OC 说一说IOS里的截屏方法_ios oc 截图-优快云博客

本文详细介绍了iOS平台下多种屏幕截图方法，包括私有API、常见方法、针对Retina屏幕的改进方法，以及如何通过PrivateFramework实现底层获取屏幕缓冲数据生成UIImage实例。特别强调了私有API的限制及其替代方案，提供了完整代码示例。

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第一种

这是IOS3时代开始就被使用的方法，废止与IOS7。IOS私有方法，效率很赞。

#import
extern "C" CGImageRef UIGetScreenImage();
UIImage * screenshot(void) NS_DEPRECATED_IOS(3_0,7_0);
UIImage * screenshot(){
    UIImage *image = [UIImage imageWithCGImage:UIGetScreenImage()];
    return image;
}

第二种

这是比较常见的截图方法，缺憾是不支持Retina屏幕。

UIImage * screenshot(UIView *);
UIImage * screenshot(UIView *view){
    UIGraphicsBeginImageContext(view.frame.size);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

第三种

从iPhone4、iPod Touch4开始，Aplle逐渐采用Retina屏幕，于是在IOS4的SDK中我们有了，上面的截图方法也自然变了。

UIImage * screenshot(UIView *) NS_AVAILABLE_IOS(4_0);
UIImage * screenshot(UIView *view){
    if(UIGraphicsBeginImageContextWithOptions != NULL)
    {
        UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, 0.0);
    } else {
        UIGraphicsBeginImageContext(view.frame.size);
    }
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

第四种

如果说Hook的是一个按钮的方法，用第三个方法的话，根本找不到view来传值，不过还好，IOS7又提供了一些UIScreen的API。

UIImage * screenshot(void) NS_AVAILABLE_IOS(7_0);
UIImage * screenshot(){
    UIView * view = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:YES];
    if(UIGraphicsBeginImageContextWithOptions != NULL)
    {
        UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, 0.0);
    } else {
        UIGraphicsBeginImageContext(view.frame.size);
    }
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

第五种

<pre name="code" class="objc">@interface SBScreenShotter : NSObject
+ (id)sharedInstance;
- (void)saveScreenshot:(_Bool)arg1;
@end

然后直接

[[SBScreenShotter sharedInstance] saveScreenshot:YES];

