What is an overlay?
An overlay is an extra image that can be added to a coloring page. Overlays can for a variety of purposes...
- Add a logo or other branding to your coloring page.
- Add shading and tints to coloring pages.
- Create photo-like coloring pages.
- Add anti-aliasing to coloring pages.
- Add other colored graphics to coloring pages.
There are two main types of overlays - those with transparency and those without.
How do I use a non-transparent overlay?
A non-transparent overlay acts like a screen to the coloring page, and can be used to create tints, shading, or antialiasing. The best format for non-transparent overlays is JPEG because of their small size.
The non-transparent overlay affects the coloring image in the following way...
- Black areas in the overlay will be black in the resulting image.
- Gray areas in the overlay will cause a shaded affect in the resulting image. Light greys shade a little, dark grays shade a lot.
- White areas have no affect. In any white areas, the coloring image is unaffected.
- Colored areas will tint the resulting image. A light color will have a light tiniting affect and a strong color a more major affect.
By combining these features you can achieve really interesting results of shading and tiniting, or you can simply use this type of overlay to give an anti-aliased appearance to the coloring page.
How do I use a transparent overlay?
Transparent overlays are VERY cool. They can do everything that a non-transparent overlay can do - and more! The catch is that the file sizes tend to be larger.
Depending on the affect you want to achieve you can either use a transparent GIF or transparent PNG.
The transparent overlay sits above the coloring page. Any transparent areas allow the coloring page to show through, any opaque areas block the view of the coloring page. The real fun is with semi-transparent areas!
As with the non-transparent overlays you can use semi-transparency to create tints and shading, but because the affect is the result of the level of opacity (the alpha), you can create a wider range of affects.
One example is that you create highlights by using a semiopaque white area. This could be used to add a sparkle to a crystal, jewels, windows, etc. You can't do that with non-transparent overlays because white has no effect.
How do I apply an overlay?
Overlays live in the /page folder alongside the coloring pages. You can either pass the name of the overlay in the url, "&o=..." or you can specify it in the book XML file.
It is generally a good idea to make you overlay exactly the same size as the coloring page, but if you do not the program will scale it to the same size as the coloring page.
What about Printing and Saving etc?
The overlay is applied to the coloring page in whatever way it is used, so it's affects will appear when the user prints the page, saves the page, or sends it to an addon (e.g. Gallery, Facebook, etc).
What else can I do with an overlay?
There are lots of possibilities. Try experimenting to see what sort of affects you can create.
The name of the overlay is passed in the url, or book XML, both of which can be dynamic. This means that you could even use a script to generate an overlay dynamically. That script could do something like taking a user input and turning it into text to add to the coloring page!
What version do I need?
Overlays were introduced in Version 2.0 of My Coloring Book. Make sure you download the latest version.