JpegImageConverter, StbImageConverter: fuzzy verification of JPEG out…

…put.

Uses DebugTools::CompareImage to verify the converted output is not too
far from the input.

src/MagnumPlugins/JpegImageConverter/Test/CMakeLists.txt

@@ -23,6 +23,8 @@
 #   DEALINGS IN THE SOFTWARE.
 #
 
+find_package(Magnum REQUIRED DebugTools)
+
 # CMake before 3.8 has broken $<TARGET_FILE*> expressions for iOS (see
 # https://gitlab.kitware.com/cmake/cmake/merge_requests/404) and since Corrade
 # doesn't support dynamic plugins on iOS, this sorta works around that. Should
@@ -44,7 +46,7 @@ else()
 endif()
 
 corrade_add_test(JpegImageConverterTest JpegImageConverterTest.cpp
-    LIBRARIES Magnum::Trade)
+    LIBRARIES Magnum::Trade Magnum::DebugTools)
 if(NOT BUILD_PLUGINS_STATIC)
     target_include_directories(JpegImageConverterTest PRIVATE $<TARGET_FILE_DIR:JpegImageConverterTest>)
 else()

src/MagnumPlugins/JpegImageConverter/Test/JpegImageConverterTest.cpp

@@ -28,6 +28,7 @@
 #include <Corrade/TestSuite/Compare/Container.h>
 #include <Corrade/Utility/ConfigurationGroup.h>
 #include <Magnum/PixelFormat.h>
+#include <Magnum/DebugTools/CompareImage.h>
 #include <Magnum/Trade/AbstractImageConverter.h>
 #include <Magnum/Trade/AbstractImporter.h>
 #include <Magnum/Trade/ImageData.h>
@@ -42,8 +43,10 @@ struct JpegImageConverterTest: TestSuite::Tester {
     void wrongFormat();
 
     void rgb80Percent();
+    void rgb100Percent();
 
     void grayscale80Percent();
+    void grayscale100Percent();
 
     /* Explicitly forbid system-wide plugin dependencies */
     PluginManager::Manager<AbstractImageConverter> _converterManager{"nonexistent"};
@@ -54,8 +57,10 @@ JpegImageConverterTest::JpegImageConverterTest() {
     addTests({&JpegImageConverterTest::wrongFormat,
 
               &JpegImageConverterTest::rgb80Percent,
+              &JpegImageConverterTest::rgb100Percent,
 
-              &JpegImageConverterTest::grayscale80Percent});
+              &JpegImageConverterTest::grayscale80Percent,
+              &JpegImageConverterTest::grayscale100Percent});
 
     /* Load the plugin directly from the build tree. Otherwise it's static and
        already loaded. */
@@ -177,6 +182,26 @@ void JpegImageConverterTest::rgb80Percent() {
         TestSuite::Compare::Container);
 }
 
+void JpegImageConverterTest::rgb100Percent() {
+    std::unique_ptr<AbstractImageConverter> converter = _converterManager.instantiate("JpegImageConverter");
+    converter->configuration().setValue("jpegQuality", 1.0f);
+
+    const auto data = converter->exportToData(OriginalRgb);
+    CORRADE_VERIFY(data);
+
+    if(_importerManager.loadState("JpegImporter") == PluginManager::LoadState::NotFound)
+        CORRADE_SKIP("JpegImporter plugin not found, cannot test");
+
+    std::unique_ptr<AbstractImporter> importer = _importerManager.instantiate("JpegImporter");
+    CORRADE_VERIFY(importer->openData(data));
+    Containers::Optional<Trade::ImageData2D> converted = importer->image2D(0);
+    CORRADE_VERIFY(converted);
+
+    /* Expect only minimal difference (single bits) */
+    CORRADE_COMPARE_WITH(*converted, OriginalRgb,
+        (DebugTools::CompareImage{3.1f, 1.4f}));
+}
+
 namespace {
     constexpr const char OriginalGrayscaleData[] = {
         0, 0, 0, 0, 0, 0, 0, 0, /* Skip */
@@ -230,6 +255,26 @@ void JpegImageConverterTest::grayscale80Percent() {
         TestSuite::Compare::Container);
 }
 
