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, 0);
[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(30, 30, 100, 100)];
cyanView.backgroundColor = [UIColor cyanColor];
cyanView.alpha = 0.5f;
[self.view addSubview:cyanView];
UIImageView *imageView = [[UIImageView alloc] initWithImage:[cyanView screenShot]];
imageView.frame = CGRectMake(80, 80, 100, 100);
[self.view addSubview:imageView];
}
@end
