/* Copyright (C) 2000 artofcode LLC.  All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gstrans.c,v 1.13.2.1.2.1 2003/01/17 00:49:03 giles Exp $ */
/* Implementation of transparency, other than rendering */
#include "gx.h"
#include "gserrors.h"
#include "gstrans.h"
#include "gsutil.h"
#include "gzstate.h"
#include "gxdevcli.h"

/* ------ Transparency-related graphics state elements ------ */

int
gs_setblendmode(gs_state *pgs, gs_blend_mode_t mode)
{
#ifdef DEBUG
    if (gs_debug_c('v')) {
	static const char *const bm_names[] = { GS_BLEND_MODE_NAMES };

	dlprintf1("[v](0x%lx)blend_mode = ", (ulong)pgs);
	if (mode >= 0 && mode < countof(bm_names))
	    dprintf1("%s\n", bm_names[mode]);
	else
	    dprintf1("%d??\n", (int)mode);
    }
#endif
    if (mode < 0 || mode > MAX_BLEND_MODE)
	return_error(gs_error_rangecheck);
    pgs->blend_mode = mode;
    return 0;
}

gs_blend_mode_t
gs_currentblendmode(const gs_state *pgs)
{
    return pgs->blend_mode;
}

int
gs_setopacityalpha(gs_state *pgs, floatp alpha)
{
    if_debug2('v', "[v](0x%lx)opacity.alpha = %g\n", (ulong)pgs, alpha);
    pgs->opacity.alpha = (alpha < 0.0 ? 0.0 : alpha > 1.0 ? 1.0 : alpha);
    return 0;
}

float
gs_currentopacityalpha(const gs_state *pgs)
{
    return pgs->opacity.alpha;
}

int
gs_setshapealpha(gs_state *pgs, floatp alpha)
{
    if_debug2('v', "[v](0x%lx)shape.alpha = %g\n", (ulong)pgs, alpha);
    pgs->shape.alpha = (alpha < 0.0 ? 0.0 : alpha > 1.0 ? 1.0 : alpha);
    return 0;
}

float
gs_currentshapealpha(const gs_state *pgs)
{
    return pgs->shape.alpha;
}

int
gs_settextknockout(gs_state *pgs, bool knockout)
{
    if_debug2('v', "[v](0x%lx)text_knockout = %s\n", (ulong)pgs,
	      (knockout ? "true" : "false"));
    pgs->text_knockout = knockout;
    return 0;
}

bool
gs_currenttextknockout(const gs_state *pgs)
{
    return pgs->text_knockout;
}

/* ------ Transparency rendering stack ------ */

/*
  This area of the transparency facilities is in flux.  Here is a proposal
  for extending the driver interface.  The material below will eventually
  go in gxdevcli.h.
*/

/*
  Push the current transparency state (*ppts) onto the associated stack,
  and set *ppts to a new transparency state of the given dimension.  The
  transparency state may copy some or all of the imager state, such as the
  current alpha and/or transparency mask values, and definitely copies the
  parameters.
*/
#define dev_t_proc_begin_transparency_group(proc, dev_t)\
  int proc(P6(gx_device *dev,\
    const gs_transparency_group_params_t *ptgp,\
    const gs_rect *pbbox,\
    gs_imager_state *pis,\
    gs_transparency_state_t **ppts,\
    gs_memory_t *mem))
#define dev_proc_begin_transparency_group(proc)\
  dev_t_proc_begin_transparency_group(proc, gx_device)

/*
  End a transparency group: blend the top element of the transparency
  stack, which must be a group, into the next-to-top element, popping the
  stack.  If the stack only had a single element, blend into the device
  output.  Set *ppts to 0 iff the stack is now empty.  If end_group fails,
  the stack is *not* popped.
*/
#define dev_t_proc_end_transparency_group(proc, dev_t)\
  int proc(P3(gx_device *dev,\
    gs_imager_state *pis,\
    gs_transparency_state_t **ppts))
#define dev_proc_end_transparency_group(proc)\
  dev_t_proc_end_transparency_group(proc, gx_device)

