Layer composition by hardware
Rules: graphics always on top of video2,
video2 always on top of the video1,
video1 always on top of the background
color (when no transparency color key
enabled and match)
Screen
Display controller boundary
Memory
Video1
Video1
Palette
Graphics layer
(always on top of
the video)
Video1 layer
Programmable
background color
key (default)
Register
programmable background color
Video2
Video
2
Video2 layer
GFX
GFX
dss-163
Additional video/graphics attributes
• format
• base address
• row increment
• pixel increment
• rotation
Display
Video1 window width
Gfx window width
Display width
( 0 , 0 )
( x , y )
Additional display attributes:
• type (STN/TFT, mono/color)
• depth
x
y
video1
graphics
background layers
view
Video1
video2
Video2
window
width
Graphics
• transparency color key
Video2
• background color
• timings
window
height
V
ideo2
dss-164
Display height
V
ideo1 window height
Gfx window height
Public Version
Display Subsystem Functional Description
www.ti.com
Figure 7-80. Overlay Manager in Alpha Mode
Figure 7-81. Display Attributes in Alpha Mode
shows the alpha blending processing in detail.
1650
Display Subsystem
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated