/* Copyright (C) 1996, 1997, 1998, 1999 Aladdin Enterprises.  All rights reserved.
  
  This software is provided AS-IS with no warranty, either express or
  implied.
  
  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gxiscale.c,v 1.7.2.1 2003/12/12 22:08:04 giles Exp $ */
/* Interpolated image procedures */
#include "gx.h"
#include "math_.h"
#include "memory_.h"
#include "gpcheck.h"
#include "gserrors.h"
#include "gxfixed.h"
#include "gxfrac.h"
#include "gxarith.h"
#include "gxmatrix.h"
#include "gsccolor.h"
#include "gspaint.h"
#include "gxdevice.h"
#include "gxcmap.h"
#include "gxdcolor.h"
#include "gxistate.h"
#include "gxdevmem.h"
#include "gxcpath.h"
#include "gximage.h"
#include "stream.h"		/* for s_alloc_state */
#include "siinterp.h"		/* for spatial interpolation */
#include "siscale.h"		/* for Mitchell filtering */

/*
 * Define whether we are using Mitchell filtering or spatial
 * interpolation to implement Interpolate.  (The latter doesn't work yet.)
 */
#define USE_MITCHELL_FILTER

/* ------ Strategy procedure ------ */

/* Check the prototype. */
iclass_proc(gs_image_class_0_interpolate);

/* If we're interpolating, use special logic. */
private irender_proc(image_render_interpolate);
irender_proc_t
gs_image_class_0_interpolate(gx_image_enum * penum)
{
    const gs_imager_state *pis = penum->pis;
    gs_memory_t *mem = penum->memory;
    stream_image_scale_params_t iss;
    stream_image_scale_state *pss;
    const stream_template *template;
    byte *line;
    const gs_color_space *pcs = penum->pcs;
    const gs_color_space *pccs;
    gs_point dst_xy;
    uint in_size;

    if (!penum->interpolate) 
	return 0;
    if (penum->use_mask_color || penum->posture != image_portrait ||
    	penum->masked || penum->alpha ||
	(penum->dev->color_info.num_components == 1 &&
	 penum->dev->color_info.max_gray < 15) ||
        (penum->dev->color_info.num_components > 1 &&
         penum->dev->color_info.max_color < 15)
       ) {
	/* We can't handle these cases yet.  Punt. */
	penum->interpolate = false;
	return 0;
    }
/*
 * USE_CONSERVATIVE_INTERPOLATION_RULES is normally NOT defined since
 * the MITCHELL digital filter seems OK as long as we are going out to
 * a device that can produce > 15 shades.
 */
#if defined(USE_MITCHELL_FILTER) && defined(USE_CONSERVATIVE_INTERPOLATION_RULES)
    /*
     * We interpolate using a digital filter, rather than Adobe's
     * spatial interpolation algorithm: this produces very bad-looking
     * results if the input resolution is close to the output resolution,
     * especially if the input has low color resolution, so we resort to
     * some hack tests on the input color resolution and scale to suppress
     * interpolation if we think the result would look especially bad.
     * If we used Adobe's spatial interpolation approach, we wouldn't need
     * to do this, but the spatial interpolation filter doesn't work yet.
     */
    if (penum->bps < 4 || penum->bps * penum->spp < 8 ||
	(fabs(penum->matrix.xx) <= 5 && fabs(penum->matrix.yy <= 5))
	) {
	penum->interpolate = false;
	return 0;
    }
#endif
    /* Non-ANSI compilers require the following casts: */
    gs_distance_transform((float)penum->rect.w, (float)penum->rect.h,
			  &penum->matrix, &dst_xy);
    iss.BitsPerComponentOut = sizeof(frac) * 8;
    iss.MaxValueOut = frac_1;
    iss.WidthOut = (int)ceil(fabs(dst_xy.x));
    iss.HeightOut = (int)ceil(fabs(dst_xy.y));
    iss.WidthIn = penum->rect.w;
    iss.HeightIn = penum->rect.h;
    pccs = cs_concrete_space(pcs, pis);
    iss.Colors = cs_num_components(pccs);
    if (penum->bps <= 8 && penum->device_color) {
	iss.BitsPerComponentIn = 8;
	iss.MaxValueIn = 0xff;
	in_size =
	    (penum->matrix.xx < 0 ?
	     /* We need a buffer for reversing each scan line. */
	     iss.WidthIn * iss.Colors : 0);
    } else {
	iss.BitsPerComponentIn = sizeof(frac) * 8;
	iss.MaxValueIn = frac_1;
	in_size = round_up(iss.WidthIn * iss.Colors * sizeof(frac),
			   align_bitmap_mod);
    }
    /* Allocate a buffer for one source/destination line. */
    {
	uint out_size =
	    iss.WidthOut * max(iss.Colors * (iss.BitsPerComponentOut / 8),
			       sizeof(gx_color_index));

