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This effect applies a general purpose convolution effect to a single source. The effect that results is completely determined by the values entered into the kernel parameters of the effect. The kernel for this convolution is always a 3–by–3 matrix of values.

The values of the cells of the convolution kernel determine the value that is assigned to each pixel of the destination frame. The convolution algorithm examines every pixel of the source, and the eight pixels surrounding it. These values are multiplied by the appropriate values in the cells and summed. This sum is then used as the value of the corresponding destination pixel.

The QTPlgEffectGeneralConvolutionDesc class implements methods and properties to setup programmatically the parameters of the convolution effect provided natively by QuickTime.







The QTPlgEffectGeneralConvolutionDesc class constructors are called when you create a new instance of the class, while the ˜QTPlgEffectGeneralConvolutionDesc 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

gets and sets the values of the 3–by–3 matrix by accessing them in an indexed way; the parameter i ranges from 0 to 8. The nine cells in the kernel are laid out as shown in the figure below

(column as integer, row as integer) as double
this getter/setter method allows you to retrieve/set values from the 3–by–3 matrix by specifying the column and row parameters; bothe these parameters range from 0 to 2
returns the value of the cell specified by the column and row parameters; if the parameters passed are incorrect returns 0.0. Check the class property for errors