Implement tiling drag

Hold floating_modifier and drag a tiling view to a new location.

7 files changed, 261 insertions, 5 deletions

diff --git a/sway/commands/move.c b/sway/commands/move.c
index 2e9c00f8..b2cca5be 100644
--- a/sway/commands/move.c
+++ b/sway/commands/move.c
@@ -235,7 +235,7 @@ static void container_move_to_container(struct sway_container *container,
         container->saved_width = container->saved_height = 0;
 
         if (destination->view) {
-                container_add_sibling(destination, container);
+                container_add_sibling(destination, container, 1);
         } else {
                 container_add_child(destination, container);
         }
diff --git a/sway/desktop/render.c b/sway/desktop/render.c
index 8a6f63aa..8b5b3e95 100644
--- a/sway/desktop/render.c
+++ b/sway/desktop/render.c
@@ -891,6 +891,21 @@ static void render_floating(struct sway_output *soutput,
         }
 }
 
+static void render_dropzones(struct sway_output *output,
+                pixman_region32_t *damage) {
+        struct sway_seat *seat;
+        wl_list_for_each(seat, &input_manager->seats, link) {
+                if (seat->operation == OP_MOVE_TILING && seat->op_target_node
+                                && node_get_output(seat->op_target_node) == output) {
+                        float color[4];
+                        memcpy(&color, config->border_colors.focused.indicator,
+                                        sizeof(float) * 4);
+                        premultiply_alpha(color, 0.5);
+                        render_rect(output->wlr_output, damage, &seat->op_drop_box, color);
+                }
+        }
+}
+
 void output_render(struct sway_output *output, struct timespec *when,
                 pixman_region32_t *damage) {
         struct wlr_output *wlr_output = output->wlr_output;
@@ -973,6 +988,8 @@ void output_render(struct sway_output *output, struct timespec *when,
                         &output->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP]);
         }
 
+        render_dropzones(output, damage);
+
         struct sway_seat *seat = input_manager_current_seat(input_manager);
         struct sway_container *focus = seat_get_focused_container(seat);
         if (focus && focus->view) {
diff --git a/sway/input/cursor.c b/sway/input/cursor.c
index cd87e976..b0f8e531 100644
--- a/sway/input/cursor.c
+++ b/sway/input/cursor.c
@@ -228,6 +228,141 @@ static void handle_move_floating_motion(struct sway_seat *seat,
         desktop_damage_whole_container(con);
 }
 
