
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 20: 2D Drawing Engine
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
20-5
Raster-ops are turned off if alpha blending is enabled.
2.3.2
Alpha Blending
The Drawing Engine supports alpha blending of source and destination data. The
destination data can be either 32-bit
αRGB:8888, 32-bit αYUV8888, 16-bit RGB:565,
16-bit aRGB 4444, or 16-bit RGBa 4534. Source data can come either from the
memory or from the host data port. The alpha calculations are based on the source
and "surface" alpha values.
Raster-ops are disabled if alpha blending is selected.
The following combinations of source and destination data are supported.
2.3.3
Source Data Location and Type
The data for the source operand can reside in either the frame buffer memory or be
provided by the host processor via the MMIO bus. There are ve source selection
options currently dened:
1. Source data is held in frame buffer memory (always full color data)
2. Source data is provided by the processor via the MMIO bus and is full color
3. Source data is provided by the processor via the MMIO bus and is a
monochrome bitmap
Table 1: Source and Destination Data
Source
Format
Destination
Format
Notes
Memory
αRGB:8888
Std alpha calculations
Host
αRGB:8888
Std alpha calculations
Host
α:4
αRGB:8888
MonoHostBColor reg provides src color
Host
α:8
αRGB:8888
MonoHostBColor reg provides src color
Memory
RGB:565
Surface reg species alpha
Host
RGB:565
Surface reg species alpha
Host
α:4
RGB:565
MonoHostBColor reg provides src color
Host
α:8
RGB:565
MonoHostBColor reg provides src color
Memory
RGB
α:4534
RGB
α:4534
Std alpha calculations
Host
RGB
α:4534
RGB
α:4534
Std alpha calculations
Host
α:4
RGB
α:4534
MonoHostBColor reg provides src color
Host
α:8
RGB
α:4534
MonoHostBColor reg provides src color
Memory
αRGB:4444
Std alpha calculations
Host
αRGB:4444
Std alpha calculations
Host
α:4
αRGB:4444
MonoHostBColor reg provides src color
Host
α:8
αRGB:4444
MonoHostBColor reg provides src color