Merge pull request #10 from alicevision/fix_oiio_raw

[imageIO] fix colorspace handling depending on OIIO version

Author: fabiencastan

appveyor.yml

@@ -9,7 +9,7 @@ platform:
   - x64
 
 environment:
-  QT5: C:\Qt\5.11.2\msvc2017_64
+  QT5: C:\Qt\5.12.2\msvc2017_64
   # APPVEYOR_SAVE_CACHE_ON_ERROR: true
 
 install:

src/imageIOHandler/QtOIIOHandler.cpp

@@ -70,24 +70,51 @@ bool QtOIIOHandler::read(QImage *image)
     // libRAW configuration
     configSpec.attribute("raw:auto_bright", 0);       // don't want exposure correction
     configSpec.attribute("raw:use_camera_wb", 1);     // want white balance correction
+#if OIIO_VERSION <= (10000 * 2 + 100 * 0 + 8) // OIIO_VERSION <= 2.0.8
+    // In these previous versions of oiio, there was no Linear option
     configSpec.attribute("raw:ColorSpace", "sRGB");   // want colorspace sRGB
+#else
+    configSpec.attribute("raw:ColorSpace", "Linear");   // want linear colorspace with sRGB primaries
+#endif    
     configSpec.attribute("raw:use_camera_matrix", 3); // want to use embeded color profile
 
     oiio::ImageBuf inBuf(path, 0, 0, NULL, &configSpec);
 
     if(!inBuf.initialized())
         throw std::runtime_error("Can't find/open image file '" + path + "'.");
 
+#if OIIO_VERSION <= (10000 * 2 + 100 * 0 + 8) // OIIO_VERSION <= 2.0.8
+    // Workaround for bug in RAW colorspace management in previous versions of OIIO:
+    //     When asking sRGB we got sRGB primaries with linear gamma,
+    //     but oiio::ColorSpace was wrongly set to sRGB.
     oiio::ImageSpec inSpec = inBuf.spec();
+    if(inSpec.get_string_attribute("oiio:ColorSpace", "") == "sRGB")
+    {
+        const auto in = oiio::ImageInput::open(path, nullptr);
+        const std::string formatStr = in->format_name();
+        if(formatStr == "raw")
+        {
+            // For the RAW plugin: override colorspace as linear (as the content is linear with sRGB primaries but declared as sRGB)
+            inSpec.attribute("oiio:ColorSpace", "Linear");
+            qDebug() << "OIIO workaround: RAW input image " << QString::fromStdString(path) << " is in Linear.";
+        }
+    }
+#else
+    const oiio::ImageSpec& inSpec = inBuf.spec();
+#endif
 
     qDebug() << "[QtOIIO] width:" << inSpec.width << ", height:" << inSpec.height << ", nchannels:" << inSpec.nchannels;
 
     if(inSpec.nchannels >= 3)
     {
         // Color conversion to sRGB
-        const std::string& colorSpace = inSpec.get_string_attribute("oiio:Colorspace", "sRGB");
-        if(colorSpace != "sRGB")
+        const std::string& colorSpace = inSpec.get_string_attribute("oiio:ColorSpace", "sRGB"); // default image color space is sRGB
+
+        if(colorSpace != "sRGB") // color conversion to sRGB
+        {
             oiio::ImageBufAlgo::colorconvert(inBuf, inBuf, colorSpace, "sRGB");
+            qDebug() << "Convert image " << QString::fromStdString(path) << " from " << QString::fromStdString(colorSpace) << " to sRGB colorspace";
+        }
     }
 
     int nchannels = 0;