几种截屏方法

      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;
      }
  
 

  
 
 

文章来源: zzzili.blog.csdn.net，作者：清雨小竹，版权归原作者所有，如需转载，请联系作者。

原文链接：zzzili.blog.csdn.net/article/details/9097135