don't draw if the window is not visible.

1 files changed, 25 insertions, 4 deletions

diff --git a/st.c b/st.c
index d2f8c2e..c9d0fb8 100644
--- a/st.c
+++ b/st.c
@@ -115,6 +115,7 @@ typedef struct {
         int ch; /* char height */
         int cw; /* char width  */
         int hasfocus;
+        int vis; /* is visible */
 } XWindow; 
 
 typedef struct {
@@ -187,6 +188,8 @@ static void xloadcols(void);
 static void xseturgency(int);
 
 static void expose(XEvent *);
+static void visibility(XEvent *);
+static void unmap(XEvent *);
 static char* kmap(KeySym);
 static void kpress(XEvent *);
 static void resize(XEvent *);
@@ -198,8 +201,10 @@ static void bmotion(XEvent *);
 
 static void (*handler[LASTEvent])(XEvent *) = {
         [KeyPress] = kpress,
-        [Expose] = expose,
         [ConfigureNotify] = resize,
+        [VisibilityNotify] = visibility,
+        [UnmapNotify] = unmap,
+        [Expose] = expose,
         [FocusIn] = focus,
         [FocusOut] = focus,
         [MotionNotify] = bmotion,
@@ -1211,9 +1216,9 @@ xinit(void) {
         attrs.background_pixel = dc.col[DefaultBG];
         attrs.border_pixel = dc.col[DefaultBG];
         attrs.bit_gravity = NorthWestGravity;
-        attrs.event_mask = ExposureMask | KeyPressMask
-                | StructureNotifyMask | FocusChangeMask | PointerMotionMask
-                | ButtonPressMask | ButtonReleaseMask;
+        attrs.event_mask = FocusChangeMask | KeyPressMask
+                | ExposureMask | VisibilityChangeMask | StructureNotifyMask
+                | PointerMotionMask | ButtonPressMask | ButtonReleaseMask;
         attrs.colormap = xw.cmap;
 
         xw.win = XCreateWindow(xw.dis, XRootWindow(xw.dis, xw.scr), 0, 0,
@@ -1321,6 +1326,9 @@ draw(int redraw_all) {
         Glyph base, new;
         char buf[DRAW_BUF_SIZ];
 
+        if(!xw.vis)
+                return;
+
         xclear(0, 0, term.col-1, term.row-1);
         for(y = 0; y < term.row; y++) {
                 base = term.line[y][0];
@@ -1358,6 +1366,19 @@ expose(XEvent *ev) {
 }
 
 void
+visibility(XEvent *ev) {
+        XVisibilityEvent *e = &ev->xvisibility;
+        /* XXX if this goes from 0 to 1, need a full redraw for next Expose,
+         * not just a buf copy */
+        xw.vis = e->state != VisibilityFullyObscured;
+}
+
+void
+unmap(XEvent *ev) {
+        xw.vis = 0;
+}
+
+void
 xseturgency(int add) {
         XWMHints *h = XGetWMHints(xw.dis, xw.win);
         h->flags = add ? (h->flags | XUrgencyHint) : (h->flags & ~XUrgencyHint);