关于图片压缩尺寸和大小

距离上次博客时间已经有十天左右，过了那么久才有时间来写博客，顿时以为坚持仍是很困难的！！！

此次开发中遇到一个很头疼的问题，是图片压缩的问题，先说下咱们的要求，咱们要求图片要在600x400的尺寸，若是在这个范围内就不做处理，若是比这个尺寸大，就要改变尺寸大小。同时要保持图片的大小要在50K以内。。。

废话不说了上代码，请路过的大神来指点下，由于个人图片问题还未彻底解决，上传的时候有的会被压缩到80K左右，仍是要改善代码的。。。。

 

+ (UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize 

{

　　//image是须要改变的image,asize是须要改变的尺寸，咱们的是600x400.

    UIImage *newImage = nil;

    CGSize imageSize = image.size;

    CGFloat width = imageSize.width;

    CGFloat height = imageSize.height;

    CGFloat targetWidth = asize.width;

    CGFloat targetHeight = asize.height;

    CGFloat scaledWidth = targetWidth;

    CGFloat scaledHeight = targetHeight;

    CGPoint thumbnailPoint = CGPointMake(0.0, 0.0);

    CGFloat sacleWidth = 0.0;

    CGFloat sacleHeigh = 0.0;

    if(CGSizeEqualToSize(imageSize, asize) == NO){

        CGFloat widthFactor = targetWidth / width;

        CGFloat heightFactor = targetHeight / height;

        CGFloat asizeFactor = targetWidth / targetHeight;

        CGFloat sizeFactor = width / height;

        //若是比例比现有比例高

        if(sizeFactor > asizeFactor){

            if(width < targetWidth){

                //高度比标准小  宽度一定比标准小

                sacleWidth = width;

                sacleHeigh = height;

            }else{

                //宽度比标准大 计算高度

                sacleWidth = 400;

                sacleHeigh = height / (width / targetWidth);

            }

        }

        else{

            if(height < targetHeight){

                //高度比标准小  宽度一定比标准小

                sacleWidth = width;

                sacleHeigh = height;

            }else{

                //宽度比标准大 计算高度

                sacleHeigh = 400;

                sacleWidth = width / (height / targetHeight);

            }

 

            

        }

        if(widthFactor > heightFactor){

            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;

        }else if(widthFactor < heightFactor){

            thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;

        }

        asize = CGSizeMake(sacleWidth, sacleHeigh);

    }

    UIGraphicsBeginImageContext(asize);

 

    UIImage *imageD = nil;

    if(newImage == nil){

        NSLog(@"scale image fail");

    } 

    [image drawInRect:CGRectMake(0,0,asize.width,asize.height)];

    UIImage* iamgeNews = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    imageD = [self imageWithJPGRepresentTationWith:iamgeNews withSacle:0.6f];

    return imageD;

    

}

// 对图片进行压缩

+ (UIImage *)imageWithJPGRepresentTationWith:(UIImage *)image withSacle:(CGFloat)sacle {

    NSData *imageData = UIImageJPEGRepresentation(image, sacle);

    NSData *imageData1 = UIImageJPEGRepresentation(image, 1.0f);

    NSData *imageData0 = UIImageJPEGRepresentation(image, 0.0f);

    UIImage *imag = nil;

//大于50k压缩，小于50k不做处理

    if(imageData.length / 1000 > 50){

        NSData *imageData2 = UIImageJPEGRepresentation(image, sacle);

        imag = [UIImage imageWithData:imageData2];

        NSLog(@"%ld",(long)imageData2.length / 1000);

    }else{

        imag = [UIImage imageWithData:imageData];

    }

    NSLog(@"%ld",(long)imageData.length / 1000);

    NSLog(@"%ld",(long)imageData1.length / 1000);

    NSLog(@"%ld",(long)imageData0.length / 1000);

    return imag;

}