2.1.1.11 FilterType Enumeration

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The FilterType enumeration defines types of filtering algorithms that can be used for text and graphics quality enhancement and image rendering.

 typedef  enum 
 {
   FilterTypeNone = 0x00,
   FilterTypePoint = 0x01,
   FilterTypeLinear = 0x02,
   FilterTypeTriangle = 0x03,
   FilterTypeBox = 0x04,
   FilterTypePyramidalQuad = 0x06,
   FilterTypeGaussianQuad = 0x07
 } FilterType;

FilterTypeNone:  Filtering is not performed.

FilterTypePoint:  Each destination pixel is computed by sampling the nearest pixel from the source image.

FilterTypeLinear:  Linear interpolation is performed using the weighted average of a 2x2 area of pixels surrounding the source pixel.

FilterTypeTriangle:  Each pixel in the source image contributes equally to the destination image. This is the slowest of filtering algorithms.

FilterTypeBox:  A box filter algorithm is used, in which each destination pixel is computed by averaging a rectangle of source pixels. This algorithm is useful only when reducing the size of an image.

FilterTypePyramidalQuad:  A 4-sample tent filter is used.

FilterTypeGaussianQuad:  A 4-sample Gaussian filter is used, which creates a blur effect on an image.

See section 2.1.1 for the specification of additional enumerations.