Basic proof of concept is working.

sources/iTermMetalFrameData.m

+//
+//  iTermMetalFrameData.m
+//  iTerm2SharedARC
+//
+//  Created by George Nachman on 10/27/17.
+//
+
+#import "iTermMetalFrameData.h"
+
+#import <MetalKit/MetalKit.h>
+
+void iTermMetalFrameDataStatsBundleInitialize(iTermMetalFrameDataStatsBundle *bundle) {
+    iTermPreciseTimerStatsInit(&bundle->mainThreadStats, "main thread");
+    iTermPreciseTimerStatsInit(&bundle->getCurrentDrawableStats, "mt.currentDrawable");
+    iTermPreciseTimerStatsInit(&bundle->getCurrentRenderPassDescriptorStats, "mt.renderPassDescr");
+    iTermPreciseTimerStatsInit(&bundle->dispatchStats, "dispatch");
+    iTermPreciseTimerStatsInit(&bundle->prepareStats, "prepare");
+    iTermPreciseTimerStatsInit(&bundle->waitForGroup, "wait for group");
+    iTermPreciseTimerStatsInit(&bundle->finalizeStats, "finalize");
+    iTermPreciseTimerStatsInit(&bundle->metalSetupStats, "metal setup");
+    iTermPreciseTimerStatsInit(&bundle->renderingStats, "rendering");
+    iTermPreciseTimerStatsInit(&bundle->endToEnd, "end to end");
+}
+
+static NSInteger gNextFrameDataNumber;
+
+@implementation iTermMetalFrameData {
+    NSTimeInterval _creation;
+    NSInteger _frameNumber;
+    iTermMetalFrameDataStatsBundle _stats;
+}
+
+- (instancetype)init {
+    self = [super init];
+    if (self) {
+        _creation = [NSDate timeIntervalSinceReferenceDate];
+        _frameNumber = gNextFrameDataNumber++;
+        iTermMetalFrameDataStatsBundleInitialize(&_stats);
+
+        iTermPreciseTimerStatsStartTimer(&_stats.endToEnd);
+        iTermPreciseTimerStatsStartTimer(&_stats.mainThreadStats);
+        self.status = @"just created";
+    }
+    return self;
+}
+
+- (NSString *)description {
+    return [NSString stringWithFormat:@"<%@: %p age=%f frameNumber=%@/%@ status=%@>",
+            self.class,
+            self,
+            [NSDate timeIntervalSinceReferenceDate] - _creation,
+            @(_frameNumber),
+            @(gNextFrameDataNumber),
+            self.status];
+}
+
+- (void)loadFromView:(MTKView *)view {
+    iTermPreciseTimerStatsStartTimer(&_stats.getCurrentDrawableStats);
+    self.drawable = view.currentDrawable;
+    iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.getCurrentDrawableStats);
+
+    iTermPreciseTimerStatsStartTimer(&_stats.getCurrentRenderPassDescriptorStats);
+    self.renderPassDescriptor = view.currentRenderPassDescriptor;
+    iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.getCurrentRenderPassDescriptorStats);
+    iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.mainThreadStats);
+}
+
+- (void)prepareWithBlock:(void (^)(void))block {
+    iTermPreciseTimerStatsStartTimer(&_stats.prepareStats);
+    self.status = @"before prepare";
+    block();
+    self.status = @"after prepare";
+    iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.prepareStats);
+}
+
+- (void)waitForUpdatesToFinishOnGroup:(dispatch_group_t)group
+                              onQueue:(dispatch_queue_t)queue
+                             finalize:(void (^)(void))finalize
+                               render:(void (^)(void))render {
+    iTermPreciseTimerStatsStartTimer(&_stats.waitForGroup);
+    dispatch_group_notify(group, queue, ^{
+        self.status = @"before finalize";
+        iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.waitForGroup);
+
+        iTermPreciseTimerStatsStartTimer(&_stats.finalizeStats);
+        self.status = @"finalizing";
+        finalize();
+        iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.finalizeStats);
+
+        iTermPreciseTimerStatsStartTimer(&_stats.metalSetupStats);
+        self.status = @"doing metal setup";
+        render();
+        self.status = @"waiting for render to complete";
+        iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.metalSetupStats);
+        
+        iTermPreciseTimerStatsStartTimer(&_stats.renderingStats);
+
+    });
+}
+
+- (void)didComplete {
+    self.status = @"complete";
+    iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.renderingStats);
+    iTermPreciseTimerStatsMeasureAndRecordTimer(&_stats.endToEnd);
+}
+
+- (void)addStatsTo:(iTermMetalFrameDataStatsBundle *)dest {
+    iTermPreciseTimerStatsRecord(&dest->mainThreadStats, _stats.mainThreadStats.mean * _stats.mainThreadStats.n, _stats.mainThreadStats.n);
+    iTermPreciseTimerStatsRecord(&dest->getCurrentDrawableStats, _stats.getCurrentDrawableStats.mean * _stats.getCurrentDrawableStats.n, _stats.getCurrentDrawableStats.n);
+    iTermPreciseTimerStatsRecord(&dest->getCurrentRenderPassDescriptorStats, _stats.getCurrentRenderPassDescriptorStats.mean * _stats.getCurrentRenderPassDescriptorStats.n, _stats.getCurrentRenderPassDescriptorStats.n);
+    iTermPreciseTimerStatsRecord(&dest->dispatchStats, _stats.dispatchStats.mean * _stats.dispatchStats.n, _stats.dispatchStats.n);
+    iTermPreciseTimerStatsRecord(&dest->prepareStats, _stats.prepareStats.mean * _stats.prepareStats.n, _stats.prepareStats.n);
+    iTermPreciseTimerStatsRecord(&dest->waitForGroup, _stats.waitForGroup.mean * _stats.waitForGroup.n, _stats.waitForGroup.n);
+    iTermPreciseTimerStatsRecord(&dest->finalizeStats, _stats.finalizeStats.mean * _stats.finalizeStats.n, _stats.finalizeStats.n);
+    iTermPreciseTimerStatsRecord(&dest->metalSetupStats, _stats.metalSetupStats.mean * _stats.metalSetupStats.n, _stats.metalSetupStats.n);
+    iTermPreciseTimerStatsRecord(&dest->renderingStats, _stats.renderingStats.mean * _stats.renderingStats.n, _stats.renderingStats.n);
+    iTermPreciseTimerStatsRecord(&dest->endToEnd, _stats.endToEnd.mean * _stats.endToEnd.n, _stats.endToEnd.n);
+}
+
+@end
+

