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
|
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Xamarin.Forms.Controls
{
public class PanGestureGalleryPage : ContentPage
{
public class PanContainer : ContentView
{
public PanContainer ()
{
var pan = new PanGestureRecognizer
{
TouchPoints = 1
};
pan.PanUpdated += (object s, PanUpdatedEventArgs e) =>
{
switch (e.StatusType) {
case GestureStatus.Started: break;
case GestureStatus.Running:
Content.TranslationX = e.TotalX;
Content.TranslationY = e.TotalY;
break;
default:
Content.TranslationX = Content.TranslationY = 0;
break;
}
};
var pinch = new PinchGestureRecognizer ();
double xOffset = 0;
double yOffset = 0;
double startScale = 1;
pinch.PinchUpdated += (sender, e) =>
{
if (e.Status == GestureStatus.Started) {
startScale = Content.Scale;
Content.AnchorX = Content.AnchorY = 0;
}
if (e.Status == GestureStatus.Running) {
_currentScale += (e.Scale - 1) * startScale;
_currentScale = Math.Max (1, _currentScale);
var renderedX = Content.X + xOffset;
var deltaX = renderedX / Width;
var deltaWidth = Width / (Content.Width * startScale);
var originX = (e.ScaleOrigin.X - deltaX) * deltaWidth;
var renderedY = Content.Y + yOffset;
var deltaY = renderedY / Height;
var deltaHeight = Height / (Content.Height * startScale);
var originY = (e.ScaleOrigin.Y - deltaY) * deltaHeight;
double targetX = xOffset - (originX * Content.Width) * (_currentScale - startScale);
double targetY = yOffset - (originY * Content.Height) * (_currentScale - startScale);
Content.TranslationX = targetX.Clamp (-Content.Width * (_currentScale - 1), 0);
Content.TranslationY = targetY.Clamp (-Content.Height * (_currentScale - 1), 0);
Content.Scale = _currentScale;
}
if (e.Status == GestureStatus.Completed) {
xOffset = Content.TranslationX;
yOffset = Content.TranslationY;
}
};
GestureRecognizers.Add (pinch);
GestureRecognizers.Add (pan);
}
double _currentScale = 1;
}
public PanGestureGalleryPage ()
{
var image = new Image { Source = "http://placehold.it/2000x2000", BackgroundColor = Color.Gray, WidthRequest = 2000, HeightRequest = 2000, VerticalOptions = LayoutOptions.Center, HorizontalOptions = LayoutOptions.Center };
var panme = new PanContainer { Content = image };
Content = new StackLayout { Children = { new Label { Text = "Use two fingers to pinch. Use one finger to pan." }, panme }, Padding = new Thickness (20) };
}
}
}
|
