/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */

/* cairo - a vector graphics library with display and print output

 *

 * Copyright © 2009 Adrian Johnson

 *

 * This library is free software; you can redistribute it and/or

 * modify it either under the terms of the GNU Lesser General Public

 * License version 2.1 as published by the Free Software Foundation

 * (the "LGPL") or, at your option, under the terms of the Mozilla

 * Public License Version 1.1 (the "MPL"). If you do not alter this

 * notice, a recipient may use your version of this file under either

 * the MPL or the LGPL.

 *

 * You should have received a copy of the LGPL along with this library

 * in the file COPYING-LGPL-2.1; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA

 * You should have received a copy of the MPL along with this library

 * in the file COPYING-MPL-1.1

 *

 * The contents of this file are subject to the Mozilla Public License

 * Version 1.1 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.mozilla.org/MPL/

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

 * OF ANY KIND, either express or implied. See the LGPL or the MPL for

 * the specific language governing rights and limitations.

 *

 * The Original Code is the cairo graphics library.

 *

 * The Initial Developer of the Original Code is Adrian Johnson.

 *

 * Contributor(s):

 *  Adrian Johnson <ajohnson@redneon.com>

 */

#include "cairoint.h"

#if CAIRO_HAS_PDF_OPERATORS

#include "cairo-pdf-shading-private.h"

#include "cairo-array-private.h"

#include "cairo-error-private.h"

#include <float.h>

static unsigned char *

encode_coordinate (unsigned char *p, double c)

{

    uint32_t f;

    f = c;

    *p++ = f >> 24;

    *p++ = (f >> 16) & 0xff;

    *p++ = (f >> 8)  & 0xff;

    *p++ = f & 0xff;

    return p;

}

static unsigned char *

encode_point (unsigned char *p, const cairo_point_double_t *point)

{

    p = encode_coordinate (p, point->x);

    p = encode_coordinate (p, point->y);

    return p;

}

static unsigned char *

encode_color_component (unsigned char *p, double color)

{

    uint16_t c;

    c = _cairo_color_double_to_short (color);

    *p++ = c >> 8;

    *p++ = c & 0xff;

    return p;

}

static unsigned char *

encode_color (unsigned char *p, const cairo_color_t *color)

{

    p = encode_color_component (p, color->red);

    p = encode_color_component (p, color->green);

    p = encode_color_component (p, color->blue);

    return p;

}

static unsigned char *

encode_alpha (unsigned char *p, const cairo_color_t *color)

{

    p = encode_color_component (p, color->alpha);

    return p;

}

static cairo_status_t

_cairo_pdf_shading_generate_decode_array (cairo_pdf_shading_t        *shading,

            const cairo_mesh_pattern_t *mesh,

            cairo_bool_t                is_alpha)

{

    unsigned int num_color_components, i;

    cairo_bool_t is_valid;

    if (is_alpha)

  num_color_components = 1;

    else

  num_color_components = 3;

    shading->decode_array_length = 4 + num_color_components * 2;

    shading->decode_array = _cairo_malloc_ab (shading->decode_array_length,

                sizeof (double));

    if (unlikely (shading->decode_array == NULL))

  return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    is_valid = _cairo_mesh_pattern_coord_box (mesh,

                &shading->decode_array[0],

                &shading->decode_array[2],

                &shading->decode_array[1],

                &shading->decode_array[3]);

    assert (is_valid);

    assert (shading->decode_array[1] - shading->decode_array[0] >= DBL_EPSILON);

    assert (shading->decode_array[3] - shading->decode_array[2] >= DBL_EPSILON);

    for (i = 0; i < num_color_components; i++) {

  shading->decode_array[4 + 2*i] = 0;

  shading->decode_array[5 + 2*i] = 1;

    }

    return CAIRO_STATUS_SUCCESS;

}

/* The ISO32000 specification mandates this order for the points which

 * define the patch. */

static const int pdf_points_order_i[16] = {

    0, 0, 0, 0, 1, 2, 3, 3, 3, 3, 2, 1, 1, 1, 2, 2 };

static const int pdf_points_order_j[16] = {

    0, 1, 2, 3, 3, 3, 3, 2, 1, 0, 0, 0, 1, 2, 2, 1 };

static cairo_status_t

_cairo_pdf_shading_generate_data (cairo_pdf_shading_t        *shading,

          const cairo_mesh_pattern_t *mesh,

          cairo_bool_t                is_alpha)

