[iOS] Upstream //ios/chrome/browser/ui

ios/chrome/browser/ui/background_generator.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.
+
+#include "ios/chrome/browser/ui/background_generator.h"
+
+#import <QuartzCore/QuartzCore.h>
+
+#include "base/mac/bundle_locations.h"
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_cftyperef.h"
+#import "base/mac/scoped_nsobject.h"
+#import "ios/chrome/browser/ui/ui_util.h"
+
+// This is a utility function that may be used as a standalone helper function
+// to generate a radial gradient UIImage.
+UIImage* GetRadialGradient(CGRect backgroundRect,
+                           CGPoint centerPoint,
+                           CGFloat radius,
+                           CGFloat centerColor,
+                           CGFloat outsideColor,
+                           UIImage* tileImage,
+                           UIImage* logoImage) {
+  UIGraphicsBeginImageContextWithOptions(backgroundRect.size, YES, 0);
+  CGContextRef context = UIGraphicsGetCurrentContext();
+  CGFloat gradient_colors[4] = {centerColor, 1.0, outsideColor, 1.0};
+  const size_t kColorCount = 2;
+  base::ScopedCFTypeRef<CGColorSpaceRef> grey_space(
+      CGColorSpaceCreateDeviceGray());
+  DCHECK_EQ(2u, CGColorSpaceGetNumberOfComponents(grey_space));
+  base::ScopedCFTypeRef<CGGradientRef> gradient(
+      CGGradientCreateWithColorComponents(grey_space, gradient_colors, nullptr,
+                                          kColorCount));
+  CGContextDrawRadialGradient(context, gradient, centerPoint, 0, centerPoint,
+                              radius, kCGGradientDrawsAfterEndLocation);
+  if (tileImage)
+    [tileImage drawAsPatternInRect:backgroundRect];
+  if (logoImage) {
+    CGPoint corner = AlignPointToPixel(
+        CGPointMake(centerPoint.x - logoImage.size.width / 2.0,
+                    centerPoint.y - logoImage.size.height / 2.0));
+    [logoImage drawAtPoint:corner];
+  }
+  UIImage* background = UIGraphicsGetImageFromCurrentImageContext();
+  UIGraphicsEndImageContext();
+  return background;
+}
+
+void InstallBackgroundInView(UIView* view) {
+  UIImageView* imageView =
+      [[[UIImageView alloc] initWithFrame:view.bounds] autorelease];
+  imageView.image = [UIImage imageNamed:@"stack_view_background_noise.jpg"];
+  imageView.contentMode = UIViewContentModeScaleAspectFill;
+  imageView.autoresizingMask =
+      UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
+  [view insertSubview:imageView atIndex:0];
+}