/* Copyright (C) 1997, 1998, 1999 Aladdin Enterprises.  All rights reserved.

   This file is part of Aladdin Ghostscript.

   Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
   or distributor accepts any responsibility for the consequences of using it,
   or for whether it serves any particular purpose or works at all, unless he
   or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
   License (the "License") for full details.

   Every copy of Aladdin Ghostscript must include a copy of the License,
   normally in a plain ASCII text file named PUBLIC.  The License grants you
   the right to copy, modify and redistribute Aladdin Ghostscript, but only
   under certain conditions described in the License.  Among other things, the
   License requires that the copyright notice and this notice be preserved on
   all copies.
 */

/*$Id: gdevpsdi.c $ */
/* Image compression for PostScript and PDF writers */
#include "math_.h"
#include "jpeglib_.h"		/* for sdct.h */
#include "gx.h"
#include "gserrors.h"
#include "gscspace.h"
#include "gdevpsdf.h"
#include "gdevpsds.h"
#include "strimpl.h"
#include "scfx.h"
#include "sdct.h"
#include "slzwx.h"
#include "spngpx.h"
#include "srlx.h"
#include "szlibx.h"

/******
 ****** HACK: The DCTEncode filter causes a crash, because of its
 ****** complex initialization requirements.  Substitute FlateEncode
 ****** if available, otherwise don't compress.
 ******/
/* Define whether to substitute for the DCTEncode filter. */
#define SUBSTITUTE_FOR_DCT_ENCODE

/* ---------------- Image compression ---------------- */

/*
 * Add a filter to expand or reduce the pixel width if needed.
 * At least one of bpc_in and bpc_out is 8; the other is 1, 2, 4, or 8,
 * except if bpc_out is 8, bpc_in may be 12.
 */
private int
pixel_resize(psdf_binary_writer * pbw, int width, int num_components,
	     int bpc_in, int bpc_out)
{
    gs_memory_t *mem = pbw->dev->v_memory;
    const stream_template *template;
    stream_1248_state *st;
    int code;

    if (bpc_out == bpc_in)
	return 0;
    if (bpc_in != 8) {
	static const stream_template *const exts[13] = {
	    0, &s_1_8_template, &s_2_8_template, 0, &s_4_8_template,
	    0, 0, 0, 0, 0, 0, 0, &s_12_8_template
	};

	template = exts[bpc_in];
    } else {
	static const stream_template *const rets[5] = {
	    0, &s_8_1_template, &s_8_2_template, 0, &s_8_4_template
	};

	template = rets[bpc_out];
    }
    st = (stream_1248_state *)
	s_alloc_state(mem, template->stype, "pixel_resize state");
    if (st == 0)
	return_error(gs_error_VMerror);
    code = psdf_encode_binary(pbw, template, (stream_state *) st);
    if (code < 0) {
	gs_free_object(mem, st, "pixel_resize state");
	return code;
    }
    s_1248_init(st, width, num_components);
    return 0;
}

/* Add the appropriate image compression filter, if any. */
private int
setup_image_compression(psdf_binary_writer *pbw, const psdf_image_params *pdip,
			const gs_image_t * pim)
{
    gx_device_psdf *pdev = pbw->dev;
    const stream_template *template = pdip->filter_template;
    stream_state *st;

    if (pdip->AutoFilter) {
	/****** AutoFilter IS NYI ******/
	/*
	 * Even though this isn't obvious from the Adobe Tech Note,
	 * it appears that if UseFlateCompression is true, the default
	 * compressor for AutoFilter is FlateEncode, not LZWEncode.
	 */
	template =
	    (pdev->params.UseFlateCompression &&
	     pdev->version >= psdf_version_ll3 ?
	     &s_zlibE_template : &s_LZWE_template);
    }
    if (!pdip->Encode || template == 0)	/* no compression */
	return 0;
    if (pim->Width * pim->Height <= 16)	/* not worth compressing */
	return 0;
    /* Only use DCTE for 8-bit data. */
    if (template == &s_DCTE_template &&
	!(pdip->Downsample ?
	  pdip->Depth == 8 ||
	  (pdip->Depth == -1 && pim->BitsPerComponent == 8) :
	  pim->BitsPerComponent == 8)
	) {
	/* Use LZW instead. */
	template = &s_LZWE_template;
    }
#ifdef SUBSTITUTE_FOR_DCT_ENCODE
    if (template == &s_DCTE_template) {
	if (pdev->version < psdf_version_ll3)
	    return 0;		/* FlateEncode is not available */
	template = &s_zlibE_template;
    }
#endif
    st = s_alloc_state(pdev->v_memory, template->stype,
		       "setup_image_compression");
    if (st == 0)
	return_error(gs_error_VMerror);
    if (template->set_defaults)
	(*template->set_defaults) (st);
    if (template == &s_CFE_template) {
	stream_CFE_state *const ss = (stream_CFE_state *) st;

