blob: 370da329b3dc95131a50c3a549f43717374bdf86 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
using System;
using System.ComponentModel;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Imaging;
using Xamarin.Forms.Internals;
#if WINDOWS_UWP
namespace Xamarin.Forms.Platform.UWP
#else
namespace Xamarin.Forms.Platform.WinRT
#endif
{
public class ImageRenderer : ViewRenderer<Image, Windows.UI.Xaml.Controls.Image>
{
bool _measured;
public override SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
{
if (Control.Source == null)
return new SizeRequest();
_measured = true;
var result = new Size { Width = ((BitmapImage)Control.Source).PixelWidth, Height = ((BitmapImage)Control.Source).PixelHeight };
return new SizeRequest(result);
}
protected override void Dispose(bool disposing)
{
if (Control != null)
{
Control.ImageOpened -= OnImageOpened;
}
base.Dispose(disposing);
}
protected override void OnElementChanged(ElementChangedEventArgs<Image> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
if (Control == null)
{
var image = new Windows.UI.Xaml.Controls.Image();
image.ImageOpened += OnImageOpened;
SetNativeControl(image);
}
UpdateSource();
UpdateAspect();
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == Image.SourceProperty.PropertyName)
UpdateSource();
else if (e.PropertyName == Image.AspectProperty.PropertyName)
UpdateAspect();
}
static Stretch GetStretch(Aspect aspect)
{
switch (aspect)
{
case Aspect.Fill:
return Stretch.Fill;
case Aspect.AspectFill:
return Stretch.UniformToFill;
default:
case Aspect.AspectFit:
return Stretch.Uniform;
}
}
void OnImageOpened(object sender, RoutedEventArgs routedEventArgs)
{
if (_measured)
{
RefreshImage();
}
}
void RefreshImage()
{
((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.RendererReady);
}
void UpdateAspect()
{
Control.Stretch = GetStretch(Element.Aspect);
if (Element.Aspect == Aspect.AspectFill) // Then Center Crop
{
Control.HorizontalAlignment = HorizontalAlignment.Center;
Control.VerticalAlignment = VerticalAlignment.Center;
}
else // Default
{
Control.HorizontalAlignment = HorizontalAlignment.Left;
Control.VerticalAlignment = VerticalAlignment.Top;
}
}
async void UpdateSource()
{
((IImageController)Element).SetIsLoading(true);
ImageSource source = Element.Source;
IImageSourceHandler handler;
if (source != null && (handler = Registrar.Registered.GetHandler<IImageSourceHandler>(source.GetType())) != null)
{
Windows.UI.Xaml.Media.ImageSource imagesource;
try
{
imagesource = await handler.LoadImageAsync(source);
}
catch (OperationCanceledException)
{
imagesource = null;
}
// In the time it takes to await the imagesource, some zippy little app
// might have disposed of this Image already.
if (Control != null)
Control.Source = imagesource;
RefreshImage();
}
else
Control.Source = null;
((IImageController)Element)?.SetIsLoading(false);
}
}
}
|
