Lots of bugs and not faster than single-threaded drawing.

iTerm2.xcodeproj/project.pbxproj

@@ -1595,6 +1595,8 @@
 		A6A2699C190319A000437DA9 /* ProfilesAdvancedPreferencesViewController.h in Headers */ = {isa = PBXBuildFile; fileRef = A6A2699A190319A000437DA9 /* ProfilesAdvancedPreferencesViewController.h */; };
 		A6A51A401B45CEA9007891F3 /* VT100DCSParserTest.m in Sources */ = {isa = PBXBuildFile; fileRef = A6A51A3F1B45CEA9007891F3 /* VT100DCSParserTest.m */; };
 		A6A5991D1887C63700CB4209 /* ToolCommandHistoryView.h in Headers */ = {isa = PBXBuildFile; fileRef = A6A5991B1887C63700CB4209 /* ToolCommandHistoryView.h */; };
+		A6AC81961D4B1F56006F2ADC /* iTermDrawingShard.h in Headers */ = {isa = PBXBuildFile; fileRef = A6AC81941D4B1F56006F2ADC /* iTermDrawingShard.h */; };
+		A6AC81971D4B1F56006F2ADC /* iTermDrawingShard.m in Sources */ = {isa = PBXBuildFile; fileRef = A6AC81951D4B1F56006F2ADC /* iTermDrawingShard.m */; };
 		A6ACD1F81B62F2210095CB57 /* iTermRuleTest.m in Sources */ = {isa = PBXBuildFile; fileRef = A6ACD1F71B62F2210095CB57 /* iTermRuleTest.m */; };
 		A6AE1ECF191FFA1C00780C19 /* iTermMouseCursor.h in Headers */ = {isa = PBXBuildFile; fileRef = A6AE1ECE191FFA1C00780C19 /* iTermMouseCursor.h */; };
 		A6AE1ED81926F89B00780C19 /* iTermAnnouncementViewController.h in Headers */ = {isa = PBXBuildFile; fileRef = A6AE1ED61926F89B00780C19 /* iTermAnnouncementViewController.h */; };
@@ -3343,6 +3345,8 @@
 		A6A51A3F1B45CEA9007891F3 /* VT100DCSParserTest.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = VT100DCSParserTest.m; sourceTree = "<group>"; };
 		A6A5991B1887C63700CB4209 /* ToolCommandHistoryView.h */ = {isa = PBXFileReference; fileEncoding = 4; indentWidth = 4; lastKnownFileType = sourcecode.c.h; path = ToolCommandHistoryView.h; sourceTree = "<group>"; tabWidth = 4; };
 		A6A5991C1887C63700CB4209 /* ToolCommandHistoryView.m */ = {isa = PBXFileReference; fileEncoding = 4; indentWidth = 4; lastKnownFileType = sourcecode.c.objc; path = ToolCommandHistoryView.m; sourceTree = "<group>"; tabWidth = 4; };
+		A6AC81941D4B1F56006F2ADC /* iTermDrawingShard.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = iTermDrawingShard.h; sourceTree = "<group>"; };
+		A6AC81951D4B1F56006F2ADC /* iTermDrawingShard.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = iTermDrawingShard.m; sourceTree = "<group>"; };
 		A6ACD1F71B62F2210095CB57 /* iTermRuleTest.m */ = {isa = PBXFileReference; fileEncoding = 4; indentWidth = 4; lastKnownFileType = sourcecode.c.objc; path = iTermRuleTest.m; sourceTree = "<group>"; };
 		A6AE1ECC191FF9DB00780C19 /* iTermMouseCursor.m */ = {isa = PBXFileReference; fileEncoding = 4; indentWidth = 4; lastKnownFileType = sourcecode.c.objc; path = iTermMouseCursor.m; sourceTree = "<group>"; tabWidth = 4; };
 		A6AE1ECE191FFA1C00780C19 /* iTermMouseCursor.h */ = {isa = PBXFileReference; fileEncoding = 4; indentWidth = 4; lastKnownFileType = sourcecode.c.h; path = iTermMouseCursor.h; sourceTree = "<group>"; tabWidth = 4; };
@@ -5154,6 +5158,8 @@
 				A6936B481D2D756200521B04 /* iTermWindowOcclusionChangeMonitor.m */,
 				A686F38B1D3951A800F08ED7 /* iTermBoxDrawingBezierCurveFactory.h */,
 				A686F38C1D3951A800F08ED7 /* iTermBoxDrawingBezierCurveFactory.m */,
+				A6AC81941D4B1F56006F2ADC /* iTermDrawingShard.h */,
+				A6AC81951D4B1F56006F2ADC /* iTermDrawingShard.m */,
 			);
 			name = Helpers;
 			sourceTree = "<group>";
@@ -6150,6 +6156,7 @@
 				A66DB8421CA24E8800233E88 /* iTermAutoMasterParser.h in Headers */,
 				A6FEA2781CF2CBCC00376F28 /* iTermAppHotKeyProvider.h in Headers */,
 				A60251681CCD3E5E009BABF1 /* NSURL+iTerm.h in Headers */,
+				A6AC81961D4B1F56006F2ADC /* iTermDrawingShard.h in Headers */,
 				1D300BAA1BD9A8BB002043F7 /* NSDate+iTerm.h in Headers */,
 				A6FEA26C1CF2C86800376F28 /* iTermBaseHotKey.h in Headers */,
 				A6EFF23F1D21949D00806EEF /* iTermShortcut.h in Headers */,
@@ -7757,6 +7764,7 @@
 				A6C7634F1B45C52B00E3C992 /* SessionTitleView.m in Sources */,
 				A6C762B21B45C52B00E3C992 /* NSDateFormatterExtras.m in Sources */,
 				A6C763A01B45C52B00E3C992 /* TmuxWindowsTable.m in Sources */,
+				A6AC81971D4B1F56006F2ADC /* iTermDrawingShard.m in Sources */,
 				A6EFF2481D21DD0700806EEF /* iTermSessionHotkeyController.m in Sources */,
 				A6C762B41B45C52B00E3C992 /* NSDictionary+Profile.m in Sources */,
 				A6C763E51B45C70100E3C992 /* SCEvent.m in Sources */,

