DebugTools: initial implementation of CompareImage class.

Currently just does per-pixel comparison and calculates absolute delta,
failing the comparison if max/mean delta threshold is above specified
values. Useful enough for the case I have right now, might fail in other
case -- but still better than whatever else I was using before :)

CMakeLists.txt

@@ -335,3 +335,8 @@ set(MAGNUM_PLUGINS_AUDIOIMPORTER_RELEASE_DIR ${MAGNUM_PLUGINS_RELEASE_DIR}/audio
 
 add_subdirectory(modules)
 add_subdirectory(src)
+
+# Build snippets as part of testing
+if(BUILD_TESTS)
+    add_subdirectory(doc/snippets)
+endif()

Doxyfile

@@ -892,7 +892,8 @@ EXCLUDE_SYMBOLS        = Magnum::*Implementation \
 # that contain example code fragments that are included (see the \include
 # command).
 
-EXAMPLE_PATH           = ../magnum-examples/src/
+EXAMPLE_PATH           = doc/snippets/ \
+                         ../magnum-examples/src/
 
 # If the value of the EXAMPLE_PATH tag contains directories, you can use the
 # EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp and
@@ -913,6 +914,7 @@ EXAMPLE_RECURSIVE      = NO
 # \image command).
 
 IMAGE_PATH             = doc/ \
+                         doc/snippets/ \
                          ../magnum-examples/src/
 
 # The INPUT_FILTER tag can be used to specify a program that doxygen should

doc/snippets/CMakeLists.txt

@@ -0,0 +1,40 @@
+#
+#   This file is part of Magnum.
+#
+#   Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016
+#             Vladimír Vondruš <mosra@centrum.cz>
+#
+#   Permission is hereby granted, free of charge, to any person obtaining a
+#   copy of this software and associated documentation files (the "Software"),
+#   to deal in the Software without restriction, including without limitation
+#   the rights to use, copy, modify, merge, publish, distribute, sublicense,
+#   and/or sell copies of the Software, and to permit persons to whom the
+#   Software is furnished to do so, subject to the following conditions:
+#
+#   The above copyright notice and this permission notice shall be included
+#   in all copies or substantial portions of the Software.
+#
+#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+#   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#   DEALINGS IN THE SOFTWARE.
+#
+
+find_package(Corrade COMPONENTS TestSuite)
+
+if(WITH_DEBUGTOOLS AND Corrade_TestSuite_FOUND)
+    set(SNIPPETS_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+    configure_file(${CMAKE_CURRENT_SOURCE_DIR}/configure.h.cmake
+                   ${CMAKE_CURRENT_BINARY_DIR}/configure.h)
+
+    # CompareImage documentation snippet. I need it executable so I can
+    # copy&paste the output to the documentation. Also mot using
+    # corrade_add_test() because it shouldn't be run as part of CTest as it
+    # purposedly fails.
+    add_executable(debugtools-compareimage debugtools-compareimage.cpp)
+    target_link_libraries(debugtools-compareimage PRIVATE MagnumDebugTools)
+    target_include_directories(debugtools-compareimage PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+endif()

doc/snippets/configure.h.cmake

@@ -0,0 +1,27 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016
+              Vladimír Vondruš <mosra@centrum.cz>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#define MAGNUM_PLUGINS_IMPORTER_DIR "${MAGNUM_PLUGINS_IMPORTER_DIR}"
+#define SNIPPETS_DIR "${SNIPPETS_DIR}"

doc/snippets/debugtools-compareimage.cpp

@@ -0,0 +1,82 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016
+              Vladimír Vondruš <mosra@centrum.cz>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#include <Corrade/PluginManager/Manager.h>
+#include <Corrade/TestSuite/Tester.h>
+#include <Corrade/Utility/Directory.h>
+
+#include "Magnum/Image.h"
+#include "Magnum/Trade/ImageData.h"
+#include "Magnum/Trade/AbstractImporter.h"
+#include "Magnum/DebugTools/CompareImage.h"
+
+#include "configure.h"
+
+using namespace Magnum;
+
+namespace {
+
+Image2D doProcessing() {
+    PluginManager::Manager<Trade::AbstractImporter> manager{MAGNUM_PLUGINS_IMPORTER_DIR};
+    std::unique_ptr<Trade::AbstractImporter> importer = manager.loadAndInstantiate("TgaImporter");
+    importer->openFile(Utility::Directory::join(SNIPPETS_DIR, "image2.tga"));
+    auto image = importer->image2D(0);
+    CORRADE_INTERNAL_ASSERT(image);
+    return Image2D{image->storage(), image->format(), image->type(), image->size(), image->release()};
+}
+
+Image2D loadExpectedImage() {
+    PluginManager::Manager<Trade::AbstractImporter> manager{MAGNUM_PLUGINS_IMPORTER_DIR};
+    std::unique_ptr<Trade::AbstractImporter> importer = manager.loadAndInstantiate("TgaImporter");
+    importer->openFile(Utility::Directory::join(SNIPPETS_DIR, "image1.tga"));
+    auto image = importer->image2D(0);
+    CORRADE_INTERNAL_ASSERT(image);
+    return Image2D{image->storage(), image->format(), image->type(), image->size(), image->release()};
+}
+
+}
+
+struct ProcessingTest: TestSuite::Tester {
+    explicit ProcessingTest();
+
+    void process();
+};
+
+ProcessingTest::ProcessingTest() {
+    addTests({&ProcessingTest::process});
+}
+
+/** [0] */
+void ProcessingTest::process() {
+    Image2D actual = doProcessing();
+    Image2D expected = loadExpectedImage();
+
+    CORRADE_COMPARE_WITH(actual, expected,
+        (DebugTools::CompareImage{170.0f, 96.0f}));
+}
+/** [0] */
+
+CORRADE_TEST_MAIN(ProcessingTest)
+

src/Magnum/DebugTools/CMakeLists.txt

@@ -43,6 +43,16 @@ if(MAGNUM_TARGET_GLES AND NOT MAGNUM_TARGET_GLES2)
     list(APPEND MagnumDebugTools_SRCS ${MagnumDebugTools_RESOURCES})
 endif()
 
+# Build the TestSuite-related functionality only if it is present
+find_package(Corrade COMPONENTS TestSuite)
+if(Corrade_TestSuite_FOUND)
+    list(APPEND MagnumDebugTools_SRCS
+        CompareImage.cpp)
+
+    list(APPEND MagnumDebugTools_HEADERS
+        CompareImage.h)
+endif()
+
 if(NOT MAGNUM_TARGET_WEBGL)
     list(APPEND MagnumDebugTools_SRCS
         BufferData.cpp)
@@ -107,6 +117,9 @@ if(BUILD_STATIC_PIC)
 endif()
 
 target_link_libraries(MagnumDebugTools Magnum)
+if(Corrade_TestSuite_FOUND)
+    target_link_libraries(MagnumDebugTools Corrade::TestSuite)
+endif()
 if(WITH_SCENEGRAPH)
     target_link_libraries(MagnumDebugTools MagnumSceneGraph)
 endif()