Click or drag to resize

PdfPredictorFunction Enumeration

Represents a predictor function that can be applied to PdfLZWDecodeFilter or PdfFlateDecodeFilter data to make the encoded data more compact.

Namespace:  GemBox.Pdf.Filters
Assembly:  GemBox.Pdf (in GemBox.Pdf.dll) Version:
public enum PdfPredictorFunction
  Member nameValueDescription
Unknown0 Prediction algorithm is unknown.
None1 No prediction (the default value).
TIFF22 TIFF Predictor 2.
PNGNoneOnAllRows10 PNG prediction (on encoding, PNG None on all rows).
PNGSubOnAllRows11 PNG prediction (on encoding, PNG Sub on all rows).
PNGUpOnAllRows12 PNG prediction (on encoding, PNG Up on all rows).
PNGAverageOnAllRows13 PNG prediction (on encoding, PNG Average on all rows).
PNGPaethOnAllRows14 PNG prediction (on encoding, PNG Paeth on all rows).
PNGOptimum15 PNG prediction (on encoding, PNG optimum).
PdfLZWDecodeFilter and PdfFlateDecodeFilter encoding compress more compactly if their input data is highly predictable. One way of increasing the predictability of many continuous-tone sampled images is to replace each sample with the difference between that sample and a PdfPredictorFunction applied to earlier neighboring samples. If the PdfPredictorFunction works well, the postprediction data clusters toward 0.
See Also