adg/adg-widget.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009 Nicola Fontana <ntd at entidi.it>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:adg-widget
  23  * @short_description: A #GtkWidget specifically designed to contain
  24  *                     an #AdgCanvas entity
  25  *
  26  * This is a #GtkDrawingArea derived object that provides an easy way
  27  * to show an ADG based canvas. Its default implementation reacts to
  28  * some mouse events: if you drag the mouse by keepeng the wheel pressed
  29  * the canvas is translated by translating its local map; if the mouse
  30  * wheel is rotated, the local map of the canvas is scaled up or down
  31  * (accordling to the wheel direction) by a factor specified in the
  32  * #AdgWidget:factor property.
  33  **/
  34
  35 /**
  36  * AdgWidget:
  37  *
  38  * All fields are private and should not be used directly.
  39  * Use its public methods instead.
  40  **/
  41
  42
  43 #include "adg-widget.h"
  44 #include "adg-widget-private.h"
  45 #include "adg-marshal.h"
  46 #include "adg-intl.h"
  47
  48 #define PARENT_WIDGET_CLASS  ((GtkWidgetClass *) adg_widget_parent_class)
  49
  50
  51 enum {
  52     PROP_0,
  53     PROP_CANVAS,
  54     PROP_FACTOR
  55 };
  56
  57 enum {
  58     CANVAS_CHANGED,
  59     LAST_SIGNAL
  60 };
  61
  62
  63 static void             dispose                 (GObject         *object);
  64 static void             get_property            (GObject         *object,
  65                                                  guint            prop_id,
  66                                                  GValue          *value,
  67                                                  GParamSpec      *pspec);
  68 static void             set_property            (GObject         *object,
  69                                                  guint            prop_id,
  70                                                  const GValue    *value,
  71                                                  GParamSpec      *pspec);
  72 static void             set_canvas              (AdgWidget       *widget,
  73                                                  AdgCanvas       *canvas);
  74 static gboolean         expose_event            (GtkWidget       *widget,
  75                                                  GdkEventExpose  *event);
  76 static gboolean         scroll_event            (GtkWidget       *widget,
  77                                                  GdkEventScroll  *event);
  78 static gboolean         button_press_event      (GtkWidget       *widget,
  79                                                  GdkEventButton  *event);
  80 static gboolean         motion_notify_event     (GtkWidget       *widget,
  81                                                  GdkEventMotion  *event);
  82 static gboolean         get_local_map           (GtkWidget       *widget,
  83                                                  AdgMatrix       *map,
  84                                                  AdgMatrix       *inverted);
  85 static void             set_local_map           (GtkWidget       *widget,
  86                                                  const AdgMatrix *map);
  87
  88 static guint signals[LAST_SIGNAL] = { 0 };
  89
  90
  91 G_DEFINE_TYPE(AdgWidget, adg_widget, GTK_TYPE_DRAWING_AREA);
  92
  93
  94 static void
  95 adg_widget_class_init(AdgWidgetClass *klass)
  96 {
  97     GObjectClass *gobject_class;
  98     GtkWidgetClass *widget_class;
  99     GParamSpec *param;
 100
 101     gobject_class = (GObjectClass *) klass;
 102     widget_class = (GtkWidgetClass *) klass;
 103
 104     g_type_class_add_private(klass, sizeof(AdgWidgetPrivate));
 105
 106     gobject_class->dispose = dispose;
 107     gobject_class->get_property = get_property;
 108     gobject_class->set_property = set_property;
 109
 110     widget_class->expose_event = expose_event;
 111     widget_class->scroll_event = scroll_event;
 112     widget_class->button_press_event = button_press_event;
 113     widget_class->motion_notify_event = motion_notify_event;
 114
 115     param = g_param_spec_object("canvas",
 116                                 P_("Canvas"),
 117                                 P_("The canvas to be shown by this widget"),
 118                                 ADG_TYPE_CANVAS,
 119                                 G_PARAM_READWRITE | G_PARAM_CONSTRUCT);
 120     g_object_class_install_property(gobject_class, PROP_CANVAS, param);
 121
 122     param = g_param_spec_double("factor",
 123                                 P_("Factor"),
 124                                 P_("The factor used in zooming in and out"),
 125                                 1., G_MAXDOUBLE, 1.05,
 126                                 G_PARAM_READWRITE);
 127     g_object_class_install_property(gobject_class, PROP_FACTOR, param);
 128
 129     /**
 130      * AdgWidget::canvas-changed:
 131      * @widget: an #AdgWidget
 132      *
 133      * Emitted when the widget has a new canvas.
