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/* -*- 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
*
* 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 */