Zoom and Pan in GMap.net

Question

I'm trying to make GMap.Net control multitouch enabled, using WPF build-in events but i wasn't successful.

I found a series of articles about multitouch like this and this one. In all of them, ManipulationContainer is a canvas and movable controls placed on it, but in GMap issue ManipulationContainer is GMapControl and there is no control over it. how can i use e.ManipulationDelta data to Zoom and Move?

The GMapControl has a Zoom property which by increase or decreasing it, you can zoom in or zoom out.

Answer 1

A quick look at the code shows that the GMapControl is an ItemsContainer.

You should be able to restyle the ItemsPanel template and supply the IsManipulationEnabled property there:

<g:GMapControl x:Name="Map" ...>
   <g:GMapControl.ItemsPanel>
       <ItemsPanelTemplate>
           <Canvas IsManipulationEnabled="True" />
       </ItemsPanelTemplate>
   </g:GMapControl.ItemsPanel>
   <!-- ... -->

At this point you need to wire up the Window:

<Window ...
    ManipulationStarting="Window_ManipulationStarting"
    ManipulationDelta="Window_ManipulationDelta"
    ManipulationInertiaStarting="Window_InertiaStarting">

And supply the appropriate methods in the Code Behind (shamelessly stolen and adapted from this MSDN Walkthrough):

void Window_ManipulationStarting(
    object sender, ManipulationStartingEventArgs e)
{
    e.ManipulationContainer = this;
    e.Handled = true;
}

void Window_ManipulationDelta(object sender, ManipulationDeltaEventArgs e)
{
    // uses the scaling value to supply the Zoom amount
    this.Map.Zoom = e.DeltaManipulation.Scale.X;
    e.Handled = true;
}

void Window_InertiaStarting(
    object sender, ManipulationInertiaStartingEventArgs e)
{
    // Decrease the velocity of the Rectangle's resizing by 
    // 0.1 inches per second every second.
    // (0.1 inches * 96 pixels per inch / (1000ms^2)
    e.ExpansionBehavior.DesiredDeceleration = 0.1 * 96 / (1000.0 * 1000.0);
    e.Handled = true;
}