This effect applies a convolution blur effect to a single source. The actual blur that is applied is determined by the convolution kernel. This is a matrix of values that are applied to each pixels of the source to produce the destination. The Blur effect takes a maximum of one source.
The QTPlgEffectBlurDesc class implements methods and properties to setup programmatically the parameters of the blur filter provided natively by QuickTime.
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The QTPlgEffectBlurDesc class constructors are called when you create a new instance of the class, while the ˜QTPlgEffectBlurDesc 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
specifies the size of the blur kernel to apply. This value must be one of 3, 5, 7,
9, 11, 13 or 15. The larger the kernel, the longer the effect will
take to run and the greater the degree of blurring
the total value of the elements of the blur kernel. Normally this value will be 1.0, which blurs the source but doesn’t change its brightness. If the value is between
0.0 and 1.0, the brightness is decreased, if the value is greater than 1.0, the brightness is increased. Acceptable values for this property range from
0.0 to 2.0