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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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-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 = 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 */
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