iTerm2.xcodeproj/xcshareddata/xcschemes/iTerm2.xcscheme

@@ -67,7 +67,7 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Development"
+      buildConfiguration = "Deployment"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"

sources/NSArray+iTerm.h

@@ -59,10 +59,12 @@
 - (NSString *)componentsJoinedWithOxfordComma;
 - (NSArray *)intersectArray:(NSArray *)other;
+- (NSArray *)arrayByShufflingArray;
 @end
 @interface NSMutableArray<ObjectType> (iTerm)
 - (void)reverse;
 - (void)removeObjectsPassingTest:(BOOL (^)(ObjectType anObject))block;
+- (void)shuffle;
 @end

sources/NSArray+iTerm.m

@@ -235,6 +235,12 @@
     return intersection;
 }
+- (NSArray *)arrayByShufflingArray {
+    NSMutableArray *result = [[self mutableCopy] autorelease];
+    [result shuffle];
+    return result;
+}
+
 @end
 @implementation NSMutableArray (iTerm)
@@ -262,4 +268,16 @@
     [self removeObjectsAtIndexes:indexes];
 }
+- (void)shuffle {
+    NSUInteger count = self.count;
+    if (!count) {
+        return;
+    }
+    for (NSUInteger i = 0; i + 1 < count; i++) {
+        NSInteger numberLeft = count - i;
+        NSInteger j = i + arc4random_uniform((u_int32_t )numberLeft);
+        [self exchangeObjectAtIndex:i withObjectAtIndex:j];
+    }
+}
+
 @end

sources/iTermAdvancedSettingsModel.h

@@ -150,5 +150,7 @@
 + (NSString *)downloadsDirectory;
 + (double)pointSizeOfTimeStamp;
 + (BOOL)showYellowMarkForJobStoppedBySignal;
++ (BOOL)parallelizeTextDrawing;
++ (int)numberOfDrawingShards;
 @end

