Gesture in Windows Phone 7

Here are some  interesting information I found on the Internet.

The ManipulationStarted event is raised when the user touches (or clicks with the mouse) any UIElement to manipulate it and is similar to a MouseDown event. The handler for the event verifies if a game is currently in progress and that one of the image elements that represents the puzzle pieces raised the event, otherwise it ignores the event. It locates the corresponding Canvas element for this piece and then calls the game’s logic to determine whether it can be moved—for this to happen, there must be an empty slot adjacent to the piece. It then stores the selected piece and then records the axis / direction where it can move.

The ManipulationDelta event is raised when the user moves the finger (or the mouse cursor) while manipulating a UIElement. The handler for this event checks if there is a piece currently being moved. If so, it captures the delta value from the only possible axis / direction. To do so, the code needs to enforce drag constraints to validate that the movement is within the available boundaries—a piece cannot overlap other pieces. The handler then updates the position for the piece by setting the property for the appropriate axis.

The ManipulationCompleted event is raised when the user lifts up the finger from the screen (or releases the mouse button) after manipulating a UIElement and is similar to a MouseUp event. The handler for this event checks if there is a puzzle piece currently being moved. If so, it determines the time when the last ManipulationCompleted was fired and, provided the time interval is lower than the value specified by the DoubleTapSpeed, it interprets this event as a Double Tap event (or double-click) and moves the piece to the adjacent empty slot. Otherwise, it calculates the offset distance of the piece into its target position and, if the piece has shifted at least one third of its size into the adjacent slot, it completes the move of the piece into that slot; if not, it pulls the piece back to its original position.

WP7 GestureService in depth | key concepts and API

31 Days of Windows Phone | Day #30: Gestures

Here is a series topics about it from jeff prosise's blog:

• Building Touch Interfaces for Windows Phones, Part 1 Mouse Events
• Building Touch Interfaces for Windows Phones, Part 2 Touch.FrameReported Events
• Building Touch Interfaces for Windows Phones, Part 3 Manipulation Events
• Building Touch Interfaces for Windows Phones, Part 4 GestureListener Class