Samsung S3C2451X User Manual page 424

2D
Line/Point Drawing
Line Drawing renders a line between the starting point (sx, sy) and the ending point (ex, ey) specified by the user.
If the distance of these two points along y axis is greater than that along x axis ( |ey - sy| > |ex - sx| ), the Major
Axis should be set to y-axis; otherwise, x-axis. If y-axis is the Major Axis, the y-coordinate of a pixel on the line is
increased or decreased by 1 from its preceding pixel, while the x-coordinate increased or decreased by X-INCR
(smaller than 1). In the same vein, if x-axis is the Major Axis, the x-coordinate is increased or decreased by 1
while the y-coordinate by Y-INCR. Note that X-INCR and Y-INCR should be given in 2's complement format as
shown below.
Related Registers
COORD_0
COORD_2
X-INCR
Y-INCR
FG_COLOR
CMD0_REG
Bit Block Transfer
A Bit Block Transfer is a transformation of a rectangular block of pixels. Typical applications include copying the
off-screen pixel data to frame buffer, combining to bitmap patterns by Raster Operation, changing the dimension
of a rectangular image and so on.
On-Screen Rendering
On-screen bit block transfer copies a rectangular block of pixels on screen to another position on the same
screen. Note that on-screen rendering has the following restriction:
1) SRC_BASE_ADDR = DEST_BASE_ADDR
2) SRC_HORI_RES_REG = DEST_HORI_RES_REG
3) SRC_COLOR_MODE = DEST_COLOR_MODE
4) If the destination block overlaps with the source block, stretch mode and rotation must not be used.
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
19-4
Figure 19-4. Data Format
Coordinate of the starting point
Coordinate of the ending point ( ignored if a point is rendered).
X increment value ( ignored if x-axis is the Major Axis or a point is rendered).
X-INCR = (ex-sx)/ |ey - sy|
Y increment value (ignored if y-axis is the Major Axis or a point is rendered).
Y-INCR = (ey – sy)/ |ex - sx|
The color of the drawn line/point
Configure the line/point drawing parameters, such as whether the Major-Axis is x-
axis or y-axis, whether to draw a line or a point, and so on. Note that writing to this
register starts the rendering process.
S3C2451X RISC MICROPROCESSOR