	line = gs_alloc_bytes(mem, in_size + out_size,
			      "image scale src+dst line");
    }
#ifdef USE_MITCHELL_FILTER
    template = &s_IScale_template;
#else
    template = &s_IIEncode_template;
#endif
    pss = (stream_image_scale_state *)
	s_alloc_state(mem, template->stype, "image scale state");
    if (line == 0 || pss == 0 ||
	(pss->params = iss, pss->template = template,
	 (*pss->template->init) ((stream_state *) pss) < 0)
	) {
	gs_free_object(mem, pss, "image scale state");
	gs_free_object(mem, line, "image scale src+dst line");
	/* Try again without interpolation. */
	penum->interpolate = false;
	return 0;
    }
    penum->line = line;
    penum->scaler = pss;
    penum->line_xy = 0;
    {
	gx_dda_fixed x0;

	x0 = penum->dda.pixel0.x;
	if (penum->matrix.xx < 0)
	    dda_advance(x0, penum->rect.w);
	penum->xyi.x = fixed2int_pixround(dda_current(x0));
    }
    penum->xyi.y = fixed2int_pixround(dda_current(penum->dda.pixel0.y));
    if_debug0('b', "[b]render=interpolate\n");
    return &image_render_interpolate;
}

/* ------ Rendering for interpolated images ------ */

private int
image_render_interpolate(gx_image_enum * penum, const byte * buffer,
			 int data_x, uint iw, int h, gx_device * dev)
{
    stream_image_scale_state *pss = penum->scaler;
    const gs_imager_state *pis = penum->pis;
    const gs_color_space *pcs = penum->pcs;
    gs_logical_operation_t lop = penum->log_op;
    int c = pss->params.Colors;
    stream_cursor_read r;
    stream_cursor_write w;
    byte *out = penum->line;

    if (h != 0) {
	/* Convert the unpacked data to concrete values in */
	/* the source buffer. */
	int sizeofPixelIn = pss->params.BitsPerComponentIn / 8;
	uint row_size = pss->params.WidthIn * c * sizeofPixelIn;
	const byte *bdata = buffer + data_x * c * sizeofPixelIn;

	if (sizeofPixelIn == 1) {
	    /* Easy case: 8-bit device color values. */
	    if (penum->matrix.xx >= 0) {
		/* Use the input data directly. */
		r.ptr = bdata - 1;
	    } else {
		/* Mirror the data in X. */
		const byte *p = bdata + row_size - c;
		byte *q = out;
		int i;

		for (i = 0; i < pss->params.WidthIn; p -= c, q += c, ++i)
		    memcpy(q, p, c);
		r.ptr = out - 1;
		out = q;
	    }
	} else {
	    /* Messy case: concretize each sample. */
	    int bps = penum->bps;
	    int dc = penum->spp;
	    const byte *pdata = bdata;
	    frac *psrc = (frac *) penum->line;
	    gs_client_color cc;
	    int i;

	    r.ptr = (byte *) psrc - 1;
	    if_debug0('B', "[B]Concrete row:\n[B]");
	    for (i = 0; i < pss->params.WidthIn; i++, psrc += c) {
		int j;