 134      **/
 135     signals[CANVAS_CHANGED] = g_signal_new("canvas-changed", ADG_TYPE_WIDGET,
 136                                            G_SIGNAL_RUN_LAST|G_SIGNAL_NO_RECURSE,
 137                                            G_STRUCT_OFFSET(AdgWidgetClass, canvas_changed),
 138                                            NULL, NULL,
 139                                            adg_marshal_VOID__VOID,
 140                                            G_TYPE_NONE, 0);
 141 }
 142
 143 static void
 144 adg_widget_init(AdgWidget *widget)
 145 {
 146     AdgWidgetPrivate *data = G_TYPE_INSTANCE_GET_PRIVATE(widget,
 147                                                          ADG_TYPE_WIDGET,
 148                                                          AdgWidgetPrivate);
 149
 150     data->canvas = NULL;
 151     data->factor = 1.05;
 152     data->x_event = 0;
 153     data->y_event = 0;
 154
 155     widget->data = data;
 156
 157     /* Enable GDK events to catch wheel rotation and drag */
 158     gtk_widget_add_events((GtkWidget *) widget,
 159                           GDK_BUTTON_PRESS_MASK|
 160                           GDK_BUTTON2_MOTION_MASK|
 161                           GDK_SCROLL_MASK);
 162 }
 163
 164 static void
 165 dispose(GObject *object)
 166 {
 167     AdgWidgetPrivate *data = ((AdgWidget *) object)->data;
 168
 169     if (data->canvas != NULL) {
 170         g_object_unref(data->canvas);
 171         data->canvas = NULL;
 172     }
 173
 174     G_OBJECT_CLASS(adg_widget_parent_class)->dispose(object);
 175 }
 176
 177 static void
 178 get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
 179 {
 180     AdgWidgetPrivate *data = ((AdgWidget *) object)->data;
 181
 182     switch (prop_id) {
 183
 184     case PROP_CANVAS:
 185         g_value_set_object(value, data->canvas);
 186         break;
 187
 188     case PROP_FACTOR:
 189         g_value_set_double(value, data->factor);
 190         break;
 191
 192     default:
 193         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 194         break;
 195     }
 196 }
 197
 198 static void
 199 set_property(GObject *object,
 200              guint prop_id, const GValue *value, GParamSpec *pspec)
 201 {
 202     AdgWidget *widget;
 203     AdgWidgetPrivate *data;
 204
 205     widget = (AdgWidget *) object;
 206     data = widget->data;
 207
 208     switch (prop_id) {
 209
 210     case PROP_CANVAS:
 211         set_canvas(widget, g_value_get_object(value));
 212         break;
 213
 214     case PROP_FACTOR:
 215         data->factor = g_value_get_double(value);
 216         break;
 217
 218     default:
 219         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 220         break;
 221     }
 222 }
 223
 224
 225 /**
 226  * adg_widget_new:
 227  * @path: the #AdgPath to stroke
 228  *
 229  * Creates a new #AdgWidget.
 230  *
 231  * Returns: the newly created widget
 232  **/
 233 GtkWidget *
 234 adg_widget_new(AdgCanvas *canvas)
 235 {
 236     g_return_val_if_fail(ADG_IS_CANVAS(canvas), NULL);
 237
 238     return g_object_new(ADG_TYPE_WIDGET, "canvas", canvas, NULL);
 239 }
 240
 241
 242 /**
 243  * adg_widget_get_canvas:
 244  * @widget: an #AdgWidget
 245  *
 246  * Gets the canvas associated to @widget.
