/* Copyright (c) 1990 Commodore-Amiga, Inc.
 *
 * This example is provided in electronic form by Commodore-Amiga, Inc. for
 * use with the 1.3 revisions of the Addison-Wesley Amiga reference manuals. 
 * The 1.3 Addison-Wesley Amiga Reference Manual series contains additional
 * information on the correct usage of the techniques and operating system
 * functions presented in this example.  The source and executable code of
 * this example may only be distributed in free electronic form, via bulletin
 * board or as part of a fully non-commercial and freely redistributable
 * diskette.  Both the source and executable code (including comments) must
 * be included, without modification, in any copy.  This example may not be
 * published in printed form or distributed with any commercial product.
 * However, the programming techniques and support routines set forth in
 * this example may be used in the development of original executable
 * software products for Commodore Amiga computers.
 * All other rights reserved.
 * This example is provided "as-is" and is subject to change; no warranties
 * are made.  All use is at your own risk.  No liability or responsibility
 * is assumed.
 */

#include <exec/types.h>
#include <devices/printer.h>
#include <devices/prtbase.h>
#include <devices/prtgfx.h>

Transfer(PInfo, y, ptr, colors, BufOffset)
struct PrtInfo *PInfo;
UWORD y;		/* row # */
UBYTE *ptr;		/* ptr to buffer */
UWORD *colors;		/* indexes to color buffers */
ULONG BufOffset;	/* used for interleaved printing */
{
	extern struct PrinterData *PD;
	extern struct PrinterExtendedData *PED;

	static UWORD bit_table[8] = {128, 64, 32, 16, 8, 4, 2, 1};
	union colorEntry *ColorInt;
	UBYTE *bptr, *yptr, *mptr, *cptr, Black, Yellow, Magenta, Cyan;
	UBYTE *dmatrix, dvalue, threshold;
	UWORD x, width, sx, *sxptr, color, bit, x3;

	/* printer non-specific, MUST DO FOR EVERY PRINTER */
	x = PInfo->pi_xpos;
	ColorInt = PInfo->pi_ColorInt;
	sxptr = PInfo->pi_ScaleX;
	width = PInfo->pi_width;

	/* printer specific */
	if (PED->ped_YDotsInch == 216) {
		BufOffset *= y % 3;
		y /= 3;
	}
	else if (PED->ped_YDotsInch == 144) {
		BufOffset *= y & 1;
		y /= 2;
	}
	else {
		BufOffset = 0;
	}
	bit = bit_table[y & 7];
	bptr = ptr + colors[0] + BufOffset;
	yptr = ptr + colors[1] + BufOffset;
	mptr = ptr + colors[2] + BufOffset;
	cptr = ptr + colors[3] + BufOffset;

	/* pre-compute threshold; are we thresholding? */
	if (threshold = PInfo->pi_threshold) { /* thresholding */
		dvalue = threshold ^ 15;
		bptr += x;
		do { /* for all source pixels */
			/* pre-compute intensity values for Black component */
			Black = ColorInt->colorByte[PCMBLACK];
			ColorInt++;

			sx = *sxptr++;

			do { /* use this pixel 'sx' times */
				if (Black > dvalue) {
					*bptr |= bit;
				}
				bptr++; /* done 1 more printer pixel */
			} while (--sx);
		} while (--width);
	}
	else { /* not thresholding, pre-compute ptr to dither matrix */
		dmatrix = PInfo->pi_dmatrix + ((y & 3) << 2);
		if (PD->pd_Preferences.PrintShade == SHADE_GREYSCALE) {
			do { /* for all source pixels */
				/* pre-compute intensity values for Black */
				Black = ColorInt->colorByte[PCMBLACK];
				ColorInt++;

				sx = *sxptr++;

				do { /* use this pixel 'sx' times */
					if (Black > dmatrix[x & 3]) {
						*(bptr + x) |= bit;
					}
					x++; /* done 1 more printer pixel */
				} while (--sx);
			} while (--width);
		}
		else { /* color */
			do { /* for all source pixels */
				/* compute intensity values for each color */
				Black = ColorInt->colorByte[PCMBLACK];
				Yellow = ColorInt->colorByte[PCMYELLOW];
				Magenta = ColorInt->colorByte[PCMMAGENTA];
				Cyan = ColorInt->colorByte[PCMCYAN];
				ColorInt++;

				sx = *sxptr++;

				do { /* use this pixel 'sx' times */
					x3 = x >> 3;
					dvalue = dmatrix[x & 3];
					if (Black > dvalue) {
						*(bptr + x) |= bit;
					}
					else  { /* black not rendered */
						if (Yellow > dvalue) {
							*(yptr + x) |= bit;
						}
						if (Magenta > dvalue) {
							*(mptr + x) |= bit;
						}
						if (Cyan > dvalue) {
							*(cptr + x) |= bit;
						}
					}
					++x; /* done 1 more printer pixel */
				} while (--sx);
			} while (--width);
		}
	}
}