（比例）在某一點放大UIView

Question

我不了解轉化的東西。 我想放大一下UIView的右上角（主視圖）。 我使用CGAffineTransformScale並嘗試設置center / anchorPoint以及CGAffineTransformMakeTranslation無濟於事。

我無法弄清楚如何正確設置翻譯，以便放大這一點。

CGAffineTransform tr = CGAffineTransformScale(self.view.transform, 2, 2);

[UIView animateWithDuration:2.5 delay:0 options:0 animations:^{
            self.view.transform = tr;
            self.view.center = CGPointMake(480,0);

} completion:^(BOOL finished) {}];

Answer 1

您正在將視圖的中心設置在右上角。 這意味着你要放大到中心左下角的某個地方。

嘗試這個

CGAffineTransform tr = CGAffineTransformScale(self.view.transform, 2, 2);
CGFloat h = self.view.frame.size.height;
[UIView animateWithDuration:2.5 delay:0 options:0 animations:^{
    self.view.transform = tr;
    self.view.center = CGPointMake(0,h);
} completion:^(BOOL finished) {}];

這會將放大視圖的中心設置為左下角，有效地放大，右上角固定。

此代碼沒有硬編碼的高度，這是一個更便攜（到iPhone 5的iPad）。

您需要先設置transform屬性之前保存h ，因為之后您不應該依賴於frame的值。

編輯

要使其適用於任何比例s ，請使用以下命令：

CGFloat s = 3;
CGAffineTransform tr = CGAffineTransformScale(self.view.transform, s, s);
CGFloat h = self.view.frame.size.height;
CGFloat w = self.view.frame.size.width;
[UIView animateWithDuration:2.5 delay:0 options:0 animations:^{
    self.view.transform = tr;
    self.view.center = CGPointMake(w-w*s/2,h*s/2);
} completion:^(BOOL finished) {}];

要使其適用於左下角，請使用以下命令：

CGFloat s = 3;
CGAffineTransform tr = CGAffineTransformScale(self.view.transform, s, s);
CGFloat h = self.view.frame.size.height;
CGFloat w = self.view.frame.size.width;
[UIView animateWithDuration:2.5 delay:0 options:0 animations:^{
    self.view.transform = tr;
    self.view.center = CGPointMake(w*s/2,h-h*s/2);
} completion:^(BOOL finished) {}];

要使其適用於右下角，請使用以下命令：

CGFloat s = 3;
CGAffineTransform tr = CGAffineTransformScale(self.view.transform, s, s);
CGFloat h = self.view.frame.size.height;
CGFloat w = self.view.frame.size.width;
[UIView animateWithDuration:2.5 delay:0 options:0 animations:^{
    self.view.transform = tr;
    self.view.center = CGPointMake(w-w*s/2,h-h*s/2);
} completion:^(BOOL finished) {}];

另請參見： 如何將UIView縮放（縮放）到給定的CGPoint

Answer 2

如果有人仍然感興趣，這里是Swift 3.0解決方案，我添加了正確淡出的可能性。

（我知道有兩個枚舉缺失，但代碼仍然可讀，我想你會得到這個概念）

func animateZoom(direction: ZoomDirection, type: ZoomType, duration: Double = 0.3, scale: CGFloat = 1.4) {
    var cx, cy: CGFloat
    var tr: CGAffineTransform = CGAffineTransform.identity

    if (type == .IN) { tr = self.transform.scaledBy(x: scale, y: scale) }

    let h: CGFloat = self.frame.size.height;
    let w: CGFloat = self.frame.size.width;

    if (type == .IN) {
        switch direction {
        case .LEFT_DOWN:
            cx = w*scale/2
            cy = h-h*scale/2
            break
        case .LEFT_UP:
            cx = w*scale/2
            cy = h*scale/2
            break
        case .RIGHT_UP:
            cx = w-w*scale/2
            cy = h*scale/2
            break
        case .RIGHT_DOWN:
            cx = w-w*scale/2
            cy = h-h*scale/2
            break
        }
    } else {
        cx = w/scale/2
        cy = h/scale/2
    }

    UIView.animate(withDuration: duration, delay: 0, options: [.curveEaseInOut], animations: {
        self.transform = tr
        self.center = CGPoint(x: cx, y: cy)
    }, completion: { finish in })
}