Rethink HiDPI output layouts, fixes everything

Except for subsurfaces not rendering at the right scale. But that part
is (somewhat) easy.

rootston/desktop.c

@@ -167,15 +167,14 @@ struct roots_view *view_at(struct roots_desktop *desktop, double lx, double ly,
 			continue;
 		}
 
-		int scale = view->wlr_surface->current->scale;
+		double view_sx = lx - view->x;
-		double view_sx = (lx - view->x) / (double)scale;
+		double view_sy = ly - view->y;
-		double view_sy = (ly - view->y) / (double)scale;
 
 		struct wlr_box box = {
 			.x = 0,
 			.y = 0,
-			.width = view->wlr_surface->current->buffer_width * scale,
+			.width = view->wlr_surface->current->buffer_width,
-			.height = view->wlr_surface->current->buffer_height * scale,
+			.height = view->wlr_surface->current->buffer_height,
 		};
 		if (view->rotation != 0.0) {
 			// Coordinates relative to the center of the view

rootston/output.c

@@ -25,6 +25,8 @@ static void render_surface(struct wlr_surface *surface,
 		int height = surface->current->buffer_height * scale_factor;
 		double ox = lx, oy = ly;
 		wlr_output_layout_output_coords(desktop->layout, wlr_output, &ox, &oy);
+		ox *= wlr_output->scale;
+		oy *= wlr_output->scale;
 
 		if (wlr_output_layout_intersects(desktop->layout, wlr_output,
 				lx, ly, lx + width, ly + height)) {

types/wlr_output.c

@@ -227,7 +227,6 @@ void wlr_output_destroy(struct wlr_output *output) {
 
 void wlr_output_effective_resolution(struct wlr_output *output,
 		int *width, int *height) {
-	// TODO: Scale factor
 	if (output->transform % 2 == 1) {
 		*width = output->height;
 		*height = output->width;
@@ -235,6 +234,8 @@ void wlr_output_effective_resolution(struct wlr_output *output,
 		*width = output->width;
 		*height = output->height;
 	}
+	*width /= output->scale;
+	*height /= output->scale;
 }
 
 void wlr_output_make_current(struct wlr_output *output) {
@@ -450,6 +451,8 @@ void wlr_output_cursor_set_surface(struct wlr_output_cursor *cursor,
 }
 
 bool wlr_output_cursor_move(struct wlr_output_cursor *cursor, int x, int y) {
+	x *= cursor->output->scale;
+	y *= cursor->output->scale;
 	cursor->x = x;
 	cursor->y = y;