sources/iTermAdvancedSettingsModel.m

@@ -210,4 +210,7 @@ DEFINE_BOOL(experimentalKeyHandling, NO, @"Experimental Features: Improved suppo
 DEFINE_BOOL(hideStuckTooltips, NO, @"Experimental Features: Hide stuck tooltips.\nWhen you hide iTerm2 using a hotkey while a tooltip is fading out it gets stuck because of an OS bug. Work around it with a nasty hack by enabling this feature.")
 DEFINE_BOOL(showYellowMarkForJobStoppedBySignal, NO, @"Experimental Features: Use a yellow for a Shell Integration prompt mark when the job is stopped by a signal.");
+DEFINE_BOOL(parallelizeTextDrawing, YES, @"Experimental Features: Parallelize drawing");
+DEFINE_INT(numberOfDrawingShards, 4, @"Experimental Features: Number of drawing shards when parallelizing drawing");
+
 @end

sources/iTermBackgroundColorRun.h

@@ -41,7 +41,7 @@ NS_INLINE BOOL iTermBackgroundColorRunsEqual(iTermBackgroundColorRun *a,
 // Line number to draw at (row - scrollbackOverflow)
 @property(nonatomic, assign) int line;
-
+@property(nonatomic, assign) int equivalentRows;
 @property(nonatomic, retain) NSArray<iTermBoxedBackgroundColorRun *> *array;
 // Creates a new autoreleased iTermBackgroundColorRunsInLine object that's ready to use.

sources/iTermDrawingShard.h

+//
+//  iTermDrawingShard.h
+//  iTerm2
+//
+//  Created by George Nachman on 7/28/16.
+//
+//
+
+#import <Cocoa/Cocoa.h>
+
+extern dispatch_queue_t gCompositingQueue;
+
+@interface iTermDrawingShard : NSObject
+@property(nonatomic, assign) CGContextRef bitmapContext;
+@property(nonatomic, assign) NSRange range;
+@property(nonatomic, assign) NSRect rect;
+@property(nonatomic, copy) void (^compositingBlock)();
+@property(nonatomic, readonly) dispatch_group_t group;
+@property(nonatomic, readonly) NSArray *events;
+@property(nonatomic, readonly) int shardNumber;
+@property(nonatomic, readonly) NSSize capacity;
+@property(nonatomic, readonly) CGLayerRef layer;
+
+- (instancetype)initWithRect:(NSRect)rect
+                       scale:(CGFloat)scale
+                       range:(NSRange)range
+               bitmapContext:(CGContextRef)bitmapContext
+                       queue:(dispatch_queue_t)queue;
+
+- (instancetype)initWithRect:(NSRect)rect
+                       scale:(CGFloat)scale
+                       range:(NSRange)range
+                 shardNumber:(int)shardNumber;
+
+- (void)addEvent:(NSString *)event;
+- (void)addDebugEvent:(NSString *)event;
+- (void)removeAllEvents;
+- (void)drawWithBlock:(void (^)())block;
+- (void)compositeWhenReady;
+- (void)setLayerContextFromContext:(CGContextRef)context;
+
+@end
+
+@interface iTermSynchronousDrawingShard : iTermDrawingShard
+@end
+
+NSTimeInterval MillisSinceDrawingEpoch();
+void ResetDrawingEpoch();
\ No newline at end of file

