Office of Digital Humanities

DigHT 310
Scripting Everything

A Totally Scriptable Architecture

LiveCode was built on the principle that virtually anything that can be done through the user interface--the menus, property palettes, and other tools--can be accomplished through scripting. For instance, instead of using the Tools Palette to create a new button, you can simply enter this command in the message box:

create button "myButton"

A button with the name indicated will be created on the current card. You may be thinking, "But it's faster to just point and click to create objects." And you may be right. However, the implication of this ability to do anything via scripting is that you can write scripts that will automatically modify your stack under whatever conditions you stipulate. For example, you might want to script the creation of new cards for each new question in a quiz, and then have a script that deletes these cards when the quiz is over. This ability to script the way your stacks look and behave gives you as the developer total control over everything that happens in your stack.

Scripting for Color

As an example of the scriptable architecture let's look at the color properties of objects in LiveCode. For example, you might want to change the background color of a field if certain conditions apply. You could script the change by changing the backgroundColor property of the field, like this:

set the backgroundColor of fld "fancyField" to colorReference

A color reference can have one of three forms:

• A color name - any standard color reference like blue or red. (A complete list can be obtained using the colorNames( ) function.)
  
• An RGB color reference, which consists of three comma-separated integers between zero and 255, specifying the levels of Red, Green and Blue, respectively.
  Examples: 0,0,255 is pure blue; 238,255,238 produces the light green in the table below; setting the three levels to exactly the same number, eg. 0,0,0; 120,120,120; 255,255,255; produces a gray scale color ranging from pure black to pure white.
  
• A hexidecimal color reference, consisting of a hash mark (#) followed by three hexadecimal numbers, one for each of red,
  green, and blue. (This is the format used in HTML). Each hexidecimal number has two digits; hexidecimal digits range from 0 to F.
  Examples: #0000FF is pure blue; #EEFFEE produces the light green in the table below; #999999 yields a medium gray.

Here is a list of LiveCode terms that affect color:

Related Scripting Elements

There are other elements of LiveCode that don't deal directly with color, but are related. In particular, there is a whole set of properties that specify patterns that are used in various parts of objects. Here are some other interesting elements:

In-Class Exercise: Scripting Everything