tilt

Suppose I have 2 bitmaps. One is smallBitmap, and one is largeBitmap. I want to draw the entire smallBitmap into largeBitmap, but only to a part of largeBitmap, and not in a straight regtangle, but into a quadrilateral instead. I think a sketch will best describe what I mean: An example of this scenario is a tilted smartphone image (like this or this ), that you need to put a screenshot into its screen. The input is: smallBitmap, largeBitmap, "quadrilateral" coordinates of the largeBitmap (where to put the smallBitmap). The "quadrilateral" of the largeBitmap just has 4 coordinates and it's not

I tried to use the Z axis data from SensorEvent.values, but it doesn't detect rotation of my phone in the XY plane, ie. around the Z-axis. I am using this as a reference for the co-ordinate axes. Is it correct? How do I measure that motion using accelerometer values? These games do something similar: Extreme Skater , Doodle Jump. PS: my phone orientation will be landscape. Essentially, there is 2 cases here: the device is laying flat and not flat. Flat here means the angle between the surface of the device screen and the world xy plane (I call it the inclination) is less than 25 degree or