UIView的无损截图

UIView的无损截图

说明

1. 烂大街的代码

2. 写成category后，方便直接从drawRect中获取绘制出来的图片

3. 可以直接绘制图片供按钮设置背景图片用

4. 无损截图（包括alpha通道值也被无损保存）

源码

//

//  UIView+ScreensShot.h

//  ColorfulView

//

//  Created by YouXianMing on 15/7/17.

//  Copyright (c) 2015年 YouXianMing. All rights reserved.

//

#import <UIKit/UIKit.h>

@interface UIView (ScreensShot)

/**

 *  无损截图

 *

 *  This function may be called from any thread of your app.

 *

 *  @return 返回生成的图片

 */

- (UIImage *)screenShot;

@end

//

//  UIView+ScreensShot.m

//  ColorfulView

//

//  Created by YouXianMing on 15/7/17.

//  Copyright (c) 2015年 YouXianMing. All rights reserved.

//

#import "UIView+ScreensShot.h"

#import <objc/runtime.h>

@implementation UIView (ScreensShot)

- (UIImage *)screenShot {

    if (self && self.frame.size.height && self.frame.size.width) {

        UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, );

        [self.layer renderInContext:UIGraphicsGetCurrentContext()];

        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

        return image;

    } else {

        return nil;

    }

}

@end

//

//  ViewController.m

//  ColorfulView

//

//  Created by YouXianMing on 15/7/10.

//  Copyright (c) 2015年 YouXianMing. All rights reserved.

//

#import "ViewController.h"

#import "UIView+ScreensShot.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    self.view.backgroundColor = [UIColor blackColor];

    UIView *cyanView         = [[UIView alloc] initWithFrame:CGRectMake(, , , )];

    cyanView.backgroundColor = [UIColor cyanColor];

    cyanView.alpha           = 0.5f;

    [self.view addSubview:cyanView];

    UIImageView *imageView   = [[UIImageView alloc] initWithImage:[cyanView screenShot]];

    imageView.frame          = CGRectMake(, , , );

    [self.view addSubview:imageView];

}

@end