Implement mousedown operation

This allows you to move the cursor off the surface while dragging its
scrollbar.

2 files changed, 46 insertions, 1 deletions

diff --git a/sway/input/cursor.c b/sway/input/cursor.c
index 3b70b471..bd0030f0 100644
--- a/sway/input/cursor.c
+++ b/sway/input/cursor.c
@@ -215,6 +215,18 @@ static enum wlr_edges find_resize_edge(struct sway_container *cont,
         return edge;
 }
 
+static void handle_mousedown_motion(struct sway_seat *seat,
+                struct sway_cursor *cursor, uint32_t time_msec) {
+        struct sway_container *con = seat->op_container;
+        if (seat_is_input_allowed(seat, con->sway_view->surface)) {
+                double moved_x = cursor->cursor->x - seat->op_ref_lx;
+                double moved_y = cursor->cursor->y - seat->op_ref_ly;
+                double sx = seat->op_ref_con_lx + moved_x;
+                double sy = seat->op_ref_con_ly + moved_y;
+                wlr_seat_pointer_notify_motion(seat->wlr_seat, time_msec, sx, sy);
+        }
+}
+
 static void handle_move_motion(struct sway_seat *seat,
                 struct sway_cursor *cursor) {
         struct sway_container *con = seat->op_container;
@@ -397,6 +409,9 @@ void cursor_send_pointer_motion(struct sway_cursor *cursor, uint32_t time_msec,
 
         if (seat->operation != OP_NONE) {
                 switch (seat->operation) {
+                case OP_MOUSEDOWN:
+                        handle_mousedown_motion(seat, cursor, time_msec);
+                        break;
                 case OP_MOVE:
                         handle_move_motion(seat, cursor);
                         break;
@@ -743,6 +758,14 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
                 }
         }
 
+        // Handle mousedown on a container surface
+        if (surface && cont && state == WLR_BUTTON_PRESSED) {
+                seat_set_focus(seat, cont);
+                seat_pointer_notify_button(seat, time_msec, button, state);
+                seat_begin_mousedown(seat, cont, button, sx, sy);
+                return;
+        }
+
         // Handle clicking a container surface
         if (cont) {
                 seat_set_focus(seat, cont);
diff --git a/sway/input/seat.c b/sway/input/seat.c
index fa41904a..045bf91a 100644
--- a/sway/input/seat.c
+++ b/sway/input/seat.c
@@ -954,6 +954,17 @@ struct seat_config *seat_get_config(struct sway_seat *seat) {
         return NULL;
 }
 
+void seat_begin_mousedown(struct sway_seat *seat, struct sway_container *con,
+                uint32_t button, double sx, double sy) {
+        seat->operation = OP_MOUSEDOWN;
+        seat->op_container = con;
+        seat->op_button = button;
+        seat->op_ref_lx = seat->cursor->cursor->x;
+        seat->op_ref_ly = seat->cursor->cursor->y;
+        seat->op_ref_con_lx = sx;
+        seat->op_ref_con_ly = sy;
+}
+
 void seat_begin_move(struct sway_seat *seat, struct sway_container *con,
                 uint32_t button) {
         if (!seat->cursor) {
@@ -1007,6 +1018,7 @@ void seat_begin_resize_tiling(struct sway_seat *seat,
 }
 
 void seat_end_mouse_operation(struct sway_seat *seat) {
+        int operation = seat->operation;
         if (seat->operation == OP_MOVE) {
                 // We "move" the container to its own location so it discovers its
                 // output again.
@@ -1015,7 +1027,17 @@ void seat_end_mouse_operation(struct sway_seat *seat) {
         }
         seat->operation = OP_NONE;
         seat->op_container = NULL;
-        cursor_set_image(seat->cursor, "left_ptr", NULL);
+        if (operation == OP_MOUSEDOWN) {
+                // Set the cursor's previous coords to the x/y at the start of the
+                // operation, so the container change will be detected if using
+                // focus_follows_mouse and the cursor moved off the original container
+                // during the operation.
+                seat->cursor->previous.x = seat->op_ref_lx;
+                seat->cursor->previous.y = seat->op_ref_ly;
+                cursor_send_pointer_motion(seat->cursor, 0, true);
+        } else {
+                cursor_set_image(seat->cursor, "left_ptr", NULL);
+        }
 }
 
 void seat_pointer_notify_button(struct sway_seat *seat, uint32_t time_msec,