SH7764 Datasheet, PDF (1149/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 23 G2D
(15) Antialias Enable (AA)
The antialias enable specification can be used with the LINE type and RLINE type commands to
reduce alias. The antialias enable specification is enabled only in 16-bit/pixel drawing. For 8-
bit/pixel drawing, the AA bit should be cleared to 0. The AA bit should be set to 1 with the
LINED and RLINED commands. The antialias enable specification cannot be used together with
the net drawing specification (NET).
(16) Alpha Blend Enable (αE)
The alpha blend enable specification can be used with the POLYGON4 type and BITBLT type
commands. The source data (color expanded data for a binary source and the specified color for
the monochrome specification) and ground data are alpha blended and drawn. The alpha value is
set in the alpha value register (ALPHR). The alpha blend enable specification is enabled only in
16-bit/pixel drawing. For 8-bit/pixel drawing, the αE bit should be cleared to 0. In the
POLYGON4 type commands, the alpha blend enable specification is enabled only when BLKE =
1. The αE bit should be cleared to 0 when BLKE = 0. In the BITBLT type commands, the alpha
blend enable specification is enabled only when the ROP code is H'CC (source copy). For other
ROP codes, the αE bit should be cleared to 0. The A value in the ARGB format is not alpha
blended. The A value is drawn according to the source A value use (SAU) and A value
(AVALUE) bits in the rendering control register (RCLR).
(17) Source Alpha Enable (SαE)
The source alpha enable specification can be used with the POLYGON4A, and BITBLTA
commands. The SαE bit is used together with the alpha blend enable bit (αE). When αE = 0, the
SαE bit should be cleared to 0. When the source pixel format bit (SPF) is 1 (ARGB format), only
the pixels whose source A value is 1 are alpha blended. Pixels whose source A value is 0 are not
alpha blended and the source data is drawn as it is. The source alpha enable specification is
enabled only when SPF = 1. The SαE bit should be cleared to 0 when SPF = 0.
(18) Block Enable (BLKE)
The block enable specification can be used with the POLYGON4 type commands. When BLKE =
1, the input vertex coordinates (DXn, DYn) are internally transformed to circumscribed rectangle
coordinates (DX'n, DY'n) and four-vertex drawing performed. When coordinate transformation is
to be performed, the transformed vertices are internally converted into a rectangle and drawn. This
is effective for vertically pasting the pattern even after coordinate transformation. When BLKE =
1, the fixed drawing direction is from the upper-left corner to the lower-right corner (up-and-down
and right-and-left directions cannot be reversed).
Rev. 1.00 Nov. 22, 2007 Page 1093 of 1692
REJ09B0360-0100