	if (pdip->Dict != 0 && pdip->Dict->template == &s_CFE_template) {
	    stream_state common;

	    common = *st;	/* save generic info */
	    *ss = *(const stream_CFE_state *)pdip->Dict;
	    *st = common;
	} else {
	    ss->K = -1;
	    ss->BlackIs1 = true;
	}
	ss->Columns = pim->Width;
	ss->Rows = (ss->EndOfBlock ? 0 : pim->Height);
    } else if ((template == &s_LZWE_template ||
		template == &s_zlibE_template) &&
	       pdev->version >= psdf_version_ll3) {
	/* Add a PNGPredictor filter. */
	int code = psdf_encode_binary(pbw, template, st);

	if (code < 0) {
	    gs_free_object(pdev->v_memory, st, "setup_image_compression");
	    return code;
	}
	template = &s_PNGPE_template;
	st = s_alloc_state(pdev->v_memory, template->stype,
			   "setup_image_compression");
	if (st == 0)
	    return_error(gs_error_VMerror);
	if (template->set_defaults)
	    (*template->set_defaults) (st);
	{
	    stream_PNGP_state *const ss = (stream_PNGP_state *) st;

	    ss->Colors = gs_color_space_num_components(pim->ColorSpace);
	    ss->Columns = pim->Width;
	}
    } else if (template == &s_DCTE_template) {
	/****** ADD PARAMETERS FROM pdip->Dict ******/
    }
    {
	int code = psdf_encode_binary(pbw, template, st);

	if (code < 0) {
	    gs_free_object(pdev->v_memory, st, "setup_image_compression");
	    return code;
	}
    }
    return 0;
}

/* Add downsampling, antialiasing, and compression filters. */
/* Uses AntiAlias, Depth, DownsampleType, Resolution. */
private int
setup_downsampling(psdf_binary_writer * pbw, const psdf_image_params * pdip,
		   gs_image_t * pim, floatp resolution)
{
    gx_device_psdf *pdev = pbw->dev;
    const stream_template *template =
	(pdip->DownsampleType == ds_Average ?
	 &s_Average_template : &s_Subsample_template);
    int factor = (int)(resolution / pdip->Resolution);
    int orig_bpc = pim->BitsPerComponent;
    int orig_width = pim->Width;
    int orig_height = pim->Height;
    stream_state *st;
    int code;

    if (factor <= 1 || pim->Width < factor || pim->Height < factor)
	return setup_image_compression(pbw, pdip, pim);		/* no downsampling */
    st = s_alloc_state(pdev->v_memory, template->stype,
		       "setup_downsampling");
    if (st == 0)
	return_error(gs_error_VMerror);
    if (template->set_defaults)
	(*template->set_defaults) (st);
    {
	stream_Downsample_state *const ss = (stream_Downsample_state *) st;

	ss->Colors = gs_color_space_num_components(pim->ColorSpace);
	ss->Columns = pim->Width;
	ss->XFactor = ss->YFactor = factor;
	ss->AntiAlias = pdip->AntiAlias;
	if (template->init)
	    (*template->init) (st);
	pim->Width /= factor;
	pim->Height /= factor;
	pim->BitsPerComponent = pdip->Depth;
	gs_matrix_scale(&pim->ImageMatrix, (double)pim->Width / orig_width,
			(double)pim->Height / orig_height,
			&pim->ImageMatrix);
	/****** NO ANTI-ALIASING YET ******/
	if ((code = setup_image_compression(pbw, pdip, pim)) < 0 ||
	    (code = pixel_resize(pbw, pim->Width, ss->Colors,
				 8, pdip->Depth)) < 0 ||
	    (code = psdf_encode_binary(pbw, template, st)) < 0 ||
	    (code = pixel_resize(pbw, orig_width, ss->Colors,
				 orig_bpc, 8)) < 0
	    ) {
	    gs_free_object(pdev->v_memory, st, "setup_image_compression");
	    return code;
	}
    }
    return 0;
}

