Datasheet

Functional Description

Datasheet 191

5.4.6.2 Popup Plane (Second Cursor)

The popup plane is used for control functions in mobile applications. Only the hardware cursor

has a higher Z-order precedence over the hardware icon. In standard modes (non VGA) either

cursor A or cursor B can be used as a Popup Icon. For VGA modes, 32-bpp data format is not

supported.

5.4.6.3 Popup Color Formats

Source color data for the popup is in an indexed format. Indexed data uses the entries in the four-

entry cursor palette to convert the two-bit index to a true color format before being passed to the

blenders. Blending of color data is only supported with data of the same format.

5.4.7 Overlay Plane

The overlay engine provides a method of merging either video capture data (from an external

Video Capture device) or data delivered by the processor, with the graphics data on the screen.

5.4.7.1 Multiple Overlays (Display C)

A single overlay plane and scalar is implemented. This overlay plane can be connected to the

primary display, secondary display or in bypass mode. In the default mode, it appears on the

primary display. The overlay may be displayed in a multi-monitor scenario for single-pipe

simultaneous displays only. Picture-in-Picture feature is supported via software through the

arithmetic stretch blitter.

5.4.7.2 Source/Destination Color/Chromakeying

Overlay source/destination chromakeying enables blending of the overlay with the underlying

graphics background. Destination color-/chromakeying can be used to handle occluded portions

of the overlay window on a pixel-by-pixel basis that is actually an underlay. Destination color

keying supports a specific color (8-bit or 15-bit) mode as well as 32-bit alpha blending.

Source color/chromakeying is used to handle transparency based on the overlay window on a

pixel-by-pixel basis. This is used when “blue screening” an image to overlay the image on a new

background later.

5.4.7.3 Gamma Correction

To compensate for overlay color intensity loss, the overlay engine supports independent gamma

correction. This allows the overlay data to be converted to linear data or corrected for the display

device when not blending.

5.4.7.4 YUV to RGB Conversion

The format conversion can be bypassed in the case of RGB source data.