rootston: rotate views!

include/rootston/input.h

@@ -83,6 +83,7 @@ struct roots_input {
 	struct roots_view *active_view;
 	int offs_x, offs_y;
 	int view_x, view_y, view_width, view_height;
+	float view_rotation;
 	uint32_t resize_edges;
 
 	// Ring buffer of input events that could trigger move/resize/rotate

rootston/cursor.c

@@ -1,6 +1,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <string.h>
+#include <math.h>
 // TODO: BSD et al
 #include <linux/input-event-codes.h>
 #include <wayland-server.h>
@@ -25,15 +26,16 @@ const struct roots_input_event *get_input_event(struct roots_input *input,
 void view_begin_move(struct roots_input *input, struct wlr_cursor *cursor,
 		struct roots_view *view) {
 	input->mode = ROOTS_CURSOR_MOVE;
-	input->offs_x = cursor->x - view->x;
+	input->offs_x = cursor->x;
-	input->offs_y = cursor->y - view->y;
+	input->offs_y = cursor->y;
+	input->view_x = view->x;
+	input->view_y = view->y;
 	wlr_seat_pointer_clear_focus(input->wl_seat);
 }
 
 void view_begin_resize(struct roots_input *input, struct wlr_cursor *cursor,
 		struct roots_view *view, uint32_t edges) {
 	input->mode = ROOTS_CURSOR_RESIZE;
-	wlr_log(L_DEBUG, "begin resize");
 	input->offs_x = cursor->x;
 	input->offs_y = cursor->y;
 	input->view_x = view->x;
@@ -46,6 +48,15 @@ void view_begin_resize(struct roots_input *input, struct wlr_cursor *cursor,
 	wlr_seat_pointer_clear_focus(input->wl_seat);
 }
 
+void view_begin_rotate(struct roots_input *input, struct wlr_cursor *cursor,
+		struct roots_view *view) {
+	input->mode = ROOTS_CURSOR_ROTATE;
+	input->offs_x = cursor->x;
+	input->offs_y = cursor->y;
+	input->view_rotation = view->rotation;
+	wlr_seat_pointer_clear_focus(input->wl_seat);
+}
+
 void cursor_update_position(struct roots_input *input, uint32_t time) {
 	struct roots_desktop *desktop = input->server->desktop;
 	struct roots_view *view;
@@ -64,16 +75,18 @@ void cursor_update_position(struct roots_input *input, uint32_t time) {
 		break;
 	case ROOTS_CURSOR_MOVE:
 		if (input->active_view) {
-			input->active_view->x = input->cursor->x - input->offs_x;
+			int dx = input->cursor->x - input->offs_x,
-			input->active_view->y = input->cursor->y - input->offs_y;
+				dy = input->cursor->y - input->offs_y;
+			input->active_view->x = input->view_x + dx;
+			input->active_view->y = input->view_y + dy;
 		}
 		break;
 	case ROOTS_CURSOR_RESIZE:
 		if (input->active_view) {
-			int dx = input->cursor->x - input->offs_x;
+			int dx = input->cursor->x - input->offs_x,
-			int dy = input->cursor->y - input->offs_y;
+				dy = input->cursor->y - input->offs_y;
-			int width = input->view_width;
+			int width = input->view_width,
-			int height = input->view_height;
+				height = input->view_height;
 			if (input->resize_edges & ROOTS_CURSOR_RESIZE_EDGE_TOP) {
 				input->active_view->y = input->view_y + dy;
 				height -= dy;
@@ -92,6 +105,17 @@ void cursor_update_position(struct roots_input *input, uint32_t time) {
 		}
 		break;
 	case ROOTS_CURSOR_ROTATE:
+		if (input->active_view) {
+			struct roots_view *view = input->active_view;
+			int ox = view->x + view->wlr_surface->current->width/2,
+				oy = view->y + view->wlr_surface->current->height/2;
+			int ux = input->offs_x - ox,
+				uy = input->offs_y - oy;
+			int vx = input->cursor->x - ox,
+				vy = input->cursor->y - oy;
+			float angle = atan2(vx*uy - vy*ux, vx*ux + vy*uy);
+			view->rotation = input->view_rotation + angle;
+		}
 		break;
 	}
 }
@@ -175,6 +199,8 @@ static void do_cursor_button_press(struct roots_input *input,
 				ROOTS_CURSOR_RESIZE_EDGE_RIGHT |
 				ROOTS_CURSOR_RESIZE_EDGE_BOTTOM);
 			break;
+		case BTN_MIDDLE:
+			view_begin_rotate(input, cursor, view);
 		}
 		return;
 	}

rootston/output.c

@@ -18,7 +18,7 @@ static inline int64_t timespec_to_msec(const struct timespec *a) {
 
 static void render_surface(struct wlr_surface *surface,
 		struct roots_desktop *desktop, struct wlr_output *wlr_output,
-		struct timespec *when, double lx, double ly) {
+		struct timespec *when, double lx, double ly, float rotation) {
 	wlr_surface_flush_damage(surface);
 	if (surface->texture->valid) {
 		int width = surface->current->buffer_width;
@@ -29,8 +29,18 @@ static void render_surface(struct wlr_surface *surface,
 		if (wlr_output_layout_intersects(desktop->layout, wlr_output,
 				lx, ly, lx + width, ly + height)) {
 			float matrix[16];
+
+			float translate_origin[16];
+			wlr_matrix_translate(&translate_origin,
+				ox + width/2, oy + height/2, 0);
+			float rotate[16];
+			wlr_matrix_rotate(&rotate, rotation);
+			float translate_center[16];
+			wlr_matrix_translate(&translate_center, -width/2, -height/2, 0);
 			float transform[16];
-			wlr_matrix_translate(&transform, ox, oy, 0);
+			wlr_matrix_mul(&translate_origin, &rotate, &transform);
+			wlr_matrix_mul(&transform, &translate_center, &transform);
+
 			wlr_surface_get_matrix(surface, &matrix,
 					&wlr_output->transform_matrix, &transform);
 			wlr_render_with_matrix(desktop->server->renderer,
@@ -48,7 +58,8 @@ static void render_surface(struct wlr_surface *surface,
 		wl_list_for_each(subsurface, &surface->subsurface_list, parent_link) {
 			render_surface(subsurface->surface, desktop, wlr_output, when,
 				lx + subsurface->surface->current->subsurface_position.x,
-				ly + subsurface->surface->current->subsurface_position.y);
+				ly + subsurface->surface->current->subsurface_position.y,
+				rotation);
 		}
 	}
 }
@@ -56,7 +67,7 @@ static void render_surface(struct wlr_surface *surface,
 static void render_view(struct roots_view *view, struct roots_desktop *desktop,
 		struct wlr_output *wlr_output, struct timespec *when) {
 	render_surface(view->wlr_surface, desktop, wlr_output, when,
-		view->x, view->y);
+		view->x, view->y, view->rotation);
 }
 
 static void output_frame_notify(struct wl_listener *listener, void *data) {