The chroma key effect combines two sources by replacing all the pixels of the first source that are the specified color with the corresponding pixels of the second source. This allows the second source to "show through" the first in those places where the first source is the given color.
This has the effect of putting the second source "behind" the first source, and making the selected color "transparent".
The chroma key effect takes a maximum of two sources
The QTPlgEffectChromaKeyTransitionDesc class implements methods and properties to setup programmatically the parameters of the chroma key effect provided natively by QuickTime.
→ → → →
The QTPlgEffectChromaKeyTransitionDesc class constructors are called when you create a new instance of the class, while the ˜QTPlgEffectChromaKeyTransitionDesc class destructor, is called automatically when the class is no more in use. Also, you can invoke the class destructor by setting the instance of the class to nil.
Once a new class instance is returned, it is good practice to check the class property to be sure that the new object can be used. For discussion about the validity of an effect description instance see the documentation relative to the .
The class provides you with the following initializer methods:
()
This is the default constructor. Use this constructor to create a completely new data descriptor container in memory.
(other as )
This is the copy constructor. The properties of the object to be copied will be used to initialize the
new class instance properties. Note that the parameter passed is a generic object; this is due to the
fact that you could use a descriptor obtained by the that returns a generic
. Anyway, the class makes a
control to check if the passed object is suitable for use and, if not, will initialize the class instance with default values
pixels of this color in the first source will be replaced by pixels from the second source