tools/gtk-path-tool-render.c

/*  Copyright 2023 Red Hat, Inc.
 *
 * GTK+ is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * GLib 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with GTK+; see the file COPYING.  If not,
 * see <http://www.gnu.org/licenses/>.
 *
 * Author: Matthias Clasen
 */

#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <glib/gi18n-lib.h>
#include <glib/gprintf.h>
#include <glib/gstdio.h>
#include <gtk/gtk.h>
#include "gtk-path-tool.h"


void
do_render (int          *argc,
           const char ***argv)
{
  GError *error = NULL;
  const char *fill = "winding";
  const char *fg_color = "black";
  const char *bg_color = "white";
  gboolean do_stroke = FALSE;
  double line_width = 1;
  const char *cap = "butt";
  const char *join = "miter";
  double miter_limit = 4;
  const char *dashes = NULL;
  double dash_offset = 0;
  const char *output_file = NULL;
  char **args = NULL;
  GOptionContext *context;
  GOptionGroup *options;
  const GOptionEntry entries[] = {
    { "fill", 0, G_OPTION_FLAG_REVERSE, G_OPTION_ARG_NONE, &do_stroke, N_("Fill the path (the default)"), NULL },
    { "stroke", 0, 0, G_OPTION_ARG_NONE, &do_stroke, N_("Stroke the path"), NULL },
    { "output", 0, 0, G_OPTION_ARG_FILENAME, &output_file, N_("The output file"), N_("FILE") },
    { "fg-color", 0, 0, G_OPTION_ARG_STRING, &fg_color, N_("Foreground color"), N_("COLOR") },
    { "bg-color", 0, 0, G_OPTION_ARG_STRING, &bg_color, N_("Background color"), N_("COLOR") },
    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, NULL, N_("PATH") },
    { NULL, }
  };
  const GOptionEntry fill_entries[] = {
    { "fill-rule", 0, 0, G_OPTION_ARG_STRING, &fill, N_("Fill rule (winding, even-odd)"), N_("VALUE") },
    { NULL, }
  };
  const GOptionEntry stroke_entries[] = {
    { "line-width", 0, 0, G_OPTION_ARG_DOUBLE, &line_width, N_("Line width (number)"), N_("VALUE") },
    { "line-cap", 0, 0, G_OPTION_ARG_STRING, &cap, N_("Line cap (butt, round, square)"), N_("VALUE") },
    { "line-join", 0, 0, G_OPTION_ARG_STRING, &join, N_("Line join (miter, miter-clip, round, bevel, arcs)"), N_("VALUE") },
    { "miter-limit", 0, 0, G_OPTION_ARG_DOUBLE, &miter_limit, N_("Miter limit (number)"), N_("VALUE") },
    { "dashes", 0, 0, G_OPTION_ARG_STRING, &dashes, N_("Dash pattern (comma-separated numbers)"), N_("VALUE") },
    { "dash-offset", 0, 0, G_OPTION_ARG_DOUBLE, &dash_offset, N_("Dash offset (number)"), N_("VALUE") },
    { NULL, }
  };

  GskPath *path;
  GskFillRule fill_rule;
  GdkRGBA fg, bg;
  graphene_rect_t bounds;
  GskRenderNode *fg_node, *nodes[2], *node;
  GdkSurface *surface;
  GskRenderer *renderer;
  GdkTexture *texture;
  const char *filename;
  GskLineCap line_cap;
  GskLineJoin line_join;
  GskStroke *stroke;

  if (gdk_display_get_default () == NULL)
    {
      g_printerr ("%s\n", _("Could not initialize windowing system"));
      exit (1);
    }

  g_set_prgname ("gtk4-path-tool render");
  context = g_option_context_new (NULL);
  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
  g_option_context_set_summary (context, _("Render the path to a png image."));

  g_option_context_add_main_entries (context, entries, NULL);

  options = g_option_group_new ("fill",
                                _("Options related to filling"),
                                _("Show help for fill options"),
                                NULL, NULL);
  g_option_group_add_entries (options, fill_entries);
  g_option_group_set_translation_domain (options, GETTEXT_PACKAGE);
  g_option_context_add_group (context, options);

  options = g_option_group_new ("stroke",
                                _("Options related to stroking"),
                                _("Show help for stroke options"),
                                NULL, NULL);
  g_option_group_add_entries (options, stroke_entries);
  g_option_group_set_translation_domain (options, GETTEXT_PACKAGE);
  g_option_context_add_group (context, options);

