IOS后台截取手机屏幕的实现(录屏)

最近自己在搞全局截屏，抓取屏幕的方法很多，但是大多都是抓取UIView的，或者只能抓取应用window的，当程序进入后台的时候就没法抓取手机桌面的，搜了很多也没有抓取全局屏幕的，只有一个利用硬件缓冲区的方式来抓取全局屏幕的方法，需要用到苹果的私有API。主要是IOKIT IOMobileFramebuffer IOSurface 三个framework、因为需要修改一些地方才可以用使用。下面我就把我整理的代码写上来，供大家参考使用

#import <IOMobileFramebuffer.h>#import <IOKit/IOKitLib.h>#import <IOSurface/IOSurface.h>#import <QuartzCore/QuartzCore.h>

extern  IOReturn IOSurfaceLock(IOSurfaceRef buffer, uint32_t options, uint32_t *seed);

extern  IOReturn IOSurfaceUnlock(IOSurfaceRef buffer, uint32_t options, uint32_t *seed);

extern  size_t IOSurfaceGetWidth(IOSurfaceRef buffer);

extern  size_t IOSurfaceGetHeight(IOSurfaceRef buffer);

extern  IOSurfaceRef IOSurfaceCreate(CFDictionaryRef properties);

extern  void *IOSurfaceGetBaseAddress(IOSurfaceRef buffer);

extern  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;

}

上面的这段代码有个问题也许大家会发现，就是IOSurfaceRef（destSurf）的释放问题，这个东西释放早了录不下屏，晚了内存会在几秒内崩溃，所以需要在用完用

CFRelease立即释放。血的教训。

编译时你会发现，编译出错了，因为IOSurfaceAcceleratorRef这个定义和IOSurfaceAcceleratorCreate，IOSurfaceAcceleratorTransferSurface这个两个函数你找不到，是因为最初的编辑者少上传了一个头文件导致的，下面我就把这个头文件给贴上来：

//// IOSurfaceAccelerator.h//#ifndef _IOSURFACE_ACCELERATOR_H#define _IOSURFACE_ACCELERATOR_H 1#include <IOSurface/IOSurfaceAPI.h>#include <IOKit/IOReturn.h>#if __cplusplusextern "C" {#endiftypedef IOReturn IOSurfaceAcceleratorReturn;enum {kIOSurfaceAcceleratorSuccess = 0,};typedef struct __IOSurfaceAccelerator *IOSurfaceAcceleratorRef;IOSurfaceAcceleratorReturn IOSurfaceAcceleratorCreate(CFAllocatorRef allocator, uint32_t type, IOSurfaceAcceleratorRef *outAccelerator);IOSurfaceAcceleratorReturn IOSurfaceAcceleratorTransferSurface(IOSurfaceAcceleratorRef accelerator, IOSurfaceRef sourceSurface, IOSurfaceRef destSurface, CFDictionaryRef dict, void *unknown);#if __cplusplus}#endif#endif

就是它了，把它拷贝下去，写到IOSurfaceAccelerator.h中，并且放到headers/IOSurface目录下，修改一下IOSurface.h文件，在文件最后添加上，

#include <IOSurface/IOSurfaceAccelerator.h>

就算完工了。剩下的就是编译了连接了。

连接的时候，你需要添加IOKit.framework,IOMobileFramebuffer.framework和IOSurface.framework这三个包，才能够顺利的编译过去。

文章前半部分引用了这个shenyi0106文章解决了我的

IOSurfaceAcceleratorRef找不到的问题。代码是我目前正在使用的内容。希望能对你们遇到同样问题的人有点帮助

稍后给上修改过的头文件

<pre name="code" class="html"><a target=_blank href="http://download.csdn.net/detail/benyoulai5/9058913" target="_blank">这里给上头文件</a>