TIFF: subtle bug -- re-opening forgot about rawcolor hint.

src/doc/pythonbindings.rst

@@ -1425,6 +1425,21 @@ awaiting a call to `reset()` or `copy()` before it is useful.
 
 
 
+.. py:method:: ImageBuf (filename, subimage, miplevel, config)
+
+    Construct a read-only ImageBuf that will read from the named file,
+    with an ImageSpec `config` giving configuration hints.
+
+    Example::
+
+        import OpenImageIO as oiio
+        ...
+        config = ImageSpec()
+        config.attribute("oiio:RawColor", 1)
+        buf = ImageBuf ("grid.tif", 0, 0, config)
+
+
+
 .. py:method:: ImageBuf (imagespec, zero = True)
 
     Construct a writeable ImageBuf of the dimensions and data format

src/libOpenImageIO/imagebuf.cpp

@@ -765,8 +765,13 @@ ImageBufImpl::init_spec(string_view filename, int subimage, int miplevel)
     m_nmiplevels   = 0;
     static ustring s_subimages("subimages"), s_miplevels("miplevels");
     static ustring s_fileformat("fileformat");
-    if (m_configspec)  // Pass configuration options to cache
-        m_imagecache->add_file(m_name, nullptr, m_configspec.get());
+    if (m_configspec) {  // Pass configuration options to cache
+        // Invalidate the file in the cache, and add with replacement
+        // because it might have a different config than last time.
+        m_imagecache->invalidate(m_name, true);
+        m_imagecache->add_file(m_name, nullptr, m_configspec.get(),
+                               /*replace=*/true);
+    }
     m_imagecache->get_image_info(m_name, subimage, miplevel, s_subimages,
                                  TypeInt, &m_nsubimages);
     m_imagecache->get_image_info(m_name, subimage, miplevel, s_miplevels,

src/python/py_imagebuf.cpp

@@ -198,6 +198,11 @@ declare_imagebuf(py::module& m)
             auto z = zero ? InitializePixels::Yes : InitializePixels::No;
             return ImageBuf(spec, z);
         }))
+        .def(py::init([](const std::string& name, int subimage, int miplevel,
+                         const ImageSpec& config) {
+                 return ImageBuf(name, subimage, miplevel, nullptr, &config);
+             }),
+             "name"_a, "subimage"_a, "miplevel"_a, "config"_a)
         .def("clear", &ImageBuf::clear)
         .def(
             "reset",

src/tiff.imageio/tiffinput.cpp

@@ -171,6 +171,8 @@ class TIFFInput final : public ImageInput {
         m_subimage_specs.clear();
     }
 
+    // Just close the TIFF file handle, but don't forget anything we
+    // learned about the contents of the file or any configuration hints.
     void close_tif()
     {
         if (m_tif) {
@@ -1428,7 +1430,14 @@ TIFFInput::read_native_scanline(int subimage, int miplevel, int y, int z,
             ImageSpec dummyspec;
             int old_subimage = current_subimage();
             int old_miplevel = current_miplevel();
-            if (!close() || !open(m_filename, dummyspec)
+            // We need to close the TIFF file s that we can re-open and
+            // seek back to the beginning of this subimage. The close_tif()
+            // accomplishes that. It's important not to do a full close()
+            // here, because that would also call init() to fully reset
+            // to a fresh ImageInput, thus forgetting any configuration
+            // settings such as raw_color or keep_unassociated_alpha.
+            close_tif();
+            if (!open(m_filename, dummyspec)
                 || !seek_subimage(old_subimage, old_miplevel)) {
                 return false;  // Somehow, the re-open failed
             }

testsuite/python-imageinput/ref/out-alt.txt

@@ -153,4 +153,30 @@ Test read_image into FLOAT:
 Opened "testu16.tif" as a tiff
 Read array typecode float32  [ 12288 ]
 
+Testing write and read of unassociated:
+  writing:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  default reading as IB:  [[[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]
+
+ [[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]]
+
+  reading as IB with unassoc hint:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  reading as II with hint, read scanlines backward: 
+    [1] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+    [0] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+
+
 Done.

testsuite/python-imageinput/ref/out-alt2.txt

@@ -153,4 +153,30 @@ Test read_image into FLOAT:
 Opened "testu16.tif" as a tiff
 Read array typecode float32  [ 12288 ]
 
+Testing write and read of unassociated:
+  writing:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  default reading as IB:  [[[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]
+
+ [[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]]
+
+  reading as IB with unassoc hint:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  reading as II with hint, read scanlines backward: 
+    [1] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+    [0] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+
+
 Done.

