Upstream //ios/chrome/browser/snapshots

ios/chrome/browser/snapshots/snapshot_manager.mm

+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/snapshots/snapshot_manager.h"
+
+#import <QuartzCore/QuartzCore.h>
+
+#include "base/logging.h"
+#import "ios/chrome/browser/snapshots/snapshot_cache.h"
+#import "ios/chrome/browser/snapshots/snapshot_overlay.h"
+
+@implementation SnapshotManager
+
+- (UIImage*)generateSnapshotForView:(UIView*)view
+                           withRect:(CGRect)rect
+                           overlays:(NSArray*)overlays {
+  DCHECK(view);
+  CGSize size = rect.size;
+  DCHECK(isnormal(size.width) && (size.width > 0))
+      << ": size.width=" << size.width;
+  DCHECK(isnormal(size.height) && (size.height > 0))
+      << ": size.height=" << size.height;
+  const CGFloat kScale = [SnapshotCache snapshotScaleForDevice];
+  UIGraphicsBeginImageContextWithOptions(size, YES, kScale);
+  CGContext* context = UIGraphicsGetCurrentContext();
+  if (!context) {
+    NOTREACHED();
+    return nil;
+  }
+
+  CGContextSaveGState(context);
+  CGContextTranslateCTM(context, -rect.origin.x, -rect.origin.y);
+#if defined(ENABLE_WKWEBVIEW)
+  // -drawViewHierarchyInRect:afterScreenUpdates:YES is buggy as of iOS 8.1.1.
+  // Using it afterScreenUpdates:YES creates unexpected GPU glitches, screen
+  // redraws during animations, broken pinch to dismiss on tablet, etc.  For now
+  // only using this with ENABLE_WKWEBVIEW, which depends on
+  // -drawViewHierarchyInRect.
+  [view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
+#else
+  [[view layer] renderInContext:context];
+#endif
+  if ([overlays count]) {
+    for (SnapshotOverlay* overlay in overlays) {
+      // Render the overlay view at the desired offset. It is achieved
+      // by shifting origin of context because view frame is ignored when
+      // drawing to context.
+      CGContextSaveGState(context);
+      CGContextTranslateCTM(context, 0, overlay.yOffset);
+#if defined(ENABLE_WKWEBVIEW)
+      CGRect overlayRect = overlay.view.bounds;
+      // TODO(jyquinn): The 0 check is needed for a UIKit crash on iOS 7.  This
+      // can be removed once iOS 7 is dropped. crbug.com/421213
+      if (overlayRect.size.width > 0 && overlayRect.size.height > 0) {
+        [overlay.view drawViewHierarchyInRect:overlay.view.bounds
+                           afterScreenUpdates:YES];
+      }
+#else
+      [[overlay.view layer] renderInContext:context];
+#endif
+      CGContextRestoreGState(context);
+    }
+  }
+  UIImage* image = UIGraphicsGetImageFromCurrentImageContext();
+  CGContextRestoreGState(context);
+  UIGraphicsEndImageContext();
+  return image;
+}
+
+- (void)retrieveImageForSessionID:(NSString*)sessionID
+                         callback:(void (^)(UIImage*))callback {
+  [[SnapshotCache sharedInstance] retrieveImageForSessionID:sessionID
+                                                   callback:callback];
+}
+
+- (void)retrieveGreyImageForSessionID:(NSString*)sessionID
+                             callback:(void (^)(UIImage*))callback {
+  [[SnapshotCache sharedInstance] retrieveGreyImageForSessionID:sessionID
+                                                       callback:callback];
+}
+
+- (void)setImage:(UIImage*)img withSessionID:(NSString*)sessionID {
+  [[SnapshotCache sharedInstance] setImage:img withSessionID:sessionID];
+}
+
+- (void)removeImageWithSessionID:(NSString*)sessionID {
+  [[SnapshotCache sharedInstance] removeImageWithSessionID:sessionID];
+}
+
+- (void)greyImageForSessionID:(NSString*)sessionID
+                     callback:(void (^)(UIImage*))callback {
+  [[SnapshotCache sharedInstance] greyImageForSessionID:sessionID
+                                               callback:callback];
+}
+
+@end