ui/tool/event-utils.cpp

/** @file
 * Collection of shorthands to deal with GDK events.
 */
/* Authors:
 *   Krzysztof Kosiński <tweenk.pl@gmail.com>
 *
 * Copyright (C) 2009 Authors
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include <cstring>
#include <gdk/gdk.h>
#include <gdk/gdkkeysyms.h>
#include "display/sp-canvas.h"
#include "ui/tool/event-utils.h"

namespace Inkscape {
namespace UI {


guint shortcut_key(GdkEventKey const &event)
{
    guint shortcut_key = 0;
    gdk_keymap_translate_keyboard_state(
            gdk_keymap_get_for_display(gdk_display_get_default()),
            event.hardware_keycode,
            (GdkModifierType) event.state,
            0   /*event->key.group*/,
            &shortcut_key, NULL, NULL, NULL);
    return shortcut_key;
}

unsigned combine_key_events(guint keyval, gint mask)
{
    GdkEvent *event_next;
    gint i = 0;

    event_next = gdk_event_get();
    // while the next event is also a key notify with the same keyval and mask,
    while (event_next && (event_next->type == GDK_KEY_PRESS || event_next->type == GDK_KEY_RELEASE)
           && event_next->key.keyval == keyval
           && (!mask || event_next->key.state & mask)) {
        if (event_next->type == GDK_KEY_PRESS)
            i ++;
        // kill it
        gdk_event_free(event_next);
        // get next
        event_next = gdk_event_get();
    }
    // otherwise, put it back onto the queue
    if (event_next) gdk_event_put(event_next);

    return i;
}

unsigned combine_motion_events(SPCanvas *canvas, GdkEventMotion &event, gint mask)
{
    if (canvas == NULL) {
        return false;
    }
    GdkEvent *event_next;
    gint i = 0;
    event.x -= canvas->_x0;
    event.y -= canvas->_y0;

    event_next = gdk_event_get();
    // while the next event is also a motion notify
    while (event_next && (event_next->type == GDK_MOTION_NOTIFY)
            && (!mask || event_next->motion.state & mask))
    {
        if (event_next->motion.device == event.device) {
            GdkEventMotion &next = event_next->motion;
            event.send_event = next.send_event;
            event.time = next.time;
            event.x = next.x;
            event.y = next.y;
            event.state = next.state;
            event.is_hint = next.is_hint;
            event.x_root = next.x_root;
            event.y_root = next.y_root;
            if (event.axes && next.axes) {
                memcpy(event.axes, next.axes, gdk_device_get_n_axes(event.device));
            }
        }

        // kill it
        gdk_event_free(event_next);
        event_next = gdk_event_get();
        i++;
    }
    // otherwise, put it back onto the queue
    if (event_next) {
        gdk_event_put(event_next);
    }
    event.x += canvas->_x0;
    event.y += canvas->_y0;

    return i;
}

/** Returns the modifier state valid after this event. Use this when you process events
 * that change the modifier state. Currently handles only Shift, Ctrl, Alt. */
unsigned state_after_event(GdkEvent *event)
{
    unsigned state = 0;
    switch (event->type) {
    case GDK_KEY_PRESS:
        state = event->key.state;
        switch(shortcut_key(event->key)) {
        case GDK_KEY_Shift_L:
        case GDK_KEY_Shift_R:
            state |= GDK_SHIFT_MASK;
            break;
        case GDK_KEY_Control_L:
        case GDK_KEY_Control_R:
            state |= GDK_CONTROL_MASK;
            break;
        case GDK_KEY_Alt_L:
        case GDK_KEY_Alt_R:
            state |= GDK_MOD1_MASK;
            break;
        default: break;
        }
        break;
    case GDK_KEY_RELEASE:
        state = event->key.state;
        switch(shortcut_key(event->key)) {
        case GDK_KEY_Shift_L:
        case GDK_KEY_Shift_R:
            state &= ~GDK_SHIFT_MASK;
            break;
        case GDK_KEY_Control_L:
        case GDK_KEY_Control_R:
            state &= ~GDK_CONTROL_MASK;
            break;
        case GDK_KEY_Alt_L:
        case GDK_KEY_Alt_R:
            state &= ~GDK_MOD1_MASK;
            break;
        default: break;
        }
        break;
    default: break;
    }
    return state;
}

} // namespace UI
} // namespace Inkscape

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :