[Magick-bugs] MSL and `modulate`

[Daniel Trebbien]

I just downloaded and installed ImageMagick-6.4.5-3-Q16-windows-dll on my
Windows 2000 laptop and I am having trouble with conjure/MSL. I think I
found a bug.

The attached `back.png` is the image that I would like to brighten.

Just to try to eliminate some variables, the following MSL script produces
an identical `back.png`:
<?xml version="1.0" encoding="UTF-8"?>
<image>
    <read filename="back.png"/>
    <write filename="back2.png" />
</image>

As does this one:
<?xml version="1.0" encoding="UTF-8"?>
<image>
    <read filename="back.png"/>
    <modulate />
    <write filename="back3.png" />
</image>

The interesting effect occurs when I try to use a parameter with <modulate>.
For example, I wanted to brighten the image, but the colors end up
yellowish:
<?xml version="1.0" encoding="UTF-8"?>
<image>
    <read filename="back.png"/>
    <modulate brightness="110" />
    <write filename="back4.png" />
</image>

The following should also produce an identical image, but it does not:
<?xml version="1.0" encoding="UTF-8"?>
<image>
    <read filename="back.png"/>
    <modulate brightness="100" />
    <write filename="back5.png" />
</image>

What's more, when using the command line, I get what I expect:
convert back.png -modulate 110 back6.png

All of these test images have been attached. I tried these scripts with the
Q8-dll version as well, and had the same problem.

Daniel