from System.Windows import Application, Point
from System.Windows.Controls import Canvas

from System.Windows.Browser import HtmlPage,HtmlEventArgs
from System import EventHandler

class DeepZoomScene(object):
	
	def __init__(self):
		self.scene = Application.Current.LoadRootVisual(Canvas(), "app.xaml")

		self.scene.msi.MouseLeftButtonDown += self.mouseButtonDown
		self.scene.msi.MouseLeftButtonUp += self.mouseButtonUp
		self.scene.msi.MouseMove += self.mouseMove
		self.scene.msi.MouseEnter += self.mouseEnter
		self.scene.msi.MouseLeave += self.mouseLeave

		if HtmlPage.IsEnabled:
			HtmlPage.Window.AttachEvent("DOMMouseScroll", EventHandler[HtmlEventArgs](self.mouseWheel))
			HtmlPage.Window.AttachEvent("onmousewheel", EventHandler[HtmlEventArgs](self.mouseWheel))
			HtmlPage.Document.AttachEvent("onmousewheel", EventHandler[HtmlEventArgs](self.mouseWheel))
			
		self.mouseButtonPressed = False
		self.mouseIsDragging = False
		self.IsMouseOver = False
		self.lastMousePos = Point()
  	
	def mouseButtonDown(self, sender,e):
		self.mouseButtonPressed = True
		self.mouseIsDragging = False
		self.dragOffset = e.GetPosition(self.scene)
		self.currentPosition = self.scene.msi.ViewportOrigin

	def mouseButtonUp(self, sender, e):
		self.mouseButtonPressed = False
		if not self.mouseIsDragging:
			self.zoom(2.0, self.lastMousePos)
		self.mouseIsDragging = False

	def mouseMove(self, o,e):
		pos = e.GetPosition(self.scene.msi)	
		self.lastMousePos = pos
		if self.mouseButtonPressed:
			self.mouseIsDragging = True
			newOrigin = Point()
			newOrigin.X = self.currentPosition.X - (((pos.X - self.dragOffset.X) /self.scene.msi.ActualWidth) * self.scene.msi.ViewportWidth)
			newOrigin.Y = self.currentPosition.Y - (((pos.Y - self.dragOffset.Y) /self.scene.msi.ActualHeight) * self.scene.msi.ViewportWidth)
			self.scene.msi.ViewportOrigin = newOrigin

	def mouseWheel(self, sender, args):
		if self.IsMouseOver:
			delta = args.EventObject.GetProperty("wheelDelta")
			if HtmlPage.Window.GetProperty("opera") != None:
				delta = -delta
			if delta == None:
				delta = -(args.EventObject.GetProperty("detail"))/3
				if HtmlPage.BrowserInformation.UserAgent.IndexOf("Macintosh") != -1:
					delta = delta*3

			if delta > 0:
				self.zoom(1.1, self.lastMousePos)
			else:
				self.zoom(0.9, self.lastMousePos)


	def mouseEnter(self, sender, e):
		self.IsMouseOver = True

	def mouseLeave(self, sender, e):
		self.IsMouseOver = False
		self.mouseIsDragging = False
	
	def zoom(self, zoomFactor, position):
		pos = self.scene.msi.ElementToLogicalPoint(position)
		self.scene.msi.ZoomAboutLogicalPoint(zoomFactor, pos.X, pos.Y)

DeepZoomScene()