docs

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz

INSTALL.md

@@ -61,8 +61,8 @@ NEW or CHANGED MINIMUM dependencies since the last major release are **bold**.
  * If you want support for GIF images:
      * giflib >= 5.0 (tested through 5.2.2)
  * If you want support for HEIF/HEIC or AVIF images:
-     * libheif >= 1.11 (1.16 required for correct orientation support,
-       tested through 1.21.1)
+     * libheif >= 1.11 (1.16 required for correct orientation support and
+       1.17 required for monochrome HEIC support; tested through 1.21.1)
      * libheif must be built with an AV1 encoder/decoder for AVIF support.
  * If you want support for DICOM medical image files:
      * DCMTK >= 3.6.1 (tested through 3.6.9)

src/cmake/externalpackages.cmake

@@ -165,7 +165,7 @@ checked_find_package (GIF VERSION_MIN 5.0)
 checked_find_package (Libheif VERSION_MIN 1.11
                       PREFER_CONFIG
                       RECOMMEND_MIN 1.16
-                      RECOMMEND_MIN_REASON "for orientation support")
+                      RECOMMEND_MIN_REASON "1.16 for orientation support, 1.17 for monochrome support")
 
 checked_find_package (LibRaw
                       VERSION_MIN 0.20.0

src/doc/builtinplugins.rst

@@ -837,6 +837,13 @@ control aspects of the writing itself:
 
 |
 
+**Additional notes and limitations**
+
+* The underlying libheif dependency must be 1.16 or newer to support the
+  "oiio:reorient" configuration option and the "heif:Orientation" metadata.
+* The underlying libheif dependency must be 1.17 or newer to support
+  monochrome HEIC images.
+
 .. _sec-bundledplugins-ico:
 
 ICO