IOS图片压缩的类

//

//  UIImage+UIImageExt.m

//  MyHomeBuy

//

//  Created by first on 13-9-13.

//  Copyright (c) 2013年 __MyCompanyName__. All rights reserved.

//

#import "UIImage+UIImageExt.h"

@implementation UIImage (UIImageExt)

- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize;

{

    UIImage *sourceImage =self;

    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;

    CGPoint thumbnailPoint =CGPointMake(0.0,0.0);

    if (CGSizeEqualToSize(imageSize, targetSize) ==NO)

    {

        CGFloat widthFactor = targetWidth / width;

        CGFloat heightFactor = targetHeight / height;

        if (widthFactor > heightFactor)

            scaleFactor = widthFactor;// scale to fit height

        else

            scaleFactor = heightFactor;// scale to fit width

        scaledWidth= width * scaleFactor;

        scaledHeight = height * scaleFactor;

        // center the image

        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;

    [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;

}

@end

//

//  UIImage+UIImageExt.h

//  MyHomeBuy

//

//  Created by first on 13-9-13.

//  Copyright (c) 2013年 __MyCompanyName__. All rights reserved.

//

#import <UIKit/UIKit.h>

@interface UIImage (UIImageExt)

- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize;

@end