From 660f6ae0ec89eef6db1261b0a708438819fe651f Mon Sep 17 00:00:00 2001
From: Sergey Sharybin <sergey@blender.org>
Date: Tue, 19 Aug 2025 12:37:24 +0200
Subject: [PATCH] Fix #144681: Add support for inactive color spaces

So far only active color spaces were queries from the OpenColorIO, which
made sense from the list of spaces displayed in the menus. However, some
logic requires knowing more details about color spaces used by displays,
for example to check if it is data, or whether color space matches the
display one.

This change makes it so our OpenColorIO integration handles inactive color
spaces by storing them in a separate array. Config::get_color_space will
now work for both active and inactive color spaces.

Pull Request: https://projects.blender.org/blender/blender/pulls/144780
---
 .../intern/libocio/libocio_config.cc          | 47 +++++++++++++++++--
 .../intern/libocio/libocio_config.hh          |  4 +-
 2 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.cc b/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.cc
index c525dc3f1f0..2855525a63b 100644
--- a/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.cc
+++ b/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.cc
@@ -78,14 +78,15 @@ LibOCIOConfig::LibOCIOConfig(const OCIO_NAMESPACE::ConstConfigRcPtr &ocio_config
   OCIO_NAMESPACE::SetCurrentConfig(ocio_config);
   ocio_config_ = OCIO_NAMESPACE::GetCurrentConfig();
 
-  initialize_color_spaces();
+  initialize_active_color_spaces();
+  initialize_inactive_color_spaces();
   initialize_looks();
   initialize_displays();
 }
 
 LibOCIOConfig::~LibOCIOConfig() {}
 
-void LibOCIOConfig::initialize_color_spaces()
+void LibOCIOConfig::initialize_active_color_spaces()
 {
   OCIO_NAMESPACE::ColorSpaceSetRcPtr ocio_color_spaces;
 
@@ -125,6 +126,34 @@ void LibOCIOConfig::initialize_color_spaces()
   });
 }
 
+void LibOCIOConfig::initialize_inactive_color_spaces()
+{
+  const int num_inactive_color_spaces = ocio_config_->getNumColorSpaces(
+      OCIO_NAMESPACE::SEARCH_REFERENCE_SPACE_ALL, OCIO_NAMESPACE::COLORSPACE_INACTIVE);
+  if (num_inactive_color_spaces < 0) {
+    report_error(fmt::format(
+        "Invalid OpenColorIO configuration: invalid number of inactive color spaces {}",
+        num_inactive_color_spaces));
+    return;
+  }
+
+  for (const int i : IndexRange(num_inactive_color_spaces)) {
+    const char *colorspace_name = ocio_config_->getColorSpaceNameByIndex(
+        OCIO_NAMESPACE::SEARCH_REFERENCE_SPACE_ALL, OCIO_NAMESPACE::COLORSPACE_INACTIVE, i);
+
+    OCIO_NAMESPACE::ConstColorSpaceRcPtr ocio_color_space;
+    try {
+      ocio_color_space = ocio_config_->getColorSpace(colorspace_name);
+    }
+    catch (OCIO_NAMESPACE::Exception &exception) {
+      report_exception(exception);
+      continue;
+    }
+
+    inactive_color_spaces_.append_as(i, ocio_config_, ocio_color_space);
+  }
+}
+
 void LibOCIOConfig::initialize_looks()
 {
   const int num_looks = ocio_config_->getNumLooks();
@@ -269,10 +298,18 @@ const ColorSpace *LibOCIOConfig::get_color_space(const StringRefNull name) const
     return nullptr;
   }
 
+  /* TODO(sergey): Is there faster way to lookup Blender-side color space?
+   * It does not seem that pointer in ConstColorSpaceRcPtr is unique enough to use for
+   * comparison. */
   for (const LibOCIOColorSpace &color_space : color_spaces_) {
-    /* TODO(sergey): Is there faster way to lookup Blender-side color space?
-     * It does not seem that pointer in ConstColorSpaceRcPtr is unique enough to use for
-     * comparison. */
+    if (color_space.name() == ocio_color_space->getName()) {
+      return &color_space;
+    }
+  }
+
+  /* Also lookup in the inactive color space, as the requested space might be coming from the
+   * display and marked as inactive to prevent it from showing up in the application menu. */
+  for (const LibOCIOColorSpace &color_space : inactive_color_spaces_) {
     if (color_space.name() == ocio_color_space->getName()) {
       return &color_space;
     }
diff --git a/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.hh b/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.hh
index e929780d9e1..ea73dc1ce79 100644
--- a/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.hh
+++ b/source/blender/imbuf/opencolorio/intern/libocio/libocio_config.hh
@@ -33,6 +33,7 @@ class LibOCIOConfig : public Config {
    * array does not contain aliases or roles. If role or alias is to be resolved OpenColorIO is to
    * be used first to provide color space name which then can be looked up in this array. */
   Vector<LibOCIOColorSpace> color_spaces_;
+  Vector<LibOCIOColorSpace> inactive_color_spaces_;
   Vector<LibOCIOLook> looks_;
   Vector<LibOCIODisplay> displays_;
 
@@ -96,7 +97,8 @@ class LibOCIOConfig : public Config {
 
   /* Initialize BLender-side representation of color spaces, displays, etc. from the current
    * OpenColorIO configuration. */
-  void initialize_color_spaces();
+  void initialize_active_color_spaces();
+  void initialize_inactive_color_spaces();
   void initialize_looks();
   void initialize_displays();
 };