/*

 * Copyright © 2011  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Google Author(s): Behdad Esfahbod

 */

#include "view-cairo.hh"

#include <assert.h>

void

view_cairo_t::render (const font_options_t *font_opts)

{

  bool vertical = HB_DIRECTION_IS_VERTICAL (direction);

  int vert  = vertical ? 1 : 0;

  int horiz = vertical ? 0 : 1;

  int x_sign = font_opts->font_size_x < 0 ? -1 : +1;

  int y_sign = font_opts->font_size_y < 0 ? -1 : +1;

  hb_font_t *font = font_opts->get_font();

  hb_font_extents_t extents;

  hb_font_get_extents_for_direction (font, direction, &extents);

  double ascent = y_sign * scalbn ((double) extents.ascender, scale_bits);

  double descent = y_sign * -scalbn ((double) extents.descender, scale_bits);

  double font_height = y_sign * scalbn ((double) extents.ascender - extents.descender + extents.line_gap, scale_bits);

  double leading = font_height + view_options.line_space;

  /* Calculate surface size. */

  double w, h;

  (vertical ? w : h) = (int) lines->len * leading - view_options.line_space;

  (vertical ? h : w) = 0;

  for (unsigned int i = 0; i < lines->len; i++) {

    helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i);

    double x_advance, y_advance;

    line.get_advance (&x_advance, &y_advance);

    if (vertical)

      h =  MAX (h, y_sign * y_advance);

    else

      w =  MAX (w, x_sign * x_advance);

  }

  cairo_scaled_font_t *scaled_font = helper_cairo_create_scaled_font (font_opts);

  /* See if font needs color. */

  cairo_content_t content = CAIRO_CONTENT_ALPHA;

  if (helper_cairo_scaled_font_has_color (scaled_font))

    content = CAIRO_CONTENT_COLOR;

  /* Create surface. */

  cairo_t *cr = helper_cairo_create_context (w + view_options.margin.l + view_options.margin.r,

					     h + view_options.margin.t + view_options.margin.b,

					     &view_options, &output_options, content);

  cairo_set_scaled_font (cr, scaled_font);

  /* Setup coordinate system. */

  cairo_translate (cr, view_options.margin.l, view_options.margin.t);

  if (vertical)

    cairo_translate (cr,

		     w /* We stack lines right to left */

		     -font_height * .5 /* "ascent" for vertical */,

		     y_sign < 0 ? h : 0);

  else

   {

    cairo_translate (cr,

		     x_sign < 0 ? w : 0,

		     y_sign < 0 ? descent : ascent);

   }

  /* Draw. */

  cairo_translate (cr, +vert * leading, -horiz * leading);

  for (unsigned int i = 0; i < lines->len; i++)

  {

    helper_cairo_line_t &l = g_array_index (lines, helper_cairo_line_t, i);

    cairo_translate (cr, -vert * leading, +horiz * leading);

    if (view_options.annotate) {

      cairo_save (cr);

      /* Draw actual glyph origins */

      cairo_set_source_rgba (cr, 1., 0., 0., .5);

      cairo_set_line_width (cr, 5);

      cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);

      for (unsigned i = 0; i < l.num_glyphs; i++) {

	cairo_move_to (cr, l.glyphs[i].x, l.glyphs[i].y);

	cairo_rel_line_to (cr, 0, 0);

      }

      cairo_stroke (cr);

      cairo_restore (cr);

    }

    if (0 && cairo_surface_get_type (cairo_get_target (cr)) == CAIRO_SURFACE_TYPE_IMAGE) {

      /* cairo_show_glyphs() doesn't support subpixel positioning */

      cairo_glyph_path (cr, l.glyphs, l.num_glyphs);

      cairo_fill (cr);

    } else if (l.num_clusters)

      cairo_show_text_glyphs (cr,

			      l.utf8, l.utf8_len,

			      l.glyphs, l.num_glyphs,

			      l.clusters, l.num_clusters,

			      l.cluster_flags);

    else

      cairo_show_glyphs (cr, l.glyphs, l.num_glyphs);

  }

  /* Clean up. */

  helper_cairo_destroy_context (cr);

  cairo_scaled_font_destroy (scaled_font);

}