test: improve color management test in imagebufalgo_test (#4063)

Add a few more assertion checks and error messages in imagebufalgo_test.

I observe that if somebody runs the testsuite with `$OCIO` set to a
config that doesn't contain the required color space names for this
test, it will fail. As a backstop, use the default built-in config if
the initial request fails. That will always give a working processor
between these spaces if OCIO >= 2.2 is being used.

Also one more tiny SPI-specific enhancement to hacky identification of
nonconforming color space names in our old configs.

Signed-off-by: Larry Gritz <[email protected]>

src/libOpenImageIO/color_ocio.cpp

@@ -612,6 +612,9 @@ ColorConfig::Impl::classify_by_name(CSInfo& cs)
     } else if (cs.name == "srgbf" || cs.name == "srgbh" || cs.name == "srgb16"
                || cs.name == "srgb8") {
         cs.setflag(CSInfo::is_srgb, srgb_alias);
+    } else if (cs.name == "srgblnf" || cs.name == "srgblnh"
+               || cs.name == "srgbln16" || cs.name == "srgbln8") {
+        cs.setflag(CSInfo::is_lin_srgb, lin_srgb_alias);
     }
 #endif
 

src/libOpenImageIO/imagebufalgo_test.cpp

@@ -1140,19 +1140,31 @@ void
 test_color_management()
 {
     ColorConfig config;
+    auto processor = config.createColorProcessor("lin_srgb", "srgb");
+    // These color spaces might not be found if the site running this test
+    // has a weirdo OCIO config that doesn't contain those names. If we fail,
+    // try again using the built-in config (OCIO 2.2+) and hope for the best.
+    if (!processor)
+        processor = ColorConfig("ocio://default")
+                        .createColorProcessor("lin_srgb", "srgb");
+    OIIO_CHECK_ASSERT(processor);
 
     // Test the IBA::colorconvert version that works on a color at a time
     {
-        auto processor = config.createColorProcessor("lin_srgb", "srgb");
-        float rgb[3]   = { 0.5f, 0.5f, 0.5f };
-        ImageBufAlgo::colorconvert(rgb, processor.get(), false);
+        float rgb[3] = { 0.5f, 0.5f, 0.5f };
+        bool r       = ImageBufAlgo::colorconvert(rgb, processor.get(), false);
+        OIIO_CHECK_ASSERT(r);
+        if (!r)
+            OIIO::print("colorconvert error: {}\n", OIIO::geterror());
         OIIO_CHECK_EQUAL_THRESH(rgb[1], 0.735356983052449f, 1.0e-5);
     }
     {
-        auto processor = config.createColorProcessor("lin_srgb", "srgb");
-        float rgb[4]   = { 0.5f, 0.5f, 0.5f, 1.0f };
-        ImageBufAlgo::colorconvert(rgb, processor.get(), true);
-        OIIO_CHECK_EQUAL_THRESH(rgb[1], 0.735356983052449f, 1.0e-5);
+        float rgba[4] = { 0.5f, 0.5f, 0.5f, 1.0f };
+        bool r        = ImageBufAlgo::colorconvert(rgba, processor.get(), true);
+        OIIO_CHECK_ASSERT(r);
+        if (!r)
+            OIIO::print("colorconvert error: {}\n", OIIO::geterror());
+        OIIO_CHECK_EQUAL_THRESH(rgba[1], 0.735356983052449f, 1.0e-5);
     }
 }