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    BitMapScale -- Perform raster scaling on a bit map. (V36)


    void BitMapScale(struct BitScaleArgs *);

    Scale a source bit map to a non-overlapping destination
    bit map.

    bitScaleArgs - structure of parameters describing scale:
        bsa_SrcX, bsa_SrcY - origin of the source bits.
        bsa_SrcWidth, bsa_SrcHeight - number of bits to scale from in x
        and y.
        bsa_DestX, bsa_DestY - origin of the destination.
        bsa_DestWidth, bsa_DestHeight - resulting number of bits in x
        and y.  NOTE: these values are set by this function.
        bsa_XSrcFactor:bsa_XDestFactor - equivalant to the ratio
            srcWidth:destWidth, but not necessarily the same
            numbers.  Each must be in the range 1..16383.
        bsa_YSrcFactor:bsa_YDestFactor - equivalant to the ratio
            srcHeight:destHeight, but not necessarily the same
            numbers.  Each must be in the range 1..16383.
        bsa_SrcBitMap - source of the bits to scale.
        bsa_DestBitMap - destination for the bits to scale.  This had
            better be big enough!
        bsa_Flags - future scaling options.  Set it to zero!
        bsa_XDDA, bsa_YDDA - for future use.  Need not be set by user.
        bsa_Reserved1, bsa_Reserved2 - for future use.  Need not be set.

    The destWidth, destHeight fields are set by this function as
    described above.

    o   This function may use the blitter.
    o   Overlapping source and destination bit maps are not
    o   No check is made to ensure destBitMap is big enough: use
        ScalerDiv to calculate a destination dimension.

    o   This function does not use the HighRes Agnus 'Big Blit'
        facility. You should not use XSrcFactor == XDestFactor,
        where SrcWidth or DestWidth > 1024.

    o   Also, the blitter is used when expanding in the Y direction.
        You should not expand in the Y direction if
        ((DestX & 0xf) + DestWidth) >= 1024 pixels. (Up to 1008 pixels
        is always safe).

    ScalerDiv()  graphics/scale.h

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