sources/iTermMetalGlue.h

+//
+//  iTermMetalGlue.h
+//  iTerm2SharedARC
+//
+//  Created by George Nachman on 10/8/17.
+//
+
+#import <Foundation/Foundation.h>
+#import "iTermMetalDriver.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class iTermTextDrawingHelper;
+@class VT100Screen;
+@class PTYTextView;
+
+@interface iTermMetalGlue : NSObject<iTermMetalDriverDataSource>
+
+@property (nullable, nonatomic, strong) PTYTextView *textView;
+@property (nonatomic, strong) VT100Screen *screen;
+
+@end
+
+NS_ASSUME_NONNULL_END

sources/iTermMetalGlyphKey.h

+//
+//  iTermMetalGlyphKey.h
+//  iTerm2
+//
+//  Created by George Nachman on 10/9/17.
+//
+
+#include <simd/simd.h>
+
+typedef struct {
+    unichar code;
+    BOOL isComplex;
+    BOOL image;
+    BOOL boxDrawing;
+    BOOL thinStrokes;
+} iTermMetalGlyphKey;
+
+typedef struct {
+    vector_float4 foregroundColor;
+    vector_float4 backgroundColor;
+} iTermMetalGlyphAttributes;
+

sources/iTermPreciseTimer.m

@@ -141,10 +141,10 @@ void iTermPreciseTimerPeriodicLog(iTermPreciseTimerStats stats[],
                iTermPreciseTimerStatsInit(&stats[i], NULL);
         }
         if (logToConsole) {
-            ELog(@"%@", log);
-        } else {
-            DLog(@"%@", log);
+            NSLog(@"%@", log);
         }
+        DLog(@"%@", log);
+
         iTermPreciseTimerStart(&gLastLog);
     }
 }

sources/iTermRootTerminalView.m

@@ -54,6 +54,8 @@ static const CGFloat kMaximumToolbeltSizeAsFractionOfWindow = 0.5;
         
