ios 工具类系列-----图片处理--imageUtil

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博文原创，转载请声明出处

电子咖啡(原id蓝岩)

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ios开发中需要用到不少的工具类，这里记录一下，可能会不完美，后续会不断的更新，也希望大家能分享自己好的工具。

Imageutil.h 可以从相册中选取图像，并且剪裁为指定大小保存到本地：

Imageutil.h

//
//  Imageutil.h
//

#import <Foundation/Foundation.h>
#import "NSData+Base64.h"
@protocol ImageutilDelegate <NSObject>
@required
-(void)didFinishPickingMedia;

@end

@interface Imageutil : NSObject<UINavigationControllerDelegate, UIImagePickerControllerDelegate>
@property (retain,nonatomic) UIViewController<ImageutilDelegate>* viewcontroller;
@property (retain,nonatomic) NSString* imageName;

-(Imageutil*)initWithViewController:(UIViewController<ImageutilDelegate>*)viewcontroller_ imageName:(NSString*)imageName_;
-(void)selectImage;
+(UIImage*)getImageByName:(NSString*)imageName;
+ (void)saveImage:(UIImage *)tempImage WithName:(NSString *)imagen;

- (UIImage*) scalingAndCroppingToSize:(CGSize)targetSize withImage:(UIImage*)sourceImage;
@end

Imageutil.m

//
//  Imageutil.m
//  Yunho2
//
//  Created by l on 12-11-5.
//
//

#import "Imageutil.h"
#define IMAGE_TYPE @"portrait"

@implementation Imageutil{
    
}
@synthesize viewcontroller;
@synthesize imageName;
-(Imageutil*)initWithViewController:(UIViewController<ImageutilDelegate>*)viewcontroller_ imageName:(NSString*)imageName_{
    if ((self=[super init]) !=nil) {
        self.viewcontroller=viewcontroller_;
        self.imageName=imageName_;
        return self;
    }
    return nil;
}
-(void)selectImage{
    UIImagePickerController *imagePicker = [[[UIImagePickerController alloc] init]autorelease];
    imagePicker.delegate = self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    imagePicker.allowsEditing = YES;    
    [viewcontroller presentModalViewController:imagePicker animated:YES];
}

+ (void)saveImage:(UIImage *)tempImage WithName:(NSString *)imagen
{
    NSData* imageData = UIImagePNGRepresentation(tempImage);
    NSString* documentsDirectory = [Imageutil getDocumentFolderPath];
    // Now we get the full path to the file and then we write it out
    NSString* imageDirPath=[documentsDirectory stringByAppendingPathComponent:IMAGE_TYPE];
    NSFileManager *manager = [NSFileManager defaultManager];
    
    if ([manager fileExistsAtPath:imageDirPath]==NO) {
        [manager createDirectoryAtPath:imageDirPath withIntermediateDirectories:YES attributes:nil error:nil];
    }
    [imageData writeToFile:[imageDirPath stringByAppendingPathComponent:imagen               ] atomically:NO];
}
+ (NSString *)getDocumentFolderPath
{
    NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    return [paths objectAtIndex:0];
}
- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage *image= [info objectForKey:@"UIImagePickerControllerOriginalImage"];
    UIImage* scaledImage=[self scalingAndCroppingToSize:CGSizeMake(64, 64) withImage:image];
    [Imageutil saveImage:scaledImage WithName:imageName];
    [viewcontroller dismissModalViewControllerAnimated:YES];
    [viewcontroller didFinishPickingMedia];

}
+(UIImage*)getImageByName:(NSString*)imageName{
    if (imageName==nil || [@"" isEqualToString:imageName]) {
        return nil;
    }
    NSString* documentsDirectory = [Imageutil getDocumentFolderPath];
    NSString* imagePath=[documentsDirectory stringByAppendingPathComponent:IMAGE_TYPE];
    return [UIImage imageWithContentsOfFile:[imagePath stringByAppendingPathComponent:imageName]];
}

//剪裁&压缩图片
- (UIImage*) scalingAndCroppingToSize:(CGSize)targetSize withImage:(UIImage*)sourceImage
{
    UIImage *newImage = nil;
    CGSize imageSize = sourceImage.size;
    CGFloat width = imageSize.width;
    CGFloat height = imageSize.height;
    CGFloat targetWidth = targetSize.width;
    CGFloat targetHeight = targetSize.height;
    CGFloat scaleFactor = 0.0;
    CGFloat scaledWidth = targetWidth;
    CGFloat scaledHeight = targetHeight;
    //剪裁点的位置，以3*2长方形剪裁为2*2正方形为例，截取image中心部分，剪切点为（0，0.5）
    CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
    
    if (CGSizeEqualToSize(imageSize, targetSize) == NO)
    {
        //compress scale
        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;
        
        //set scaleFactoras lesser scale,fit lesser scale
        if (widthFactor > heightFactor)
            scaleFactor = widthFactor; // scale to fit height
        else
            scaleFactor = heightFactor; // scale to fit width
        
        //reset the target size with the new scale factor
        scaledWidth  = width * scaleFactor;
        scaledHeight = height * scaleFactor;
        
        // get cropping point
        if (widthFactor > heightFactor)
        {
            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
        }
        else if (widthFactor < heightFactor)
        {
            thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
        }
    }
    
    UIGraphicsBeginImageContext(targetSize); // this will crop
    
    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = thumbnailPoint;
    thumbnailRect.size.width  = scaledWidth;
    thumbnailRect.size.height = scaledHeight;
    
    //corpping image to special rectangle
    [sourceImage drawInRect:thumbnailRect];
    
    newImage = UIGraphicsGetImageFromCurrentImageContext();
    if(newImage == nil)
        NSLog(@"could not scale image");
    
    //pop the context to get back to the default
    UIGraphicsEndImageContext();
    return newImage;
}


-(void)dealloc{
    [super dealloc];
    [viewcontroller release];
    [imageName release];
}
@end