iOS图片的处理

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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-Cswif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-Cswif版：https://github.com/GaoQianpu/QPImageToor

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