+static void resize_box(struct wlr_box *box, enum wlr_edges edge,
+                size_t thickness) {
+        switch (edge) {
+        case WLR_EDGE_TOP:
+                box->height = thickness;
+                break;
+        case WLR_EDGE_LEFT:
+                box->width = thickness;
+                break;
+        case WLR_EDGE_RIGHT:
+                box->x = box->x + box->width - thickness;
+                box->width = thickness;
+                break;
+        case WLR_EDGE_BOTTOM:
+                box->y = box->y + box->height - thickness;
+                box->height = thickness;
+                break;
+        case WLR_EDGE_NONE:
+                box->x += thickness;
+                box->y += thickness;
+                box->width -= thickness * 2;
+                box->height -= thickness * 2;
+                break;
+        }
+}
+
+static void handle_move_tiling_motion(struct sway_seat *seat,
+                struct sway_cursor *cursor) {
+        struct wlr_surface *surface = NULL;
+        double sx, sy;
+        struct sway_node *node = node_at_coords(seat,
+                        cursor->cursor->x, cursor->cursor->y, &surface, &sx, &sy);
+        // Damage the old location
+        desktop_damage_box(&seat->op_drop_box);
+
+        if (!node) {
+                // Eg. hovered over a layer surface such as swaybar
+                seat->op_target_node = NULL;
+                seat->op_target_edge = WLR_EDGE_NONE;
+                return;
+        }
+
+        if (node->type == N_WORKSPACE) {
+                // Emtpy workspace
+                seat->op_target_node = node;
+                seat->op_target_edge = WLR_EDGE_NONE;
+                workspace_get_box(node->sway_workspace, &seat->op_drop_box);
+                desktop_damage_box(&seat->op_drop_box);
+                return;
+        }
+
+        // Deny moving within own workspace if this is the only child
+        struct sway_container *con = node->sway_container;
+        if (workspace_num_tiling_views(seat->op_container->workspace) == 1 &&
+                        con->workspace == seat->op_container->workspace) {
+                seat->op_target_node = NULL;
+                seat->op_target_edge = WLR_EDGE_NONE;
+                return;
+        }
+
+        // Traverse the ancestors, trying to find a layout container perpendicular
+        // to the edge. Eg. close to the top or bottom of a horiz layout.
+        while (con) {
+                enum wlr_edges edge = WLR_EDGE_NONE;
+                enum sway_container_layout layout = container_parent_layout(con);
+                struct wlr_box parent;
+                con->parent ? container_get_box(con->parent, &parent) :
+                        workspace_get_box(con->workspace, &parent);
+                if (layout == L_HORIZ || layout == L_TABBED) {
+                        if (cursor->cursor->y < parent.y + 30) {
+                                edge = WLR_EDGE_TOP;
+                        } else if (cursor->cursor->y > parent.y + parent.height - 30) {
+                                edge = WLR_EDGE_BOTTOM;
+                        }
+                } else if (layout == L_VERT || layout == L_STACKED) {
+                        if (cursor->cursor->x < parent.x + 30) {
+                                edge = WLR_EDGE_LEFT;
+                        } else if (cursor->cursor->x > parent.x + parent.width - 30) {
+                                edge = WLR_EDGE_RIGHT;
+                        }
+                }
+                if (edge) {
+                        seat->op_target_node = node_get_parent(&con->node);
+                        seat->op_target_edge = edge;
+                        node_get_box(seat->op_target_node, &seat->op_drop_box);
+                        resize_box(&seat->op_drop_box, edge, 30);
+                        desktop_damage_box(&seat->op_drop_box);
+                        return;
+                }
+                con = con->parent;
+        }
+
+        // Use the hovered view - but we must be over the actual surface
+        con = node->sway_container;
+        if (!con->view->surface || node == &seat->op_container->node) {
+                seat->op_target_node = NULL;
+                seat->op_target_edge = WLR_EDGE_NONE;
+                return;
+        }
+
+        // Find the closest edge
+        size_t thickness = fmin(con->view->width, con->view->height) * 0.3;
+        size_t closest_dist = INT_MAX;
+        size_t dist;
+        seat->op_target_edge = WLR_EDGE_NONE;
+        if ((dist = cursor->cursor->y - con->y) < closest_dist) {
+                closest_dist = dist;
+                seat->op_target_edge = WLR_EDGE_TOP;
+        }
+        if ((dist = cursor->cursor->x - con->x) < closest_dist) {
+                closest_dist = dist;
+                seat->op_target_edge = WLR_EDGE_LEFT;
+        }
+        if ((dist = con->x + con->width - cursor->cursor->x) < closest_dist) {
+                closest_dist = dist;
+                seat->op_target_edge = WLR_EDGE_RIGHT;
+        }
+        if ((dist = con->y + con->height - cursor->cursor->y) < closest_dist) {
+                closest_dist = dist;
+                seat->op_target_edge = WLR_EDGE_BOTTOM;
+        }
+
+        if (closest_dist > thickness) {
+                seat->op_target_edge = WLR_EDGE_NONE;
+        }
+
+        seat->op_target_node = node;
+        seat->op_drop_box.x = con->view->x;
+        seat->op_drop_box.y = con->view->y;
+        seat->op_drop_box.width = con->view->width;
+        seat->op_drop_box.height = con->view->height;
+        resize_box(&seat->op_drop_box, seat->op_target_edge, thickness);
+        desktop_damage_box(&seat->op_drop_box);
+}
+
 static void calculate_floating_constraints(struct sway_container *con,
                 int *min_width, int *max_width, int *min_height, int *max_height) {
         if (config->floating_minimum_width == -1) { // no minimum
@@ -405,6 +540,9 @@ void cursor_send_pointer_motion(struct sway_cursor *cursor, uint32_t time_msec,
                 case OP_MOVE_FLOATING:
                         handle_move_floating_motion(seat, cursor);
                         break;
+                case OP_MOVE_TILING:
+                        handle_move_tiling_motion(seat, cursor);
+                        break;
                 case OP_RESIZE_FLOATING:
                         handle_resize_floating_motion(seat, cursor);
                         break;
@@ -751,6 +889,14 @@ void dispatch_cursor_button(struct sway_cursor *cursor,
                 }
         }
 