/* Set up compression and downsampling filters for an image. */
/* Note that this may modify the image parameters. */
int
psdf_setup_image_filters(gx_device_psdf * pdev, psdf_binary_writer * pbw,
			 gs_image_t * pim, const gs_matrix * pctm,
			 const gs_imager_state * pis)
{
    /*
     * The following algorithms are per Adobe Tech Note # 5151,
     * "Acrobat Distiller Parameters", revised 16 September 1996
     * for Acrobat(TM) Distiller(TM) 3.0.
     *
     * The control structure is a little tricky, because filter
     * pipelines must be constructed back-to-front.
     */
    int code = 0;
    psdf_image_params params;

    if (pim->ImageMask) {
	params = pdev->params.MonoImage;
	params.Depth = 1;
    } else {
	int ncomp = gs_color_space_num_components(pim->ColorSpace);
	int bpc = pim->BitsPerComponent;
	int bpc_out = pim->BitsPerComponent = min(bpc, 8);

	/*
	 * We can compute the image resolution by:
	 *    W / (W * ImageMatrix^-1 * CTM / HWResolution).
	 * We can replace W by 1 to simplify the computation.
	 */
	double resolution;

	if (pctm == 0)
	    resolution = -1;
	else {
	    gs_point pt;

	    /* We could do both X and Y, but why bother? */
	    gs_distance_transform_inverse(1.0, 0.0, &pim->ImageMatrix, &pt);
	    gs_distance_transform(pt.x, pt.y, pctm, &pt);
	    resolution = 1.0 / hypot(pt.x / pdev->HWResolution[0],
				     pt.y / pdev->HWResolution[1]);
	}
	if (ncomp == 1) {
	    /* Monochrome or gray */
	    if (bpc == 1)
		params = pdev->params.MonoImage;
	    else
		params = pdev->params.GrayImage;
	    if (params.Depth == -1)
		params.Depth = bpc;
	    /* Check for downsampling. */
	    if (params.Downsample && params.Resolution <= resolution / 2) {
		/* Use the downsampled depth, not the original data depth. */
		if (params.Depth == 1) {
		    params.Filter = pdev->params.MonoImage.Filter;
		    params.filter_template = pdev->params.MonoImage.filter_template;
		    params.Dict = pdev->params.MonoImage.Dict;
		} else {
		    params.Filter = pdev->params.GrayImage.Filter;
		    params.filter_template = pdev->params.GrayImage.filter_template;
		    params.Dict = pdev->params.GrayImage.Dict;
		}
		code = setup_downsampling(pbw, &params, pim, resolution);
	    } else {
		code = setup_image_compression(pbw, &params, pim);
	    }
	    if (code < 0)
		return code;
	    code = pixel_resize(pbw, pim->Width, ncomp, bpc, bpc_out);
	} else {
	    /* Color */
	    bool cmyk_to_rgb =
		pdev->params.ConvertCMYKImagesToRGB &&
		pis != 0 &&
		gs_color_space_get_index(pim->ColorSpace) ==
		  gs_color_space_index_DeviceCMYK;

	    if (cmyk_to_rgb)
		pim->ColorSpace = gs_cspace_DeviceRGB(pis);
	    params = pdev->params.ColorImage;
	    if (params.Depth == -1)
		params.Depth = (cmyk_to_rgb ? 8 : bpc_out);
	    if (params.Downsample && params.Resolution <= resolution / 2) {
		code = setup_downsampling(pbw, &params, pim, resolution);
	    } else {
		code = setup_image_compression(pbw, &params, pim);
	    }
	    if (cmyk_to_rgb) {
		gs_memory_t *mem = pdev->v_memory;
		stream_C2R_state *ss = (stream_C2R_state *)
		s_alloc_state(mem, s_C2R_template.stype, "C2R state");
		int code = pixel_resize(pbw, pim->Width, 3, 8, bpc_out);
		    
		if (code < 0 ||
		    (code = psdf_encode_binary(pbw, &s_C2R_template,
					       (stream_state *) ss)) < 0 ||
		    (code = pixel_resize(pbw, pim->Width, 4, bpc, 8)) < 0
		    )
		    return code;
		s_C2R_init(ss, pis);
	    } else {
		code = pixel_resize(pbw, pim->Width, ncomp, bpc, bpc_out);
		if (code < 0)
		    return code;
	    }
	}
    }
    return code;
}
