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Programming Interfaces
External Program Interfaces : Using COM Objects in ABL : Managing COM objects in an application : Managing COM object font and color settings : Managing colors
Managing colors
COM objects accept color specifications in the form of an RGB (Red/Green/Blue) integer value. However, ABL widgets accept color specifications in the form of an integer index into a color table managed by the COLOR-TABLE system handle. To support color management for COM objects, ABL provides techniques that work with or without the ABL color table.
ABL provides three ways to obtain a color value to set colors for a COM object:
*Use the value from the property or method of another COM object.
*Use the GET-RGB-VALUE( ) method of the COLOR-TABLE system handle.
*Use the RGB-VALUE function.
To use a color value from another COM object, simply assign the color value returned by one of its properties or methods to a color property or as a method parameter of your Automation object or ActiveX control.
To use the GET-RGB-VALUE( ) method, pass it an index to a color stored in the ABL color table and the method returns an integer that represents the RGB value of the specified color. You can then assign this value to a COM object color property. For example:
myObject:BorderColor = COLOR-TABLE:GET-RGB-VALUE(5).
This example assigns the RGB value of color number 5 from the color table to the BorderColor property of myObject.
To use the RGB-VALUE function, you pass the function three color values between 0 and 255 and it returns a single RGB value that represents the color. For example:
myObject:BorderColor = RGB-VALUE(127, 255, 75). /* Red, Green, Blue */