NativeImage#copyImageData not copying correctly

After doing some testing I can confirm this is a bug in Vanilla minecraft.

When using NativeImage.copyImageData() it will not copy correctly if the target image is larger than the original.

For example, this code right here:

private static void testNativeImg() {
        //Generate two instances of NativeImage, one larger than the other
        final NativeImage imgOld = new NativeImage(64, 64, true);
        final NativeImage imgNew = new NativeImage(128, 128, true);
                        
        //Filling imgOld with red        
        imgOld.fillAreaRGBA(0, 0, 64, 64, 255 | -16777216);
        
        //Filling imgNew with blue
        imgNew.fillAreaRGBA(0, 0, 128, 128, 16711680 | -16777216);
        
        //Copying imgOld to imgNew. This should make a 64x64 square of pixels on imgNew
        imgNew.copyImageData(imgOld);        
          
        //Lets write the result the file system
        try {
            imgOld.write(new File("img" + System.currentTimeMillis() / 1000 + ".png"));
            imgNew.write(new File("imgNew" + System.currentTimeMillis() / 1000 + ".png"));
        } catch (IOException e) { 
            e.printStackTrace();
        }
        
        //Close imgOld and imgNew
        imgOld.close();
        imgNew.close();
    }

Using Mojang mappings

import java.io.File;
import java.io.IOException;

import com.mojang.blaze3d.platform.NativeImage;

public class NativeImageTest {
    public static void main(String[] args) throws IOException {
        try (
            NativeImage imgOld = new NativeImage(64, 64, true);
            NativeImage imgNew = new NativeImage(128, 128, true);
        ) {
            //Filling imgOld with red        
            imgOld.fillRect(0, 0, 64, 64, 255 | -16777216);
            
            //Filling imgNew with blue
            imgNew.fillRect(0, 0, 128, 128, 16711680 | -16777216);
            
            //Copying imgOld to imgNew. This should make a 64x64 square of pixels on imgNew
            imgNew.copyFrom(imgOld);        
              
            //Lets write the result the file system
            imgOld.writeToFile(new File("img" + System.currentTimeMillis() / 1000 + ".png"));
            imgNew.writeToFile(new File("imgNew" + System.currentTimeMillis() / 1000 + ".png"));
        }
    }
}

Will create the 2 images below

Cause

The bytes value passed to MemoryUtil.memCopy is Math.min(this.getWidth(), nativeImage.getWidth()). The multiplication with format.components() is missing.