Window Compositor Catalog Items and Sysgen Variables (Compact 7)

3/12/2014

In Windows Embedded Compact, you can implement functionality to compose windows on the display screen by using alpha blending.

For more information, see Window Compositor.

For more information about how to add or remove catalog items, see Design Your First OS.

Hardware and Software Requirements

A device with a display screen.
A shell. For more information, see Shell Catalog Items and Sysgen Variables.
The Minimal Window Manager Configuration catalog item (SYSGEN_MINWMGR). For more information, see GWES Catalog Items and Sysgen Variables.
The OpenGL version of Window Compositor requires an OpenGL graphics driver that supports OpenGL ES 2.0. For the OpenGL 2.X specification, see the Khronos OpenGL ES API Registry webpage. The OpenGL graphics driver must also support the following OpenGL extensions: EGL_KHR_image_base, EGL_KHR_image_pixmap, GL_OES_EGL_image.
The Graphics Device Interface (GDI) version of Window Compositor requires a DirectDraw display driver that uses the GDI API and emulates in software any GDI functions that are not available in the device hardware.
Graphics hardware as described in Silverlight for Windows Embedded Hardware Recommendations.

The following table describes the catalog items and associated SYSGEN variables that you can use to add Window Compositor to your OS.

Catalog item	SYSGEN variable	Description	Dependencies
Window Compositor	SYSGEN_COMPOSITION	Supports different composition modes for each window in the OS, including alpha transparency for 16-bit and 32-bit display modes.	Requires environment variable BSP_GLES2COMPOSITOR to use the OpenGL compositor and OpenGL driver. Otherwise, SYSGEN_COMPOSITION adds the default Windows Embedded Compact GDI compositor. For more information, see BSP Environment Variables.