forked from AuroraMiddleware/gtk
509 lines
15 KiB
C
509 lines
15 KiB
C
/* GTK - The GIMP Toolkit
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* Copyright (C) 2017, Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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* Author(s): Carlos Garnacho <carlosg@gnome.org>
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*/
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/**
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* SECTION:gtkeventcontrollerscroll
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* @Short_description: Event controller for scroll events
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* @Title: GtkEventControllerScroll
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* @See_also: #GtkEventController
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*
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* #GtkEventControllerScroll is an event controller meant to handle
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* scroll events from mice and touchpads. It is capable of handling
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* both discrete and continuous scroll events, abstracting them both
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* on the #GtkEventControllerScroll::scroll signal (deltas in the
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* discrete case are multiples of 1).
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*
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* In the case of continuous scroll events, #GtkEventControllerScroll
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* encloses all #GtkEventControllerScroll::scroll events between two
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* #GtkEventControllerScroll::scroll-begin and #GtkEventControllerScroll::scroll-end
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* signals.
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*
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* The behavior of the event controller can be modified by the
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* flags given at creation time, or modified at a later point through
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* gtk_event_controller_scroll_set_flags() (e.g. because the scrolling
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* conditions of the widget changed).
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*
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* The controller can be set up to emit motion for either/both vertical
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* and horizontal scroll events through #GTK_EVENT_CONTROLLER_SCROLL_VERTICAL,
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* #GTK_EVENT_CONTROLLER_SCROLL_HORIZONTAL and #GTK_EVENT_CONTROLLER_SCROLL_BOTH_AXES.
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* If any axis is disabled, the respective #GtkEventControllerScroll::scroll
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* delta will be 0. Vertical scroll events will be translated to horizontal
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* motion for the devices incapable of horizontal scrolling.
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*
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* The event controller can also be forced to emit discrete events on all devices
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* through #GTK_EVENT_CONTROLLER_SCROLL_DISCRETE. This can be used to implement
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* discrete actions triggered through scroll events (e.g. switching across
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* combobox options).
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*
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* The #GTK_EVENT_CONTROLLER_SCROLL_KINETIC flag toggles the emission of the
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* #GtkEventControllerScroll::decelerate signal, emitted at the end of scrolling
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* with two X/Y velocity arguments that are consistent with the motion that
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* was received.
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**/
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#include "config.h"
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#include "gtkintl.h"
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#include "gtkwidget.h"
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#include "gtkeventcontrollerprivate.h"
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#include "gtkeventcontrollerscroll.h"
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#include "gtktypebuiltins.h"
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#include "gtkmarshalers.h"
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#include "gtkprivate.h"
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#define SCROLL_CAPTURE_THRESHOLD_MS 150
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typedef struct
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{
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double dx;
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double dy;
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guint32 evtime;
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} ScrollHistoryElem;
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struct _GtkEventControllerScroll
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{
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GtkEventController parent_instance;
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GtkEventControllerScrollFlags flags;
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GArray *scroll_history;
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/* For discrete event coalescing */
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double cur_dx;
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double cur_dy;
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guint active : 1;
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};
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struct _GtkEventControllerScrollClass
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{
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GtkEventControllerClass parent_class;
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};
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enum {
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SCROLL_BEGIN,
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SCROLL,
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SCROLL_END,
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DECELERATE,
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N_SIGNALS
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};
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enum {
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PROP_0,
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PROP_FLAGS,
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N_PROPS
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};
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static GParamSpec *pspecs[N_PROPS] = { NULL };
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static guint signals[N_SIGNALS] = { 0 };
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G_DEFINE_TYPE (GtkEventControllerScroll, gtk_event_controller_scroll,
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GTK_TYPE_EVENT_CONTROLLER)
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static void
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scroll_history_push (GtkEventControllerScroll *scroll,
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double delta_x,
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double delta_y,
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guint32 evtime)
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{
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ScrollHistoryElem new_item;
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guint i;
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for (i = 0; i < scroll->scroll_history->len; i++)
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{
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ScrollHistoryElem *elem;
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elem = &g_array_index (scroll->scroll_history, ScrollHistoryElem, i);
