webkit2gtk mouse gestures

browser.c

#include <stdio.h>
#include <stdlib.h>
#include <gtk/gtk.h>
#include <webkit2/webkit2.h>

struct Client
{
    GtkWidget *web_view;
    GtkWidget *win;
    gdouble mouse_down_x, mouse_down_y;
};

gboolean
key_web_view(GtkWidget *widget, GdkEvent *event, gpointer data)
{
    struct Client *c = (struct Client *)data;
    gdouble dx, dy;
    gdouble rx, ry;

    if (event->type == GDK_BUTTON_PRESS)
    {
        switch (((GdkEventButton *)event)->button)
        {
            case 3:
                c->mouse_down_x = ((GdkEventButton *)event)->x;
                c->mouse_down_y = ((GdkEventButton *)event)->y;

                /* XXX Returning TRUE prevents the context menu from
                 * showing up. */
                return TRUE;
        }
    }
    else if (event->type == GDK_BUTTON_RELEASE)
    {
        if ((((GdkEventButton *)event)->button) == 3)
        {
            rx = ((GdkEventButton *)event)->x;
            ry = ((GdkEventButton *)event)->y;

            dx = c->mouse_down_x - rx;
            dy = c->mouse_down_y - ry;
            if (abs(dx) > abs(dy))
            {
                if (dx > 30) /* navigate backward */
                {
                    webkit_web_view_go_back(WEBKIT_WEB_VIEW(c->web_view));
                    return TRUE;
                }
                else if (dx < -30) /* navigate forward */
                {
                    webkit_web_view_go_forward(WEBKIT_WEB_VIEW(c->web_view));
                    return TRUE;
                }
            }
            else
            {
                if (dy > 30) /* reload */
                {
                    webkit_web_view_reload_bypass_cache(WEBKIT_WEB_VIEW(c->web_view));
                    return TRUE;
                }
                else if (dy < -30) /* new tab */
                {
                    printf("opening new tab, not implemented here\n");
                    return TRUE;
                }
            }

            /* XXX If we end up here, we should open webkit's context
             * menu, because the right mouse button was released but it
             * was not a valid/known gesture. */
        }
    }

    return FALSE;
}

int
main(int argc, char **argv)
{
    struct Client c;

    gtk_init(&argc, &argv);

    c.win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    c.web_view = webkit_web_view_new();

    g_signal_connect(G_OBJECT(c.win), "destroy",
                     G_CALLBACK(gtk_main_quit), NULL);
    g_signal_connect(G_OBJECT(c.web_view), "close",
                     G_CALLBACK(gtk_main_quit), NULL);
    g_signal_connect(G_OBJECT(c.web_view), "button-press-event",
                     G_CALLBACK(key_web_view), &c);
    g_signal_connect(G_OBJECT(c.web_view), "button-release-event",
                     G_CALLBACK(key_web_view), &c);

    gtk_container_add(GTK_CONTAINER(c.win), c.web_view);
    gtk_widget_show_all(c.win);

    webkit_web_view_load_uri(WEBKIT_WEB_VIEW(c.web_view),
                             "https://www.google.com");
    gtk_main();

    exit(EXIT_SUCCESS);
}

Makefile

CFLAGS += -Wall -Wextra -Wno-unused-parameter -O3

browser: browser.c
	$(CC) $(CFLAGS) $(LDFLAGS) \
		-o $@ $< \
		`pkg-config --cflags --libs gtk+-3.0 glib-2.0 webkit2gtk-4.0`