Call GetImageDistortion instead of IsImagesEqual to fix the issue rep…

…orted in #1342 (#1343)
rmagick · Jul 15, 2022 · 7decabd · 7decabd
1 parent c97f107
commit 7decabd
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/ext/RMagick/rmimage.c b/ext/RMagick/rmimage.c
@@ -5205,6 +5205,7 @@ Image_difference(VALUE self, VALUE other)
     Image *image2;
     VALUE mean, nmean, nmax;
 #if defined(IMAGEMAGICK_7)
+    double distortion;
     ExceptionInfo *exception;
 #endif
 
@@ -5214,7 +5215,7 @@ Image_difference(VALUE self, VALUE other)
 
 #if defined(IMAGEMAGICK_7)
     exception = AcquireExceptionInfo();
-    IsImagesEqual(image, image2, exception);
+    GetImageDistortion(image, image2, MeanErrorPerPixelErrorMetric, &distortion, exception);
     CHECK_EXCEPTION();
     DestroyExceptionInfo(exception);
 #else

diff --git a/spec/rmagick/image/difference_spec.rb b/spec/rmagick/image/difference_spec.rb
@@ -7,8 +7,11 @@
     expect(result).to be_instance_of(Array)
     expect(result.length).to eq(3)
     expect(result[0]).to be_instance_of(Float)
+    expect(result[0]).not_to eq(0.0)
     expect(result[1]).to be_instance_of(Float)
+    expect(result[1]).not_to eq(0.0)
     expect(result[2]).to be_instance_of(Float)
+    expect(result[2]).not_to eq(0.0)
 
     expect { image1.difference(2) }.to raise_error(NoMethodError)
     image2.destroy!