關於圖片壓縮尺寸和大小

距離上次博客時間已經有十天左右，過了那麼久纔有時間來寫博客，頓時以爲堅持仍是很困難的！！！

此次開發中遇到一個很頭疼的問題，是圖片壓縮的問題，先說下咱們的要求，咱們要求圖片要在600x400的尺寸，若是在這個範圍內就不做處理，若是比這個尺寸大，就要改變尺寸大小。同時要保持圖片的大小要在50K以內。。。

廢話不說了上代碼，請路過的大神來指點下，由於個人圖片問題還未徹底解決，上傳的時候有的會被壓縮到80K左右，仍是要改善代碼的。。。。

 

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

{

　　//image是須要改變的image,asize是須要改變的尺寸，咱們的是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;

        //若是比例比現有比例高

        if(sizeFactor > asizeFactor){

            if(width < targetWidth){

                //高度比標準小  寬度一定比標準小

                sacleWidth = width;

                sacleHeigh = height;

            }else{

                //寬度比標準大 計算高度

                sacleWidth = 400;

                sacleHeigh = height / (width / targetWidth);

            }

        }

        else{

            if(height < targetHeight){

                //高度比標準小  寬度一定比標準小

                sacleWidth = width;

                sacleHeigh = height;

            }else{

                //寬度比標準大 計算高度

                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;

    

}

// 對圖片進行壓縮

+ (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;

//大於50k壓縮，小於50k不做處理

    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;

}