Document default extend modes

2 files changed, 10 insertions, 2 deletions

diff --git a/src/cairo-pattern.c b/src/cairo-pattern.c
index e1d4b5c86..097fc394c 100644
--- a/src/cairo-pattern.c
+++ b/src/cairo-pattern.c
@@ -1084,6 +1084,9 @@ cairo_pattern_get_filter (cairo_pattern_t *pattern)
  * Sets the mode to be used for drawing outside the area of a pattern.
  * See #cairo_extend_t for details on the semantics of each extend
  * strategy.
+ *
+ * The default extend mode is %CAIRO_EXTEND_NONE for surface patterns
+ * and %CAIRO_EXTEND_PAD for gradient patterns.
  **/
 void
 cairo_pattern_set_extend (cairo_pattern_t *pattern, cairo_extend_t extend)
diff --git a/src/cairo.h b/src/cairo.h
index 542a99628..560178b0e 100644
--- a/src/cairo.h
+++ b/src/cairo.h
@@ -1794,8 +1794,13 @@ cairo_pattern_get_matrix (cairo_pattern_t *pattern,
  *   the closest pixel from the source (Since 1.2; but only
  *   implemented for surface patterns since 1.6)
  *
- * #cairo_extend_t is used to describe how the area outside
- * of a pattern will be drawn.
+ * #cairo_extend_t is used to describe how pattern color/alpha will be
+ * determined for areas "outside" the pattern's natural area, (for
+ * example, outside the surface bounds or outside the gradient
+ * geometry).
+ *
+ * The default extend mode is %CAIRO_EXTEND_NONE for surface patterns
+ * and %CAIRO_EXTEND_PAD for gradient patterns.
  *
  * New entries may be added in future versions.
  **/