docs: Add new relative positioning scene functions

docs/sphinx/reference-scenes.rst

@@ -369,6 +369,18 @@ Scene Item Functions
 
 ---------------------
 
+.. function:: void obs_sceneitem_set_relative_pos(obs_sceneitem_t *item, const struct vec2 *pos)
+              void obs_sceneitem_get_relative_pos(const obs_sceneitem_t *item, struct vec2 *pos)
+
+   Sets/gets the position of a scene item in relative coordinates.
+   In this system `(0.0, 0.0)` is the center of the screen, `(0, -1.0)` the bottom and `(0, 1.0)` the top.
+   The visible range of the horizontal axis depends on aspect ratio, for example, with 16:9 (1.7777...) this is `[-1.777.., -1.777..]`.
+   Positions are rounded to the nearest half-pixel when converting from relative to absolute pixel values to maintain backwards compaibility.
+
+   .. versionadded:: 31.0
+
+---------------------
+
 .. function:: void obs_sceneitem_set_rot(obs_sceneitem_t *item, float rot_deg)
               float obs_sceneitem_get_rot(const obs_sceneitem_t *item)
 
@@ -461,6 +473,16 @@ Scene Item Functions
 
 ---------------------
 
+.. function:: void obs_sceneitem_set_relative_bounds(obs_sceneitem_t *item, const struct vec2 *bounds)
+              void obs_sceneitem_get_relative_bounds(const obs_sceneitem_t *item, struct vec2 *bounds)
+
+   Sets/gets the bounding box width/height of the scene item in relative sizes.
+   See :c:func:`obs_sceneitem_get_relative_pos()`/:c:func:`obs_sceneitem_set_relative_pos()` for details on the relative coordinate system.
+   
+   .. versionadded:: 31.0
+
+---------------------
+
 .. function:: void obs_sceneitem_set_info(obs_sceneitem_t *item, const struct obs_transform_info *info)
               void obs_sceneitem_get_info(const obs_sceneitem_t *item, struct obs_transform_info *info)
 
@@ -468,6 +490,26 @@ Scene Item Functions
 
 ---------------------
 
+.. function:: void obs_sceneitem_set_info2(obs_sceneitem_t *item, const struct obs_transform_info *info)
+              void obs_sceneitem_get_info2(const obs_sceneitem_t *item, struct obs_transform_info *info)
+
+   Sets/gets the transform information of the scene item.
+   This version of the function also sets the `crop_to_bounds` member of `obs_transform_info`.
+
+   .. versionadded:: 30.1
+
+---------------------
+
+.. function:: void obs_sceneitem_set_info3(obs_sceneitem_t *item, const struct obs_transform_info *info)
+              void obs_sceneitem_get_info3(const obs_sceneitem_t *item, struct obs_transform_info *info)
+
+   Sets/gets the transform information of the scene item.
+   This version uses relative coordinates, see :c:func:`obs_sceneitem_get_relative_pos()`/:c:func:`obs_sceneitem_set_relative_pos()` for details.
+
+   .. versionadded:: 31.0
+
+---------------------
+
 .. function:: void obs_sceneitem_get_draw_transform(const obs_sceneitem_t *item, struct matrix4 *transform)
 
    Gets the transform matrix of the scene item used for drawing the