From 0d26ea1e12a28136b3969f44b067df11a2195599 Mon Sep 17 00:00:00 2001
From: Kevin Walzer <kw@codebykevin.com>
Date: Wed, 24 Dec 2014 04:44:16 +0000
Subject: All on Tk/Cocoa: Improve view performance during resizing; implement
 custom drawing of scroller to remove flickering and ghosted appearance during
 window operations; reduce flickering of menubutton during resizing, but do
 not completely eliminate ghosted rendering when widget is unmapped

---
 macosx/tkMacOSXScrlbr.c      | 53 +++++++++++++++++++++++++++++++++++++++++++-
 macosx/tkMacOSXWindowEvent.c | 41 +++++++++++++++-------------------
 2 files changed, 70 insertions(+), 24 deletions(-)

diff --git a/macosx/tkMacOSXScrlbr.c b/macosx/tkMacOSXScrlbr.c
index 3658f7e..a34ce88 100644
--- a/macosx/tkMacOSXScrlbr.c
+++ b/macosx/tkMacOSXScrlbr.c
@@ -7,6 +7,8 @@
  * Copyright (c) 1996 by Sun Microsystems, Inc.
  * Copyright 2001-2009, Apple Inc.
  * Copyright (c) 2006-2009 Daniel A. Steffen <das@users.sourceforge.net>
+*  Copyright (c) 2014 Marc Culler.
+ * Copyright (c) 2014 Kevin Walzer/WordTech Commununications LLC.
  *
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
@@ -31,11 +33,22 @@ NSRect                  TkMacOSXGetScrollFrame(TkScrollbar *scrlPtr);
  * aware of the state of its Tk parent.  This subclass overrides the drawRect
  * method so that it will not draw itself if the widget is completely outside
  * of its container.
+ *
+ * Custom drawing of the knob seems to work around the flickering visible after  
+ * private API's were removed. Based on technique outlined at 
+ * http://stackoverflow.com/questions/1604682/nsscroller-
+ * graphical-glitches-lag. Only supported on 10.7 and above.
  */
+ 
 
 @interface TkNSScroller: NSScroller
 -(void) drawRect:(NSRect)dirtyRect;
-
+#if MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
+-(BOOL) isHorizontal;
+-(void) drawKnob;
+- (void)drawArrow:(NSScrollerArrow)arrow highlightPart:(int)flag;
+- (void)drawKnobSlotInRect:(NSRect)rect highlight:(BOOL)highlight;
+#endif
 @end
 
 @implementation TkNSScroller
@@ -77,6 +90,44 @@ NSRect                  TkMacOSXGetScrollFrame(TkScrollbar *scrlPtr);
 	}
 	[super drawRect:dirtyRect];
     }
+    
+ #if MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
+- (BOOL)isHorizontal {
+    NSRect bounds = [self bounds];
+    return NSWidth(bounds) < NSHeight (bounds);
+}
+
+
+- (void)drawKnob
+{
+    NSRect knobRect = [self rectForPart:NSScrollerKnob];
+    
+    if ([self isHorizontal]) {
+	NSRect newRect = NSMakeRect(knobRect.origin.x, knobRect.origin.y, knobRect.size.width - 5, knobRect.size.height);
+	NSBezierPath *path = [NSBezierPath bezierPathWithRoundedRect:newRect xRadius:7 yRadius:7];
+ 
+        [[NSColor lightGrayColor] set];
+	[path fill];
+    } else {
+	NSRect newRect = NSMakeRect(knobRect.origin.x, knobRect.origin.y, knobRect.size.width, knobRect.size.height - 5);
+	NSBezierPath *path = [NSBezierPath bezierPathWithRoundedRect:newRect xRadius:7 yRadius:7];
+ 
+    [[NSColor lightGrayColor] set];
+	[path fill];
+    }
+       
+}
+
+- (void)drawArrow:(NSScrollerArrow)arrow highlightPart:(int)flag
+{
+    // We don't want arrows
+}
+
+- (void)drawKnobSlotInRect:(NSRect)rect highlight:(BOOL)highlight
+{
+
+}
+#endif   
 
 @end
 
diff --git a/macosx/tkMacOSXWindowEvent.c b/macosx/tkMacOSXWindowEvent.c
index f5e506f..13a9f10 100644
--- a/macosx/tkMacOSXWindowEvent.c
+++ b/macosx/tkMacOSXWindowEvent.c
@@ -771,6 +771,8 @@ Tk_MacOSXIsAppInFront(void)
 @interface TKContentView(TKWindowEvent)
 - (void) drawRect: (NSRect) rect;
 - (void) generateExposeEvents: (HIMutableShapeRef) shape;
+- (BOOL) preservesContentDuringLiveResize;
+- (void) viewWillStartLiveResize;
 - (void) viewDidEndLiveResize;
 - (void) viewWillDraw;
 - (BOOL) isOpaque;
@@ -782,15 +784,6 @@ Tk_MacOSXIsAppInFront(void)
 @implementation TKContentView
 @end
 
-double drawTime;
-
-/*
- * Set a minimum time for drawing to render. With removal of private NSView API's, default drawing
- * is slower and less responsive. This number, which seems feasible after some experimentatation, skips
- * some drawing to avoid lag. 
- */
-
-#define MAX_DYNAMIC_TIME .000000001
 
 /*Restrict event processing to Expose events.*/
 static Tk_RestrictAction
@@ -818,11 +811,6 @@ ExposeRestrictProc(
 	    NSCompositeSourceOver);
 #endif
 
-    NSDate *beginTime=[NSDate date];
-
-    /*Skip drawing during live resize if redraw is too slow.*/
-    if([self inLiveResize] && drawTime>MAX_DYNAMIC_TIME) return;
-
     CGFloat height = [self bounds].size.height;
     HIMutableShapeRef drawShape = HIShapeCreateMutable();
 
@@ -842,23 +830,30 @@ ExposeRestrictProc(
 			nil]];
     }
     CFRelease(drawShape);
-    drawTime=-[beginTime timeIntervalSinceNow];
-    [super setNeedsDisplayInRect:rect];
 }
 
-/*At conclusion of resize event, send notification and set view for redraw if earlier drawing was skipped because of lagginess.*/
+/*Provide more fine-grained control over resizing of content to reduce flicker after removal of private API's.*/
+
+- (BOOL) preservesContentDuringLiveResize
+{
+    return YES;
+}
+
+- (void)viewWillStartLiveResize
+{
+  [super viewWillStartLiveResize];
+}
+
+
 - (void)viewDidEndLiveResize
 {
-    if(drawTime>MAX_DYNAMIC_TIME) {
+
     [self setNeedsDisplay:YES];
+    [super setNeedsDisplay:YES];
     [super viewDidEndLiveResize];
-    }
+     
 }
 
--(void) viewWillDraw  {
-	[self setNeedsDisplay:YES];
-    } 
-
 - (void) generateExposeEvents: (HIMutableShapeRef) shape
 {
 
-- 
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