testsuite/python-imageinput/ref/out-python3.txt

@@ -153,4 +153,30 @@ Test read_image into FLOAT:
 Opened "testu16.tif" as a tiff
 Read array typecode float32  [ 12288 ]
 
+Testing write and read of unassociated:
+  writing:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  default reading as IB:  [[[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]
+
+ [[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]]
+
+  reading as IB with unassoc hint:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  reading as II with hint, read scanlines backward: 
+    [1] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+    [0] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+
+
 Done.

testsuite/python-imageinput/ref/out-travis.txt

@@ -153,4 +153,30 @@ Test read_image into FLOAT:
 Opened "testu16.tif" as a tiff
 Read array typecode float32  [ 12288 ]
 
+Testing write and read of unassociated:
+  writing:  [[[ 0.5  0.5  0.5  0.5]
+  [ 0.5  0.5  0.5  0.5]]
+
+ [[ 0.5  0.5  0.5  0.5]
+  [ 0.5  0.5  0.5  0.5]]]
+
+  default reading as IB:  [[[ 0.25  0.25  0.25  0.5 ]
+  [ 0.25  0.25  0.25  0.5 ]]
+
+ [[ 0.25  0.25  0.25  0.5 ]
+  [ 0.25  0.25  0.25  0.5 ]]]
+
+  reading as IB with unassoc hint:  [[[ 0.5  0.5  0.5  0.5]
+  [ 0.5  0.5  0.5  0.5]]
+
+ [[ 0.5  0.5  0.5  0.5]
+  [ 0.5  0.5  0.5  0.5]]]
+
+  reading as II with hint, read scanlines backward: 
+    [1] =  [[ 0.5  0.5  0.5  0.5]
+ [ 0.5  0.5  0.5  0.5]]
+    [0] =  [[ 0.5  0.5  0.5  0.5]
+ [ 0.5  0.5  0.5  0.5]]
+
+
 Done.

testsuite/python-imageinput/ref/out.txt

@@ -153,4 +153,30 @@ Test read_image into FLOAT:
 Opened "testu16.tif" as a tiff
 Read array typecode float32  [ 12288 ]
 
+Testing write and read of unassociated:
+  writing:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  default reading as IB:  [[[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]
+
+ [[0.25 0.25 0.25 0.5 ]
+  [0.25 0.25 0.25 0.5 ]]]
+
+  reading as IB with unassoc hint:  [[[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]
+
+ [[0.5 0.5 0.5 0.5]
+  [0.5 0.5 0.5 0.5]]]
+
+  reading as II with hint, read scanlines backward: 
+    [1] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+    [0] =  [[0.5 0.5 0.5 0.5]
+ [0.5 0.5 0.5 0.5]]
+
+
 Done.

testsuite/python-imageinput/src/test_imageinput.py

@@ -198,6 +198,32 @@ def write (image, filename, format=oiio.UNKNOWN) :
         print ("Error writing", filename, ":", image.geterror())
 
 
+# Regression test for #2285: configuration settings were "forgotten" if the
+# scanline read order necessitated closing and reopening the file.
+def test_tiff_remembering_config() :
+    # Create a file that has unassociated alpha
+    print ("Testing write and read of unassociated:")
+    spec = oiio.ImageSpec(2,2,4,"float")
+    spec.attribute("oiio:UnassociatedAlpha", 1)
+    wbuf = oiio.ImageBuf(spec)
+    oiio.ImageBufAlgo.fill(wbuf, (0.5, 0.5, 0.5, 0.5))
+    print ("  writing: ", wbuf.get_pixels())
+    wbuf.write("test_unassoc.tif")
+    rbuf = oiio.ImageBuf("test_unassoc.tif")
+    print ("\n  default reading as IB: ", rbuf.get_pixels())
+    config = oiio.ImageSpec()
+    config.attribute("oiio:UnassociatedAlpha", 1)
+    rbuf = oiio.ImageBuf("test_unassoc.tif", 0, 0, config)
+    print ("\n  reading as IB with unassoc hint: ", rbuf.get_pixels())
+    print ("\n  reading as II with hint, read scanlines backward: ")
+    ii = oiio.ImageInput.open("test_unassoc.tif", config)
+    print ("    [1] = ", ii.read_scanline(1))
+    print ("    [0] = ", ii.read_scanline(0))
+    print ("\n")
+
+
+
+
 ######################################################################
 # main test starts here
 
@@ -258,6 +284,8 @@ def write (image, filename, format=oiio.UNKNOWN) :
     test_readimage ("testu16.tif", method="image", type="float",
                     keep_unknown=True, print_pixels=False)
 
+    test_tiff_remembering_config()
+
     print ("Done.")
 except Exception as detail:
     print ("Unknown exception:", detail)