sources/iTermDrawingShard.m

+//
+//  iTermDrawingShard.m
+//  iTerm2
+//
+//  Created by George Nachman on 7/28/16.
+//
+//
+
+#import "iTermDrawingShard.h"
+
+static uint64_t gDrawingEpoch;
+dispatch_queue_t gCompositingQueue;
+
+void ResetDrawingEpoch() {
+    gDrawingEpoch = mach_absolute_time();
+}
+
+NSTimeInterval MillisSinceDrawingEpoch() {
+    static mach_timebase_info_data_t sTimebaseInfo;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        mach_timebase_info(&sTimebaseInfo);
+    });
+
+    double nanoseconds = (mach_absolute_time() - gDrawingEpoch) * sTimebaseInfo.numer / sTimebaseInfo.denom;
+    double ms = nanoseconds / 1000000.0;
+    return ms;
+}
+
+
+@implementation iTermDrawingShard {
+    NSMutableData *_data;
+    dispatch_queue_t _queue;
+    NSMutableArray *_events;
+    CGFloat _scale;
+}
+
++ (dispatch_queue_t)queueForShardNumber:(int)shardNumber {
+    static NSMutableArray<dispatch_queue_t> *queues;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        queues = [[NSMutableArray alloc] init];
+    });
+    while (queues.count <= shardNumber) {
+        [queues addObject:dispatch_queue_create("com.googlecode.iterm2.DrawingQueue", DISPATCH_QUEUE_SERIAL)];
+    }
+    
+    return queues[shardNumber];
+}
+
++ (CGLayerRef)layerOfSize:(NSSize)size scale:(CGFloat)scale data:(NSMutableData *)data context:(CGContextRef)context {
+    CGSize scaledSize = CGSizeMake(size.width * scale, size.height * scale);
+    return CGLayerCreateWithContext(context, scaledSize, NULL);
+}
+
++ (CGContextRef)bitmapContextOfSize:(NSSize)size scale:(CGFloat)scale data:(NSMutableData *)data {
+    NSInteger bytesPerRow = size.width * scale * 4;
+    NSUInteger storageNeeded = bytesPerRow * scale * size.height;
+    NSLog(@"%0.6fms: Calling setLength: %d", MillisSinceDrawingEpoch(), (int)storageNeeded);
+    [data setLength:storageNeeded];
+    
+    NSLog(@"%0.6fms: Calling CGColorSpaceCreateDeviceRGB", MillisSinceDrawingEpoch());
+
+    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+    NSLog(@"%0.6fms: Calling CGBitmapContextCreate", MillisSinceDrawingEpoch());
+
+    CGContextRef bitmapContext = CGBitmapContextCreate((void *)data.mutableBytes,
+                                                       size.width * scale,
+                                                       size.height * scale,
+                                                       8,
+                                                       bytesPerRow,
+                                                       colorSpace,
+                                                       (CGBitmapInfo)kCGImageAlphaPremultipliedLast);
+    NSLog(@"%0.6fms: Returned from CGBitmapContextCreate", MillisSinceDrawingEpoch());
+    assert(bitmapContext);
+    CGColorSpaceRelease(colorSpace);
+    CGContextScaleCTM(bitmapContext, scale, scale);
+    return bitmapContext;
+
+}
+
+- (instancetype)initWithRect:(NSRect)rect
+                       scale:(CGFloat)scale
+                       range:(NSRange)range
+               bitmapContext:(CGContextRef)bitmapContext
+                       queue:(dispatch_queue_t)queue {
+    self = [super init];
+    if (self) {
+        _data = [[NSMutableData alloc] init];
+        _events = [[NSMutableArray alloc] init];
+        [self addEvent:@"Begin Initialize shard"];
+        _range = range;
+        _rect = rect;
+        _scale = scale;
+        _group = dispatch_group_create();
+        self.bitmapContext = bitmapContext;
+        _queue = queue;
+        _capacity = rect.size;
+        if (queue) {
+            dispatch_retain(queue);
+        }
+        if (bitmapContext) {
+            CFRetain(bitmapContext);
+        }
