SH7764 Datasheet, PDF (1203/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 23 G2D
(c) Description
Draws a polygon with n – 1 vertices at work coordinates. Paints n – 1 trapezoids at work
coordinates using binary EOR, with X = Xmin as the left-hand side, and line segments specified
by the relative shift (DX, DY) from the current pointer values (XC, YC) ((XC, YC) – (XC + DX1,
YC + DY1), (XC + DX1, YC + DY1) – (XC + DX1 + DX2, YC + DY1 + DY2), ..., (XC + ... +
DXn – 1, YC + ... + DYn – 1) – (XC + ... + DXn – 1 + DXn, YC + ...+ DYn – 1 + DYn)) as the
right-hand sides, and with the top and bottom bases parallel to the X-axis. Bottom base drawing is
not performed.
The final coordinate point is stored as the current pointer values (XC, YC). Set (DX1 + DX2 + ...+
DXn = 0, DY1 + DY2 + ... + DYn = 0) to give a closed figure. If the rendering attribute EDG bit
is set to 1, an edge line is drawn after the paint operation. The line drawing data is selected with
the EOS bit.
The RFTRAPC command performs coordinate transformation by internally obtaining the four
vertices from the coordinates for the circumscribed quadrangle of the input polygon and then
transforming the coordinates for these four vertices. The transformed four vertices are then
internally converted into a circumscribed rectangle, the left edge obtained, and the polygon drawn.
Notes: 1. The final coordinate point before coordinate transformation is stored as the current
pointer values (XC, YC).
2. When enabling edge drawing (EDG = 1), Z pre-clipping is not performed for the edge
line.
Rev. 1.00 Nov. 22, 2007 Page 1147 of 1692
REJ09B0360-0100