Convert widget coordinates from global to local and vice versa.

Add two widget callbacks:
  * (make_global): convert widget coordinates from local (relative to
    owner) to global (screen).
  * (make_local): convert widget coordinates from global (screen) to
    local (relative to owner).

Such conversions are required when nested widgets and groups are added to
or removed from another groups.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

lib/widget/group.c

@@ -176,6 +176,74 @@ group_send_broadcast_msg_custom (WGroup * g, widget_msg_t msg, gboolean reverse,
 
 /* --------------------------------------------------------------------------------------------- */
 
+/**
+  * Default group callback to convert group coordinates from local (relative to owner) to global
+  * (relative to screen).
+  *
+  * @param w widget
+  */
+
+static void
+group_default_make_global (Widget * w, const WRect * delta)
+{
+    GList *iter;
+
+    if (delta != NULL)
+    {
+        /* change own coordinates */
+        widget_default_make_global (w, delta);
+        /* change child widget coordinates */
+        for (iter = GROUP (w)->widgets; iter != NULL; iter = g_list_next (iter))
+            WIDGET (iter->data)->make_global (WIDGET (iter->data), delta);
+    }
+    else if (w->owner != NULL)
+    {
+        WRect r = { WIDGET (w->owner)->y, WIDGET (w->owner)->x, 0, 0 };
+
+        /* change own coordinates */
+        widget_default_make_global (w, &r);
+        /* change child widget coordinates */
+        for (iter = GROUP (w)->widgets; iter != NULL; iter = g_list_next (iter))
+            WIDGET (iter->data)->make_global (WIDGET (iter->data), &r);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+  * Default group callback to convert group coordinates from global (relative to screen) to local
+  * (relative to owner).
+  *
+  * @param w widget
+  */
+
+static void
+group_default_make_local (Widget * w, const WRect * delta)
+{
+    GList *iter;
+
+    if (delta != NULL)
+    {
+        /* change own coordinates */
+        widget_default_make_local (w, delta);
+        /* change child widget coordinates */
+        for (iter = GROUP (w)->widgets; iter != NULL; iter = g_list_next (iter))
+            WIDGET (iter->data)->make_local (WIDGET (iter->data), delta);
+    }
+    else if (w->owner != NULL)
+    {
+        WRect r = { WIDGET (w->owner)->y, WIDGET (w->owner)->x, 0, 0 };
+
+        /* change own coordinates */
+        widget_default_make_local (w, &r);
+        /* change child widget coordinates */
+        for (iter = GROUP (w)->widgets; iter != NULL; iter = g_list_next (iter))
+            WIDGET (iter->data)->make_local (WIDGET (iter->data), &r);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
 /**
  * Default group callback function to find widget in the group.
  *
@@ -539,6 +607,9 @@ group_init (WGroup * g, int y1, int x1, int lines, int cols, widget_cb_fn callba
 
     w->mouse_handler = group_handle_mouse_event;
 
+    w->make_global = group_default_make_global;
+    w->make_local = group_default_make_local;
+
     w->find = group_default_find;
     w->find_by_type = group_default_find_by_type;
     w->find_by_id = group_default_find_by_id;
@@ -704,14 +775,13 @@ group_add_widget_autopos (WGroup * g, void *w, widget_pos_flags_t pos_flags, con
 
     if ((pos_flags & WPOS_CENTER_HORZ) != 0)
         ww->x = (wg->cols - ww->cols) / 2;
-    ww->x += wg->x;
 
     if ((pos_flags & WPOS_CENTER_VERT) != 0)
         ww->y = (wg->lines - ww->lines) / 2;
-    ww->y += wg->y;
 
     ww->owner = g;
     ww->pos_flags = pos_flags;
+    widget_make_global (ww);
 
     if (g->widgets == NULL || before == NULL)
     {
@@ -757,15 +827,16 @@ group_add_widget_autopos (WGroup * g, void *w, widget_pos_flags_t pos_flags, con
 void
 group_remove_widget (void *w)
 {
+    Widget *ww = WIDGET (w);
     WGroup *g;
     GList *d;
 
     /* Don't accept NULL widget. This shouldn't happen */
     assert (w != NULL);
 
-    g = WIDGET (w)->owner;
+    g = ww->owner;
 
-    d = g_list_find (g->widgets, w);
+    d = g_list_find (g->widgets, ww);
     if (d == g->current)
         group_set_current_widget_next (g);
 
@@ -780,7 +851,8 @@ group_remove_widget (void *w)
         group_select_current_widget (g);
     }
 
