UIView的Animation(十ㄧ)

在UIView的矩陣轉換後結果的評估

如果在正式轉換前，我們需要評估圖區轉換後的位置，並適當地加入控制程式在轉換後的位置，就必須應用下面三個Function，分別可以得到點/位置/大小。
不另外做試驗程式，僅作資料整理。


Apple 原始資料
https://developer.apple.com/library/mac/#documentation/graphicsimaging/reference/CGAffineTransform/Reference/reference.html

CGPointApplyAffineTransform

Returns the point resulting from an affine transformation of an existing point.

CGPoint CGPointApplyAffineTransform (
   CGPoint point,
   CGAffineTransform t
); 

CGRectApplyAffineTransform

Applies an affine transform to a rectangle.

CGRect CGRectApplyAffineTransform ( CGRect rect, CGAffineTransform t );

CGSizeApplyAffineTransform

Returns the height and width resulting from a transformation of an existing height and width.

CGSize CGSizeApplyAffineTransform (
   CGSize size,
   CGAffineTransform t
);

example1

CGAffineTransform translateTransform = CGAffineTransformMakeTransation(point.x, point.y);

CGAffineTransform rotateTransform = CGAffineTransformMakeRotation(angle);

CGAffineTransform customTransform = CGAffineTransformConcat(CGAffineTransformConcat(
CGAffineTransformInvert(translateTransform), rotateTransform), translateTransform);

newPoint = CGPointApplyAffineTransform(initialPoint, customTransform);

example2

CGFloat factor = [(UIPinchGestureRecognizer *)sender scale];
CGAffineTransform zt = CGAffineTransformScale(CGAffineTransformIdentity, factor, factor); senderView.frame = CGRectApplyAffineTransform(initialFrame, zt);




example3

CGRect imgRect = CGRectMake(0, 0, width, height);
CGAffineTransform transform = CGAffineTransformMakeRotation(angleInRadians);
CGRect rotatedRect = CGRectApplyAffineTransform(imgRect, transform);


example4

CGSize imageViewSize = previewImage.size; 

CGSize imageSize = previewImage.image.size; 

// Find the scaling required for the image

 to fit the image view (as for aspect fill). 

CGFloat imageWidthScale = fabsf(imageViewSize.width / imageSize.width); 

CGFloat imageHeightScale = fabsf(imageViewSize.height / imageSize.height); 

CGFloat imageScale = (imageWidthScale > imageHeightScale) ? 

imageWidthScale : imageHeightScale; 

// Determine the new image size, after scaling. 

CGSize scaledImageSize = CGSizeApplyAffineTransform(imageSize, CGAffineTransformMakeScale(imageScale, imageScale));

example5

CGSize oldImageSize = imageView.bounds.size;
// Transforming code here
CGAffineTransform currentTransform = imageView.transform;
CGSize newImageSize = CGSizeApplyAffineTransform(oldImageSize, currentTransform);