Graphic Orders
BLT2F_XHD
13-30
MC68322 USER’S MANUAL
MOTOROLA
The XOFF:XMUL parameter is divided into two fields. The least-significant four bits contain
the XMUL field, which specifies the factor used to scale the unexpanded source bitmap in
the X dimension. XMUL must equal a specific value from 0–15, which represents a scaling
factor of 1–16. Only certain scaling factors are supported, as defined in Table 13-3. Values
other than those listed are ignored and no X scaling is performed.
The XOFF field occupies the four most-significant bits and indicates the number of bits to be
clipped at the left edge of the expanded source bitmap. XOFF ranges from 0–XMUL. If
XOFF is zero, no clipping occurs at the left extent, but if it is non-zero, XOFF number of bits
in the left edge of the expanded bitmap are skipped and the next bit is the first one
transferred to the destination bitmap. The YOFF:YMUL parameter is also divided into two
fields. The least-significant four bits contain the YMUL field, which specifies the factor used
to scale the unexpanded source bitmap in the Y dimension. YMUL can equal any value from
0–15, which represents a scaling factor of 1–16.
The YOFF field occupies the four most-significant bits and indicates the number of scanlines
to be clipped at the top edge of the expanded source bitmap. YOFF ranges from 0–YMUL.
If YOFF is zero, no clipping occurs at the top or bottom extent, but if it is non-zero, YOFF
number of scanlines at the top edge of the expanded bitmap are skipped and the next
scanline is the first one transferred to the destination bitmap.
Halftone tiled patterns are typically anchored to the page. A bitBLT 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 upper left corners of the source and destination
frames. 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; to start at the lower right, HXR and HYR must be set to one. The HA parameter defines
a physical bit address within the halftone bitmap and must point to the upper left corner of
the transfer frame. HA must be consistent with HXR and HYR.
Related Graphic Orders
SET_BOOL_SHD
SET_HTBMAP
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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