diff options
Diffstat (limited to 'Xamarin.Forms.Core/Image.cs')
| -rw-r--r-- | Xamarin.Forms.Core/Image.cs | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/Image.cs b/Xamarin.Forms.Core/Image.cs new file mode 100644 index 00000000..9e329331 --- /dev/null +++ b/Xamarin.Forms.Core/Image.cs @@ -0,0 +1,145 @@ +using System; +using Xamarin.Forms.Platform; + +namespace Xamarin.Forms +{ + [RenderWith(typeof(_ImageRenderer))] + public class Image : View + { + public static readonly BindableProperty SourceProperty = BindableProperty.Create("Source", typeof(ImageSource), typeof(Image), default(ImageSource), propertyChanging: OnSourcePropertyChanging, + propertyChanged: OnSourcePropertyChanged); + + public static readonly BindableProperty AspectProperty = BindableProperty.Create("Aspect", typeof(Aspect), typeof(Image), Aspect.AspectFit); + + public static readonly BindableProperty IsOpaqueProperty = BindableProperty.Create("IsOpaque", typeof(bool), typeof(Image), false); + + internal static readonly BindablePropertyKey IsLoadingPropertyKey = BindableProperty.CreateReadOnly("IsLoading", typeof(bool), typeof(Image), default(bool)); + + public static readonly BindableProperty IsLoadingProperty = IsLoadingPropertyKey.BindableProperty; + + public Aspect Aspect + { + get { return (Aspect)GetValue(AspectProperty); } + set { SetValue(AspectProperty, value); } + } + + public bool IsLoading + { + get { return (bool)GetValue(IsLoadingProperty); } + } + + public bool IsOpaque + { + get { return (bool)GetValue(IsOpaqueProperty); } + set { SetValue(IsOpaqueProperty, value); } + } + + [TypeConverter(typeof(ImageSourceConverter))] + public ImageSource Source + { + get { return (ImageSource)GetValue(SourceProperty); } + set { SetValue(SourceProperty, value); } + } + + protected override void OnBindingContextChanged() + { + if (Source != null) + SetInheritedBindingContext(Source, BindingContext); + + base.OnBindingContextChanged(); + } + + [Obsolete("Use OnMeasure")] + protected override SizeRequest OnSizeRequest(double widthConstraint, double heightConstraint) + { + SizeRequest desiredSize = base.OnSizeRequest(double.PositiveInfinity, double.PositiveInfinity); + + double desiredAspect = desiredSize.Request.Width / desiredSize.Request.Height; + double constraintAspect = widthConstraint / heightConstraint; + + double desiredWidth = desiredSize.Request.Width; + double desiredHeight = desiredSize.Request.Height; + + if (desiredWidth == 0 || desiredHeight == 0) + return new SizeRequest(new Size(0, 0)); + + double width = desiredWidth; + double height = desiredHeight; + if (constraintAspect > desiredAspect) + { + // constraint area is proportionally wider than image + switch (Aspect) + { + case Aspect.AspectFit: + case Aspect.AspectFill: + height = Math.Min(desiredHeight, heightConstraint); + width = desiredWidth * (height / desiredHeight); + break; + case Aspect.Fill: + width = Math.Min(desiredWidth, widthConstraint); + height = desiredHeight * (width / desiredWidth); + break; + } + } + else if (constraintAspect < desiredAspect) + { + // constraint area is proportionally taller than image + switch (Aspect) + { + case Aspect.AspectFit: + case Aspect.AspectFill: + width = Math.Min(desiredWidth, widthConstraint); + height = desiredHeight * (width / desiredWidth); + break; + case Aspect.Fill: + height = Math.Min(desiredHeight, heightConstraint); + width = desiredWidth * (height / desiredHeight); + break; + } + } + else + { + // constraint area is same aspect as image + width = Math.Min(desiredWidth, widthConstraint); + height = desiredHeight * (width / desiredWidth); + } + + return new SizeRequest(new Size(width, height)); + } + + void OnSourceChanged(object sender, EventArgs eventArgs) + { + OnPropertyChanged(SourceProperty.PropertyName); + InvalidateMeasure(InvalidationTrigger.MeasureChanged); + } + + static void OnSourcePropertyChanged(BindableObject bindable, object oldvalue, object newvalue) + { + ((Image)bindable).OnSourcePropertyChanged((ImageSource)oldvalue, (ImageSource)newvalue); + } + + void OnSourcePropertyChanged(ImageSource oldvalue, ImageSource newvalue) + { + if (newvalue != null) + { + newvalue.SourceChanged += OnSourceChanged; + SetInheritedBindingContext(newvalue, BindingContext); + } + InvalidateMeasure(InvalidationTrigger.MeasureChanged); + } + + static void OnSourcePropertyChanging(BindableObject bindable, object oldvalue, object newvalue) + { + ((Image)bindable).OnSourcePropertyChanging((ImageSource)oldvalue, (ImageSource)newvalue); + } + + async void OnSourcePropertyChanging(ImageSource oldvalue, ImageSource newvalue) + { + if (oldvalue == null) + return; + + oldvalue.SourceChanged -= OnSourceChanged; + await oldvalue.Cancel(); + } + } +}
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