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GPR_$BIT_BLT                      GPR Calls                       GPR_$BIT_BLT


NAME
     gpr_$bit_blt - performs a bit block transfer.

FORMAT
     gpr_$bit_blt (source_bitmap_desc, source_window, source_plane,
                   dest_origin, dest_plane, status)

DESCRIPTION
     This routine performs a bit block transfer from a single plane of any
     bitmap to a single plane of the current bitmap.

     Both the source and destination bitmaps can be in any bitmap.

     The source window origin is added to the coordinate origin for the source
     bitmap, and the result is the actual origin of the source rectangle for
     the BLT.  Similarly, the destination origin is added to the coordinate
     origin for the current bitmap, and the result is the actual origin of the
     destination rectangle for the BLT.

   Input Parameters
     source_bitmap_desc
          Descriptor of the source bitmap which contains the source window to
          be transferred, in gpr_$bitmap_desc_t format.  This is a 4-byte
          integer.

     source_window
          Rectangular section of the bitmap from which to transfer pixels, in
          gpr_$window_t format.  This data type is 8 bytes long.

     source_plane
          Identifier of the single plane of the source bitmap to move, in
          gpr_$rgb_plane_t format.  This is a 2-byte integer.  Valid values
          are in the range 0 through the identifier of the source bitmap's
          highest plane.  (The current limits are 31 for main memory bitmaps
          and 23 for display memory bitmaps.)

     dest_origin
          Start position (top left coordinate position) of the destination
          rectangle, in gpr_$position_t format.

     dest_plane
          Identifier of the plane of the destination bitmap, in
          gpr_$rgb_plane_t format.  This is a 2-byte integer.  Valid values
          are in the range 0 through the identifier of the destination
          bitmap's highest plane.

   Output Parameters
     status
          Completion status, in status_$t format.

NOTES
     If the source bitmap is a Display Manager frame, the only allowed raster
     op codes are 0, 5, A, and F.  These are the raster operations in which
     the source plays no role.

     If a rectangle is transferred by a BLT to a Display Manager frame and the
     frame is refreshed for any reason, the BLT is re-executed.  Therefore, if
     the information in the source bitmap has changed, the appearance of the
     frame changes accordingly.

Typewritten Software • bear@typewritten.org • Edmonds, WA 98026