 247  *
 248  * Returns: the requested #AdgCanvas object or %NULL on errors
 249  **/
 250 AdgCanvas *
 251 adg_widget_get_canvas(AdgWidget *widget)
 252 {
 253     AdgWidgetPrivate *data;
 254
 255     g_return_val_if_fail(ADG_IS_WIDGET(widget), NULL);
 256
 257     data = widget->data;
 258
 259     return data->canvas;
 260 }
 261
 262 /**
 263  * adg_widget_set_canvas:
 264  * @widget: an #AdgWidget
 265  * @canvas: the new #AdgCanvas
 266  *
 267  * Sets a new canvas on @widget. The old canvas, if presents, is
 268  * unreferenced.
 269  **/
 270 void
 271 adg_widget_set_canvas(AdgWidget *widget, AdgCanvas *canvas)
 272 {
 273     g_return_if_fail(ADG_IS_WIDGET(widget));
 274
 275     set_canvas(widget, canvas);
 276
 277     g_object_notify((GObject *) widget, "canvas");
 278 }
 279
 280 /**
 281  * adg_widget_get_factor:
 282  * @widget: an #AdgWidget
 283  *
 284  * Gets the zoom factor associated to @widget. The zoom factor is
 285  * directly used to zoom in (that is, the default zoom factor of
 286  * 1.05 will zoom of 5% every iteration) and it is reversed while
 287  * zooming out (that is, the default factor will use 1/1.05).
 288  *
 289  * Returns: the requested zoom factor or 0 on error
 290  **/
 291 gdouble
 292 adg_widget_get_factor(AdgWidget *widget)
 293 {
 294     AdgWidgetPrivate *data;
 295
 296     g_return_val_if_fail(ADG_IS_WIDGET(widget), 0.);
 297
 298     data = widget->data;
 299
 300     return data->factor;
 301 }
 302
 303 /**
 304  * adg_widget_set_factor:
 305  * @widget: an #AdgWidget
 306  * @factor: the new zoom factor
 307  *
 308  * Sets a new zoom factor to @widget. If the factor is less than
 309  * 1, it will be clamped to 1.
 310  **/
 311 void
 312 adg_widget_set_factor(AdgWidget *widget, gdouble factor)
 313 {
 314     AdgWidgetPrivate *data;
 315
 316     g_return_if_fail(ADG_IS_WIDGET(widget));
 317
 318     data = widget->data;
 319     data->factor = CLAMP(factor, 1., G_MAXDOUBLE);
 320
 321     g_object_notify((GObject *) widget, "factor");
 322 }
 323
 324
 325 static void
 326 set_canvas(AdgWidget *widget, AdgCanvas *canvas)
 327 {
 328     AdgWidgetPrivate *data = widget->data;
 329
 330     if (data->canvas != NULL)
 331         g_object_unref(data->canvas);
 332
 333     data->canvas = canvas;
 334
 335     if (canvas != NULL)
 336         g_object_ref(data->canvas);
 337
 338     g_signal_emit(widget, signals[CANVAS_CHANGED], 0);
 339 }
 340
 341 static gboolean
 342 expose_event(GtkWidget *widget, GdkEventExpose *event)
 343 {
 344     AdgWidgetPrivate *data;
 345     AdgCanvas *canvas;
 346
 347     data = ((AdgWidget *) widget)->data;
 348     canvas = data->canvas;
 349
 350     if (canvas != NULL) {
 351         cairo_t *cr = gdk_cairo_create(widget->window);
 352         adg_entity_render((AdgEntity *) canvas, cr);
 353         cairo_destroy(cr);
 354     }
 355
 356     if (PARENT_WIDGET_CLASS->expose_event == NULL)
 357         return FALSE;
 358
 359     return PARENT_WIDGET_CLASS->expose_event(widget, event);
 360 }
 361
 362 static gboolean
 363 scroll_event(GtkWidget *widget, GdkEventScroll *event)
 364 {
 365     AdgWidgetPrivate *data;
 366     AdgMatrix map, inverted;
 367
