URI: 
       copy dirty lines to screen, add select() timeout & min time between draw() calls. - st - simple terminal
  HTML git clone https://git.parazyd.org/st
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   DIR LICENSE
       ---
   DIR commit 896310e5928b6daab5f594acd9648ffe8233022e
   DIR parent 13a8eeb810ccfdaefd58c52328dd0ec867e3ae8d
  HTML Author: Aurélien Aptel <aurelien.aptel@gmail.com>
       Date:   Sat, 21 Jan 2012 23:14:41 +0100
       
       copy dirty lines to screen, add select() timeout & min time between draw() calls.
       
       
       * add a timeout value (SELECT_TIMEOUT) of 20ms in the select() call
       * wait at least 20ms (DRAW_TIMEOUT) between draw() calls
       * only copy dirty lines from the buffer to the screen
       
       what draw() does:
       * clears dirty lines in the buffer
       * draws the longest same-attributes string of each
         dirty line to the buffer with multiple xdraws() call
       * copies the current dirty line from buffer to the screen with a single
         xcopy() call
       
       this changeset makes st run ~10x faster.
       Diffstat:
         M st.c                                |      53 +++++++++++++++++++++++++------
       
       1 file changed, 44 insertions(+), 9 deletions(-)
       ---
   DIR diff --git a/st.c b/st.c
       @@ -13,8 +13,10 @@
        #include <sys/ioctl.h>
        #include <sys/select.h>
        #include <sys/stat.h>
       +#include <sys/time.h>
        #include <sys/types.h>
        #include <sys/wait.h>
       +#include <time.h>
        #include <unistd.h>
        #include <X11/Xatom.h>
        #include <X11/Xlib.h>
       @@ -22,9 +24,6 @@
        #include <X11/cursorfont.h>
        #include <X11/keysym.h>
        
       -#include <sys/time.h>
       -#include <time.h>
       -
        #if   defined(__linux)
         #include <pty.h>
        #elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
       @@ -50,6 +49,9 @@
        #define XK_NO_MOD     UINT_MAX
        #define XK_ANY_MOD    0
        
       +#define SELECT_TIMEOUT (20*1000) /* 20 ms */
       +#define DRAW_TIMEOUT  (20*1000) /* 20 ms */
       +
        #define SERRNO strerror(errno)
        #define MIN(a, b)  ((a) < (b) ? (a) : (b))
        #define MAX(a, b)  ((a) < (b) ? (b) : (a))
       @@ -138,6 +140,7 @@ typedef struct {
                int ch; /* char height */
                int cw; /* char width  */
                char state; /* focus, redraw, visible */
       +        struct timeval lastdraw;
        } XWindow;
        
        typedef struct {
       @@ -179,6 +182,7 @@ static void drawregion(int, int, int, int);
        static void execsh(void);
        static void sigchld(int);
        static void run(void);
       +static int last_draw_too_old(void);
        
        static void csidump(void);
        static void csihandle(void);
       @@ -214,6 +218,7 @@ static void ttywrite(const char *, size_t);
        static void xdraws(char *, Glyph, int, int, int, int);
        static void xhints(void);
        static void xclear(int, int, int, int);
       +static void xcopy(int, int, int, int);
        static void xdrawcursor(void);
        static void xinit(void);
        static void xloadcols(void);
       @@ -224,7 +229,7 @@ static void xresize(int, int);
        static void expose(XEvent *);
        static void visibility(XEvent *);
        static void unmap(XEvent *);
       -static char* kmap(KeySym, unsigned int state);
       +static char* kmap(KeySym, unsigned int);
        static void kpress(XEvent *);
        static void cmessage(XEvent *);
        static void resize(XEvent *);
       @@ -1786,6 +1791,14 @@ xdraws(char *s, Glyph base, int x, int y, int charlen, int bytelen) {
                        XDrawLine(xw.dpy, xw.buf, dc.gc, winx, winy+1, winx+width-1, winy+1);
        }
        