         // Create the tab view.
         self.tabView = [[[PTYTabView alloc] initWithFrame:self.bounds] autorelease];
+#warning This should be only for the metal code path
+        self.tabView.drawsBackground = NO;
         _tabView.autoresizingMask = (NSViewWidthSizable | NSViewHeightSizable);
         _tabView.autoresizesSubviews = YES;
         _tabView.allowsTruncatedLabels = NO;

sources/iTermTextDrawingHelper.h

@@ -19,6 +19,8 @@
 @class PTYFontInfo;
 @class VT100ScreenMark;
+BOOL CheckFindMatchAtIndex(NSData *findMatches, int index);
+
 @protocol iTermTextDrawingHelperDelegate <NSObject>
 - (void)drawingHelperDrawBackgroundImageInRect:(NSRect)rect
@@ -48,7 +50,7 @@
                           isBackground:(BOOL)isBackground;
 - (PTYFontInfo *)drawingHelperFontForChar:(UniChar)ch
-                                isComplex:(BOOL)complex
+                                isComplex:(BOOL)isComplex
                                renderBold:(BOOL *)renderBold
                              renderItalic:(BOOL *)renderItalic;
@@ -275,7 +277,11 @@
                          rectsPtr:(const NSRect *)rectArray
                         rectCount:(NSInteger)rectCount;
+- (NSImage *)imageForCoord:(VT100GridCoord)coord size:(CGSize)size;
+
 // Draw timestamps. Returns the width of the widest timestamp.
 - (CGFloat)drawTimestamps;
+- (VT100GridCoordRange)coordRangeForRect:(NSRect)rect;
+
 @end