会闪一道白光，模拟用户截屏的动作，不过这个方法在真截屏时候比较好，如果是对着录像，那就瞎了。况且UIImage的也拼不成一个视频啊。

现在我们有5种方法了，第一种是私有API，私有API通常效率和质量都比其他的要好，但是IOS7之后，它没有了，有可以代替的嘛？

YES！

用Pirvate Framework来完成这项任务！直接走底层拿屏幕的缓冲数据，然后生成UIImage的实例。

第六种

#import #import #import #import #import extern "C" IOReturn IOSurfaceLock(IOSurfaceRef buffer, uint32_t options, uint32_t *seed);
extern "C" IOReturn IOSurfaceUnlock(IOSurfaceRef buffer, uint32_t options, uint32_t *seed);
extern "C" size_t IOSurfaceGetWidth(IOSurfaceRef buffer);
extern "C" size_t IOSurfaceGetHeight(IOSurfaceRef buffer);
extern "C" IOSurfaceRef IOSurfaceCreate(CFDictionaryRef properties);
extern "C" void *IOSurfaceGetBaseAddress(IOSurfaceRef buffer);
extern "C" size_t IOSurfaceGetBytesPerRow(IOSurfaceRef buffer);
extern const CFStringRef kIOSurfaceAllocSize;
extern const CFStringRef kIOSurfaceWidth;
extern const CFStringRef kIOSurfaceHeight;
extern const CFStringRef kIOSurfaceIsGlobal;
extern const CFStringRef kIOSurfaceBytesPerRow;
extern const CFStringRef kIOSurfaceBytesPerElement;
extern const CFStringRef kIOSurfacePixelFormat;
enum
{
    kIOSurfaceLockReadOnly  =0x00000001,
    kIOSurfaceLockAvoidSync =0x00000002
};
UIImage * screenshot(void);
UIImage * screenshot(){
    IOMobileFramebufferConnection connect;
    kern_return_t result;
CoreSurfaceBufferRef screenSurface = NULL;
    io_service_t framebufferService = IOServiceGetMatchingService(kIOMasterPortDefault,IOServiceMatching("AppleH1CLCD"));
if(!framebufferService)
        framebufferService = IOServiceGetMatchingService(kIOMasterPortDefault,IOServiceMatching("AppleM2CLCD"));
if(!framebufferService)
        framebufferService = IOServiceGetMatchingService(kIOMasterPortDefault,IOServiceMatching("AppleCLCD"));
result = IOMobileFramebufferOpen(framebufferService, mach_task_self(), 0, &connect);
result = IOMobileFramebufferGetLayerDefaultSurface(connect, 0, &screenSurface);
    uint32_t aseed;
    IOSurfaceLock((IOSurfaceRef)screenSurface, 0x00000001, &aseed);
    size_t width = IOSurfaceGetWidth((IOSurfaceRef)screenSurface);
    size_t height = IOSurfaceGetHeight((IOSurfaceRef)screenSurface);
    CFMutableDictionaryRef dict;
size_t pitch = width*4, size = width*height*4;
    int bPE=4;
    char pixelFormat[4] = {'A','R','G','B'};
    dict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
    CFDictionarySetValue(dict, kIOSurfaceIsGlobal, kCFBooleanTrue);
    CFDictionarySetValue(dict, kIOSurfaceBytesPerRow, CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type, &pitch));
    CFDictionarySetValue(dict, kIOSurfaceBytesPerElement, CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type, &bPE));
    CFDictionarySetValue(dict, kIOSurfaceWidth, CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type, &width));
    CFDictionarySetValue(dict, kIOSurfaceHeight, CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type, &height));
    CFDictionarySetValue(dict, kIOSurfacePixelFormat, CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type, pixelFormat));
    CFDictionarySetValue(dict, kIOSurfaceAllocSize, CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type, &size));
    IOSurfaceRef destSurf = IOSurfaceCreate(dict);
    IOSurfaceAcceleratorRef outAcc;
    IOSurfaceAcceleratorCreate(NULL, 0, &outAcc);
    IOSurfaceAcceleratorTransferSurface(outAcc, (IOSurfaceRef)screenSurface, destSurf, dict,NULL);
    IOSurfaceUnlock((IOSurfaceRef)screenSurface, kIOSurfaceLockReadOnly, &aseed);
CFRelease(outAcc);
    CGDataProviderRef provider =  CGDataProviderCreateWithData(NULL,  IOSurfaceGetBaseAddress(destSurf), (width * height * 4), NULL);
    CGImageRef cgImage = CGImageCreate(width, height, 8,
8*4, IOSurfaceGetBytesPerRow(destSurf),
 CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst |kCGBitmapByteOrder32Little,provider, NULL, YES, kCGRenderingIntentDefault);
    UIImage *image = [UIImage imageWithCGImage:cgImage];
    return image;
}

需要注意的是，第五种方法也需要修改一下IOMobileFramebuffer的头文件。

typedef void * IOMobileFramebufferConnection;

In the reversed header, IOMobileFramebufferConnection is typedef'd to io_connect_t, which is typedef'd to io_object_t, which is mach_port_t, which is __darwin_mach_port_t, which is __darwin_mach_port_name_t, which is __darwin_natural_t, which is unsigned int! Int just happens to be pointer-sized on 32-bit, but is not under 64-bit。

如果你使用的是theos的话，记得在Makefile里写上，

YOUR_TWEAK_NAME_PRIVATE_FRAMEWORKS = IOSurface IOKit IOMobileFramebuffer

YOUR_TWEAK_NAME_CFLAGS = -I./headers/ -I./headers/IOSurface

如果是XCode上的Logos Tweak的话，在Build Settings -> Search Paths -> Header Search Paths里面添加一项：$(PROJECT_DIR)/YOUR_PROJECT_NAME/headers, 搜索方式为recursive. 最后在Build Phases里Link上IOSurface IOKit IOMobileFramebuffer这三个私有Framework。