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using System;
using System.ComponentModel;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Foundation;
using UIKit;
using RectangleF = CoreGraphics.CGRect;
namespace Xamarin.Forms.Platform.iOS
{
public static class ImageExtensions
{
public static UIViewContentMode ToUIViewContentMode(this Aspect aspect)
{
switch (aspect)
{
case Aspect.AspectFill:
return UIViewContentMode.ScaleAspectFill;
case Aspect.Fill:
return UIViewContentMode.ScaleToFill;
case Aspect.AspectFit:
default:
return UIViewContentMode.ScaleAspectFit;
}
}
}
public class ImageRenderer : ViewRenderer<Image, UIImageView>
{
bool _isDisposed;
IElementController ElementController => Element as IElementController;
protected override void Dispose(bool disposing)
{
if (_isDisposed)
return;
if (disposing)
{
UIImage oldUIImage;
if (Control != null && (oldUIImage = Control.Image) != null)
{
oldUIImage.Dispose();
oldUIImage = null;
}
}
_isDisposed = true;
base.Dispose(disposing);
}
protected override void OnElementChanged(ElementChangedEventArgs<Image> e)
{
if (Control == null)
{
var imageView = new UIImageView(RectangleF.Empty);
imageView.ContentMode = UIViewContentMode.ScaleAspectFit;
imageView.ClipsToBounds = true;
SetNativeControl(imageView);
}
if (e.NewElement != null)
{
SetAspect();
SetImage(e.OldElement);
SetOpacity();
}
base.OnElementChanged(e);
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == Image.SourceProperty.PropertyName)
SetImage();
else if (e.PropertyName == Image.IsOpaqueProperty.PropertyName)
SetOpacity();
else if (e.PropertyName == Image.AspectProperty.PropertyName)
SetAspect();
}
void SetAspect()
{
Control.ContentMode = Element.Aspect.ToUIViewContentMode();
}
async void SetImage(Image oldElement = null)
{
var source = Element.Source;
if (oldElement != null)
{
var oldSource = oldElement.Source;
if (Equals(oldSource, source))
return;
if (oldSource is FileImageSource && source is FileImageSource && ((FileImageSource)oldSource).File == ((FileImageSource)source).File)
return;
Control.Image = null;
}
IImageSourceHandler handler;
Element.SetIsLoading(true);
if (source != null && (handler = Internals.Registrar.Registered.GetHandler<IImageSourceHandler>(source.GetType())) != null)
{
UIImage uiimage;
try
{
uiimage = await handler.LoadImageAsync(source, scale: (float)UIScreen.MainScreen.Scale);
}
catch (OperationCanceledException)
{
uiimage = null;
}
var imageView = Control;
if (imageView != null)
imageView.Image = uiimage;
if (!_isDisposed)
((IVisualElementController)Element).NativeSizeChanged();
}
else
Control.Image = null;
if (!_isDisposed)
Element.SetIsLoading(false);
}
void SetOpacity()
{
Control.Opaque = Element.IsOpaque;
}
}
public interface IImageSourceHandler : IRegisterable
{
Task<UIImage> LoadImageAsync(ImageSource imagesource, CancellationToken cancelationToken = default(CancellationToken), float scale = 1);
}
public sealed class FileImageSourceHandler : IImageSourceHandler
{
public Task<UIImage> LoadImageAsync(ImageSource imagesource, CancellationToken cancelationToken = default(CancellationToken), float scale = 1f)
{
UIImage image = null;
var filesource = imagesource as FileImageSource;
if (filesource != null)
{
var file = filesource.File;
if (!string.IsNullOrEmpty(file))
image = File.Exists(file) ? new UIImage(file) : UIImage.FromBundle(file);
}
return Task.FromResult(image);
}
}
public sealed class StreamImagesourceHandler : IImageSourceHandler
{
public async Task<UIImage> LoadImageAsync(ImageSource imagesource, CancellationToken cancelationToken = default(CancellationToken), float scale = 1f)
{
UIImage image = null;
var streamsource = imagesource as StreamImageSource;
if (streamsource != null && streamsource.Stream != null)
{
using (var streamImage = await ((IStreamImageSource)streamsource).GetStreamAsync(cancelationToken).ConfigureAwait(false))
{
if (streamImage != null)
image = UIImage.LoadFromData(NSData.FromStream(streamImage), scale);
}
}
return image;
}
}
public sealed class ImageLoaderSourceHandler : IImageSourceHandler
{
public async Task<UIImage> LoadImageAsync(ImageSource imagesource, CancellationToken cancelationToken = default(CancellationToken), float scale = 1f)
{
UIImage image = null;
var imageLoader = imagesource as UriImageSource;
if (imageLoader != null && imageLoader.Uri != null)
{
using (var streamImage = await imageLoader.GetStreamAsync(cancelationToken).ConfigureAwait(false))
{
if (streamImage != null)
image = UIImage.LoadFromData(NSData.FromStream(streamImage), scale);
}
}
return image;
}
}
}
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