+void JpegImageConverterTest::grayscale100Percent() {
+    std::unique_ptr<AbstractImageConverter> converter = _converterManager.instantiate("JpegImageConverter");
+    converter->configuration().setValue("jpegQuality", 1.0f);
+
+    const auto data = converter->exportToData(OriginalGrayscale);
+    CORRADE_VERIFY(data);
+
+    if(_importerManager.loadState("JpegImporter") == PluginManager::LoadState::NotFound)
+        CORRADE_SKIP("JpegImporter plugin not found, cannot test");
+
+    std::unique_ptr<AbstractImporter> importer = _importerManager.instantiate("JpegImporter");
+    CORRADE_VERIFY(importer->openData(data));
+    Containers::Optional<Trade::ImageData2D> converted = importer->image2D(0);
+    CORRADE_VERIFY(converted);
+
+    /* Expect only minimal difference (single bits) */
+    CORRADE_COMPARE_WITH(*converted, OriginalGrayscale,
+        (DebugTools::CompareImage{1.0f, 0.085f}));
+}
+
 }}}
 
 CORRADE_TEST_MAIN(Magnum::Trade::Test::JpegImageConverterTest)

src/MagnumPlugins/StbImageConverter/Test/CMakeLists.txt

@@ -23,6 +23,8 @@
 #   DEALINGS IN THE SOFTWARE.
 #
 
+find_package(Magnum REQUIRED DebugTools)
+
 # CMake before 3.8 has broken $<TARGET_FILE*> expressions for iOS (see
 # https://gitlab.kitware.com/cmake/cmake/merge_requests/404) and since Corrade
 # doesn't support dynamic plugins on iOS, this sorta works around that. Should
@@ -44,7 +46,7 @@ else()
 endif()
 
 corrade_add_test(StbImageConverterTest StbImageConverterTest.cpp
-    LIBRARIES Magnum::Trade)
+    LIBRARIES Magnum::Trade Magnum::DebugTools)
 if(NOT BUILD_PLUGINS_STATIC)
     target_include_directories(StbImageConverterTest PRIVATE $<TARGET_FILE_DIR:StbImageConverterTest>)
 else()

src/MagnumPlugins/StbImageConverter/Test/StbImageConverterTest.cpp

@@ -28,6 +28,7 @@
 #include <Corrade/TestSuite/Compare/Container.h>
 #include <Corrade/Utility/ConfigurationGroup.h>
 #include <Magnum/PixelFormat.h>
+#include <Magnum/DebugTools/CompareImage.h>
 #include <Magnum/Trade/AbstractImageConverter.h>
 #include <Magnum/Trade/AbstractImporter.h>
 #include <Magnum/Trade/ImageData.h>
@@ -50,7 +51,9 @@ struct StbImageConverterTest: TestSuite::Tester {
     void hdrGrayscale();
 
     void jpegRgb80Percent();
+    void jpegRgb100Percent();
     void jpegGrayscale80Percent();
+    /* Can't grayscale 100% because stb_image_write expands to RGB */
 
     void pngRgb();
     void pngGrayscale();
@@ -72,6 +75,7 @@ StbImageConverterTest::StbImageConverterTest() {
               &StbImageConverterTest::hdrGrayscale,
 
               &StbImageConverterTest::jpegRgb80Percent,
+              &StbImageConverterTest::jpegRgb100Percent,
               &StbImageConverterTest::jpegGrayscale80Percent,
 
               &StbImageConverterTest::pngRgb,
@@ -266,6 +270,26 @@ void StbImageConverterTest::jpegRgb80Percent() {
         TestSuite::Compare::Container);
 }
 
+void StbImageConverterTest::jpegRgb100Percent() {
+    std::unique_ptr<AbstractImageConverter> converter = _converterManager.instantiate("StbJpegImageConverter");
+    converter->configuration().setValue("jpegQuality", 1.0f);
+
+    const auto data = converter->exportToData(OriginalJpegRgb);
+    CORRADE_VERIFY(data);
+
+    if(_importerManager.loadState("StbImageImporter") == PluginManager::LoadState::NotFound)
+        CORRADE_SKIP("StbImageImporter plugin not found, cannot test");
+
+    std::unique_ptr<AbstractImporter> importer = _importerManager.instantiate("StbImageImporter");
+    CORRADE_VERIFY(importer->openData(data));
+    Containers::Optional<Trade::ImageData2D> converted = importer->image2D(0);
+    CORRADE_VERIFY(converted);
+
+    /* Expect only minimal difference (single bits) */
+    CORRADE_COMPARE_WITH(*converted, OriginalJpegRgb,
+        (DebugTools::CompareImage{1.0f, 0.39f}));
+}
+
 namespace {
     constexpr const char OriginalJpegGrayscaleData[] = {
         0, 0, 0, 0, 0, 0, 0, 0, /* Skip */