-    WIDGET (w)->owner = NULL;
+    widget_make_local (ww);
+    ww->owner = NULL;
 }
 
 /* --------------------------------------------------------------------------------------------- */

lib/widget/widget-common.c

@@ -334,6 +334,12 @@ widget_init (Widget * w, int y, int x, int lines, int cols,
     w->options = WOP_DEFAULT;
     w->state = WST_CONSTRUCT | WST_VISIBLE;
 
+    w->make_global = widget_default_make_global;
+    w->make_local = widget_default_make_local;
+
+    w->make_global = widget_default_make_global;
+    w->make_local = widget_default_make_local;
+
     w->find = widget_default_find;
     w->find_by_type = widget_default_find_by_type;
     w->find_by_id = widget_default_find_by_id;
@@ -686,6 +692,56 @@ widget_lookup_key (Widget * w, int key)
     return keybind_lookup_keymap_command (w->keymap, key);
 }
 
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+  * Default widget callback to convert widget coordinates from local (relative to owner) to global
+  * (relative to screen).
+  *
+  * @param w widget
+  * @delta offset for top-left corner coordinates. Used for child widgets of WGroup
+  */
+
+void
+widget_default_make_global (Widget * w, const WRect * delta)
+{
+    if (delta != NULL)
+    {
+        w->y += delta->y;
+        w->x += delta->x;
+    }
+    else if (w->owner != NULL)
+    {
+        w->y += WIDGET (w->owner)->y;
+        w->x += WIDGET (w->owner)->x;
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+  * Default widget callback to convert widget coordinates from global (relative to screen) to local
+  * (relative to owner).
+  *
+  * @param w widget
+  * @delta offset for top-left corner coordinates. Used for child widgets of WGroup
+  */
+
+void
+widget_default_make_local (Widget * w, const WRect * delta)
+{
+    if (delta != NULL)
+    {
+        w->y -= delta->y;
+        w->x -= delta->x;
+    }
+    else if (w->owner != NULL)
+    {
+        w->y -= WIDGET (w->owner)->y;
+        w->x -= WIDGET (w->owner)->x;
+    }
+}
+
 /* --------------------------------------------------------------------------------------------- */
 /**
  * Default callback function to find widget.

lib/widget/widget-common.h

@@ -158,6 +158,9 @@ struct Widget
         int last_buttons_down;
     } mouse;
 
+    void (*make_global) (Widget * w, const WRect * delta);
+    void (*make_local) (Widget * w, const WRect * delta);
+
     GList *(*find) (const Widget * w, const Widget * what);
     Widget *(*find_by_type) (const Widget * w, widget_cb_fn cb);
     Widget *(*find_by_id) (const Widget * w, unsigned long id);
@@ -221,6 +224,9 @@ void widget_set_bottom (Widget * w);
 
 long widget_lookup_key (Widget * w, int key);
 
+void widget_default_make_global (Widget * w, const WRect * delta);
+void widget_default_make_local (Widget * w, const WRect * delta);
+
 GList *widget_default_find (const Widget * w, const Widget * what);
 Widget *widget_default_find_by_type (const Widget * w, widget_cb_fn cb);
 Widget *widget_default_find_by_id (const Widget * w, unsigned long id);
@@ -281,6 +287,34 @@ widget_get_state (const Widget * w, widget_state_t state)
 
 /* --------------------------------------------------------------------------------------------- */
 
+/**
+  * Convert widget coordinates from local (relative to owner) to global (relative to screen).
+  *
+  * @param w widget
+  */
+
+static inline void
+widget_make_global (Widget * w)
+{
+    w->make_global (w, NULL);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+  * Convert widget coordinates from global (relative to screen) to local (relative to owner).
+  *
+  * @param w widget
+  */
+
+static inline void
+widget_make_local (Widget * w)
+{
+    w->make_local (w, NULL);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
 /**
  * Find widget.
  *

tests/lib/widget/Makefile.am

@@ -19,7 +19,8 @@ TESTS = \
 	complete_engine \
 	hotkey_equal \
 	group_init_destroy \
-	widget_find_by_id
+	widget_find_by_id \
+	widget_make_global_local
 
 check_PROGRAMS = $(TESTS)
 