/*
  Push the transparency state and prepare to render a transparency mask.
  This is similar to begin_transparency_group except that it only
  accumulates coverage values, not full pixel values.
*/
#define dev_t_proc_begin_transparency_mask(proc, dev_t)\
  int proc(P6(gx_device *dev,\
    const gs_transparency_mask_params_t *ptmp,\
    const gs_rect *pbbox,\
    gs_imager_state *pis,\
    gs_transparency_state_t **ppts,\
    gs_memory_t *mem))
#define dev_proc_begin_transparency_mask(proc)\
  dev_t_proc_begin_transparency_mask(proc, gx_device)

/*
  Store a pointer to the rendered transparency mask into *pptm, popping the
  stack like end_group.  Normally, the client will follow this by using
  rc_assign to store the rendered mask into pis->{opacity,shape}.mask.  If
  end_mask fails, the stack is *not* popped.
*/
#define dev_t_proc_end_transparency_mask(proc, dev_t)\
  int proc(P2(gx_device *dev,\
    gs_transparency_mask_t **pptm))
#define dev_proc_end_transparency_mask(proc)\
  dev_t_proc_end_transparency_mask(proc, gx_device)

/*
  Pop the transparency stack, discarding the top element, which may be
  either a group or a mask.  Set *ppts to 0 iff the stack is now empty.
*/
#define dev_t_proc_discard_transparency_layer(proc, dev_t)\
  int proc(P2(gx_device *dev,\
    gs_transparency_state_t **ppts))
#define dev_proc_discard_transparency_layer(proc)\
  dev_t_proc_discard_transparency_layer(proc, gx_device)

     /* (end of proposed driver interface extensions) */

gs_transparency_state_type_t
gs_current_transparency_type(const gs_state *pgs)
{
    return (pgs->transparency_stack == 0 ? 0 :
	    pgs->transparency_stack->type);
}

/* Support for dummy implementation */
gs_private_st_ptrs1(st_transparency_state, gs_transparency_state_t,
		    "gs_transparency_state_t", transparency_state_enum_ptrs,
		    transparency_state_reloc_ptrs, saved);
private int
push_transparency_stack(gs_state *pgs, gs_transparency_state_type_t type,
			client_name_t cname)
{
    gs_transparency_state_t *pts =
	gs_alloc_struct(pgs->memory, gs_transparency_state_t,
			&st_transparency_state, cname);

    if (pts == 0)
	return_error(gs_error_VMerror);
    pts->saved = pgs->transparency_stack;
    pts->type = type;
    pgs->transparency_stack = pts;
    return 0;
}
private void
pop_transparency_stack(gs_state *pgs, client_name_t cname)
{
    gs_transparency_state_t *pts = pgs->transparency_stack; /* known non-0 */
    gs_transparency_state_t *saved = pts->saved;

    gs_free_object(pgs->memory, pts, cname);
    pgs->transparency_stack = saved;

}

void
gs_trans_group_params_init(gs_transparency_group_params_t *ptgp)
{
    ptgp->ColorSpace = 0;	/* bogus, but can't do better */
    ptgp->Isolated = false;
    ptgp->Knockout = false;
}

int
gs_begin_transparency_group(gs_state *pgs,
			    const gs_transparency_group_params_t *ptgp,
			    const gs_rect *pbbox)
{
    /****** NYI, DUMMY ******/
#ifdef DEBUG
    if (gs_debug_c('v')) {
	static const char *const cs_names[] = {
	    GS_COLOR_SPACE_TYPE_NAMES
	};

	dlprintf5("[v](0x%lx)begin_transparency_group [%g %g %g %g]\n",
		  (ulong)pgs, pbbox->p.x, pbbox->p.y, pbbox->q.x, pbbox->q.y);
	if (ptgp->ColorSpace)
	    dprintf1("     CS = %s",
		cs_names[(int)gs_color_space_get_index(ptgp->ColorSpace)]);
	else
	    dputs("     (no CS)");
	dprintf2("  Isolated = %d  Knockout = %d\n",
		 ptgp->Isolated, ptgp->Knockout);
    }
#endif
    return (*dev_proc(pgs->device, begin_transparency_group)) (pgs->device, ptgp,
							    pbbox, (gs_imager_state *)pgs,
							    NULL, NULL);
#if 0
    return push_transparency_stack(pgs, TRANSPARENCY_STATE_Group,
				   "gs_begin_transparency_group");
#endif
}

