docs: Convert ImageInput-unassociatedalpha examples from docs to tests (#4468)

Convert error checking C++ and Python examples from the "imageinput"
chapter into tests within the "docs-examples" testsuites
(#3992).

I grabbed unpremut.tif from the output of another test.

--

Signed-off-by: Paul Franz <pfranz@laika.com>

Author: pfranz

src/doc/imageinput.rst

@@ -902,37 +902,19 @@ Examples:
     automatically be converted to associated alpha.
 
     .. tabs::
-    
-       .. code-tab:: c++
-    
-          // Set up an ImageSpec that holds the configuration hints.
-          ImageSpec config;
-          config["oiio:UnassociatedAlpha"] = 1;
-    
-          // Open the file, passing in the config.
-          auto inp = ImageInput::open (filename, config);
-          const ImageSpec &spec = inp->spec();
-          auto pixels = std::unique_ptr<unsigned char[]>(new unsigned char[spec.image_pixels() * spec.nchannels]);
-          inp->read_image (0, 0, 0, spec.nchannels, TypeDesc::UINT8, pixels.data());
-          if (spec.get_int_attribute("oiio:UnassociatedAlpha"))
-              printf("pixels holds unassociated alpha\n");
-          else
-              printf("pixels holds associated alpha\n");
-
-       .. code-tab:: py
-    
-          # Set up an ImageSpec that holds the configuration hints.
-          config = ImageSpec()
-          config["oiio:UnassociatedAlpha"] = 1
-    
-          # Open the file, passing in the config.
-          inp = ImageInput.open (filename, config)
-          spec = inp.spec()
-          pixels = inp.read_image (0, 0, 0, spec.nchannels, "uint8")
-          if (spec["oiio:UnassociatedAlpha"] == 1)
-              print("pixels holds unassociated alpha")
-          else
-              print("pixels holds associated alpha")
+
+        .. tab:: C++
+            .. literalinclude:: ../../testsuite/docs-examples-cpp/src/docs-examples-imageinput.cpp
+                :language: c++
+                :start-after: BEGIN-imageinput-unassociatedalpha
+                :end-before: END-imageinput-unassociatedalpha
+
+        .. tab:: Python
+            .. literalinclude:: ../../testsuite/docs-examples-python/src/docs-examples-imageinput.py
+                :language: py
+                :start-after: BEGIN-imageinput-unassociatedalpha
+                :end-before: END-imageinput-unassociatedalpha
+
 
 .. _sec-imageinput-ioproxy:
 

testsuite/common/unpremult.tif

@@ -1,3 +1,4 @@
+pixels holds unassociated alpha
 example_output_error1
 error: Uninitialized input image
 example_output_error2

testsuite/docs-examples-cpp/ref/out-arm.txt

@@ -1,3 +1,4 @@
+pixels holds unassociated alpha
 example_output_error1
 error: Uninitialized input image
 example_output_error2

testsuite/docs-examples-cpp/ref/out.txt

@@ -17,6 +17,7 @@
 command += run_app("cmake -E copy " + test_source_dir + "/../common/grid-small.exr B.exr")
 command += run_app("cmake -E copy " + test_source_dir + "/../common/with_nans.tif with_nans.tif")
 command += run_app("cmake -E copy " + test_source_dir + "/../common/checker_with_alpha.exr checker_with_alpha.exr")
+command += run_app("cmake -E copy " + test_source_dir + "/../common/unpremult.tif unpremult.tif")
 
 # Copy the grid to both a tiled and scanline version
 command += oiio_app("iconvert") + "../common/grid.tif --scanline scanline.tif > out.txt ;" 

testsuite/docs-examples-cpp/run.py

@@ -99,6 +99,27 @@ void tiles_read()
 // END-imageinput-tiles
 }
 
+void unassociatedalpha()
+{
+    const char* filename = "unpremult.tif";
+
+// BEGIN-imageinput-unassociatedalpha
+    // Set up an ImageSpec that holds the configuration hints.
+    ImageSpec config;
+    config["oiio:UnassociatedAlpha"] = 1;
+
+    // Open the file, passing in the config.
+    auto inp = ImageInput::open (filename, &config);
+    const ImageSpec &spec = inp->spec();
+    auto pixels = std::unique_ptr<unsigned char[]>(new unsigned char[spec.image_pixels() * spec.nchannels]);
+    inp->read_image (0, 0, 0, spec.nchannels, TypeDesc::UINT8, &pixels[0]);
+    if (spec.get_int_attribute("oiio:UnassociatedAlpha"))
+        printf("pixels holds unassociated alpha\n");
+    else
+        printf("pixels holds associated alpha\n");
+// END-imageinput-unassociatedalpha
+}
+
 
 // BEGIN-imageinput-errorchecking
 #include <OpenImageIO/imageio.h>
@@ -142,6 +163,7 @@ int main(int /*argc*/, char** /*argv*/)
     simple_read();
     scanlines_read();
     tiles_read();
+    unassociatedalpha();
     error_checking();
     return 0;
 }

testsuite/docs-examples-cpp/src/docs-examples-imageinput.cpp

@@ -1,3 +1,4 @@
+pixels holds unassociated alpha
 example1
 example_output_error1
 error: Uninitialized input image

testsuite/docs-examples-python/ref/out-arm.txt

@@ -1,3 +1,4 @@
+pixels holds unassociated alpha
 example1
 example_output_error1
 error: Uninitialized input image

testsuite/docs-examples-python/ref/out.txt

@@ -17,6 +17,7 @@
 command += run_app("cmake -E copy " + test_source_dir + "/../common/grid-small.exr B.exr")
 command += run_app("cmake -E copy " + test_source_dir + "/../common/with_nans.tif with_nans.tif")
 command += run_app("cmake -E copy " + test_source_dir + "/../common/checker_with_alpha.exr checker_with_alpha.exr")
+command += run_app("cmake -E copy " + test_source_dir + "/../common/unpremult.tif unpremult.tif")
 
 # Copy the grid to both a tiled and scanline version
 command += oiio_app("iconvert") + "../common/grid.tif --scanline scanline.tif > out.txt ;" 

testsuite/docs-examples-python/run.py

@@ -86,6 +86,24 @@ def tiles_read() :
     # END-imageinput-tiles
 
 
+def unassociated_alpha():
+    filename = "unpremult.tif"
+
+    # BEGIN-imageinput-unassociatedalpha
+    # Set up an ImageSpec that holds the configuration hints.
+    config = oiio.ImageSpec()
+    config["oiio:UnassociatedAlpha"] = 1
+
+    # Open the file, passing in the config.
+    inp = oiio.ImageInput.open (filename, config)
+    spec = inp.spec()
+    pixels = inp.read_image (0, 0, 0, spec.nchannels, "uint8")
+    if (spec["oiio:UnassociatedAlpha"] == 1):
+        print("pixels holds unassociated alpha")
+    else:
+        print("pixels holds associated alpha")
+    # END-imageinput-unassociatedalpha
+
 def error_checking():
 # BEGIN-imageinput-errorchecking
     import OpenImageIO as oiio
@@ -119,4 +137,5 @@ def error_checking():
     simple_read()
     scanlines_read()
     tiles_read()
+    unassociated_alpha()
     error_checking()