--- a/Framework/Radiography/RadiographyAlphaLayer.cpp	Sat Dec 07 18:41:54 2019 +0100
+++ b/Framework/Radiography/RadiographyAlphaLayer.cpp	Mon Dec 09 16:38:02 2019 +0100
@@ -91,6 +91,7 @@
       return;  // layer is outside the buffer
     }
 
+    printf("rendering alpha: %d \n", y1);
     t.Apply(tmp, cropped, interpolation, true /* clear */);
 
     float value = foreground_;

--- a/Framework/Toolbox/TextRenderer.cpp	Sat Dec 07 18:41:54 2019 +0100
+++ b/Framework/Toolbox/TextRenderer.cpp	Mon Dec 09 16:38:02 2019 +0100
@@ -57,7 +57,22 @@
       posInString += utf8CharLength;
     }
 
-    return alphabet->RenderText(utf8String);
+
+    std::auto_ptr<Orthanc::ImageAccessor> renderedText(alphabet->RenderText(utf8String));
+
+    // add a blank line on top of the text (to improve bilinear filtering of the topmost line)
+    std::auto_ptr<Orthanc::Image> renderedTextExtended(new Orthanc::Image(renderedText->GetFormat(), renderedText->GetWidth(), renderedText->GetHeight() + 1, true));
+
+    Orthanc::ImageAccessor textRegion;
+    Orthanc::ImageAccessor firstLineRegion;
+
+    renderedTextExtended->GetRegion(firstLineRegion, 0, 0, renderedText->GetWidth(), 1);
+    Orthanc::ImageProcessing::Set(firstLineRegion, 0);
+
+    renderedTextExtended->GetRegion(textRegion, 0, 1, renderedText->GetWidth(), renderedText->GetHeight());
+    Orthanc::ImageProcessing::Copy(textRegion, *renderedText);
+
+    return renderedTextExtended.release();
   }