Filters and Effects
Another common task is applying filters to images to correct
blurriness or to smooth out imperfections. A Sharpen( )
filter, for example, can be
applied to an image after it is resized to clean up some of the
blurring effects of resampling. Some of the methods described in this
section, such as OilPaint( )
,
Whirl( )
, or Implode( )
, can also be used to add special
effects to an image.
The Convolve( )
method is an
all-purpose filter; many of the other filters utilize the Convolve( )
routine with built-in presets.
If you know what a convolution kernel is, you may want to experiment
with your own filters (or add to the built-in ones) with this
function.
The Mogrify( )
method is also
interesting. It acts as an alternative interface to the API, where you
can specify filter or other method names with a text string. The
MogrifyRegion( )
method lets you
apply a filter or effect to a limited area of the image.
The two attributes in Table 3-8 may be read or set for use with certain filter methods.
Attribute | Read | Write | Description |
| Yes | Yes | The fuzz distance is
used by ImageMagick functions that operate on all pixels of a
certain color (e.g., the |
| Yes | Yes | The |
The following filters and special effects ...
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