Hide window shadow in mojave when there is a transparent session. Thanks apple

Author: gnachman

sources/PTYTab.m

@@ -490,6 +490,7 @@ - (void)numberOfSessionsDidChange {
     if (self.isBroadcasting) {
         [[NSNotificationCenter defaultCenter] postNotificationName:iTermBroadcastDomainsDidChangeNotification object:nil];
     }
+    [_delegate numberOfSessionsDidChangeInTab:self];
 }
 
 + (void)_recursiveSetDelegateIn:(NSSplitView *)node to:(id)delegate {

sources/PTYTabDelegate.h

@@ -44,5 +44,6 @@ typedef NS_OPTIONS(NSUInteger, PTYTabState) {
                       image:(NSImage *)image;
 - (BOOL)tabCanUseMetal:(PTYTab *)tab reason:(out iTermMetalUnavailableReason *)reason;
 - (BOOL)tabShouldUseTransparency:(PTYTab *)tab;
+- (void)numberOfSessionsDidChangeInTab:(PTYTab *)tab;
 
 @end

sources/PTYTextView.m

@@ -1207,7 +1207,9 @@ - (void)drawRect:(NSRect)rect {
     if (![_delegate textViewShouldDrawRect]) {
         // Metal code path in use
         [super drawRect:rect];
-        [self maybeInvalidateWindowShadow];
+        if (![iTermAdvancedSettingsModel disableWindowShadowWhenTransparencyOnMojave]) {
+            [self maybeInvalidateWindowShadow];
+        }
         return;
     }
     if (_dataSource.width <= 0) {

sources/PseudoTerminal.m

@@ -2588,6 +2588,7 @@ - (BOOL)restoreTabsFromArrangement:(NSDictionary *)arrangement sessions:(NSArray
             return NO;
         }
     }
+    [self updateUseTransparency];
     return YES;
 }
 
@@ -3769,6 +3770,13 @@ - (void)updateUseTransparency {
     }
     [[self currentTab] recheckBlur];
     [self updateTabColors];  // Updates the window's background color as a side-effect
+    [self updateWindowShadow];
+}
+
+- (BOOL)anySessionInCurrentTabHasTransparency {
+    return [self.currentTab.sessions anyWithBlock:^BOOL(PTYSession *session) {
+        return session.textview.transparencyAlpha < 1;
+    }];
 }
 
 - (IBAction)toggleUseTransparency:(id)sender
@@ -4163,6 +4171,17 @@ - (void)toggleTraditionalFullScreenMode {
     [self didChangeCompactness];
     [self updateTouchBarIfNeeded:NO];
     [self updateUseMetalInAllTabs];
+    [self updateWindowShadow];
+}
+
+- (void)updateWindowShadow {
+    if (@available(macOS 10.14, *)) {
+        if ([iTermAdvancedSettingsModel disableWindowShadowWhenTransparencyOnMojave]) {
+            const BOOL haveTransparency = [self anySessionInCurrentTabHasTransparency];
+            DLog(@"%@: have transparency = %@ for sessions %@ in tab %@", self, @(haveTransparency), self.currentTab.sessions, self.currentTab);
+            self.window.hasShadow = !haveTransparency;
+        }
+    }
 }
 
 - (void)didChangeCompactness {
@@ -4287,6 +4306,7 @@ - (void)windowWillEnterFullScreen:(NSNotification *)notification {
     togglingLionFullScreen_ = YES;
     [self didChangeAnyFullScreen];
     [self updateUseMetalInAllTabs];
+    [self updateWindowShadow];
     [self repositionWidgets];
     [_contentView didChangeCompactness];
 }
@@ -4319,6 +4339,7 @@ - (void)windowDidEnterFullScreen:(NSNotification *)notification
     }
     [self updateTouchBarIfNeeded:NO];
     [self updateUseMetalInAllTabs];
+    [self updateWindowShadow];
 }
 
 - (void)windowDidFailToEnterFullScreen:(NSWindow *)window {
@@ -4353,6 +4374,7 @@ - (void)windowWillExitFullScreen:(NSNotification *)notification
     [self repositionWidgets];
     self.window.hasShadow = YES;
     [self updateUseMetalInAllTabs];
+    [self updateWindowShadow];
 }
 