       +/* copy buffer pixmap to screen pixmap */
       +void
       +xcopy(int x, int y, int cols, int rows) {
       +        int src_x = x*xw.cw, src_y = y*xw.ch, src_w = cols*xw.cw, src_h = rows*xw.ch;
       +        int dst_x = BORDER+src_x, dst_y = BORDER+src_y;
       +        XCopyArea(xw.dpy, xw.buf, xw.win, dc.gc, src_x, src_y, src_w, src_h, dst_x, dst_y);
       +}
       +
        void
        xdrawcursor(void) {
                static int oldx = 0;
       @@ -1805,7 +1818,9 @@ xdrawcursor(void) {
                        xdraws(term.line[oldy][oldx].c, term.line[oldy][oldx], oldx, oldy, 1, sl);
                } else
                        xclear(oldx, oldy, oldx, oldy);
       -        
       +
       +        xcopy(oldx, oldy, 1, 1);
       +
                /* draw the new one */
                if(!(term.c.state & CURSOR_HIDE) && (xw.state & WIN_FOCUSED)) {
                        sl = utf8size(g.c);
       @@ -1814,11 +1829,14 @@ xdrawcursor(void) {
                        xdraws(g.c, g, term.c.x, term.c.y, 1, sl);
                        oldx = term.c.x, oldy = term.c.y;
                }
       +
       +        xcopy(term.c.x, term.c.y, 1, 1);
        }
        
        void
        draw() {
                drawregion(0, 0, term.col, term.row);
       +        gettimeofday(&xw.lastdraw, NULL);
        }
        
        void
       @@ -1859,9 +1877,9 @@ drawregion(int x1, int y1, int x2, int y2) {
                        }
                        if(ib > 0)
                                xdraws(buf, base, ox, y, ic, ib);
       +                xcopy(0, y, term.col, 1);
                }
                xdrawcursor();
       -        XCopyArea(xw.dpy, xw.buf, xw.win, dc.gc, x1*xw.cw, y1*xw.ch, x2*xw.cw, y2*xw.ch, BORDER, BORDER);
        }
        
        void
       @@ -2006,25 +2024,42 @@ resize(XEvent *e) {
                xresize(col, row);
        }
        
       +int
       +last_draw_too_old(void) {
       +        struct timeval now;
       +        gettimeofday(&now, NULL);
       +        return TIMEDIFF(now, xw.lastdraw) >= PRINT_TIMEOUT/1000;
       +}
       +
        void
        run(void) {
                XEvent ev;
                fd_set rfd;
                int xfd = XConnectionNumber(xw.dpy);
       -
       +        struct timeval timeout = {0};
       +        int stuff_to_print = 0;
       +        
                for(;;) {
                        FD_ZERO(&rfd);
                        FD_SET(cmdfd, &rfd);
                        FD_SET(xfd, &rfd);
       -                if(select(MAX(xfd, cmdfd)+1, &rfd, NULL, NULL, NULL) < 0) {
       +                timeout.tv_sec  = 0;
       +                timeout.tv_usec = SELECT_TIMEOUT;
       +                if(select(MAX(xfd, cmdfd)+1, &rfd, NULL, NULL, &timeout) < 0) {
                                if(errno == EINTR)
                                        continue;
                                die("select failed: %s\n", SERRNO);
                        }
                        if(FD_ISSET(cmdfd, &rfd)) {
                                ttyread();
       +                        stuff_to_print = 1;
       +                }
       +
       +                if(stuff_to_print && last_draw_too_old()) {
       +                        stuff_to_print = 0;
                                draw();
                        }
       +
                        while(XPending(xw.dpy)) {
                                XNextEvent(xw.dpy, &ev);
                                if(XFilterEvent(&ev, xw.win))
       @@ -2050,7 +2085,7 @@ main(int argc, char *argv[]) {
                        case 'w':
                                if(++i < argc) opt_embed = argv[i];
                                break;
       -                case 'e': 
       +                case 'e':
                                /* eat every remaining arguments */
                                if(++i < argc) opt_cmd = &argv[i];
                                goto run;