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Graphic Orders
SL2UB_HD
13-58
MC68322 USER’S MANUAL
MOTOROLA
SL2UB_HD
Halftone/Destination Scanline Transfer to Unbanded Bitmap
The SL2UB_HD graphic order causes the MC68322 to render a scanline table image to an
unbanded bitmap and apply a halftone bitmap in the process. The destination and halftone
pixels are combined as specified by the Boolean code last set by the SET_BOOL_HD
graphic order. The SET_UBMAP graphic order must previously define the destination
unbanded bitmap warp and the SET_HTBMAP graphic order must do the same for the
halftone bitmap dimensions.
Halftone tiled patterns are typically anchored to the page. Thus, the rendering of a scanline
table may need to take on the halftone pattern starting at various points in the halftone
bitmap, depending on where it is positioned on the page. The halftone parameters HXR,
HYR, and HA define the precise halftone pixel that corresponds to the initial destination
address given in the graphic order. Remember that the initial destination address is not
where the first pixel is drawn—it is the point to which the first bit string specifier’s
displacement is added.
HXR specifies the number of pixels remaining to the right edge of the bitmap and HYR
defines the number of scanlines remaining to the bottom edge. HXR and HYR must be in
the following ranges: 1
≤ HXR ≤ HW and 1 ≤ HYR ≤ HH, where HW and HH are the width
and height of the halftone bitmap, respectively. For example, if the starting pixel in the
halftone bitmap is determined to be at the upper left, HXR must be set to HW, and HYR to
HH.
HTTA and SLTA point to the most-significant byte of the first specifier in their respective
tables and DA, HXR, HYR, and HA refer to the pixel to which the displacement of the first
bit string specifier is added (not necessarily the first bit of the first run). Since both the
scanline table and companion halftone table’s specifiers must be placed at word
boundaries, HTTA and SLTA must be word-aligned.
Related Graphic Orders
SET_BOOL_HD
SET_HTBMAP
SET_UBMAP
PARAMETERS
SIZE
DESCRIPTION
0x25
0x00
DA
HXR
HYR
HA
HTTA
SLTA
Byte
Long Word
Word
Long Word
28 of 32 bits
SL2F_HD Opcode.
Reserved.
Destination physical bit address.
Halftone X remainder.
Halftone Y remainder.
Halftone physical address of the starting pixel.
Companion halftone table physical byte address, word aligned.
Scanline table physical byte address, word aligned.