4 files changed, 51 insertions, 43 deletions

diff --git a/src/app.c b/src/app.c
index 31bd33ed..0611b6dd 100644
--- a/src/app.c
+++ b/src/app.c
@@ -837,6 +837,9 @@ void trimCache_App(void) {
 }
 
 iLocalDef iBool isWaitingAllowed_App_(iApp *d) {
+    if (!isEmpty_Periodic(&d->periodic)) {
+        return iFalse;
+    }
     if (d->warmupFrames > 0) {
         return iFalse;
     }
@@ -853,14 +856,26 @@ iLocalDef iBool isWaitingAllowed_App_(iApp *d) {
     return !value_Atomic(&d->pendingRefresh) && isEmpty_SortedArray(&d->tickers);
 }
 
+static iBool nextEvent_App_(iApp *d, enum iAppEventMode eventMode, SDL_Event *event) {
+    if (eventMode == waitForNewEvents_AppEventMode && isWaitingAllowed_App_(d)) {
+        /* If there are periodic commands pending, wait only for a short while. */
+        if (!isEmpty_Periodic(&d->periodic)) {
+            return SDL_WaitEventTimeout(event, 500);
+        }
+        /* We may be allowed to block here until an event comes in. */
+        if (isWaitingAllowed_App_(d)) {
+            return SDL_WaitEvent(event);
+        }
+    }
+    return SDL_PollEvent(event);
+}
+
 void processEvents_App(enum iAppEventMode eventMode) {
     iApp *d = &app_;
     SDL_Event ev;
     iBool gotEvents = iFalse;
-    while ((isWaitingAllowed_App_(d) && eventMode == waitForNewEvents_AppEventMode &&
-            SDL_WaitEvent(&ev)) ||
-           ((!isWaitingAllowed_App_(d) || eventMode == postedEventsOnly_AppEventMode) &&
-            SDL_PollEvent(&ev))) {
+    postCommands_Periodic(&d->periodic);
+    while (nextEvent_App_(d, eventMode, &ev)) {
 #if defined (iPlatformAppleMobile)
         if (processEvent_iOS(&ev)) {
             continue;
@@ -1064,13 +1079,18 @@ static int run_App_(iApp *d) {
 
 void refresh_App(void) {
     iApp *d = &app_;
+    destroyPending_Widget();
 #if defined (LAGRANGE_IDLE_SLEEP)
     if (d->warmupFrames == 0 && d->isIdling) {
         return;
     }
 #endif
-    set_Atomic(&d->pendingRefresh, iFalse);
-    destroyPending_Widget();
+    if (!exchange_Atomic(&d->pendingRefresh, iFalse)) {
+        /* Refreshing wasn't pending. */
+        if (isFinished_Anim(&d->window->rootOffset)) {
+            return;
+        }
+    }
 //    iTime draw;
 //    initCurrent_Time(&draw);
     draw_Window(d->window);
diff --git a/src/periodic.c b/src/periodic.c
index c039097d..29c26de9 100644
--- a/src/periodic.c
+++ b/src/periodic.c
@@ -52,50 +52,35 @@ iDefineTypeConstructionArgs(PeriodicCommand, (iAny *ctx, const char *cmd), ctx,
 
 /*----------------------------------------------------------------------------------------------*/
 
-//static uint32_t postCommands_Periodic_(uint32_t interval, void *param) {
-static iThreadResult poster_Periodic_(iThread *thread) {
-    iPeriodic *d = userData_Thread(thread);
+static const uint32_t postingInterval_Periodic_ = 500;
+
+iBool postCommands_Periodic(iPeriodic *d) {
+    const uint32_t now = SDL_GetTicks();
+    if (now - d->lastPostTime < postingInterval_Periodic_) {
+        return iFalse;
+    }
+    d->lastPostTime = now;
+    iBool wasPosted = iFalse;
     lock_Mutex(d->mutex);
-    while (!value_Atomic(&d->isStopping)) {
-        if (isEmpty_SortedArray(&d->commands)) {
-            /* Sleep until we have something to post. */
-            wait_Condition(&d->haveCommands, d->mutex);
-            continue;
-        }
-        iConstForEach(Array, i, &d->commands.values) {
-            postCommandString_App(&((const iPeriodicCommand *) i.value)->command);
-        }
-        /* Sleep for a while. */
-        iTime until;
-        initTimeout_Time(&until, 0.5f);
-        waitTimeout_Condition(&d->haveCommands, d->mutex, &until);
+    iConstForEach(Array, i, &d->commands.values) {
+        postCommandString_App(&((const iPeriodicCommand *) i.value)->command);
+        wasPosted = iTrue;
     }
     unlock_Mutex(d->mutex);
-    return 0;
+    return wasPosted;
 }
 
