时间 2014-12-22 09:20:48CocoaChina
原文http://www.cocoachina.com/ios/20141222/10713.html
主题iOS开发
昨天写了个用到截屏功能的插件，结果问题不断，今天终于解决好了，把debug过程中所有尝试过的截屏方法都贴出来吧～
第一种
这是iOS 3时代开始就被使用的方法，它被废止于iOS 7。iOS的私有方法，效率很高。
#importextern"C"CGImageRefUIGetScreenImage();UIImage* screenshot(void)NS_DEPRECATED_IOS(3_0,7_0);UIImage* screenshot(){UIImage*image = [UIImageimageWithCGImage:UIGetScreenImage()];returnimage;}
第二种
这是在比较常见的截图方法，不过不支持Retina屏幕。
UIImage* screenshot(UIView*);UIImage* screenshot(UIView*view){UIGraphicsBeginImageContext(view.frame.size);[view.layer renderInContext:UIGraphicsGetCurrentContext()];UIImage*image =UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();returnimage;}
第三种
从iPhone 4、iPod Touch 4开始，Apple逐渐采用Retina屏幕，于是在iOS 4的SDK中我们有了，上面的截图方法也自然变成了这样。
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();returnimage;}
第四种
或许你会说有时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，iOS 7又提供了一些UIScreen的API。
UIImage* screenshot(void)NS_AVAILABLE_IOS(7_0);UIImage* screenshot(){UIView* view = [[UIScreenmainScreen] 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();returnimage;}
第五种
@interfaceSBScreenShotter: NSObject+ (id)sharedInstance;-(void)saveScreenshot:(_Bool)arg1;@end
然后直接
[[SBScreenShotter sharedInstance] saveScreenshot:YES];
一道白光之后，咱们就模拟了用户截屏的动作，不过这个方法在只需要截屏时比较好，如果要对屏幕录像（其实就是不断截图）的话，那不得闪瞎了。。而且我们也拿不到UIImage的实例去拼成一个视频呀。即使通过Hook别的类拿到UIImage的实例，这个私有API的效率大概也是达不到30FPS的视频要求的。
那么现在我们有5种方法了，第一种是私有API，私有API通常效率和质量都比Documented API的好，可是它在iOS 7以后就被废除了啊，就没有别的了吗？
答案当然是————有的！用Private 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(CFDictionaryRefproperties);extern"C"void*IOSurfaceGetBaseAddress(IOSurfaceRef buffer);extern"C"size_t IOSurfaceGetBytesPerRow(IOSurfaceRef buffer);externconstCFStringRefkIOSurfaceAllocSize;externconstCFStringRefkIOSurfaceWidth;externconstCFStringRefkIOSurfaceHeight;externconstCFStringRefkIOSurfaceIsGlobal;externconstCFStringRefkIOSurfaceBytesPerRow;externconstCFStringRefkIOSurfaceBytesPerElement;externconstCFStringRefkIOSurfacePixelFormat;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);CFMutableDictionaryRefdict;size_t pitch = width*4, size = width*height*4;intbPE=4;charpixelFormat[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);CGDataProviderRefprovider =CGDataProviderCreateWithData(NULL, IOSurfaceGetBaseAddress(destSurf), (width * height *4),NULL);CGImageRefcgImage =CGImageCreate(width, height,8,8*4, IOSurfaceGetBytesPerRow(destSurf),CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst |kCGBitmapByteOrder32Little,provider,NULL,YES, kCGRenderingIntentDefault);UIImage*image = [UIImageimageWithCGImage:cgImage];returnimage;}
需要注意的是，第五种方法需要修改一下IOMobileFramebuffer的头文件。
typedefvoid* 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。
修改好的头文件顺便也丢上来吧，解压后放在Project的根目录下。
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。
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