图片处理

1、旋转
2、裁剪
3、截取
4、平铺

自由拉伸

func imageWithResizedImage(name:String,width:CGFloat,height:CGFloat) ->UIImage? {
    let image = UIImage(named: name)
    return image?.stretchableImage(withLeftCapWidth: Int(width), topCapHeight: Int(height))
}

等比例缩放

func imageWithOriginImage(image:UIImage,defineWidth:CGFloat)->UIImage? {
    let imageSize = image.size
    let width = imageSize.width
    let height = imageSize.height
    let targetWidth = defineWidth
    let targetHeight = height / (width / targetWidth)
    
    let size = CGSize(width: targetWidth, height: targetHeight)
    
    UIGraphicsBeginImageContext(size)//size 为CGSize类型，即你所需要的图片尺寸
    
    image.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
    
    let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
    
    UIGraphicsEndImageContext()
    
    return scaledImage
}

根据颜色生成图片

func imageWithColor(color:UIColor,size:CGSize) ->UIImage? {
    let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    //开启位图上下文
    UIGraphicsBeginImageContext(rect.size)
    //获取上下文
    let context = UIGraphicsGetCurrentContext()
    context?.setFillColor(color.cgColor)
    context?.fill(rect)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    
    //关闭上下文
    UIGraphicsEndImageContext()
    
    return image
}

截取某个view视图

func imageWithCaptureView(captureView:UIView) ->UIImage? {
    //开启位图上下文
    UIGraphicsBeginImageContextWithOptions(captureView.bounds.size, false, 0)
    //获取上下文
    if let ctx = UIGraphicsGetCurrentContext() {
        //把控件上的图层渲染到上下文
        captureView.layer.render(in: ctx)
        
        let screenImage = UIGraphicsGetImageFromCurrentImageContext()
        
        //关闭上下文
        UIGraphicsEndImageContext()
        
        return screenImage
    }
    return nil
}

文字水印

func imageWithWaterMarkImage(imageName:String,str:String,point:CGPoint,dict:NSDictionary) ->UIImage? {
    if let image = UIImage(named: imageName) {
        UIGraphicsBeginImageContextWithOptions(image.size, false, 0)
        
        //把图片画上去
        image.draw(at: CGPoint.zero)
        
        //绘制文字到图片
        (str as! NSString).draw(at: point, withAttributes: dict as! [NSAttributedStringKey : Any])
        
        // 从上下文获取图片
        let imageWater = UIGraphicsGetImageFromCurrentImageContext()
        
        //关闭上下文
        UIGraphicsEndImageContext()
        
        return imageWater
    }
    return nil
}

图片水印

func imageWithWaterMarkImage(image:UIImage,waterImage:UIImage,rect:CGRect) ->UIImage? {
    //1.开启上下文
    UIGraphicsBeginImageContextWithOptions(image.size, false, 0)
    //2.绘制背景图片
    image.draw(in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
    //绘制水印图片到当前上下文
    waterImage.draw(in: rect)
    //3.从上下文中获取新图片
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    //4.关闭图形上下文
    UIGraphicsEndImageContext()
    //返回图片
    return newImage
}

图片切圆

func imageWithClipImage(image:UIImage,borderWidth:CGFloat,color:UIColor) ->UIImage? {
    // 图片的宽度和高度
    let imageWH = image.size.width
    
    // 设置圆环的宽度
    let border = borderWidth
    
    // 圆形的宽度和高度
    let ovalWH = imageWH + 2 * border
    
    // 1.开启上下文
    UIGraphicsBeginImageContextWithOptions(CGSize(width: ovalWH, height: ovalWH), false, 0)
    
    // 2.画大圆
    let path = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: ovalWH, height: ovalWH))
    color.set()
    
    path.fill()
    
    // 3.设置裁剪区域
    let clipPath = UIBezierPath(ovalIn: CGRect(x: border, y: border, width: imageWH, height: imageWH))
    clipPath.addClip()
    
    // 4.绘制图片
    image.draw(at: CGPoint(x: border, y: border))
    
    // 5.获取图片
    let clipImage = UIGraphicsGetImageFromCurrentImageContext()
    
    // 6.关闭上下文
    UIGraphicsEndImageContext()
    return clipImage
}