@@ -34,3 +35,6 @@ group_init_destroy_SOURCES = \
 
 widget_find_by_id_SOURCES = \
 	widget_find_by_id.c
+
+widget_make_global_local_SOURCES = \
+	widget_make_global_local.c

tests/lib/widget/widget_make_global_local.c

@@ -0,0 +1,138 @@
+/*
+   libmc - checks for search widget with requested ID
+
+   Copyright (C) 2021
+   The Free Software Foundation, Inc.
+
+   Written by:
+   Andrew Borodin <aborodin@vmail.ru>, 2021
+
+   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/>.
+ */
+
+#define TEST_SUITE_NAME "lib/widget"
+
+#include <config.h>
+
+#include <check.h>
+
+#include "lib/widget.h"
+
+#include "tests/mctest.h"
+
+/* --------------------------------------------------------------------------------------------- */
+
+/* *INDENT-OFF* */
+START_TEST (test_widget_make_global_local)
+/* *INDENT-ON* */
+{
+    WGroup *g0, *g1, *g2;
+    Widget *w0, *w1, *w2;
+
+    /* top level group */
+    g0 = g_new0 (WGroup, 1);
+    group_init (g0, 20, 20, 40, 40, NULL, NULL);
+
+    /* g0 child */
+    w0 = g_new0 (Widget, 1);
+    widget_init (w0, 1, 1, 5, 5, widget_default_callback, NULL);
+    group_add_widget (g0, w0);
+
+    /* g0 child */
+    g1 = g_new0 (WGroup, 1);
+    group_init (g1, 5, 5, 30, 30, NULL, NULL);
+
+    /* g1 child */
+    w1 = g_new0 (Widget, 1);
+    widget_init (w1, 5, 5, 10, 10, widget_default_callback, NULL);
+    group_add_widget (g1, w1);
+
+    /* g1 child */
+    g2 = g_new0 (WGroup, 1);
+    group_init (g2, 15, 15, 20, 20, NULL, NULL);
+    group_add_widget (g1, g2);
+
+    /* g2 child */
+    w2 = g_new0 (Widget, 1);
+    widget_init (w2, 15, 15, 5, 5, widget_default_callback, NULL);
+    group_add_widget (g2, w2);
+
+    /* g0 child */
+    group_add_widget (g0, g1);
+
+    /* test global coordinates */
+    /* w0 is a member of g0 */
+    ck_assert_int_eq (w0->y, 21);
+    ck_assert_int_eq (w0->x, 21);
+    /* g1 is a member of g0 */
+    ck_assert_int_eq (WIDGET (g1)->y, 25);
+    ck_assert_int_eq (WIDGET (g1)->x, 25);
+    /* w1 is a member of g1 */
+    ck_assert_int_eq (w1->y, 30);
+    ck_assert_int_eq (w1->x, 30);
+    /* g2 is a member of g1 */
+    ck_assert_int_eq (WIDGET (g2)->y, 40);
+    ck_assert_int_eq (WIDGET (g2)->x, 40);
+    /* w2 is a member of g2 */
+    ck_assert_int_eq (w2->y, 55);
+    ck_assert_int_eq (w2->x, 55);
+
+    group_remove_widget (w0);
+    group_remove_widget (g1);
+
+    /* test local coordinates */
+    /* w0 is not a member of g0 */
+    ck_assert_int_eq (w0->y, 1);
+    ck_assert_int_eq (w0->x, 1);
+
+    /* g1 is not a member of g0 */
+    ck_assert_int_eq (WIDGET (g1)->y, 5);
+    ck_assert_int_eq (WIDGET (g1)->x, 5);
+    /* w1 is a member of g1 */
+    ck_assert_int_eq (w1->y, 10);
+    ck_assert_int_eq (w1->x, 10);
+    /* g2 is not a member of g1 */
+    ck_assert_int_eq (WIDGET (g2)->y, 20);
+    ck_assert_int_eq (WIDGET (g2)->x, 20);
+    /* w2 is a member of g2 */
+    ck_assert_int_eq (w2->y, 35);
+    ck_assert_int_eq (w2->x, 35);
+
+    widget_destroy (w0);
+    widget_destroy (WIDGET (g1));
+    widget_destroy (WIDGET (g0));
+}
+/* *INDENT-OFF* */
+END_TEST
+/* *INDENT-ON* */
+
+/* --------------------------------------------------------------------------------------------- */
+
+int
+main (void)
+{
+    TCase *tc_core;
+
+    tc_core = tcase_create ("Core");
+
+    /* Add new tests here: *************** */
+    tcase_add_test (tc_core, test_widget_make_global_local);
+    /* *********************************** */
+
+    return mctest_run_all (tc_core);
+}
+
+/* --------------------------------------------------------------------------------------------- */