1 files changed, 225 insertions, 0 deletions
diff --git a/lib/widget/mouse.c b/lib/widget/mouse.c
new file mode 100644
index 0000000..0c573e8
--- /dev/null
+++ b/lib/widget/mouse.c
@@ -0,0 +1,225 @@
+/*
+   Widgets for the Midnight Commander
+
+   Copyright (C) 2016-2022
+   Free Software Foundation, Inc.
+
+   Authors:
+   Human beings.
+
+   This file is part of the Midnight Commander.
+
+   The Midnight Commander 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.
+
+   The Midnight Commander 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 <http://www.gnu.org/licenses/>.
+ */
+
+/** \file mouse.c
+ *  \brief Header: High-level mouse API
+ */
+
+#include <config.h>
+
+#include "lib/global.h"
+#include "lib/widget.h"
+
+#include "lib/widget/mouse.h"
+
+/*** global variables ****************************************************************************/
+
+/*** file scope macro definitions ****************************************************************/
+
+/*** file scope type declarations ****************************************************************/
+
+/*** file scope variables ************************************************************************/
+
+/* --------------------------------------------------------------------------------------------- */
+/*** file scope functions ************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Constructs a mouse event structure.
+ *
+ * It receives a Gpm_Event event and translates it into a higher level protocol.
+ *
+ * Tip: for details on the C mouse API, see MC's lib/tty/mouse.h,
+ * or GPM's excellent 'info' manual:
+ *
+ *    http://www.fifi.org/cgi-bin/info2www?(gpm)Event+Types
+ */
+static void
+init_mouse_event (mouse_event_t * event, mouse_msg_t msg, const Gpm_Event * global_gpm,
+                  const Widget * w)
+{
+    event->msg = msg;
+    event->x = global_gpm->x - w->rect.x - 1;   /* '-1' because Gpm_Event is 1-based. */
+    event->y = global_gpm->y - w->rect.y - 1;
+    event->count = global_gpm->type & (GPM_SINGLE | GPM_DOUBLE | GPM_TRIPLE);
+    event->buttons = global_gpm->buttons;
+    event->result.abort = FALSE;
+    event->result.repeat = FALSE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Translate GPM event to high-level event,
+ *
+ * @param w Widget object
+ * @param event GPM event
+ *
+ * @return high level mouse event
+ */
+static mouse_event_t
+mouse_translate_event (Widget * w, Gpm_Event * event)
+{
+    gboolean in_widget;
+    mouse_msg_t msg = MSG_MOUSE_NONE;
+    mouse_event_t local;
+
+    /*
+     * Very special widgets may want to control area outside their bounds.
+     * For such widgets you will have to turn on the 'forced_capture' flag.
+     * You'll also need, in your mouse handler, to inform the system of
+     * events you want to pass on by setting 'event->result.abort' to TRUE.
+     */
+    in_widget = w->mouse.forced_capture || mouse_global_in_widget (event, w);
+
+    if ((event->type & GPM_DOWN) != 0)
+    {
+        if (in_widget)
+        {
+            if ((event->buttons & GPM_B_UP) != 0)
+                msg = MSG_MOUSE_SCROLL_UP;
+            else if ((event->buttons & GPM_B_DOWN) != 0)
+                msg = MSG_MOUSE_SCROLL_DOWN;
+            else
+            {
+                /* Handle normal buttons: anything but the mouse wheel's.
+                 *
+                 * (Note that turning on capturing for the mouse wheel
+                 * buttons doesn't make sense as they don't generate a
+                 * mouse_up event, which means we'd never get uncaptured.)
+                 */
+                w->mouse.capture = TRUE;
+                msg = MSG_MOUSE_DOWN;
+
+                w->mouse.last_buttons_down = event->buttons;
+            }
+        }
+    }
+    else if ((event->type & GPM_UP) != 0)
+    {
+        /* We trigger the mouse_up event even when !in_widget. That's
+         * because, for example, a paint application should stop drawing
+         * lines when the button is released even outside the canvas. */
+        if (w->mouse.capture)
+        {
+            w->mouse.capture = FALSE;
+            msg = MSG_MOUSE_UP;
+
+            /*
+             * When using xterm, event->buttons reports the buttons' state
+             * after the event occurred (meaning that event->buttons is zero,
+             * because the mouse button is now released). When using GPM,
+             * however, that field reports the button(s) that was released.
+             *
+             * The following makes xterm behave effectively like GPM:
+             */
+            if (event->buttons == 0)
+                event->buttons = w->mouse.last_buttons_down;
+        }
+    }
+    else if ((event->type & GPM_DRAG) != 0)
+    {
+        if (w->mouse.capture)
+            msg = MSG_MOUSE_DRAG;
+    }
+    else if ((event->type & GPM_MOVE) != 0)
+    {
+        if (in_widget)
+            msg = MSG_MOUSE_MOVE;
+    }
+
+    init_mouse_event (&local, msg, event, w);
+
+    return local;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Call widget mouse handler to process high-level mouse event.
+ *
+ * Besides sending to the widget the event itself, this function may also
+ * send one or more pseudo events. Currently, MSG_MOUSE_CLICK is the only
+ * pseudo event in existence but in the future (e.g., with the introduction
+ * of a drag-drop API) there may be more.
+ *
+ * @param w Widget object
+ * @param event high level mouse event
+ *
+ * @return result of mouse event handling
+ */
+static int
+mouse_process_event (Widget * w, mouse_event_t * event)
+{
+    int ret = MOU_UNHANDLED;
+
+    if (event->msg != MSG_MOUSE_NONE)
+    {
+        w->mouse_callback (w, event->msg, event);
+
+        /* If a widget aborts a MSG_MOUSE_DOWN, we uncapture it so it
+         * doesn't steal events from other widgets. */
+        if (event->msg == MSG_MOUSE_DOWN && event->result.abort)
+            w->mouse.capture = FALSE;
+
+        /* Upon releasing the mouse button: if the mouse hasn't been dragged
+         * since the MSG_MOUSE_DOWN, we also trigger a click. */
+        if (event->msg == MSG_MOUSE_UP && w->mouse.last_msg == MSG_MOUSE_DOWN)
+            w->mouse_callback (w, MSG_MOUSE_CLICK, event);
+
+        /* Record the current event type for the benefit of the next event. */
+        w->mouse.last_msg = event->msg;
+
+        if (!event->result.abort)
+            ret = event->result.repeat ? MOU_REPEAT : MOU_NORMAL;
+    }
+
+    return ret;
+}
+
+
+/* --------------------------------------------------------------------------------------------- */
+/*** public functions ****************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Translate GPM event to high-level event and process it
+ *
+ * @param w Widget object
+ * @param event GPM event
+ *
+ * @return result of mouse event handling
+ */
+int
+mouse_handle_event (Widget * w, Gpm_Event * event)
+{
+    mouse_event_t me;
+
+    me = mouse_translate_event (w, event);
+
+    return mouse_process_event (w, &me);
+}
+
+/* --------------------------------------------------------------------------------------------- */