Previewing the GUI skins in Photoshop
From C4 Engine Wiki
Here's a tip for artists who wish to interactively preview their GUI skins in Photoshop.
1. First layer your "gui1", "gui2", and "$buttonColor" layers as follows:
http://www.mainlandgaming.com/dev/gui1_base_normal.png
2. Now set the "$buttonColor" colorization layer to Multiply mode, as shown here (I've used the factory default color of "40D0FF"):
http://www.mainlandgaming.com/dev/buttonColor_multiply.png
3. Then set your "gui2" highlight layer to Screen blending mode, as shown here:
http://www.mainlandgaming.com/dev/gui2_hilite_screen.png
Now you can hide the "$buttonColor" layer to display the buttons with the normal highlighted appearance:
http://www.mainlandgaming.com/dev/gui_compositeWithHilite.png
Or show the "$buttonColor" layer to display the buttons with the default push button or checked appearance:
http://www.mainlandgaming.com/dev/gui_compositeWithButtonColor.png
With this setup, you can modify your GUI skin and see what it will look like interactively, without having to constantly re-load your game in C4 Engine.
