iOS开发－截屏方法

1.

        UIGraphicsBeginImageContextWithOptions(pageView.page.bounds.size, YES, zoomScale);

        [pageView.page.layer renderInContext:UIGraphicsGetCurrentContext()];

        UIImage *uiImage = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

2.

- (UIImage *) glToUIImage {

     

    DWScrollView *pageView = [self getActivePageView];

       pageView.page.backgroundColor = [UIColor clearColor];

  //  self.backgroundColor=[UIColor clearColor];

    NSInteger myDataLength = 320 * 308 * 4;

     

    // allocate array and read pixels into it.

    GLubyte *buffer = (GLubyte *) malloc(myDataLength);

    glReadPixels(0, 0, 320, 308, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

     

    // gl renders "upside down" so swap top to bottom into new array.

    // there's gotta be a better way, but this works.

    GLubyte *buffer2 = (GLubyte *) malloc(myDataLength);

     

    for(int y = 0; y <308; y++)

    {

        for(int x = 0; x <320 * 4; x++)

        {

            if(buffer[y* 4 * 320 + x]==0)

                buffer2[(307 - y) * 320 * 4 + x]=1;

            else

                buffer2[(307 - y) * 320 * 4 + x] = buffer[y* 4 * 320 + x];

        }

    }

     

    // make data provider with data.

    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer2, myDataLength, NULL);

     

    // prep the ingredients

    int bitsPerComponent = 8;

    int bitsPerPixel = 32;

    int bytesPerRow = 4 * 320;

    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();

    CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;

    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

     

    // make the cgimage

    CGImageRef imageRef = CGImageCreate(320, 308, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);

     

    // then make the uiimage from that

    UIImage *myImage = [UIImage imageWithCGImage:imageRef];

    UIImageWriteToSavedPhotosAlbum(myImage, nil, nil, nil);

    return myImage;

}

 

3.

// get screen

- (void)grabScreen {

    unsigned char buffer[320*480*4];

    glReadPixels(0,0,320,480,GL_RGBA,GL_UNSIGNED_BYTE,&buffer);

     

    CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, &buffer, 320*480*4, NULL);

    CGImageRef iref = CGImageCreate(320,480,8,32,320*4,CGColorSpaceCreateDeviceRGB(),kCGBitmapByteOrderDefault,ref,NULL,true,kCGRenderingIntentDefault);

    CGFloat width = CGImageGetWidth(iref);

    CGFloat height = CGImageGetHeight(iref);

    size_t length = width*height*4;

    uint32_t *pixels = (uint32_t *)malloc(length);

    CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, 320*4, CGImageGetColorSpace(iref), kCGImageAlphaLast | kCGBitmapByteOrder32Big);

    CGContextTranslateCTM(context, 0.0, height);

    CGContextScaleCTM(context, 1.0, -1.0);

    CGContextDrawImage(context, CGRectMake(0.0, 0.0, width, height), iref);

    CGImageRef outputRef = CGBitmapContextCreateImage(context);

    UIImage *outputImage = [UIImage imageWithCGImage:outputRef];

     

    UIImageWriteToSavedPhotosAlbum(outputImage, nil, nil, nil);

     

    CGContextRelease(context);

    CGImageRelease(iref);

    CGDataProviderRelease(ref);

}

4.

CGImageRef UIGetScreenImage();

void SaveScreenImage(NSString *path)

{

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    CGImageRef cgImage = UIGetScreenImage();

        void *imageBytes = NULL;

        if (cgImage == NULL) {

                CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();

                imageBytes = malloc(320 * 480 * 4);

                CGContextRef context = CGBitmapContextCreate(imageBytes, 320, 480, 8, 320 * 4, colorspace, kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Big);

                CGColorSpaceRelease(colorspace);

                for (UIWindow *window in [[UIApplication sharedApplication] windows]) {

                        CGRect bounds = [window bounds];

                        CALayer *layer = [window layer];

                        CGContextSaveGState(context);

                        if ([layer contentsAreFlipped]) {

                                CGContextTranslateCTM(context, 0.0f, bounds.size.height);

                                CGContextScaleCTM(context, 1.0f, -1.0f);

                        }

                        [layer renderInContext:(CGContextRef)context];

                        CGContextRestoreGState(context);

                }

                cgImage = CGBitmapContextCreateImage(context);

                CGContextRelease(context);

        }

    NSData *pngData = UIImagePNGRepresentation([UIImage imageWithCGImage:cgImage]);

    CGImageRelease(cgImage);

        if (imageBytes)

                free(imageBytes);

    [pngData writeToFile:path atomically:YES];

    [pool release];

}

 

5.

  + (UIImage *)imageWithScreenContents

{

     CGImageRef cgScreen = UIGetScreenImage();

     if (cgScreen) {

         UIImage *result = [UIImage imageWithCGImage:cgScreen];

         CGImageRelease(cgScreen);

         return result;

     }

     return nil;

}

 

 

在程序中如何把两张图片合成为一张图片  

- (UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2 { 

    UIGraphicsBeginImageContext(image1.size); 

 

    // Draw image1 

    [image1 drawInRect:CGRectMake(0, 0, image1.size.width, image1.size.height)]; 

 

    // Draw image2 

    [image2 drawInRect:CGRectMake(0, 0, image2.size.width, image2.size.height)]; 

 

    UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext(); 

 

    UIGraphicsEndImageContext(); 

 

    return resultingImage; 

}