+        // Handle moving a tiling container
+        if (config->tiling_drag && mod_pressed && !is_floating_or_child &&
+                        !cont->is_fullscreen) {
+                seat_pointer_notify_button(seat, time_msec, button, state);
+                seat_begin_move_tiling(seat, cont, button);
+                return;
+        }
+
         // Handle mousedown on a container surface
         if (surface && cont && state == WLR_BUTTON_PRESSED) {
                 seat_set_focus_container(seat, cont);
diff --git a/sway/input/seat.c b/sway/input/seat.c
index a908560a..86e5f809 100644
--- a/sway/input/seat.c
+++ b/sway/input/seat.c
@@ -975,6 +975,16 @@ void seat_begin_move_floating(struct sway_seat *seat,
         cursor_set_image(seat->cursor, "grab", NULL);
 }
 
+void seat_begin_move_tiling(struct sway_seat *seat,
+                struct sway_container *con, uint32_t button) {
+        seat->operation = OP_MOVE_TILING;
+        seat->op_container = con;
+        seat->op_button = button;
+        seat->op_target_node = NULL;
+        seat->op_target_edge = 0;
+        cursor_set_image(seat->cursor, "grab", NULL);
+}
+
 void seat_begin_resize_floating(struct sway_seat *seat,
                 struct sway_container *con, uint32_t button, enum wlr_edges edge) {
         if (!seat->cursor) {
@@ -1015,6 +1025,68 @@ void seat_begin_resize_tiling(struct sway_seat *seat,
         seat->op_ref_height = con->height;
 }
 
+static bool is_parallel(enum sway_container_layout layout,
+                enum wlr_edges edge) {
+        bool layout_is_horiz = layout == L_HORIZ || layout == L_TABBED;
+        bool edge_is_horiz = edge == WLR_EDGE_LEFT || edge == WLR_EDGE_RIGHT;
+        return layout_is_horiz == edge_is_horiz;
+}
+
+static void seat_end_move_tiling(struct sway_seat *seat) {
+        struct sway_container *con = seat->op_container;
+        struct sway_container *old_parent = con->parent;
+        struct sway_workspace *old_ws = con->workspace;
+        struct sway_node *target_node = seat->op_target_node;
+        struct sway_workspace *new_ws = target_node->type == N_WORKSPACE ?
+                target_node->sway_workspace : target_node->sway_container->workspace;
+        enum wlr_edges edge = seat->op_target_edge;
+        int after = edge != WLR_EDGE_TOP && edge != WLR_EDGE_LEFT;
+
+        container_detach(con);
+        if (old_parent) {
+                container_reap_empty(old_parent);
+        }
+
+        // Moving container into empty workspace
+        if (target_node->type == N_WORKSPACE && edge == WLR_EDGE_NONE) {
+                workspace_add_tiling(new_ws, con);
+
+        // Moving container before/after another
+        } else if (target_node->type == N_CONTAINER) {
+                struct sway_container *target = target_node->sway_container;
+                enum sway_container_layout layout = container_parent_layout(target);
+                if (edge && !is_parallel(layout, edge)) {
+                        enum sway_container_layout new_layout = edge == WLR_EDGE_TOP ||
+                                edge == WLR_EDGE_BOTTOM ? L_VERT : L_HORIZ;
+                        container_split(target, new_layout);
+                }
+                container_add_sibling(target, con, after);
+
+        // Target is a workspace which requires splitting
+        } else {
+                enum sway_container_layout new_layout = edge == WLR_EDGE_TOP ||
+                        edge == WLR_EDGE_BOTTOM ? L_VERT : L_HORIZ;
+                workspace_split(new_ws, new_layout);
+                workspace_insert_tiling(new_ws, con, after);
+        }
+
+        // This is a bit dirty, but we'll set the dimensions to that of a sibling.
+        // I don't think there's any other way to make it consistent without
+        // changing how we auto-size containers.
+        list_t *siblings = container_get_siblings(con);
+        if (siblings->length > 1) {
+                int index = list_find(siblings, con);
+                struct sway_container *sibling = index == 0 ? siblings->items[1] : siblings->items[index - 1];
+                con->width = sibling->width;
+                con->height = sibling->height;
+        }
+
+        arrange_workspace(old_ws);
+        if (new_ws != old_ws) {
+                arrange_workspace(new_ws);
+        }
+}
+
 void seat_end_mouse_operation(struct sway_seat *seat) {
         enum sway_seat_operation operation = seat->operation;
         if (seat->operation == OP_MOVE_FLOATING) {
@@ -1022,6 +1094,8 @@ void seat_end_mouse_operation(struct sway_seat *seat) {
                 // output again.
                 struct sway_container *con = seat->op_container;
                 container_floating_move_to(con, con->x, con->y);
+        } else if (seat->operation == OP_MOVE_TILING && seat->op_target_node) {
+                seat_end_move_tiling(seat);
         }
         seat->operation = OP_NONE;
         seat->op_container = NULL;
diff --git a/sway/tree/container.c b/sway/tree/container.c
index 0a69f8d5..ff10c1ab 100644
--- a/sway/tree/container.c
+++ b/sway/tree/container.c
@@ -835,8 +835,14 @@ void container_end_mouse_operation(struct sway_container *container) {
         struct sway_seat *seat;
         wl_list_for_each(seat, &input_manager->seats, link) {
                 if (seat->op_container == container) {
+                        seat->op_target_node = NULL; // ensure tiling move doesn't apply
                         seat_end_mouse_operation(seat);
                 }
+                // If the user is doing a tiling drag over this container,
+                // keep the operation active but unset the target container.
+                if (seat->op_target_node == &container->node) {
+                        seat->op_target_node = NULL;
+                }
         }
 }
 