 void init_Periodic(iPeriodic *d) {
     d->mutex = new_Mutex();
     init_SortedArray(&d->commands, sizeof(iPeriodicCommand), cmp_PeriodicCommand_);
-//    d->timer = SDL_AddTimer(500, postCommands_Periodic_, d);
-    set_Atomic(&d->isStopping, iFalse);
-    init_Condition(&d->haveCommands);
-    d->thread = new_Thread(poster_Periodic_);
-    setUserData_Thread(d->thread, d);
-    start_Thread(d->thread);
+    d->lastPostTime = 0;
 }
 
 void deinit_Periodic(iPeriodic *d) {
-//    SDL_RemoveTimer(d->timer);
-    set_Atomic(&d->isStopping, iTrue);
-    signal_Condition(&d->haveCommands);
-    join_Thread(d->thread);
-    iRelease(d->thread);
     iForEach(Array, i, &d->commands.values) {
         deinit_PeriodicCommand(i.value);
     }
     deinit_SortedArray(&d->commands);
-    deinit_Condition(&d->haveCommands);
     delete_Mutex(d->mutex);
 }
 
@@ -112,7 +97,6 @@ void add_Periodic(iPeriodic *d, iAny *context, const char *command) {
         init_PeriodicCommand(&pc, context, command);
         insert_SortedArray(&d->commands, &pc);
     }
-    signal_Condition(&d->haveCommands);
     unlock_Mutex(d->mutex);
 }
 
diff --git a/src/periodic.h b/src/periodic.h
index c643a2fe..db90b848 100644
--- a/src/periodic.h
+++ b/src/periodic.h
@@ -26,17 +26,21 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
 iDeclareType(Periodic)
 iDeclareType(Thread)
 
-/* Animation utility. Not per frame but several times per second. */
+/* Animation utility. Not per frame but several times per second. Thread safe. */
 struct Impl_Periodic {
     iMutex *     mutex;
     iSortedArray commands;
-    iCondition   haveCommands;
-    iThread *    thread;
-    iAtomicInt   isStopping;
+    uint32_t     lastPostTime;
 };
 
 void    init_Periodic   (iPeriodic *);
 void    deinit_Periodic (iPeriodic *);
 
-void    add_Periodic    (iPeriodic *, iAny *context, const char *command);
-void    remove_Periodic (iPeriodic *, iAny *context);
+iLocalDef iBool isEmpty_Periodic(const iPeriodic *d) {
+    return isEmpty_SortedArray(&d->commands);
+}
+
+void    add_Periodic            (iPeriodic *, iAny *context, const char *command);
+void    remove_Periodic         (iPeriodic *, iAny *context);
+
+iBool   postCommands_Periodic   (iPeriodic *);
diff --git a/src/ui/scrollwidget.c b/src/ui/scrollwidget.c
index b5b204a1..55ede426 100644
--- a/src/ui/scrollwidget.c
+++ b/src/ui/scrollwidget.c
@@ -112,7 +112,7 @@ static void unfade_ScrollWidget_(iScrollWidget *d, float opacity) {
         d->willCheckFade = iTrue;
         /* TODO: This causes an inexplicable refresh issue on macOS: the drawing of one frame
            takes 100ms for some reason (not the current frame but some time after). */
-//        add_Periodic(periodic_App(), d, "scrollbar.fade");
+        add_Periodic(periodic_App(), d, "scrollbar.fade");
     }
     refresh_Widget(d);
 }