  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
    {
      g_printerr ("%s\n", error->message);
      g_error_free (error);
      exit (1);
    }

  g_option_context_free (context);

  if (args == NULL)
    {
      g_printerr ("%s\n", _("No path specified"));
      exit (1);
    }

  if (g_strv_length (args) > 1)
    {
      g_printerr ("%s\n", _("Can only render a single path"));
      exit (1);
    }

  path = get_path (args[0]);

  fill_rule = get_enum_value (GSK_TYPE_FILL_RULE, _("fill rule"), fill);
  get_color (&fg, fg_color);
  get_color (&bg, bg_color);

  line_cap = get_enum_value (GSK_TYPE_LINE_CAP, _("line cap"), cap);
  line_join = get_enum_value (GSK_TYPE_LINE_JOIN, _("line join"), join);

  stroke = gsk_stroke_new (line_width);
  gsk_stroke_set_line_cap (stroke, line_cap);
  gsk_stroke_set_line_join (stroke, line_join);

  gsk_stroke_set_miter_limit (stroke, miter_limit);

  if (dashes != NULL)
    {
      GArray *d = g_array_new (FALSE, FALSE, sizeof (float));
      char **strings;

      strings = g_strsplit (dashes, ",", 0);

      for (unsigned int i = 0; strings[i]; i++)
        {
          char *end = NULL;
          float f;

          f = (float) g_ascii_strtod (strings[i], &end);

          if (*end != '\0')
            {
              char *msg = g_strdup_printf (_("Failed to parse '%s' as number"), strings[i]);
              g_printerr ("%s\n", msg);
              exit (1);
            }

          g_array_append_val (d, f);
        }

      g_strfreev (strings);

      gsk_stroke_set_dash (stroke, (const float *)d->data, d->len);

      g_array_unref (d);
    }

  gsk_stroke_set_dash_offset (stroke, dash_offset);

  if (do_stroke)
    gsk_path_get_stroke_bounds (path, stroke, &bounds);
  else
    gsk_path_get_bounds (path, &bounds);
  graphene_rect_inset (&bounds, -10, -10);

  nodes[0] = gsk_color_node_new (&bg, &bounds);
  fg_node = gsk_color_node_new (&fg, &bounds);
  if (do_stroke)
    nodes[1] = gsk_stroke_node_new (fg_node, path, stroke);
  else
    nodes[1] = gsk_fill_node_new (fg_node, path, fill_rule);

  node = gsk_container_node_new (nodes, 2);

  gsk_render_node_unref (fg_node);
  gsk_render_node_unref (nodes[0]);
  gsk_render_node_unref (nodes[1]);

  surface = gdk_surface_new_toplevel (gdk_display_get_default ());
  renderer = gsk_renderer_new_for_surface (surface);

  texture = gsk_renderer_render_texture (renderer, node, &bounds);

  filename = output_file ? output_file : "path.png";
  if (!gdk_texture_save_to_png (texture, filename))
    {
      char *msg = g_strdup_printf (_("Saving png to '%s' failed"), filename);
      g_printerr ("%s\n", msg);
      exit (1);
    }

  if (output_file == NULL)
    {
      char *msg = g_strdup_printf (_("Output written to '%s'."), filename);
      g_print ("%s\n", msg);
      g_free (msg);
    }

  g_object_unref (texture);
  gsk_renderer_unrealize (renderer);
  g_object_unref (renderer);
  g_object_unref (surface);
  gsk_render_node_unref (node);

  gsk_path_unref (path);

  g_strfreev (args);
}