iOS适合屏幕的图像

Question

我有一张646x289的图像，我试图在屏幕宽高比方面适合它。

这是我目前的做法：

控制器：

public override void ViewDidLayoutSubviews() 
{ 
    base.ViewDidLayoutSubviews(); 
    _imnLogo.ContentMode = UIViewContentMode.ScaleAspectFit; 
    _imnLogo.SizeToFit(); 
    _imnLogo.Frame = new CGRect(
     View.Bounds.Left + 2 * Globals.MarginGrid, 
     View.Bounds.Top + Globals.MarginGrid, 
     _scaledImage.Size.Width, _scaledImage.Size.Height); 
} 

public override void LoadView() 
{ 
    base.LoadView(); 
    _scaledImage = MaxResizeImage(
     UIImage.FromFile("imn_logo.png"), (float) View.Bounds.Width, (float) View.Bounds.Height); 

    _imnLogo = new UIImageView(_scaledImage); 
    View.AddSubview(_imnLogo); 
} 

public UIImage MaxResizeImage(UIImage sourceImage, float maxWidth, float maxHeight) 
{ 
    var sourceSize = sourceImage.Size; 
    var maxResizeFactor = Math.Max(maxWidth/sourceSize.Width, maxHeight/sourceSize.Height); 
    if (maxResizeFactor > 1) return sourceImage; 

    var width = maxResizeFactor * sourceSize.Width; 
    var height = maxResizeFactor * sourceSize.Height; 
    UIGraphics.BeginImageContext(new SizeF((float) width, (float) height)); 
    sourceImage.Draw(new RectangleF(0, 0, (float) width, (float) height)); 
    var resultImage = UIGraphics.GetImageFromCurrentImageContext(); 
    UIGraphics.EndImageContext(); 
    return resultImage; 
} 

当这种负载，形象的方式过大，不适合在屏幕上。我正在用C＃构建我的所有接口（使用Xamarin），所以我需要能够使用框架和边界来实现这一点。

Answer 1

使用UIImageView的ContentMode来控制图像如何缩放，您可以跳过手动调整大小：

public override void LoadView() 
{ 
    base.LoadView(); 
    _imnLogo = new UIImageView(UIImage.FromFile("imn_logo.png")); 
    _imnLogo.Frame = View.Frame; 
    _imnLogo.ContentMode = UIViewContentMode.ScaleAspectFill; 
    View.AddSubview(imageView); 
    View.SendSubviewToBack(imnLogo); // Do this if you want to place other `View`s on top of the logo... 
} 

编号：https://developer.apple.com/reference/uikit/uiviewcontentmode