Upscaling shifts the image

[m35]

To reproduce

git clone https://github.com/mortennobel/java-image-scaling.git
Copy attached Test.java file under src/main/java
cd java-image-scaling
mvn clean install
Put testupscale.png in the current directory
java -cp target\java-image-scaling-0.8.7-SNAPSHOT.jar Test

Compare testupscale-gimp-none.png with boxImg.png

Compare testupscale-gimp-cubic.png with bicubicImg.png

This affects all algorithms.

Test.java