iPhone幾種截屏的代碼分享

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[3204804];
  glReadPixels(0,0,320,480,GL_RGBA,GL_UNSIGNED_BYTE,&buffer);
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, &buffer, 3204804, NULL);
  CGImageRef iref = CGImageCreate(320,480,8,32,3204,CGColorSpaceCreateDeviceRGB(),kCGBitmapByteOrderDefault,ref,NULL,true,kCGRenderingIntentDefault);
  CGFloat width = CGImageGetWidth(iref);
  CGFloat height = CGImageGetHeight(iref);
  size_t length = widthheight4;
  uint32_t pixels = (uint32_t )malloc(length);
  CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, 3204, 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;
} 

在程序中如何把兩張圖片合成為一張圖片

(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;

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