iOS图片的处理

最近几个月一直在忙项目，项目昨天做了上线，今天的时间比较充足，对项目中的图片处理做个简单的总结，希望广大朋友们支持一下

完整Demo地址

OC版：https://github.com/GaoQianpu/QPImageToor_Obj-C swif版：https://github.com/GaoQianpu/QPImageToor

1、改变image的size

    CGRect rect =CGRectMake(0,0, size.width, size.height);

    UIGraphicsBeginImageContextWithOptions(size,NO,2.0);

//关键步骤：在rect内将该图片画进去

    [image drawInRect:rect];

    UIImage * scaledImage =UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

   

2、image的裁剪（此处我将图片居中裁剪成为正方形，大家可根据自己的需求调整）

此处swift和OC使用不同的API，但是原理还是相同的 注意！！在进行截图的时候自己一定要算对尺寸，因为当裁剪范围超出 图片范围后，得到的image为空 当然这里也可以用贝塞尔曲线，选择出自己需要的区域，然后再把这部分图像给画上去，这部分代码在后续写贝塞尔曲线的时候再写，这里就不赘述了

OC:

  CGRect rect =CGRectZero;

//计算rect使截图居中

    if (image.size.width>image.size.height) {

        rect = CGRectMake((image.size.width-image.size.height)*0.5,0, image.size.height, image.size.height);

    }else{

        rect = CGRectMake(0, (image.size.height-image.size.width)*0.5, image.size.width, image.size.width);

    }

    

    CGImageRef subImageRef =CGImageCreateWithImageInRect(image.CGImage, rect);

    CGRect smallBounds =CGRectMake(0,0,CGImageGetWidth(subImageRef),CGImageGetHeight(subImageRef));

    UIGraphicsBeginImageContextWithOptions(smallBounds.size,NO,2.0);

    CGContextRef context =UIGraphicsGetCurrentContext();

    CGContextDrawImage(context, smallBounds, subImageRef);

    UIImage * newImage = [UIImageimageWithCGImage:subImageRef];

    UIGraphicsEndImageContext();

swift: //因为在swif中， CGImageRef被取消，不过本质还是指image的CGImage

  var point =CGPoint.zero

        var size =CGSize.zero

        if image.size.width > image.size.height {

            point = CGPoint(x: (image.size.width - image.size.height) * 0.5, y: 0)

            size.height = image.size.height

            size.width = image.size.height

        }else{

            point = CGPoint(x:0, y: (image.size.height - image.size.width) *0.5)

            size.width = image.size.width

            size.height = image.size.width

        }

        let imageRef = image.cgImage

        let subImageRef = imageRef!.cropping(to:CGRect(origin: point, size: size))

        let newImage =UIImage(cgImage: subImageRef!)

2、image的拉伸

正常情况下修改UIImageView，UIButton等控件的size，会随意拉伸其中的UIImage，使图片变形，如果图形全靠美工妹子切的话，那可怜的猿猿们该单身到多会儿啊，为了广大单身同志的幸福，大家肯定是愿意多写几行代码，而不是葬送自己撩到妹的机会，因为毕竟搞开发的平时很难接触到太多的妹子，你们说是不？

现在iOS已经基本上都在iOS 8以上了，所以iOS 8以前的API基本上用不到了，不过我还是把代码贴出来让大家一饱眼福

iOS 6以上

CGFloat top = image.size.height * 0.5;

        CGFloat left = image.size.width * 0.5;

        CGFloat bottom = image.size.height * 0.5;

        CGFloat right = image.size.width * 0.5;    

        UIEdgeInsets edgeInsets =UIEdgeInsetsMake(top, left, bottom, right);

       UIImageResizingMode mode =UIImageResizingModeStretch;

        newImage = [imageresizableImageWithCapInsets:edgeInsetsresizingMode:mode];

iOS 5 --- iOS 6

            CGFloat top = image.size.height *0.5;

            CGFloat left = image.size.width *0.5;

            CGFloat bottom = image.size.height *0.5;

            CGFloat right = image.size.width *0.5;

            

            UIEdgeInsets edgeInsets =UIEdgeInsetsMake(top, left, bottom, right);

            UIImageResizingMode mode =UIImageResizingModeStretch;

            newImage = [image resizableImageWithCapInsets:edgeInsets resizingMode:mode];

iOS 5以下

        CGFloat top = image.size.height *0.5;

            CGFloat left = image.size.width *0.5;

            CGFloat bottom = image.size.height *0.5;

            CGFloat right = image.size.width *0.5;

            UIEdgeInsets edgeInsets =UIEdgeInsetsMake(top, left, bottom, right);

            newImage = [image resizableImageWithCapInsets:edgeInsets];

3、image的拼接

//拼接尺寸及坐标

    UIImage * image1 = [UIImage imageNamed:@"1"];

    UIImage * image2 = [UIImage imageNamed:@"2"];

    CGRect rect1 =CGRectMake(0,0, image1.size.width ,image1.size.height);

    CGRect rect2 =CGRectMake(0,image1.size.height +5, image2.size.width, im2.size.height);

//拼接图片后的总大小

    CGSize size =CGSizeMake(200,image1.size.height + im2.size.height + 5);

    UIGraphicsBeginImageContextWithOptions(size,false, 2.0);

    [image1drawInRect:rect1]; //把第一张图画上去

    [image2 drawInRect:rect2];//把第二张画上去

    UIImage * drawImage =UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

最后，再给大家说下我的Demo下载地址

完整Demo地址

OC版：https://github.com/GaoQianpu/QPImageToor_Obj-C swif版：https://github.com/GaoQianpu/QPImageToor