[英]iOS Fit Image to Screen
我有一个646x289的图像,该图像要根据屏幕的长宽比进行调整。
这是我目前的方法:
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;
}
加载时,图像太大,不适合屏幕。
我也正在C#中构造所有接口(使用Xamarin),因此我需要能够使用框架和界限做到这一点。
使用UIImageView
的ContentMode
来控制图像的缩放方式,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...
}
参考: https : //developer.apple.com/reference/uikit/uiviewcontentmode
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