Variant:
This topic builds on the material -in the following topics:
This topic covers the following:
Call
When an application needs to receive advanced pointer events
-in a window, it must call
If advanced pointers are
-not enabled for a window, it receives only standard
However,
-the new
Call
Now we need to test -whether the pointer event contains advanced pointer data. If it is not an -advanced pointer, the code leaves.
If it is an advanced pointer, we -call functions to detect proximity, pressure, "proximity and pressure" data -and coordinates.
Proximity is always negative and pressure is always positive.
-Internally they are combined together as a Z coordinate. When Z > 0, the proximity
-is 0 and the Z value represents the pressure. When Z < 0, the pressure
-is 0 and the Z value represents the proximity. Some APIs use only a Z coordinate
-(such as the threshold getters and setters and
This
-example shows an easy way to pinch zoom an image when the screen receives
-pointer events from two pointers. There are two functions in this code that
-must be implemented by the programmer:
The high-level steps to -perform pinch zooming are:
Define the coordinates,
-equivalent to the given on-screen coordinates. In the code example, this is
-done using the function
Define the ID of the
-pointer by using
For each pointer assign -its coordinates to a local variable. We assume there are only two pointers -handled by the system here.
Use the
Variant:
This topic builds +on the material in the following topics:
This topic covers +the following:
Call
When an application needs to receive advanced pointer
+events in a window, it must call
If advanced
+pointers are not enabled for a window, it receives only standard
However, the new
Call
Now we need +to test whether the pointer event contains advanced pointer data. +If it is not an advanced pointer, the code leaves.
If it is +an advanced pointer, we call functions to detect proximity, pressure, +"proximity and pressure" data and coordinates.
Proximity is always negative and pressure is always positive. Internally they are combined together as a Z coordinate.
+When Z > 0, the proximity is 0 and the Z value represents the pressure.
+When Z < 0, the pressure is 0 and the Z value represents the proximity.
+Some APIs use only a Z coordinate (such as the threshold getters and
+setters and
This example shows an easy way to pinch zoom an
+image when the screen receives pointer events from two pointers. There
+are two functions in this code that must be implemented by the programmer:
The high-level +steps to perform pinch zooming are:
Define the coordinates,
+equivalent to the given on-screen coordinates. In the code example,
+this is done using the function
Define the ID
+of the pointer by using
For each pointer +assign its coordinates to a local variable. We assume there are only +two pointers handled by the system here.
Use the