int
gs_end_transparency_group(gs_state *pgs)
{
    /****** NYI, DUMMY ******/
    return (*dev_proc(pgs->device, end_transparency_group)) (pgs->device, (gs_imager_state *)pgs,
							     NULL);
#if 0
    gs_transparency_state_t *pts = pgs->transparency_stack;

    if_debug1('v', "[v](0x%lx)end_transparency_group\n", (ulong)pgs);
    if (!pts || pts->type != TRANSPARENCY_STATE_Group)
	return_error(gs_error_rangecheck);
    pop_transparency_stack(pgs, "gs_end_transparency_group");
    return 0;
#endif
}

private int
mask_transfer_identity(floatp in, float *out, void *proc_data)
{
    *out = in;
    return 0;
}
void
gs_trans_mask_params_init(gs_transparency_mask_params_t *ptmp,
			  gs_transparency_mask_subtype_t subtype)
{
    ptmp->subtype = subtype;
    ptmp->has_Background = false;
    ptmp->TransferFunction = mask_transfer_identity;
    ptmp->TransferFunction_data = 0;
}

int
gs_begin_transparency_mask(gs_state *pgs,
			   const gs_transparency_mask_params_t *ptmp,
			   const gs_rect *pbbox)
{
    /****** NYI, DUMMY ******/
    if_debug8('v', "[v](0x%lx)begin_transparency_mask [%g %g %g %g]\n\
      subtype = %d  has_Background = %d  %s\n",
	      (ulong)pgs, pbbox->p.x, pbbox->p.y, pbbox->q.x, pbbox->q.y,
	      (int)ptmp->subtype, ptmp->has_Background,
	      (ptmp->TransferFunction == mask_transfer_identity ? "no TR" :
	       "has TR"));
    return push_transparency_stack(pgs, TRANSPARENCY_STATE_Mask,
				   "gs_begin_transparency_group");
}

int
gs_end_transparency_mask(gs_state *pgs,
			 gs_transparency_channel_selector_t csel)
{
    /****** NYI, DUMMY ******/
    gs_transparency_state_t *pts = pgs->transparency_stack;

    if_debug2('v', "[v](0x%lx)end_transparency_mask(%d)\n", (ulong)pgs,
	      (int)csel);
    if (!pts || pts->type != TRANSPARENCY_STATE_Mask)
	return_error(gs_error_rangecheck);
    pop_transparency_stack(pgs, "gs_end_transparency_mask");
    return 0;
}

int
gs_discard_transparency_layer(gs_state *pgs)
{
    /****** NYI, DUMMY ******/
    gs_transparency_state_t *pts = pgs->transparency_stack;

    if_debug1('v', "[v](0x%lx)discard_transparency_layer\n", (ulong)pgs);
    if (!pts)
	return_error(gs_error_rangecheck);
    pop_transparency_stack(pgs, "gs_discard_transparency_layer");
    return 0;
}

int
gs_init_transparency_mask(gs_state *pgs,
			  gs_transparency_channel_selector_t csel)
{
    /****** NYI, DUMMY ******/
    gs_transparency_source_t *ptm;

    if_debug2('v', "[v](0x%lx)init_transparency_mask(%d)\n", (ulong)pgs,
	      (int)csel);
    switch (csel) {
    case TRANSPARENCY_CHANNEL_Opacity: ptm = &pgs->opacity; break;
    case TRANSPARENCY_CHANNEL_Shape: ptm = &pgs->shape; break;
    default: return_error(gs_error_rangecheck);
    }
    rc_decrement_only(ptm->mask, "gs_init_transparency_mask");
    ptm->mask = 0;
    return 0;
}