rio, libdraw: experimental removal of redundant flushimage() calls for roundtrip latency reduction

- remove redundant flushimage() calls before readmouse()
- remove flushimage() calls for allocimage(),freeimage() and originwindow()

this is experimental. it will break allocimage() error handling unless the
caller does explicit flushimage() calls, tho the gains
in usability over high latency connections is huge. in most cases, programs
will just terminate when encountering these errors.

1 files changed, 0 insertions, 8 deletions

diff --git a/sys/src/libdraw/alloc.c b/sys/src/libdraw/alloc.c
index 90289a6aa..28caaac02 100644
--- a/sys/src/libdraw/alloc.c
+++ b/sys/src/libdraw/alloc.c
@@ -47,8 +47,6 @@ _allocimage(Image *ai, Display *d, Rectangle r, ulong chan, int repl, ulong col,
 		return nil;
 	}
 
-	/* flush pending data so we don't get error allocating the image */
-	flushimage(d, 0);
 	a = bufimage(d, 1+4+4+1+4+1+4*4+4*4+4);
 	if(a == nil)
 		goto Error;
@@ -74,8 +72,6 @@ _allocimage(Image *ai, Display *d, Rectangle r, ulong chan, int repl, ulong col,
 	BPLONG(a+39, clipr.max.x);
 	BPLONG(a+43, clipr.max.y);
 	BPLONG(a+47, col);
-	if(flushimage(d, 0) < 0)
-		goto Error;
 
 	if(ai != nil)
 		i = ai;
@@ -207,7 +203,6 @@ _freeimage1(Image *i)
 	if(i == nil || i->display == nil)
 		return 0;
 	d = i->display;
-	flushimage(d, 0);
 	if(i->screen != nil){
 		w = d->windows;
 		if(w == i)
@@ -226,9 +221,6 @@ _freeimage1(Image *i)
 		return -1;
 	a[0] = 'f';
 	BPLONG(a+1, i->id);
-	if(flushimage(d, i->screen!=nil) < 0)
-		return -1;
-
 	return 0;
 }