PIKApp/app/text/pikatext-vectors.c

/* PIKA - Photo and Image Kooker Application
 * a rebranding of The GNU Image Manipulation Program (created with heckimp)
 * A derived work which may be trivial. However, any changes may be (C)2023 by Aldercone Studio
 *
 * Original copyright, applying to most contents (license remains unchanged): 
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * PikaText-vectors
 * Copyright (C) 2003  Sven Neumann <sven@gimp.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <gdk-pixbuf/gdk-pixbuf.h>
#include <pango/pangocairo.h>
#include <gegl.h>

#include "text-types.h"

#include "core/pika.h"
#include "core/pikaimage.h"

#include "vectors/pikabezierstroke.h"
#include "vectors/pikavectors.h"
#include "vectors/pikaanchor.h"

#include "pikatext.h"
#include "pikatext-vectors.h"
#include "pikatextlayout.h"
#include "pikatextlayout-render.h"


typedef struct
{
  PikaVectors *vectors;
  PikaStroke  *stroke;
  PikaAnchor  *anchor;
} RenderContext;


static void  pika_text_render_vectors (cairo_t       *cr,
                                       RenderContext *context);


PikaVectors *
pika_text_vectors_new (PikaImage *image,
                       PikaText  *text)
{
  PikaVectors   *vectors;
  RenderContext  context = { NULL, };

  g_return_val_if_fail (PIKA_IS_IMAGE (image), NULL);
  g_return_val_if_fail (PIKA_IS_TEXT (text), NULL);

  vectors = pika_vectors_new (image, NULL);

  if (text->text || text->markup)
    {
      PikaTextLayout  *layout;
      cairo_surface_t *surface;
      cairo_t         *cr;
      gdouble          xres;
      gdouble          yres;
      GError          *error = NULL;

      if (text->text)
        pika_object_set_name_safe (PIKA_OBJECT (vectors), text->text);

      context.vectors = vectors;

      surface = cairo_recording_surface_create (CAIRO_CONTENT_ALPHA, NULL);
      cr = cairo_create (surface);

      pika_image_get_resolution (image, &xres, &yres);

      layout = pika_text_layout_new (text, xres, yres, &error);
      if (error)
        {
          pika_message_literal (image->pika, NULL, PIKA_MESSAGE_ERROR, error->message);
          g_error_free (error);
        }
      pika_text_layout_render (layout, cr, text->base_dir, TRUE);
      g_object_unref (layout);

      pika_text_render_vectors (cr, &context);

      cairo_destroy (cr);
      cairo_surface_destroy (surface);

      if (context.stroke)
        pika_stroke_close (context.stroke);
    }

  return vectors;
}


static inline void
pika_text_vector_coords (const double  x,
                         const double  y,
                         PikaCoords   *coords)
{
  const PikaCoords default_values = PIKA_COORDS_DEFAULT_VALUES;

  *coords = default_values;

  coords->x = x;
  coords->y = y;
}

static gint
moveto (RenderContext *context,
        const double   x,
        const double   y)
{
  PikaCoords     start;

#if PIKA_TEXT_DEBUG
  g_printerr ("moveto  %f, %f\n", x, y);
#endif

  pika_text_vector_coords (x, y, &start);

  if (context->stroke)
    pika_stroke_close (context->stroke);

  context->stroke = pika_bezier_stroke_new_moveto (&start);

  pika_vectors_stroke_add (context->vectors, context->stroke);
  g_object_unref (context->stroke);

  return 0;
}

static gint
lineto (RenderContext *context,
        const double   x,
        const double   y)
{
  PikaCoords     end;

#if PIKA_TEXT_DEBUG
  g_printerr ("lineto  %f, %f\n", x, y);
#endif

  if (! context->stroke)
    return 0;

  pika_text_vector_coords (x, y, &end);

  pika_bezier_stroke_lineto (context->stroke, &end);

  return 0;
}

static gint
cubicto (RenderContext *context,
         const double   x1,
         const double   y1,
         const double   x2,
         const double   y2,
         const double   x3,
         const double   y3)
{
  PikaCoords     control1;
  PikaCoords     control2;
  PikaCoords     end;

#if PIKA_TEXT_DEBUG
  g_printerr ("cubicto %f, %f\n", x3, y3);
#endif

  if (! context->stroke)
    return 0;

  pika_text_vector_coords (x1, y1, &control1);
  pika_text_vector_coords (x2, y2, &control2);
  pika_text_vector_coords (x3, y3, &end);

  pika_bezier_stroke_cubicto (context->stroke, &control1, &control2, &end);

  return 0;
}

static gint
closepath (RenderContext *context)
{
#if PIKA_TEXT_DEBUG
  g_printerr ("moveto\n");
#endif

  if (! context->stroke)
    return 0;

  pika_stroke_close (context->stroke);

  context->stroke = NULL;

  return 0;
}

static void
pika_text_render_vectors (cairo_t       *cr,
                          RenderContext *context)
{
  cairo_path_t *path;
  gint          i;

  path = cairo_copy_path (cr);

  for (i = 0; i < path->num_data; i += path->data[i].header.length)
    {
      cairo_path_data_t *data = &path->data[i];

      /* if the drawing operation is the final moveto of the glyph,
       * break to avoid creating an empty point. This is because cairo
       * always adds a moveto after each closepath.
       */
      if (i + data->header.length >= path->num_data)
        break;

      switch (data->header.type)
        {
        case CAIRO_PATH_MOVE_TO:
          moveto (context, data[1].point.x, data[1].point.y);
          break;

        case CAIRO_PATH_LINE_TO:
          lineto (context, data[1].point.x, data[1].point.y);
          break;

        case CAIRO_PATH_CURVE_TO:
          cubicto (context,
                   data[1].point.x, data[1].point.y,
                   data[2].point.x, data[2].point.y,
                   data[3].point.x, data[3].point.y);
          break;

        case CAIRO_PATH_CLOSE_PATH:
          closepath (context);
          break;
        }
    }

  cairo_path_destroy (path);
}