added image manipulation class

src/Bunch-o-Tools.h

@@ -25,4 +25,7 @@
 #import "UIColor+BOTFactories.h"
 
 //UIFont Categories
-#import "UIFont+BOTHelpers.h"
+#import "UIFont+BOTHelpers.h"
+
+//UIImage Categories
+#import "UIImage+BOTManipulation.h"

src/UIImage+Manipulation/UIImage+BOTManipulation.h

@@ -0,0 +1,17 @@
+//
+//  UIImage+BOTManipulation.h
+//
+
+#import <UIKit/UIKit.h>
+
+@interface UIImage (BOTManipulation)
+
+//scale image to a new size
+- (UIImage *) scaleToSize:(CGSize) size;
+- (UIImage *) scaleToSize:(CGSize) size retainAspect:(BOOL) retainAspect fit:(BOOL) fit;
+- (UIImage *) scaleByValue:(float) scaleValue;
+
+//inset image
+- (UIImage *) inset:(UIEdgeInsets) insets;
+
+@end

src/UIImage+Manipulation/UIImage+BOTManipulation.m

@@ -0,0 +1,112 @@
+//
+//  UIImage+BOTManipulation.m
+//
+
+#import "UIImage+BOTManipulation.h"
+
+@implementation UIImage (BOTManipulation)
+
+#pragma mark - scaling
+
+- (UIImage *) scaleToSize:(CGSize) size retainAspect:(BOOL) retainAspect fit:(BOOL) fit
+{
+    //prepare vars
+    CGRect frame = CGRectZero;
+    CGSize targetSize = size;
+    frame.size = targetSize;
+
+    //make sure ratio is preserved
+    if ( retainAspect ) {
+        float imageRatio = self.size.width / self.size.height;
+        float targetRatio = targetSize.width / targetSize.height;
+
+        //determine if we need to scale the height or the width to get to
+        //the right ratio
+        BOOL scaleHeight = imageRatio > targetRatio;
+
+        //if we want to fill instead of fit, reverse this
+        if ( !fit ) scaleHeight = !scaleHeight;
+
+        if ( scaleHeight ) {
+            //image breiter als target
+            targetSize.height = targetSize.width / imageRatio;
+        } else {
+            //image höher als target
+            targetSize.width = targetSize.height * imageRatio;
+        }
+
+        frame.size = targetSize;
+
+        // if fill
+        if ( !fit ) {
+            //move frame
+            frame.origin.x -= (targetSize.width - size.width) / 2.;
+            frame.origin.y -= (targetSize.height - size.height) / 2. ;
+
+            //target size is the original size requested
+            targetSize = size;
+        }
+    }
+
+    //begin context
+    UIGraphicsBeginImageContextWithOptions(targetSize, YES, self.scale);
+
+    //setup context, need to transform coordinates to screen space
+    CGContextRef context = UIGraphicsGetCurrentContext();
+    CGContextTranslateCTM(context, 0.0, targetSize.height);
+    CGContextScaleCTM(context, 1.0, -1.0);
+
+    CGContextDrawImage(context, frame, self.CGImage);
+    UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
+
+    UIGraphicsEndImageContext();
+    return scaledImage;
+}
+
+- (UIImage *) scaleToSize:(CGSize) size
+{
+    return [self scaleToSize:size retainAspect:NO fit:NO];
+}
+
+-(UIImage *)scaleByValue:(float)scaleValue
+{
+    //we just need to scale the size of the new image
+    CGSize size = self.size;
+    size.width *= scaleValue;
+    size.height *= scaleValue;
+    return [self scaleToSize:size];
+}
+
+#pragma mark - insetting
+
+-(UIImage *)inset:(UIEdgeInsets)insets
+{
+    //prepare vars
+    CGRect frame = CGRectZero; frame.size = self.size;
+
+    //offset frame
+    frame.origin.y -= insets.top;
+    frame.origin.x -= insets.left;
+
+    //size of new image
+    CGSize newImageSize = self.size;
+    newImageSize.width -= (insets.left + insets.right);
+    newImageSize.height -= (insets.top + insets.bottom);
+
+    //begin context
+    UIGraphicsBeginImageContextWithOptions(newImageSize, YES, self.scale);
+
+    //setup context, need to transform coordinates to screen space
+    CGContextRef context = UIGraphicsGetCurrentContext();
+    CGContextTranslateCTM(context, 0.0, newImageSize.height);
+    CGContextScaleCTM(context, 1.0, -1.0);
+
+    CGContextDrawImage(context, frame, self.CGImage);
+
+    UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
+
+    UIGraphicsEndImageContext();
+    return scaledImage;
+}
+
+@end