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if (elem->evtime >= evtime - SCROLL_CAPTURE_THRESHOLD_MS)
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break;
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}
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if (i > 0)
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g_array_remove_range (scroll->scroll_history, 0, i);
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new_item.dx = delta_x;
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new_item.dy = delta_y;
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new_item.evtime = evtime;
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g_array_append_val (scroll->scroll_history, new_item);
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}
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static void
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scroll_history_reset (GtkEventControllerScroll *scroll)
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{
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if (scroll->scroll_history->len == 0)
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return;
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g_array_remove_range (scroll->scroll_history, 0,
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scroll->scroll_history->len);
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}
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static void
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scroll_history_finish (GtkEventControllerScroll *scroll,
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double *velocity_x,
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double *velocity_y)
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{
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double accum_dx = 0, accum_dy = 0;
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guint32 first = 0, last = 0;
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guint i;
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*velocity_x = 0;
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*velocity_y = 0;
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if (scroll->scroll_history->len == 0)
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return;
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for (i = 0; i < scroll->scroll_history->len; i++)
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{
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ScrollHistoryElem *elem;
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elem = &g_array_index (scroll->scroll_history, ScrollHistoryElem, i);
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accum_dx += elem->dx;
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accum_dy += elem->dy;
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last = elem->evtime;
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if (i == 0)
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first = elem->evtime;
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}
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if (last != first)
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{
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*velocity_x = (accum_dx * 1000) / (last - first);
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*velocity_y = (accum_dy * 1000) / (last - first);
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}
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scroll_history_reset (scroll);
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}
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static void
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gtk_event_controller_scroll_finalize (GObject *object)
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{
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GtkEventControllerScroll *scroll = GTK_EVENT_CONTROLLER_SCROLL (object);
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g_array_unref (scroll->scroll_history);
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G_OBJECT_CLASS (gtk_event_controller_scroll_parent_class)->finalize (object);
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}
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static void
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gtk_event_controller_scroll_set_property (GObject *object,
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guint prop_id,
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const GValue *value,
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GParamSpec *pspec)
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{
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GtkEventControllerScroll *scroll = GTK_EVENT_CONTROLLER_SCROLL (object);
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switch (prop_id)
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{
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case PROP_FLAGS:
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gtk_event_controller_scroll_set_flags (scroll, g_value_get_flags (value));
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static void
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gtk_event_controller_scroll_get_property (GObject *object,
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guint prop_id,
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GValue *value,
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GParamSpec *pspec)
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{
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GtkEventControllerScroll *scroll = GTK_EVENT_CONTROLLER_SCROLL (object);
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switch (prop_id)
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{
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case PROP_FLAGS:
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g_value_set_flags (value, scroll->flags);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static gboolean
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gtk_event_controller_scroll_handle_event (GtkEventController *controller,
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GdkEvent *event,
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double x,
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double y)
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{
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GtkEventControllerScroll *scroll = GTK_EVENT_CONTROLLER_SCROLL (controller);
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GdkScrollDirection direction = GDK_SCROLL_SMOOTH;
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double dx = 0, dy = 0;
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gboolean handled = GDK_EVENT_PROPAGATE;
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if (gdk_event_get_event_type (event) != GDK_SCROLL)
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return FALSE;
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if ((scroll->flags & (GTK_EVENT_CONTROLLER_SCROLL_VERTICAL |
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GTK_EVENT_CONTROLLER_SCROLL_HORIZONTAL)) == 0)
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return FALSE;
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/* FIXME: Handle device changes */
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direction = gdk_scroll_event_get_direction (event);
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if (direction == GDK_SCROLL_SMOOTH)
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{
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gdk_scroll_event_get_deltas (event, &dx, &dy);
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if (!scroll->active)
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{
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g_signal_emit (controller, signals[SCROLL_BEGIN], 0);
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scroll_history_reset (scroll);
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scroll->active = TRUE;
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}
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if ((scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_VERTICAL) == 0)
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dy = 0;
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if ((scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_HORIZONTAL) == 0)
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dx = 0;
