iOS UIImage縮放和裁剪，實際上是放大圖像還是縮小圖像？

Question

我使用別人的捏手勢代碼進行縮放，效果很好，但是可以在我的照片編輯應用中縮放我的圖像，一旦用戶按完成縮放，我就需要反映並保存所做的更改，或者用其他方式說它需要圖像實際上，如果有人使用縮放來放大和裁剪。 我想我可以使用它們縮放的數量* uigraphicsbeginimagecontext的幀大小，但是該策略不起作用，因為當用戶縮放圖像並單擊完成按鈕時，圖像會保存得更小，因為現在這非常大的尺寸被擠壓到視圖中當我真正想要的東西沒有任何剩余物而沒有做任何擬合時。

- (IBAction)pinchGest:(UIPinchGestureRecognizer *)sender{


if (sender.state == UIGestureRecognizerStateEnded
    || sender.state == UIGestureRecognizerStateChanged) {
    NSLog(@"sender.scale = %f", sender.scale);

    CGFloat currentScale = self.activeImageView.frame.size.width / self.activeImageView.bounds.size.width;
    CGFloat newScale = currentScale * sender.scale;

    if (newScale < .5) {
        newScale = .5;
    }
    if (newScale > 4) {
        newScale = 4;
    }

    CGAffineTransform transform = CGAffineTransformMakeScale(newScale, newScale);
    self.activeImageView.transform = transform;
    scalersOfficialChange = newScale;
    sender.scale = 1;

}
}

- (IBAction)doneMoverViewButtonPressed:(UIButton *)sender {
// turn off ability to move & scale
moverViewActive = NO;

NSLog(@"%f %f",dragOfficialChange.x,dragOfficialChange.y);
NSLog(@"%f",rotationOfficialChange);
NSLog(@"%f",scalersOfficialChange);


//problem area below...
CGSize newSize = CGSizeMake(self.activeImageView.bounds.size.width * scalersOfficialChange, self.activeImageView.bounds.size.height * scalersOfficialChange );

UIGraphicsBeginImageContext(newSize);

[self.activeImageView.image drawInRect:CGRectMake(dragOfficialChange.x, dragOfficialChange.y, self.layerContainerView.bounds.size.width, self.layerContainerView.bounds.size.height)];

self.activeImageView.image = UIGraphicsGetImageFromCurrentImageContext();


UIGraphicsEndImageContext();

[self hideMoveViewerAnimation];

//resets activeimageview coords
CGRect myFrame = self.layerContainerView.bounds;
myFrame.origin.x = 0;
myFrame.origin.y = 0;
self.activeImageView.frame = myFrame;

//reset changes values
dragOfficialChange.x = 0;
dragOfficialChange.y = 0;
rotationOfficialChange = 0;
scalersOfficialChange = 0;

}

Answer 1

首先，您能使您的問題更清楚嗎？ 我建議您將圖像繪制成矩形，而不要擠壓圖像，對嗎？

然后讓我們嘗試這種方法：

//The method: drawInRect:(CGRect) will scale your pic and squeeze it to fit the Rect area
//So if you dont want to scale your pic, you can use the method below
[image drawAsPatternInRect：(CGRect)_rect];
//This method would not scale your image and cut the needless part