 - (void)windowDidExitFullScreen:(NSNotification *)notification
@@ -4385,6 +4407,7 @@ - (void)windowDidExitFullScreen:(NSNotification *)notification
     [self updateUseMetalInAllTabs];
     [_contentView didChangeCompactness];
     [_contentView layoutSubviews];
+    [self updateWindowShadow];
 }
 
 - (NSRect)windowWillUseStandardFrame:(NSWindow *)sender defaultFrame:(NSRect)defaultFrame {
@@ -4707,6 +4730,7 @@ - (void)tabView:(NSTabView *)tabView didSelectTabViewItem:(NSTabViewItem *)tabVi
     [self updateCurrentLocation];
     [self updateUseMetalInAllTabs];
     [self.scope setValue:self.currentTab.variables forVariableNamed:iTermVariableKeyWindowCurrentTab];
+    [self updateWindowShadow];
     [[NSNotificationCenter defaultCenter] postNotificationName:iTermSelectedTabDidChange object:tab];
 }
 
@@ -8691,6 +8715,7 @@ - (void)tabSessionDidChangeBackgroundColor:(PTYTab *)tab {
     if (preferredStyle == TAB_STYLE_MINIMAL) {
         [self.contentView setNeedsDisplay:YES];
     }
+    [self updateWindowShadow];
 }
 
 - (void)tab:(PTYTab *)tab didChangeToState:(PTYTabState)newState {
@@ -8732,6 +8757,12 @@ - (void)currentSessionWordAtCursorDidBecome:(NSString *)word {
     }];
 }
 
+- (void)numberOfSessionsDidChangeInTab:(PTYTab *)tab {
+    if (tab == self.currentTab) {
+        [self updateUseTransparency];
+    }
+}
+
 #pragma mark - Toolbelt
 
 - (void)toolbeltUpdateMouseCursor {

sources/iTermAdvancedSettingsModel.h

@@ -65,6 +65,7 @@ extern NSString *const iTermAdvancedSettingsDidChange;
 + (BOOL)disableMetalWhenIdle;
 + (BOOL)disablePasswordManagerAnimations;
 + (BOOL)disablePotentiallyInsecureEscapeSequences;
++ (BOOL)disableWindowShadowWhenTransparencyOnMojave;
 + (BOOL)disableWindowSizeSnap;
 + (BOOL)disallowCopyEmptyString;
 + (BOOL)dockIconTogglesWindow DEPRECATED_ATTRIBUTE;

sources/iTermAdvancedSettingsModel.m

@@ -423,8 +423,8 @@ + (void)enumerateDictionaries:(void (^)(NSDictionary *))block {
 DEFINE_BOOL(fontChangeAffectsBroadcastingSessions, NO, SECTION_WINDOWS @"Should growing or shrinking the font in a session that's broadcasting input affect all session that broadcast input?\nThis only applies to changing the font size with Make Text Bigger, Make Text Normal Size, and Make Text Smaller");
 DEFINE_BOOL(serializeOpeningMultipleFullScreenWindows, YES, SECTION_WINDOWS @"When opening multiple fullscreen windows, enter fullscreen one window at a time.");
 DEFINE_BOOL(trackingRunloopForLiveResize, YES, SECTION_WINDOWS @"Use a tracking runloop for live resizing.\nThis allows the terminal to redraw during a resizing drag.");
-DEFINE_BOOL(invalidateShadowAfterEachDraw, YES, SECTION_WINDOWS @"Invalidate shadow after each draw to prevent ghosting.");
 DEFINE_FLOAT(invalidateShadowTimesPerSecond, 15, SECTION_WINDOWS @"How many times per second to update the shadow of transparent windows to prevent ghosting.\nThis works around a macOS Mojave bug that leaves a ghost of past window contents behind in transparent windows. It hurts performance to do it frequently, especially in large windows. Set to 0 to disable.");
+DEFINE_BOOL(disableWindowShadowWhenTransparencyOnMojave, YES, SECTION_WINDOWS @"Disable the window shadow on Mojave when the window has a transparent session to improve performance.");
 
 #pragma mark tmux