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BltBitMap.md

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NAME

BltBitMap -- Move a rectangular region of bits in a BitMap.

SYNOPSIS

    planecnt = BltBitMap(SrcBitMap, SrcX, SrcY, DstBitMap,
    D0                   A0         D0:16 D1:16 A1
        DstX, DstY, SizeX, SizeY, Minterm, Mask [, TempA])
        D2:16 D3:16 D4:16  D5:16  D6:8     D7:8   [A2]

    ULONG BltBitMap(struct BitMap *, WORD, WORD, struct BitMap *,
        WORD, WORD, WORD, WORD, UBYTE, UBYTE, UWORD *);

Links: BitMap BitMap

FUNCTION

Perform non-destructive blits to move a rectangle from one area in a BitMap to another area, which can be on a different BitMap. This blit is assumed to be friendly: no error conditions (e.g. a rectangle outside the BitMap bounds) are tested or reported.

INPUTS

SrcBitMap, DstBitMap - the BitMap(s) containing the rectangles

  • the planes copied from the source to the destination are only those whose plane numbers are identical and less than the minimum Depth of either BitMap and whose Mask bit for that plane is non-zero.
  • as a special case, if a plane pointer in the SrcBitMap is zero, it acts as a pointer to a plane of all zeros, and if the plane pointer is 0xffffffff, it acts as a pointer to a plane of all ones. (Note: new for V36)
  • SrcBitMap and DstBitMap can be identical if they point to actual planes. SrcX, SrcY - the x and y coordinates of the upper left corner of the source rectangle. Valid range is positive signed integer such that the raster word's offset 0..(32767-Size) DstX, DstY - the x and y coordinates of the upper left corner of the destination for the rectangle. Valid range is as for Src. SizeX, SizeY - the size of the rectangle to be moved. Valid range is (X: 1..976; Y: 1..1023 such that final raster word's offset is 0..32767) Minterm - the logic function to apply to the rectangle when A is non-zero (i.e. within the rectangle). B is the source rectangle and C, D is the destination for the rectangle.
  • $0C0 is a vanilla copy
  • $030 inverts the source before the copy
  • $050 ignores the source and inverts the destination
  • see the hardware reference manual for other combinations Mask - the write mask to apply to this operation. Bits set indicate the corresponding planes (if not greater than the minimum plane count) are to participate in the operation. Typically this is set to 0xff. TempA - If the copy overlaps exactly to the left or right (i.e. the scan line addresses overlap), and TempA is non-zero, it points to enough chip accessable memory to hold a line of A source for the blit (ie CHIP RAM). BitBitMap will allocate (and free) the needed TempA if none is provided and one is needed. Blit overlap is determined from the relation of the first non-masked planes in the source and destination bit maps.

RESULTS

planecnt - the number of planes actually involved in the blit.

NOTES o This function may use the blitter.

SEE ALSO

ClipBlit graphics/gfx.h hardware/blit.h