
-               /*
-                * Stop after a certain number of reads so the user does not
-                * feel like the system is stuttering.
-                */
-               if(i < 1000 && FD_ISSET(cmdfd, &rfd)) {
-                       ttyread();
+               gettimeofday(&now, NULL);
+               /* usecs until (next) frame */
+               drawtimeout.tv_sec = 0;
+               drawtimeout.tv_usec = \
+                       ((1000/framespersecond) - TIMEDIFF(now, last)) * 1000;
 
-                       /*
-                        * Just wait a bit so it isn't disturbing the
-                        * user and the system is able to write something.
-                        */
-                       drawtimeout.tv_sec = 0;
-                       drawtimeout.tv_usec = 5;
-                       tv = &drawtimeout;
-                       continue;
+               /* Let us draw a frame. */
+               if(drawtimeout.tv_usec <= 0) {
+                       draw();
+                       XFlush(xw.dpy);
+
+                       last = now;
+                       tv = NULL;
                }
-               i = 0;
-               tv = NULL;
 
-               while(XPending(xw.dpy)) {
-                       XNextEvent(xw.dpy, &ev);
-                       if(XFilterEvent(&ev, None))
-                               continue;
-                       if(handler[ev.type])
-                               (handler[ev.type])(&ev);
+               if(FD_ISSET(cmdfd, &rfd))
+                       ttyread();
+
+               if(FD_ISSET(xfd, &rfd)) {
+                       while(XPending(xw.dpy)) {
+                               XNextEvent(xw.dpy, &ev);
+                               if(XFilterEvent(&ev, None))
+                                       continue;
+                               if(handler[ev.type])
+                                       (handler[ev.type])(&ev);
+                       }
+
+                       if(drawtimeout.tv_usec <= 0) {
+                               draw();
+                               XFlush(xw.dpy);
+                       }
                }
 
-               draw();
-               XFlush(xw.dpy);
+               /* There is still some time to wait until next frame. */
+               if(drawtimeout.tv_usec > 0) {
+                       tv = &drawtimeout;
+                       continue;
+               }
        }
 }