+Output *get_first_output(void);
+
+/**
+ * Returns the output with the given name or NULL.
+ * If require_active is true, only active outputs are considered.
+ *
+ */
+Output *get_output_by_name(const char *name, const bool require_active);
+
+/**
+ * Returns the active (!) output which contains the coordinates x, y or NULL
+ * if there is no output which contains these coordinates.
+ *
+ */
+Output *get_output_containing(unsigned int x, unsigned int y);
+
+/**
+ * Returns the active output which contains the midpoint of the given rect. If
+ * such an output doesn't exist, returns the output which contains most of the
+ * rectangle or NULL if there is no output which intersects with it.
+ *
+ */
+Output *get_output_from_rect(Rect rect);
+
+/**
+ * Returns the active output which spans exactly the area specified by
+ * rect or NULL if there is no output like this.
+ *
+ */
+Output *get_output_with_dimensions(Rect rect);
+
+/**
+ * In output_containing_rect, we check if any active output contains part of the container.
+ * We do this by checking if the output rect is intersected by the Rect.
+ * This is the 2-dimensional counterpart of get_output_containing.
+ * Returns the output with the maximum intersecting area.
+ *
+ */
+Output *output_containing_rect(Rect rect);