Img32.Resamplers

Resampling is used whenever an image's geometry (size or shape) is changed, whether by scaling, rotating, skewing or any other transformation. There are multiple resampling functions because each has its strengths and weaknesses.

The library supplies four resampling functions which can be selected using a unique numeric identifier:

rNearestResampler: "nearest neighbour" is very fast but sacrifices quality.
rBilinearResampler: "bilinear" is average speed and produces very good quality images
rBicubicResampler: "bicubic" is relatively slow but produces excellent quality images.
rWeightedBilinear: "weighted bilinear" is just as fast as bilinear while a little less blurry, but also with slightly more pixelation.

Additional resamplers can be added using the RegisterResampler function. (The resampling function's unique identifier will be assigned when it's registered.)

When a TImage32 object is created, it's assigned the DefaultResampler (rBilinearResampler), which will be used if or when the image's geometry is changed. The TImage32's resampling function can easily be changed through its Resampler property.

From resampling example ...

starting with this image

scaling and rotating produces

rNearestResampler Fast but also pixelated 0.98 msec	rBilinearResampler Moderately blurred 5.01 msec
rWeightedBilinear Mildly pixelated and mildly blurred 5.38 msec	rBicubicResampler Clearest image but slowest 15.5 msec

Routines

BoxDownSampling

Img32.Resamplers

Contents

See Also