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if (scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_DISCRETE)
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{
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int steps;
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scroll->cur_dx += dx;
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scroll->cur_dy += dy;
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dx = dy = 0;
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if (ABS (scroll->cur_dx) >= 1)
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{
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steps = trunc (scroll->cur_dx);
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scroll->cur_dx -= steps;
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dx = steps;
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}
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if (ABS (scroll->cur_dy) >= 1)
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{
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steps = trunc (scroll->cur_dy);
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scroll->cur_dy -= steps;
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dy = steps;
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}
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}
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}
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else
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{
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switch (direction)
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{
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case GDK_SCROLL_UP:
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dy -= 1;
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break;
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case GDK_SCROLL_DOWN:
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dy += 1;
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break;
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case GDK_SCROLL_LEFT:
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dx -= 1;
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break;
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case GDK_SCROLL_RIGHT:
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dx += 1;
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break;
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case GDK_SCROLL_SMOOTH:
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default:
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g_assert_not_reached ();
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break;
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}
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if ((scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_VERTICAL) == 0)
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dy = 0;
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if ((scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_HORIZONTAL) == 0)
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dx = 0;
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}
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if (dx != 0 || dy != 0)
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g_signal_emit (controller, signals[SCROLL], 0, dx, dy, &handled);
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if (direction == GDK_SCROLL_SMOOTH &&
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scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_KINETIC)
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scroll_history_push (scroll, dx, dy, gdk_event_get_time (event));
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if (scroll->active && gdk_scroll_event_is_stop (event))
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{
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g_signal_emit (controller, signals[SCROLL_END], 0);
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scroll->active = FALSE;
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if (scroll->flags & GTK_EVENT_CONTROLLER_SCROLL_KINETIC)
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{
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double vel_x, vel_y;
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scroll_history_finish (scroll, &vel_x, &vel_y);
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g_signal_emit (controller, signals[DECELERATE], 0, vel_x, vel_y);
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}
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}
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return handled;
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}
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static void
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gtk_event_controller_scroll_class_init (GtkEventControllerScrollClass *klass)
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{
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GtkEventControllerClass *controller_class = GTK_EVENT_CONTROLLER_CLASS (klass);
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GObjectClass *object_class = G_OBJECT_CLASS (klass);
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object_class->finalize = gtk_event_controller_scroll_finalize;
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object_class->set_property = gtk_event_controller_scroll_set_property;
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object_class->get_property = gtk_event_controller_scroll_get_property;
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controller_class->handle_event = gtk_event_controller_scroll_handle_event;
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/**
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* GtkEventControllerScroll:flags:
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*
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* The flags affecting event controller behavior
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**/
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pspecs[PROP_FLAGS] =
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g_param_spec_flags ("flags",
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P_("Flags"),
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P_("Flags"),
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GTK_TYPE_EVENT_CONTROLLER_SCROLL_FLAGS,
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GTK_EVENT_CONTROLLER_SCROLL_NONE,
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GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
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/**
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* GtkEventControllerScroll::scroll-begin:
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* @controller: The object that received the signal
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*
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* Signals that a new scrolling operation has begun. It will
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* only be emitted on devices capable of it.
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**/
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signals[SCROLL_BEGIN] =
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g_signal_new (I_("scroll-begin"),
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GTK_TYPE_EVENT_CONTROLLER_SCROLL,
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G_SIGNAL_RUN_FIRST,
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0, NULL, NULL,
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NULL,
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G_TYPE_NONE, 0);
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/**
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* GtkEventControllerScroll::scroll:
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* @controller: The object that received the signal
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* @dx: X delta
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* @dy: Y delta
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*
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* Signals that the widget should scroll by the
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* amount specified by @dx and @dy.
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*
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* Returns: %TRUE if the scroll event was handled, %FALSE otherwise.
