From c7f56d0f7ff41fdb99c1e97f447e5aa843e7d9ef Mon Sep 17 00:00:00 2001
From: "gtm.daemon" <gtm.daemon@7dc7ac4e-7543-0410-b95c-c1676fc8e2a3>
Date: Tue, 2 Jun 2009 17:47:08 +0000
Subject: [Author: altse]

Add category extension to UIImage to allow resizing while preserving aspect
 ratios and optional image clipping.

R=thomasvl,dmaclach
DELTA=507  (507 added, 0 deleted, 0 changed)
---
 iPhone/GTMUIImage+Resize.m | 100 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 iPhone/GTMUIImage+Resize.m

(limited to 'iPhone/GTMUIImage+Resize.m')

diff --git a/iPhone/GTMUIImage+Resize.m b/iPhone/GTMUIImage+Resize.m
new file mode 100644
index 0000000..f93a521
--- /dev/null
+++ b/iPhone/GTMUIImage+Resize.m
@@ -0,0 +1,100 @@
+//
+//  GTMUIImage+Resize.m
+//
+//  Copyright 2009 Google Inc.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+//  use this file except in compliance with the License.  You may obtain a copy
+//  of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+//  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+//  License for the specific language governing permissions and limitations under
+//  the License.
+//
+
+#import "GTMUIImage+Resize.h"
+
+@implementation UIImage (GTMUIImageResizeAdditions)
+
+- (UIImage *)gtm_imageByResizingToSize:(CGSize)targetSize
+                   preserveAspectRatio:(BOOL)preserveAspectRatio
+                             trimToFit:(BOOL)trimToFit {
+  CGSize imageSize = [self size];
+  if (imageSize.height < 1 || imageSize.width < 1) {
+    return nil;
+  }
+  if (targetSize.height < 1 || targetSize.width < 1) {
+    return nil;
+  }
+  CGFloat aspectRatio = imageSize.width / imageSize.height;
+  CGFloat targetAspectRatio = targetSize.width / targetSize.height;
+
+  CGRect projectTo = CGRectZero;
+  if (preserveAspectRatio) {
+    if (trimToFit) {
+      // Scale and clip image so that the aspect ratio is preserved and the
+      // target size is filled.
+      if (targetAspectRatio < aspectRatio) {
+        // clip the x-axis.
+        projectTo.size.width = targetSize.height * aspectRatio;
+        projectTo.size.height = targetSize.height;
+        projectTo.origin.x = (targetSize.width - projectTo.size.width) / 2;
+        projectTo.origin.y = 0;
+      } else {
+        // clip the y-axis.
+        projectTo.size.width = targetSize.width;
+        projectTo.size.height = targetSize.width / aspectRatio;
+        projectTo.origin.x = 0;
+        projectTo.origin.y = (targetSize.height - projectTo.size.height) / 2;
+      }
+    } else {
+      // Scale image to ensure it fits inside the specified targetSize.
+      if (targetAspectRatio < aspectRatio) {
+        // target is less wide than the original.
+        projectTo.size.width = targetSize.width;
+        projectTo.size.height = projectTo.size.width / aspectRatio;
+        targetSize = projectTo.size;
+      } else {
+        // target is wider than the original.
+        projectTo.size.height = targetSize.height;
+        projectTo.size.width = projectTo.size.height * aspectRatio;
+        targetSize = projectTo.size;
+      }
+    } // if (clip)
+  } else {
+    // Don't preserve the aspect ratio.
+    projectTo.size = targetSize;
+  }
+
+  projectTo = CGRectIntegral(projectTo);
+  // There's no CGSizeIntegral, so we fake our own.
+  CGRect integralRect = CGRectZero;
+  integralRect.size = targetSize;
+  targetSize = CGRectIntegral(integralRect).size;
+
+  // iPhone recommended settings.
+  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+  CGBitmapInfo bitmapInfo = (kCGBitmapByteOrder32Little |
+                             kCGImageAlphaPremultipliedFirst);
+
+  CGContextRef context = CGBitmapContextCreate(nil,  // data
+                                               targetSize.width,
+                                               targetSize.height,
+                                               8,  // bitsPerPixel
+                                               0,  // bytesPerRow
+                                               colorSpace,
+                                               bitmapInfo);
+  CGColorSpaceRelease(colorSpace);
+  // Produce the image
+  CGContextDrawImage(context, projectTo, [self CGImage]);
+  CGImageRef resizedRef = CGBitmapContextCreateImage(context);
+  CGContextRelease(context);
+  UIImage *resized = [UIImage imageWithCGImage:resizedRef];
+  CGImageRelease(resizedRef);
+  return resized;
+}
+@end
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