[gtk: 1/2] Mark various GskTransform functions as nullable in their return value

[Matthias Clasen <matthiasc src gnome org>]

commit c44badd26a66488a50fb4f8ef5c8692de4981462
Author: Sebastian Dröge <sebastian centricular com>
Date:   Fri Jan 14 11:57:23 2022 +0200

    Mark various GskTransform functions as nullable in their return value
    
    Various transforms are normalized with their next transform, and if they
    end up being the identity transform will return NULL.
    
    For example a translation by (x,y,z) and followed by (-x,-y,-z) will
    result in NULL.

 gsk/gsktransform.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)
---
diff --git a/gsk/gsktransform.c b/gsk/gsktransform.c
index b690cec714..4f7174d349 100644
--- a/gsk/gsktransform.c
+++ b/gsk/gsktransform.c
@@ -623,7 +623,7 @@ static const GskTransformClass GSK_TRANSLATE_TRANSFORM_CLASS =
  *
  * Translates @next in 2-dimensional space by @point.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  **/
 GskTransform *
 gsk_transform_translate (GskTransform           *next,
@@ -643,7 +643,7 @@ gsk_transform_translate (GskTransform           *next,
  *
  * Translates @next by @point.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  **/
 GskTransform *
 gsk_transform_translate_3d (GskTransform             *next,
@@ -859,7 +859,7 @@ normalize_angle (float angle)
  *
  * Rotates @next @angle degrees in 2D - or in 3D-speak, around the z axis.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  */
 GskTransform *
 gsk_transform_rotate (GskTransform *next,
@@ -987,7 +987,7 @@ static const GskTransformClass GSK_ROTATE3D_TRANSFORM_CLASS =
  *
  * For a rotation in 2D space, use [method@Gsk.Transform.rotate]
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  */
 GskTransform *
 gsk_transform_rotate_3d (GskTransform          *next,
@@ -1163,7 +1163,7 @@ static const GskTransformClass GSK_SKEW_TRANSFORM_CLASS =
  *
  * Applies a skew transform.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  *
  * Since: 4.6
  */
@@ -1335,7 +1335,7 @@ static const GskTransformClass GSK_SCALE_TRANSFORM_CLASS =
  *
  * Use [method@Gsk.Transform.scale_3d] to scale in all 3 dimensions.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  **/
 GskTransform *
 gsk_transform_scale (GskTransform *next,
@@ -1354,7 +1354,7 @@ gsk_transform_scale (GskTransform *next,
  *
  * Scales @next by the given factors.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  **/
 GskTransform *
 gsk_transform_scale_3d (GskTransform *next,
@@ -1523,7 +1523,7 @@ gsk_transform_perspective (GskTransform *next,
  *
  * Acquires a reference on the given `GskTransform`.
  *
- * Returns: (transfer none): the `GskTransform` with an additional reference
+ * Returns: (nullable) (transfer none): the `GskTransform` with an additional reference
  */
 GskTransform *
 gsk_transform_ref (GskTransform *self)
@@ -1898,7 +1898,7 @@ gsk_transform_to_translate (GskTransform *self,
  *
  * Applies all the operations from @other to @next.
  *
- * Returns: The new transform
+ * Returns: (nullable): The new transform
  */
 GskTransform *
 gsk_transform_transform (GskTransform *next,