{

    const cairo_mesh_patch_t *patch;

    double x_off, y_off, x_scale, y_scale;

    unsigned int num_patches;

    unsigned int num_color_components;

    unsigned char *p;

    unsigned int i, j;

    if (is_alpha)

  num_color_components = 1;

    else

  num_color_components = 3;

    num_patches = _cairo_array_num_elements (&mesh->patches);

    patch = _cairo_array_index_const (&mesh->patches, 0);

    /* Each patch requires:

     *

     * 1 flag - 1 byte

     * 16 points. Each point is 2 coordinates. Each coordinate is

     * stored in 4 bytes.

     *

     * 4 colors. Each color is stored in 2 bytes * num_color_components.

     */

    shading->data_length = num_patches * (1 + 16 * 2 * 4 + 4 * 2 * num_color_components);

    shading->data = _cairo_malloc (shading->data_length);

    if (unlikely (shading->data == NULL))

  return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    x_off = shading->decode_array[0];

    y_off = shading->decode_array[2];

    x_scale = UINT32_MAX / (shading->decode_array[1] - x_off);

    y_scale = UINT32_MAX / (shading->decode_array[3] - y_off);

    p = shading->data;

    for (i = 0; i < num_patches; i++) {

  /* edge flag */

  *p++ = 0;

  /* 16 points */

  for (j = 0; j < 16; j++) {

      cairo_point_double_t point;

      int pi, pj;

      pi = pdf_points_order_i[j];

      pj = pdf_points_order_j[j];

      point = patch[i].points[pi][pj];

      /* Transform the point as specified in the decode array */

      point.x -= x_off;

      point.y -= y_off;

      point.x *= x_scale;

      point.y *= y_scale;

      /* Make sure that rounding errors don't cause

       * wraparounds */

      point.x = _cairo_restrict_value (point.x, 0, UINT32_MAX);

      point.y = _cairo_restrict_value (point.y, 0, UINT32_MAX);

      p = encode_point (p, &point);

  }

  /* 4 colors */

  for (j = 0; j < 4; j++) {

      if (is_alpha)

    p = encode_alpha (p, &patch[i].colors[j]);

      else

    p = encode_color (p, &patch[i].colors[j]);

  }

    }

    assert (p == shading->data + shading->data_length);

    return CAIRO_STATUS_SUCCESS;

}

static cairo_status_t

_cairo_pdf_shading_init (cairo_pdf_shading_t        *shading,

       const cairo_mesh_pattern_t *mesh,

       cairo_bool_t                is_alpha)

{

    cairo_status_t status;

    assert (mesh->base.status == CAIRO_STATUS_SUCCESS);

    assert (mesh->current_patch == NULL);

    shading->shading_type = 7;

    /*

     * Coordinates from the minimum to the maximum value of the mesh

     * map to the [0..UINT32_MAX] range and are represented as

     * uint32_t values.

     *

     * Color components are represented as uint16_t (in a 0.16 fixed

     * point format, as in the rest of cairo).

     */

    shading->bits_per_coordinate = 32;

    shading->bits_per_component = 16;

    shading->bits_per_flag = 8;

    shading->decode_array = NULL;

    shading->data = NULL;

    status = _cairo_pdf_shading_generate_decode_array (shading, mesh, is_alpha);

    if (unlikely (status))

  return status;

    return _cairo_pdf_shading_generate_data (shading, mesh, is_alpha);

}

cairo_status_t

_cairo_pdf_shading_init_color (cairo_pdf_shading_t        *shading,

             const cairo_mesh_pattern_t *pattern)

{

    return _cairo_pdf_shading_init (shading, pattern, FALSE);

}

cairo_status_t

_cairo_pdf_shading_init_alpha (cairo_pdf_shading_t        *shading,

             const cairo_mesh_pattern_t *pattern)

{

    return _cairo_pdf_shading_init (shading, pattern, TRUE);

}

void

_cairo_pdf_shading_fini (cairo_pdf_shading_t *shading)

{

    free (shading->data);

    free (shading->decode_array);

}

#endif /* CAIRO_HAS_PDF_OPERATORS */