sources/iTermTextDrawingHelper.m

@@ -46,6 +46,13 @@ static const int kBadgeMargin = 4;
 extern void CGContextSetFontSmoothingStyle(CGContextRef, int);
 extern int CGContextGetFontSmoothingStyle(CGContextRef);
+BOOL CheckFindMatchAtIndex(NSData *findMatches, int index) {
+    int theIndex = index / 8;
+    int mask = 1 << (index & 7);
+    const char *matchBytes = findMatches.bytes;
+    return !!(theIndex < [findMatches length] && (matchBytes[theIndex] & mask));
+}
+
 @interface iTermTextDrawingHelper() <iTermCursorDelegate>
 @end
@@ -288,6 +295,37 @@ typedef struct iTermTextColorContext {
     DLog(@"end drawRect:%@ in view %@", [NSValue valueWithRect:rect], _delegate);
 }
+- (NSImage *)imageForCoord:(VT100GridCoord)coord size:(CGSize)size {
+    NSData *rawMatches = [_delegate drawingHelperMatchesOnLine:coord.y];
+    screen_char_t *line = [_delegate drawingHelperLineAtIndex:coord.y];
+    iTermBackgroundColorRun backgroundRun = {
+        .range = { coord.x, 1 },
+        .bgColor = line[coord.x].backgroundColor,
+        .bgGreen = line[coord.x].bgGreen,
+        .bgBlue = line[coord.x].bgBlue,
+        .bgColorMode = line[coord.x].backgroundColorMode,
+        .selected = [[_selection selectedIndexesOnLine:coord.y] containsIndex:coord.x],
+        .isMatch = CheckFindMatchAtIndex(rawMatches, coord.x),
+    };
+    iTermBoxedBackgroundColorRun *boxedRun = [iTermBoxedBackgroundColorRun boxedBackgroundColorRunWithValue:backgroundRun];
+    NSColor *color = [self unprocessedColorForBackgroundRun:&backgroundRun];
+    // The unprocessed color is needed for minimum contrast computation for text color.
+    boxedRun.unprocessedBackgroundColor = color;
+    boxedRun.backgroundColor = [_colorMap processedBackgroundColorForBackgroundColor:color];
+    NSImage *image = [[NSImage alloc] initWithSize:size];
+
+    [image lockFocus];
+    [[NSColor redColor] set];
+    NSRectFill(NSMakeRect(0, 0, size.width, size.height));
+    [self drawForegroundForLineNumber:coord.y
+                                    y:0
+                       backgroundRuns:@[ boxedRun ]
+                              context:[[NSGraphicsContext currentContext] graphicsPort]];
+    [image unlockFocus];
+
+    return image;
+}
+
 - (NSInteger)numberOfEquivalentBackgroundColorLinesInRunArrays:(NSArray<iTermBackgroundColorRunsInLine *> *)backgroundRunArrays
                                                      fromIndex:(NSInteger)startIndex {
     NSInteger count = 1;
@@ -1229,7 +1267,6 @@ typedef struct iTermTextColorContext {
         CGContextSetBlendMode(ctx, kCGBlendModeSourceAtop);
     }
     CGContextSetFillColor(ctx, components);
-
     double y = point.y + _cellSize.height + _baselineOffset;
     int x = point.x + positions[0];
     // Flip vertically and translate to (x, y).
@@ -1240,6 +1277,7 @@ typedef struct iTermTextColorContext {
     CGContextSetTextMatrix(ctx, CGAffineTransformMake(1.0,  0.0,
                                                       m21, -1.0,
                                                       x, y));
+
     CGPoint points[length];
     for (int i = 0; i < length; i++) {
         points[i].x = positions[i] - positions[0];
@@ -1257,7 +1295,6 @@ typedef struct iTermTextColorContext {
         CGContextShowGlyphsAtPositions(ctx, glyphs, points, length);
     }
-
 #if 0
     // Indicates which regions were drawn with the fastpath
     [[NSColor yellowColor] set];
@@ -1562,10 +1599,10 @@ typedef struct iTermTextColorContext {
     return maskContext;
 }
-static NSColor *iTermTextDrawingHelperGetTextColor(screen_char_t *c,
-                                                   BOOL inUnderlinedRange,
-                                                   int index,
-                                                   iTermTextColorContext *context) {
+NSColor *iTermTextDrawingHelperGetTextColor(screen_char_t *c,
+                                            BOOL inUnderlinedRange,
+                                            int index,
+                                            iTermTextColorContext *context) {
     NSColor *rawColor = nil;
     BOOL isMatch = NO;
     const BOOL needsProcessing = context->backgroundColor && (context->minimumContrast > 0.001 ||
@@ -1765,16 +1802,16 @@ static BOOL iTermTextDrawingHelperIsCharacterDrawable(screen_char_t *c,
                                                                          textColorContext);
     }
-    const BOOL complex = c->complexChar;
+    const BOOL isComplex = c->complexChar;
     const unichar code = c->code;
-    attributes->boxDrawing = !complex && [[iTermBoxDrawingBezierCurveFactory boxDrawingCharactersWithBezierPaths] characterIsMember:code];
+    attributes->boxDrawing = !isComplex && [[iTermBoxDrawingBezierCurveFactory boxDrawingCharactersWithBezierPaths] characterIsMember:code];
     attributes->bold = c->bold;
     attributes->fakeBold = c->bold;  // default value
     attributes->fakeItalic = c->italic;  // default value
     PTYFontInfo *fontInfo = [_delegate drawingHelperFontForChar:code
-                                                      isComplex:complex
+                                                      isComplex:isComplex
                                                      renderBold:&attributes->fakeBold
                                                    renderItalic:&attributes->fakeItalic];
@@ -1912,10 +1949,10 @@ static BOOL iTermTextDrawingHelperIsCharacterDrawable(screen_char_t *c,
         iTermPreciseTimerStatsStartTimer(&_stats[TIMER_ATTRS_FOR_CHAR]);
         screen_char_t c = line[i];
         unichar code = c.code;
-        BOOL complex = c.complexChar;
+        BOOL isComplex = c.complexChar;
         NSString *charAsString;
-        if (complex) {
+        if (isComplex) {
             charAsString = ComplexCharToStr(c.code);
         } else {
             charAsString = nil;

sources/iTermUpdateCadenceController.m

@@ -15,7 +15,7 @@
 // Timer period between updates when active (not idle, tab is visible or title bar is changing,
 // etc.)
-static const NSTimeInterval kActiveUpdateCadence = 1 / 20.0;
+static const NSTimeInterval kActiveUpdateCadence = 1 / 60.0;
 // Timer period between updates when adaptive frame rate is enabled and throughput is low but not 0.
 static const NSTimeInterval kFastUpdateCadence = 1.0 / 60.0;