@@ -1086,13 +1092,13 @@ void container_insert_child(struct sway_container *parent,
 }
 
 void container_add_sibling(struct sway_container *fixed,
-                struct sway_container *active) {
+                struct sway_container *active, int side) {
         if (active->workspace) {
                 container_detach(active);
         }
         list_t *siblings = container_get_siblings(fixed);
         int index = list_find(siblings, fixed);
-        list_insert(siblings, index + 1, active);
+        list_insert(siblings, index + side, active);
         active->parent = fixed->parent;
         active->workspace = fixed->workspace;
         container_for_each_child(active, set_workspace, NULL);
@@ -1145,7 +1151,7 @@ void container_detach(struct sway_container *child) {
 
 void container_replace(struct sway_container *container,
                 struct sway_container *replacement) {
-        container_add_sibling(container, replacement);
+        container_add_sibling(container, replacement, 1);
         container_detach(container);
 }
 
diff --git a/sway/tree/view.c b/sway/tree/view.c
index 65ac8b32..d4ffa06b 100644
--- a/sway/tree/view.c
+++ b/sway/tree/view.c
@@ -529,7 +529,7 @@ void view_map(struct sway_view *view, struct wlr_surface *wlr_surface) {
 
         view->container = container_create(view);
         if (target_sibling) {
-                container_add_sibling(target_sibling, view->container);
+                container_add_sibling(target_sibling, view->container, 1);
         } else {
                 workspace_add_tiling(ws, view->container);
         }
diff --git a/sway/tree/workspace.c b/sway/tree/workspace.c
index b8e90892..d4b57a0f 100644
--- a/sway/tree/workspace.c
+++ b/sway/tree/workspace.c
@@ -694,3 +694,16 @@ void workspace_get_box(struct sway_workspace *workspace, struct wlr_box *box) {
         box->width = workspace->width;
         box->height = workspace->height;
 }
+
+static void count_tiling_views(struct sway_container *con, void *data) {
+        if (con->view && !container_is_floating_or_child(con)) {
+                size_t *count = data;
+                *count += 1;
+        }
+}
+
+size_t workspace_num_tiling_views(struct sway_workspace *ws) {
+        size_t count = 0;
+        workspace_for_each_container(ws, count_tiling_views, &count);
+        return count;
+}