+        [self addEvent:@"End Initialize shard"];
+    }
+    return self;
+}
+
+- (void)setBitmapContext:(CGContextRef)bitmapContext {
+    if (_bitmapContext) {
+        CFRelease(_bitmapContext);
+    }
+    _bitmapContext = bitmapContext;
+    if (bitmapContext) {
+        CFRetain(bitmapContext);
+    }
+}
+
+// [[iTermDrawingShard alloc] initWithSize:NSMakeSize(width * scale, _cellSize.height * scale) scale:self.isRetina ? 2.0 : 1.0];
+- (instancetype)initWithRect:(NSRect)rect scale:(CGFloat)scale range:(NSRange)range shardNumber:(int)shardNumber {
+    if (range.length == 0 || rect.size.height <= 0) {
+        return nil;
+    }
+    NSLog(@"%0.6fms: Creating bitmap context for shard %d", MillisSinceDrawingEpoch(), shardNumber);
+//    CGContextRef bitmapContext = [iTermDrawingShard bitmapContextOfSize:rect.size scale:scale data:_data];
+    NSLog(@"%0.6fms: Done creating bitmap context for shard %d", MillisSinceDrawingEpoch(), shardNumber);
+    dispatch_queue_t queue = [iTermDrawingShard queueForShardNumber:shardNumber];
+    self = [self initWithRect:rect scale:scale range:range bitmapContext:nil queue:queue];
+//    CFRelease(bitmapContext);
+    CFRelease(queue);
+    if (self) {
+        if (shardNumber >= 0) {
+            _shardNumber = shardNumber;
+            dispatch_retain(_queue);
+        }
+    }
+    return self;
+}
+
+- (void)dealloc {
+    if (_bitmapContext) {
+        CFRelease(_bitmapContext);
+    }
+    if (_queue) {
+        dispatch_release(_queue);
+    }
+    dispatch_release(_group);
+    [_events release];
+    [_data release];
+    [super dealloc];
+}
+
+- (void)setLayerContextFromContext:(CGContextRef)context {
+    if (_layer) {
+        CFRelease(_layer);
+        _layer = nil;
+    }
+    if (context) {
+        _layer = [iTermDrawingShard layerOfSize:_rect.size scale:_scale data:_data context:context];
+        self.bitmapContext = CGLayerGetContext(_layer);
+    } else {
+        self.bitmapContext = nil;
+    }
+}
+
+- (NSString *)description {
+    return [NSString stringWithFormat:@"<%@: %p number=%d destination=%@ range=%@>",
+            NSStringFromClass([self class]), self, _shardNumber, NSStringFromRect(_rect),
+            NSStringFromRange(_range)];
+}
+
+- (void)addDebugEvent:(NSString *)event {
+    [self addEvent:event];
+}
+
+- (void)addEvent:(NSString *)event {
+    @synchronized(self) {
+        [_events addObject:[NSString stringWithFormat:@"%0.6fms: %@", MillisSinceDrawingEpoch(), event]];
+    }
+}
+
+- (void)removeAllEvents {
+    @synchronized(self) {
+        [_events removeAllObjects];
+    }
+}
+
+- (void)drawWithBlock:(void (^)())block {
+    [self addDebugEvent:@"Queue drawing block"];
+    dispatch_group_enter(_group);
+    dispatch_async(_queue, ^{
+        [self addDebugEvent:@"Begin drawing"];
+        block();
+        [self addDebugEvent:@"End drawing"];
+        [self addEvent:[NSString stringWithFormat:@"Shard %d drew", _shardNumber]];
+        dispatch_group_leave(_group);
+    });
+}
+
+- (void)compositeWhenReady {
+    if (_compositingBlock) {
+        dispatch_group_notify(_group, gCompositingQueue, ^() {
+            [self addEvent:@"Begin compositing"];
+            _compositingBlock();
+            [self addEvent:@"End compositing"];
+        });
+    }
+}
+
+@end
+
+@implementation iTermSynchronousDrawingShard
+
+- (void)drawWithBlock:(void (^)())block {
+//    NSLog(@"Perform draw on synchronous shard");
+    block();
+}
+
+@end
+

sources/iTermTextDrawingHelper.h

@@ -264,8 +264,4 @@
 // Draw timestamps. Returns the width of the widest timestamp.
 - (CGFloat)drawTimestamps;
-#pragma mark - Testing Only
-
-- (void)clipAndDrawRect:(NSRect)rect;
-
 @end