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**/
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signals[SCROLL] =
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g_signal_new (I_("scroll"),
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GTK_TYPE_EVENT_CONTROLLER_SCROLL,
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G_SIGNAL_RUN_LAST,
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0, NULL, NULL,
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_gtk_marshal_BOOLEAN__DOUBLE_DOUBLE,
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G_TYPE_BOOLEAN, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
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g_signal_set_va_marshaller (signals[SCROLL],
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G_TYPE_FROM_CLASS (klass),
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_gtk_marshal_BOOLEAN__DOUBLE_DOUBLEv);
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/**
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* GtkEventControllerScroll::scroll-end:
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* @controller: The object that received the signal
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*
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* Signals that a new scrolling operation has finished. It will
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* only be emitted on devices capable of it.
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**/
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signals[SCROLL_END] =
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g_signal_new (I_("scroll-end"),
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GTK_TYPE_EVENT_CONTROLLER_SCROLL,
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G_SIGNAL_RUN_FIRST,
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0, NULL, NULL,
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NULL,
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G_TYPE_NONE, 0);
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/**
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* GtkEventControllerScroll::decelerate:
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* @controller: The object that received the signal
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* @vel_x: X velocity
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* @vel_y: Y velocity
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*
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* Emitted after scroll is finished if the #GTK_EVENT_CONTROLLER_SCROLL_KINETIC
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* flag is set. @vel_x and @vel_y express the initial velocity that was
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* imprinted by the scroll events. @vel_x and @vel_y are expressed in
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* pixels/ms.
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**/
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signals[DECELERATE] =
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g_signal_new (I_("decelerate"),
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GTK_TYPE_EVENT_CONTROLLER_SCROLL,
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G_SIGNAL_RUN_FIRST,
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0, NULL, NULL,
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_gtk_marshal_VOID__DOUBLE_DOUBLE,
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G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
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g_signal_set_va_marshaller (signals[DECELERATE],
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G_TYPE_FROM_CLASS (klass),
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_gtk_marshal_VOID__DOUBLE_DOUBLEv);
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g_object_class_install_properties (object_class, N_PROPS, pspecs);
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}
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static void
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gtk_event_controller_scroll_init (GtkEventControllerScroll *scroll)
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{
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scroll->scroll_history = g_array_new (FALSE, FALSE,
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sizeof (ScrollHistoryElem));
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}
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/**
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* gtk_event_controller_scroll_new:
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* @flags: behavior flags
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*
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* Creates a new event controller that will handle scroll events.
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*
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* Returns: a new #GtkEventControllerScroll
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**/
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GtkEventController *
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gtk_event_controller_scroll_new (GtkEventControllerScrollFlags flags)
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{
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return g_object_new (GTK_TYPE_EVENT_CONTROLLER_SCROLL,
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"flags", flags,
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NULL);
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}
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/**
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* gtk_event_controller_scroll_set_flags:
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* @scroll: a #GtkEventControllerScroll
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* @flags: behavior flags
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*
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* Sets the flags conditioning scroll controller behavior.
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**/
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void
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gtk_event_controller_scroll_set_flags (GtkEventControllerScroll *scroll,
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GtkEventControllerScrollFlags flags)
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{
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g_return_if_fail (GTK_IS_EVENT_CONTROLLER_SCROLL (scroll));
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if (scroll->flags == flags)
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return;
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scroll->flags = flags;
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g_object_notify_by_pspec (G_OBJECT (scroll), pspecs[PROP_FLAGS]);
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}
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/**
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* gtk_event_controller_scroll_get_flags:
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* @scroll: a #GtkEventControllerScroll
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*
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* Gets the flags conditioning the scroll controller behavior.
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*
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* Returns: the controller flags.
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**/
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GtkEventControllerScrollFlags
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gtk_event_controller_scroll_get_flags (GtkEventControllerScroll *scroll)
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{
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g_return_val_if_fail (GTK_IS_EVENT_CONTROLLER_SCROLL (scroll),
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GTK_EVENT_CONTROLLER_SCROLL_NONE);
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return scroll->flags;
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}
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