		if (bps <= 8)
		    for (j = 0; j < dc; ++pdata, ++j) {
			decode_sample(*pdata, cc, j);
		} else		/* bps == 12 */
		    for (j = 0; j < dc; pdata += sizeof(frac), ++j) {
			decode_frac(*(const frac *)pdata, cc, j);
		    }
		(*pcs->type->concretize_color) (&cc, pcs, psrc, pis);
#ifdef DEBUG
		if (gs_debug_c('B')) {
		    int ci;

		    for (ci = 0; ci < c; ++ci)
			dprintf2("%c%04x", (ci == 0 ? ' ' : ','), psrc[ci]);
		}
#endif
	    }
	    out += round_up(pss->params.WidthIn * c * sizeof(frac),
			    align_bitmap_mod);
	    if_debug0('B', "\n");
	}
	r.limit = r.ptr + row_size;
    } else			/* h == 0 */
	r.ptr = 0, r.limit = 0;

    /*
     * Process input and/or collect output.  By construction, the pixels are
     * 1-for-1 with the device, but the Y coordinate might be inverted.
     */

    {
	int xo = penum->xyi.x;
	int yo = penum->xyi.y;
	int width = pss->params.WidthOut;
	int sizeofPixelOut = pss->params.BitsPerComponentOut / 8;
	int dy;
	const gs_color_space *pconcs = cs_concrete_space(pcs, pis);
	int bpp = dev->color_info.depth;
	uint raster = bitmap_raster(width * bpp);

	if (penum->matrix.yy > 0)
	    dy = 1;
	else
	    dy = -1, yo--;
	for (;;) {
	    int ry = yo + penum->line_xy * dy;
	    int x;
	    const frac *psrc;
	    gx_device_color devc;
	    int status, code;

	    DECLARE_LINE_ACCUM_COPY(out, bpp, xo);

	    w.limit = out + width *
		max(c * sizeofPixelOut, sizeof(gx_color_index)) - 1;
	    w.ptr = w.limit - width * c * sizeofPixelOut;
	    psrc = (const frac *)(w.ptr + 1);
	    status = (*pss->template->process)
		((stream_state *) pss, &r, &w, h == 0);
	    if (status < 0 && status != EOFC)
		return_error(gs_error_ioerror);
	    if (w.ptr == w.limit) {
		int xe = xo + width;

		if_debug1('B', "[B]Interpolated row %d:\n[B]",
			  penum->line_xy);
		for (x = xo; x < xe;) {
#ifdef DEBUG
		    if (gs_debug_c('B')) {
			int ci;

			for (ci = 0; ci < c; ++ci)
			    dprintf2("%c%04x", (ci == 0 ? ' ' : ','),
				     psrc[ci]);
		    }
#endif
		    code = (*pconcs->type->remap_concrete_color)
			(psrc, pcs, &devc, pis, dev, gs_color_select_source);
		    if (code < 0)
			return code;
		    if (color_is_pure(&devc)) {
			/* Just pack colors into a scan line. */
			gx_color_index color = devc.colors.pure;

			/* Skip RGB runs quickly. */
			if (c == 3) {
			    do {
				LINE_ACCUM(color, bpp);
				x++, psrc += 3;
			    } while (x < xe && psrc[-3] == psrc[0] &&
				     psrc[-2] == psrc[1] &&
				     psrc[-1] == psrc[2]);
			} else {
			    LINE_ACCUM(color, bpp);
			    x++, psrc += c;
			}
		    } else {
			int rcode;

			LINE_ACCUM_COPY(dev, out, bpp, xo, x, raster, ry);
			rcode = gx_fill_rectangle_device_rop(x, ry,
						     1, 1, &devc, dev, lop);
			if (rcode < 0)
			    return rcode;
			LINE_ACCUM_SKIP(bpp);
			l_xprev = x + 1;
			x++, psrc += c;
		    }
		}
		LINE_ACCUM_COPY(dev, out, bpp, xo, x, raster, ry);
		penum->line_xy++;
		if_debug0('B', "\n");
	    }
	    if ((status == 0 && r.ptr == r.limit) || status == EOFC)
		break;
	}
    }

    return (h == 0 ? 0 : 1);
}
