在OpenGL的環境下把畫面存圖片 Code Snippet

在glpaint裡要把畫面存成照片需要加入以下的程式碼。

void ProviderReleaseData ( void *info, const void *data, size_t size ) {

free((void*)data);

}

-(UIImage*) upsideDownImageRepresenation{

int imageWidth = CGRectGetWidth([self bounds]);

int imageHeight = CGRectGetHeight([self bounds]);

//image buffer for export

NSInteger myDataLength = imageWidth* imageHeight * 4;

// allocate array and read pixels into it.

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

    

    glReadPixels(0, 0, imageWidth, imageHeight, GL_RGBA, GL_UNSIGNED_BYTE, tempImagebuffer);

// make data provider with data.

CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, tempImagebuffer, myDataLength, ProviderReleaseData);

// prep the ingredients

int bitsPerComponent = 8;

int bitsPerPixel = 32;

int bytesPerRow = 4 * imageWidth;

CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();

CGBitmapInfo bitmapInfo = kCGImageAlphaPremultipliedLast;

CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

// make the cgimage

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

// then make the uiimage from that

UIImage *myImage =  [UIImage imageWithCGImage:imageRef] ;

CGDataProviderRelease(provider);

CGImageRelease(imageRef);

CGColorSpaceRelease(colorSpaceRef);

    

    //make sure it is in the autorelease pool

[[myImage retain] autorelease];

    return myImage;

}

-(UIImage*) imageRepresentation{

UIImageView* upsideDownImageView=[[UIImageView alloc] initWithImage: [self upsideDownImageRepresenation]];

    

upsideDownImageView.transform=CGAffineTransformScale(upsideDownImageView.transform, 1, -1);

UIView* container=[[UIView alloc] initWithFrame:upsideDownImageView.frame];

[container addSubview:upsideDownImageView];

UIImage* toReturn=nil;

    

UIGraphicsBeginImageContext(container.frame.size);

[container.layer renderInContext:UIGraphicsGetCurrentContext()];

toReturn = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

[upsideDownImageView release];

[container release];

 　　　　return toReturn;

}

設定存檔按鈕

-(void) saveImage{

    UIImageWriteToSavedPhotosAlbum([drawingView imageRepresentation], self, @selector(image:didFinishSavingWithError:contextInfo:), nil);

}