THPDFImageRecompressionCostInfo Record

Telemetry of a visual-cost image recompression pass: scanned and candidate counts, per-codec outcomes, trial and rejection counters, quality and error aggregates and byte savings

Declaration

THPDFImageRecompressionCostInfo= record
  ScannedImageCount: Integer;
  CandidateImageCount: Integer;
  RecompressedImageCount: Integer;
  RecompressedJPEGCount: Integer;
  RecompressedJPEG2000Count: Integer;
  EncodingTrialCount: Integer;
  VisualErrorRejectionCount: Integer;
  ByteCostRejectionCount: Integer;
  SelectedQualitySum: Integer;
  MaximumSelectedPerceptualError: Double;
  BytesBefore: Int64;
  BytesAfter: Int64;
  BytesSaved: Int64;
  DeterministicSelection: boolean;
end;

Unit

HPDFDoc

Fields

Field	Purpose
`ScannedImageCount`	Images inspected by the pass
`CandidateImageCount`	Images that entered the quality search once eligibility checks had passed
`RecompressedImageCount`	Images that were actually re-encoded and written back
`RecompressedJPEGCount`	Re-encoded images whose final filter is JPEG
`RecompressedJPEG2000Count`	Re-encoded images whose final filter is JPEG 2000
`EncodingTrialCount`	Trial encodings performed whilst sweeping the quality range
`VisualErrorRejectionCount`	Trials rejected because the perceptual error went over the budget
`ByteCostRejectionCount`	Trials rejected because the byte-cost weight swamped the score
`SelectedQualitySum`	Sum of the qualities chosen per recompressed image, for averaging
`MaximumSelectedPerceptualError`	Highest perceptual error across the accepted recompressions
`BytesBefore` / `BytesAfter`	Image stream bytes taken before and after the pass
`BytesSaved`	Byte difference achieved; compare against the options' minimum-savings threshold
`DeterministicSelection`	`true` when every reported choice arose from the deterministic cost comparison

Usage notes

Filled by THotPDF.OptimizeLoadedImagesByVisualCost; the function result is the number of images recompressed and the record carries the complete accounting
Divide SelectedQualitySum by RecompressedImageCount to obtain the average chosen quality
Read BytesBefore, BytesAfter and BytesSaved after the call to confirm the pass met the configured savings goal

THPDFImageRecompressionCostInfo Record

Declaration

Unit

Fields

Usage notes

Related APIs