 368     data = ((AdgWidget *) widget)->data;
 369
 370     if ((event->direction == GDK_SCROLL_UP ||
 371          event->direction == GDK_SCROLL_DOWN) &&
 372         get_local_map(widget, &map, &inverted)) {
 373         double factor, x, y;
 374
 375         if (event->direction == GDK_SCROLL_UP) {
 376             factor = data->factor;
 377         } else {
 378             factor = 1. / data->factor;
 379         }
 380
 381         x = event->x;
 382         y = event->y;
 383
 384         cairo_matrix_transform_point(&inverted, &x, &y);
 385
 386         cairo_matrix_scale(&map, factor, factor);
 387         cairo_matrix_translate(&map, x/factor - x, y/factor - y);
 388
 389         set_local_map(widget, &map);
 390
 391         gtk_widget_queue_draw(widget);
 392     }
 393
 394     if (PARENT_WIDGET_CLASS->scroll_event == NULL)
 395         return FALSE;
 396
 397     return PARENT_WIDGET_CLASS->scroll_event(widget, event);
 398 }
 399
 400 static gboolean
 401 button_press_event(GtkWidget *widget, GdkEventButton *event)
 402 {
 403     AdgWidgetPrivate *data = ((AdgWidget *) widget)->data;
 404
 405     if (event->type == GDK_BUTTON_PRESS && event->button == 2) {
 406         data->x_event = event->x;
 407         data->y_event = event->y;
 408     }
 409
 410     if (PARENT_WIDGET_CLASS->button_press_event == NULL)
 411         return FALSE;
 412
 413     return PARENT_WIDGET_CLASS->button_press_event(widget, event);
 414 }
 415
 416 static gboolean
 417 motion_notify_event(GtkWidget *widget, GdkEventMotion *event)
 418 {
 419     AdgWidgetPrivate *data;
 420     AdgMatrix map, inverted;
 421
 422     data = ((AdgWidget *) widget)->data;
 423
 424     if ((event->state & GDK_BUTTON2_MASK) > 0 &&
 425         get_local_map(widget, &map, &inverted)) {
 426         double x, y;
 427
 428         x = event->x - data->x_event;
 429         y = event->y - data->y_event;
 430
 431         cairo_matrix_transform_distance(&inverted, &x, &y);
 432         cairo_matrix_translate(&map, x, y);
 433         data->x_event = event->x;
 434         data->y_event = event->y;
 435
 436         set_local_map(widget, &map);
 437
 438         gtk_widget_queue_draw(widget);
 439     }
 440
 441     if (PARENT_WIDGET_CLASS->motion_notify_event == NULL)
 442         return FALSE;
 443
 444     return PARENT_WIDGET_CLASS->motion_notify_event(widget, event);
 445 }
 446
 447 static gboolean
 448 get_local_map(GtkWidget *widget, AdgMatrix *map, AdgMatrix *inverted)
 449 {
 450     AdgWidgetPrivate *data;
 451     AdgCanvas *canvas;
 452
 453     data = ((AdgWidget *) widget)->data;
 454     canvas = data->canvas;
 455     if (canvas == NULL)
 456         return FALSE;
 457
 458     adg_entity_get_local_map((AdgEntity *) canvas, map);
 459     adg_matrix_copy(inverted, map);
 460
 461     return cairo_matrix_invert(inverted) == CAIRO_STATUS_SUCCESS;
 462 }
 463
 464 static void
 465 set_local_map(GtkWidget *widget, const AdgMatrix *map)
 466 {
 467     AdgWidgetPrivate *data;
 468     AdgCanvas *canvas;
 469
 470     data = ((AdgWidget *) widget)->data;
 471     canvas = data->canvas;
 472
 473     if (canvas != NULL)
 474         adg_entity_set_local_map((AdgEntity *) canvas, map);
 475 }