From 809ead2220f5a9ed66f88b1ae84a93e334e2717f Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Sat, 12 Sep 2015 19:45:02 -0400
Subject: Add puglWaitForEvent for blocking main loops.

---
 pugl/pugl.h       | 14 +++++++++++++-
 pugl/pugl_osx.m   | 18 ++++++++++++++++--
 pugl/pugl_win.cpp |  7 +++++++
 pugl/pugl_x11.c   |  9 +++++++++
 pugl_cairo_test.c |  1 +
 pugl_test.c       |  1 +
 6 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/pugl/pugl.h b/pugl/pugl.h
index 3ff66f9..8dca956 100644
--- a/pugl/pugl.h
+++ b/pugl/pugl.h
@@ -361,11 +361,23 @@ puglSetReshapeFunc(PuglView* view, PuglReshapeFunc reshapeFunc);
 PUGL_API void
 puglGrabFocus(PuglView* view);
 
+/**
+   Block and wait for an event to be ready.
+
+   This can be used in a loop to only process events via puglProcessEvents when
+   necessary.  This function will block indefinitely if no events are
+   available, so is not appropriate for use in programs that need to perform
+   regular updates (e.g. animation).
+*/
+PUGL_API PuglStatus
+puglWaitForEvent(PuglView* view);
+
 /**
    Process all pending window events.
 
    This handles input events as well as rendering, so it should be called
-   regularly and rapidly enough to keep the UI responsive.
+   regularly and rapidly enough to keep the UI responsive.  This function does
+   not block if no events are pending.
 */
 PUGL_API PuglStatus
 puglProcessEvents(PuglView* view);
diff --git a/pugl/pugl_osx.m b/pugl/pugl_osx.m
index 85e71a8..47c8138 100644
--- a/pugl/pugl_osx.m
+++ b/pugl/pugl_osx.m
@@ -524,11 +524,25 @@ puglGrabFocus(PuglView* view)
 	// TODO
 }
 
+PuglStatus
+puglWaitForEvent(PuglView* view)
+{
+	[view->impl->window nextEventMatchingMask: NSAnyEventMask
+	                                untilDate: [NSDate distantFuture]
+	                                  dequeue: NO];
+
+	return PUGL_SUCCESS;
+}
+
 PuglStatus
 puglProcessEvents(PuglView* view)
 {
-	NSEvent* ev = [view->impl->window nextEventMatchingMask: NSAnyEventMask];
-	[view->impl->app sendEvent: ev];
+	NSEvent* ev = [view->impl->window nextEventMatchingMask: NSAnyEventMask
+	                                              untilDate: [NSDate distantPast]];
+
+	if (ev) {
+		[view->impl->app sendEvent: ev];
+	}
 
 	return PUGL_SUCCESS;
 }
diff --git a/pugl/pugl_win.cpp b/pugl/pugl_win.cpp
index 04bc4b6..850947d 100644
--- a/pugl/pugl_win.cpp
+++ b/pugl/pugl_win.cpp
@@ -424,6 +424,13 @@ puglGrabFocus(PuglView* view)
 	// TODO
 }
 
+PuglStatus
+puglWaitForEvent(PuglView* view)
+{
+	WaitMessage();
+	return PUGL_SUCCESS;
+}
+
 PuglStatus
 puglProcessEvents(PuglView* view)
 {
diff --git a/pugl/pugl_x11.c b/pugl/pugl_x11.c
index 6375609..32501da 100644
--- a/pugl/pugl_x11.c
+++ b/pugl/pugl_x11.c
@@ -493,6 +493,14 @@ puglGrabFocus(PuglView* view)
 		view->impl->display, view->impl->win, RevertToPointerRoot, CurrentTime);
 }
 
+PuglStatus
+puglWaitForEvent(PuglView* view)
+{
+	XEvent xevent;
+	XPeekEvent(view->impl->display, &xevent);
+	return PUGL_SUCCESS;
+}
+
 PuglStatus
 puglProcessEvents(PuglView* view)
 {
@@ -544,6 +552,7 @@ puglProcessEvents(PuglView* view)
 		if (view->ctx_type == PUGL_CAIRO) {
 			cairo_xlib_surface_set_size(
 				view->impl->surface, view->width, view->height);
+			view->redisplay = true;
 		}
 #endif
 	}
diff --git a/pugl_cairo_test.c b/pugl_cairo_test.c
index bd97668..9c1bef8 100644
--- a/pugl_cairo_test.c
+++ b/pugl_cairo_test.c
@@ -166,6 +166,7 @@ main(int argc, char** argv)
 	puglShowWindow(view);
 
 	while (!quit) {
+		puglWaitForEvent(view);
 		puglProcessEvents(view);
 	}
 
diff --git a/pugl_test.c b/pugl_test.c
index 248a49a..af51e53 100644
--- a/pugl_test.c
+++ b/pugl_test.c
@@ -191,6 +191,7 @@ main(int argc, char** argv)
 	puglShowWindow(view);
 
 	while (!quit) {
+		puglWaitForEvent(view);
 		puglProcessEvents(view);
 	}
 
-- 
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