core-graphics

In my iOS application, I am trying to draw curves using CoreGraphics. The drawing itself works fine, but on the retina display the image gets drawn using the same resolution, and does not get pixel doubled. The result is a pixelated image. I am drawing using the following functions: - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; CGPoint currentPoint = [touch locationInView:self.canvasView]; UIGraphicsBeginImageContext(self.canvasView.frame.size); [canvasView.image drawInRect:self.canvasView.frame]; CGContextRef ctx =

Ok using coregraphics, I'm building up an image which will later be used in a CGContextClipToMask operation. It looks something like the following: UIImage *eyes = [UIImage imageNamed:@"eyes"]; UIImage *mouth = [UIImage imageNamed:@"mouth"]; UIGraphicsBeginImageContext(CGSizeMake(150, 150)); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetRGBFillColor(context, 0, 0, 0, 1); CGContextFillRect(context, bounds); [eyes drawInRect:bounds blendMode:kCGBlendModeMultiply alpha:1]; [mouth drawInRect:bounds blendMode:kCGBlendModeMultiply alpha:1]; // how can i now get a CGImageRef here

this is the code in the continuation of this question.... Allow horizontal scrolling only in the core-plot barchart? -(BOOL)pointingDeviceDraggedAtPoint:(CGPoint)interactionPoint { if ( !self.allowsUserInteraction || !self.graph.plotArea ) { return NO; } CGPoint pointInPlotArea = [self.graph.plotArea convertPoint:interactionPoint toLayer:self.graph.plotArea]; if ( isDragging ) { pointInPlotArea.y = lastDragPoint.y;//-- Madhup Changed it for allwoing scrolling only in horizontal direction --// //-- Madhup Changed it for allwoing scrolling only in horizontal direction --// //CGPoint displacement

I have an "ImageManipulator" class that performs some cropping, resizing and rotating of camera images on the iPhone. At the moment, everything works as expected but I keep getting a few huge spikes in memory consumption which occasionally cause the app to crash. I have managed to isolate the problem to a part of the code where I check for the current image orientation property and rotate it accordingly to UIImageOrientationUp . I then get the image from the bitmap context and save it to disk. This is currently what I am doing: CGAffineTransform transform = CGAffineTransformIdentity; // Check

I'd like to take an affine matrix that I have from OpenCV: Mat T = getAffineTransform(src_pt, dst_pt); and then convert it into a CGAffineTransform for use in Core Graphics/Objective-C/iOS. ( CGAffineTransform docs ) I've tried: CGAffineTransform t = CGAffineTransformIdentity; t.a = T.at<float>(0,0); t.b = T.at<float>(0,1); t.c = T.at<float>(1,0); t.d = T.at<float>(1,1); t.tx = T.at<float>(0,2); t.ty = T.at<float>(1,2); This works fine for x and y translations, but NOT if there is any rotation in the matrix. Something seems to be missing since the resulting image seems to be skewed strangely.