IOS截屏，View截图的基本方法

IOS截屏的方法网上有很多，以下是我个人认为比较好的一个，我稍微改了一点

来源：SDScreenshotCapture

#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)

UIImage *getImageWithFullScreenshot(void)
{
    // Source (Under MIT License): https://github.com/shinydevelopment/SDScreenshotCapture/blob/master/SDScreenshotCapture/SDScreenshotCapture.m#L35
    
    BOOL ignoreOrientation = SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"8.0");
    
    UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
    
    CGSize imageSize = CGSizeZero;
    if (UIInterfaceOrientationIsPortrait(orientation) || ignoreOrientation)
        imageSize = [UIScreen mainScreen].bounds.size;
    else
        imageSize = CGSizeMake([UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width);
    
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, [UIScreen mainScreen].scale);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    for (UIWindow *window in [[UIApplication sharedApplication] windows])
    {
        CGContextSaveGState(context);
        CGContextTranslateCTM(context, window.center.x, window.center.y);
        CGContextConcatCTM(context, window.transform);
        CGContextTranslateCTM(context, -window.bounds.size.width * window.layer.anchorPoint.x, -window.bounds.size.height * window.layer.anchorPoint.y);
        
        // Correct for the screen orientation
        if(!ignoreOrientation)
        {
            if(orientation == UIInterfaceOrientationLandscapeLeft)
            {
                CGContextRotateCTM(context, (CGFloat)M_PI_2);
                CGContextTranslateCTM(context, 0, -imageSize.width);
            }
            else if(orientation == UIInterfaceOrientationLandscapeRight)
            {
                CGContextRotateCTM(context, (CGFloat)-M_PI_2);
                CGContextTranslateCTM(context, -imageSize.height, 0);
            }
            else if(orientation == UIInterfaceOrientationPortraitUpsideDown)
            {
                CGContextRotateCTM(context, (CGFloat)M_PI);
                CGContextTranslateCTM(context, -imageSize.width, -imageSize.height);
            }
        }
        
        if([window respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)])
            [window drawViewHierarchyInRect:window.bounds afterScreenUpdates:NO];
        else
            [window.layer renderInContext:UIGraphicsGetCurrentContext()];
        
        CGContextRestoreGState(context);
    }
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return image;
}

h文件

#import <UIKit/UIKit.h>

@interface UIWindow (Category)

- (UIImage *)screenshot;
- (UIImage *)screenshotWithRect:(CGRect)rect;

@end

#import "UIWindow+Category.h"

@implementation UIWindow (Category)

- (UIImage *)screenshot
{
    return [self screenshotWithRect:self.bounds];
}

- (UIImage *)screenshotWithRect:(CGRect)rect
{
    // Source (Under MIT License): https://github.com/shinydevelopment/SDScreenshotCapture/blob/master/SDScreenshotCapture/SDScreenshotCapture.m#L35
    
    BOOL ignoreOrientation = SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"8.0");
    
    UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
    
    CGSize imageSize = CGSizeZero;
    CGFloat width = rect.size.width, height = rect.size.height;
    CGFloat x = rect.origin.x, y = rect.origin.y;
    
//    imageSize = CGSizeMake(width, height);
//    UIGraphicsBeginImageContextWithOptions(imageSize, NO, [UIScreen mainScreen].scale);
    if (UIInterfaceOrientationIsPortrait(orientation) || ignoreOrientation)
    {
        //imageSize = [UIScreen mainScreen].bounds.size;
        imageSize = CGSizeMake(width, height);
        x = rect.origin.x, y = rect.origin.y;
    }
    else
    {
        //imageSize = CGSizeMake([UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width);
        imageSize = CGSizeMake(height, width);
        x = rect.origin.y, y = rect.origin.x;
    }
    
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, [UIScreen mainScreen].scale);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);
    CGContextTranslateCTM(context, self.center.x, self.center.y);
    CGContextConcatCTM(context, self.transform);
    CGContextTranslateCTM(context, -self.bounds.size.width * self.layer.anchorPoint.x, -self.bounds.size.height * self.layer.anchorPoint.y);
    
    // Correct for the screen orientation
    if(!ignoreOrientation)
    {
        if(orientation == UIInterfaceOrientationLandscapeLeft)
        {
            CGContextRotateCTM(context, (CGFloat)M_PI_2);
            CGContextTranslateCTM(context, 0, -self.bounds.size.height);
            CGContextTranslateCTM(context, -x, y);
        }
        else if(orientation == UIInterfaceOrientationLandscapeRight)
        {
            CGContextRotateCTM(context, (CGFloat)-M_PI_2);
            CGContextTranslateCTM(context, -self.bounds.size.width, 0);
            CGContextTranslateCTM(context, x, -y);
        }
        else if(orientation == UIInterfaceOrientationPortraitUpsideDown)
        {
            CGContextRotateCTM(context, (CGFloat)M_PI);
            CGContextTranslateCTM(context, -self.bounds.size.height, -self.bounds.size.width);
            CGContextTranslateCTM(context, x, y);
        }
        else
        {
            CGContextTranslateCTM(context, -x, -y);
        }
    }
    else
    {
        CGContextTranslateCTM(context, -x, -y);
    }
    
    //[self layoutIfNeeded];
    
    if([self respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)])
        [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:NO];
    else
        [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    
    CGContextRestoreGState(context);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

@end

此代码在旋转后，裁剪区域是相对左上角为原点旋转的，一般使用不到旋转情况

View截图

h文件

@interface UIView (Screenshot)
- (UIImage *)screenshot;
- (UIImage *)screenshotWithRect:(CGRect)rect;
@end

m文件

@implementation UIView (Screenshot)

- (UIImage *)screenshot
{
    return [self screenshotWithRect:self.bounds];
}

- (UIImage *)screenshotWithRect:(CGRect)rect;
{
    UIGraphicsBeginImageContextWithOptions(rect.size, NO, [UIScreen mainScreen].scale);

    CGContextRef context = UIGraphicsGetCurrentContext();
    if (context == NULL)
    {
        return nil;
    }
    CGContextSaveGState(context);
    CGContextTranslateCTM(context, -rect.origin.x, -rect.origin.y);
    
    //[self layoutIfNeeded];

    if( [self respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)])
    {
        [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:NO];
    }
    else
    {
        [self.layer renderInContext:context];
    }
    
    CGContextRestoreGState(context);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
//    NSData *imageData = UIImageJPEGRepresentation(image, 1); // convert to jpeg
//    image = [UIImage imageWithData:imageData scale:[UIScreen mainScreen].scale];
    
    return image;
}