3 files changed, 34 insertions, 16 deletions

diff --git a/src/views/mac/SkNSView.h b/src/views/mac/SkNSView.h
index 60727eb3e6..bf6e67c71c 100644
--- a/src/views/mac/SkNSView.h
+++ b/src/views/mac/SkNSView.h
@@ -42,7 +42,7 @@ class SkEvent;
 - (void)postInvalWithRect:(const SkIRect*)rectOrNil;
 - (BOOL)onHandleEvent:(const SkEvent&)event;
 
-- (bool)attach:(SkOSWindow::SkBackEndTypes)attachType;
+- (bool)attach:(SkOSWindow::SkBackEndTypes)attachType withMSAASampleCount:(int) sampleCount;
 - (void)detach;
 - (void)present;
 @end
diff --git a/src/views/mac/SkNSView.mm b/src/views/mac/SkNSView.mm
index a6aa59cbef..9d52814afa 100644
--- a/src/views/mac/SkNSView.mm
+++ b/src/views/mac/SkNSView.mm
@@ -225,25 +225,36 @@ static SkKey raw2key(UInt32 raw)
 ///////////////////////////////////////////////////////////////////////////////
 #include <OpenGL/OpenGL.h>
 
-CGLContextObj createGLContext() {
+namespace { 
+CGLContextObj createGLContext(int msaaSampleCount) {
     GLint major, minor;
     CGLGetVersion(&major, &minor);
     
-    const CGLPixelFormatAttribute attributes[] = {
+    static const CGLPixelFormatAttribute attributes[] = {
         kCGLPFAStencilSize, (CGLPixelFormatAttribute)8,
-#if USE_MSAA
-        kCGLPFASampleBuffers, 1,
-        kCGLPFAMultisample,
-        kCGLPFASamples, 8,
-#endif
         kCGLPFAAccelerated,
         kCGLPFADoubleBuffer,
         (CGLPixelFormatAttribute)0
     };
     
     CGLPixelFormatObj format;
-    GLint npix;
-    CGLChoosePixelFormat(attributes, &format, &npix);
+    GLint npix = 0;
+    if (msaaSampleCount > 0) {
+        static int kAttributeCount = SK_ARRAY_COUNT(attributes);
+        CGLPixelFormatAttribute msaaAttributes[kAttributeCount + 5];
+        memcpy(msaaAttributes, attributes, sizeof(attributes));
+        SkASSERT(0 == msaaAttributes[kAttributeCount - 1]);
+        msaaAttributes[kAttributeCount - 1] = kCGLPFASampleBuffers;
+        msaaAttributes[kAttributeCount + 0] = (CGLPixelFormatAttribute)1;
+        msaaAttributes[kAttributeCount + 1] = kCGLPFAMultisample;
+        msaaAttributes[kAttributeCount + 2] = kCGLPFASamples;
+        msaaAttributes[kAttributeCount + 3] = (CGLPixelFormatAttribute)msaaSampleCount;
+        msaaAttributes[kAttributeCount + 4] = (CGLPixelFormatAttribute)0;
+        CGLChoosePixelFormat(msaaAttributes, &format, &npix);
+    }
+    if (!npix) {
+        CGLChoosePixelFormat(attributes, &format, &npix);
+    }
     
     CGLContextObj ctx;
     CGLCreateContext(format, NULL, &ctx);
@@ -254,6 +265,7 @@ CGLContextObj createGLContext() {
     CGLSetCurrentContext(ctx);
     return ctx;
 }
+}
 
 - (void)viewDidMoveToWindow {
     [super viewDidMoveToWindow];
@@ -265,12 +277,15 @@ CGLContextObj createGLContext() {
         [fGLContext setView:self];
     }
 }
-- (bool)attach:(SkOSWindow::SkBackEndTypes)attachType {
+- (bool)attach:(SkOSWindow::SkBackEndTypes)attachType withMSAASampleCount:(int) sampleCount {
     if (nil == fGLContext) {
-        fGLContext = [[NSOpenGLContext alloc] initWithCGLContextObj:createGLContext()];
+        CGLContextObj ctx = createGLContext(sampleCount);
+        fGLContext = [[NSOpenGLContext alloc] initWithCGLContextObj:ctx];
+        CGLReleaseContext(ctx);
         if (NULL == fGLContext) {
             return false;
         }
+        [fGLContext setView:self];
     }
     
     [fGLContext makeCurrentContext];
@@ -283,10 +298,13 @@ CGLContextObj createGLContext() {
 }
 
 - (void)detach {
-    [fGLContext clearDrawable];
+    [fGLContext release];
+    fGLContext = nil;
 }
 
 - (void)present {
-    [fGLContext flushBuffer];
+    if (nil != fGLContext) {
+        [fGLContext flushBuffer];
+    }
 }
 @end
diff --git a/src/views/mac/SkOSWindow_Mac.mm b/src/views/mac/SkOSWindow_Mac.mm
index 4aa4eb5ff8..a5d3fef706 100644
--- a/src/views/mac/SkOSWindow_Mac.mm
+++ b/src/views/mac/SkOSWindow_Mac.mm
@@ -63,8 +63,8 @@ void SkOSWindow::onUpdateMenu(const SkOSMenu* menu) {
     [(SkNSView*)fHWND onUpdateMenu:menu];
 }
 
-bool SkOSWindow::attach(SkBackEndTypes attachType) {
-    return [(SkNSView*)fHWND attach:attachType];
+bool SkOSWindow::attach(SkBackEndTypes attachType, int sampleCount) {
+    return [(SkNSView*)fHWND attach:attachType withMSAASampleCount:sampleCount];
 }
 
 void SkOSWindow::detach() {