How can I adjust image sharpness/aliasing when rendering a PDF using PDFDraw?

Q: I need to add sharpness to my image while extracting from PDF using
PDFDraw. How can i achieve this?
A: If you are using built-in rasterizer you can improve the quality of
anti-aliased image output and can (to some extent) decrease the
appearance common anti-aliasing artifacts (such as pixel width lines
between polygons) using PDFDraw.SetGamma(factor) method. Typical
values for gamma factor are in the range from 0.1 to 3. The optimal
results may require some manual tweaking since the optimal paramater
is somewhat subjective.

Another way to decrease the appearance of some aliasing effects is to
render a PDF at a higher resolution and then down-sample/resample the

Q: Thank you very much for that response and help… the problem with
higher resolution and downsample is that the text gets blurry…
that’s what we are trying to get away with… when we resample high
go down to say 960 pixels wide… the text is blurrier than if we
convert from pdf to image with a dimension of 960 wide… your

A: It really depends on the re-sampling algorithm and the size of the
original image. If you are using a high-quality algorithm (e.g. bi-
cubic sampling or better) and the input image is ‘say’ 4 times larger
(in width & height) than then target image you should get fairly good