Declaration
property ImageQuality: Double;
Description
Specifies the quality to use when saving an
HDP,
HEIF or
WebP file via
WIC or
ImageMagick (and
LibWebP for WebP).
The range is 0.0 to 1.0, where 0.0 produces the lowest possible quality, and 1.0 produces the highest quality.
It also provides generic access to the quality settings for other formats. Seeing ImageQuality will also set:
◼JPEG_Quality
◼DICOM_JPEGQuality
◼TIFF_JPEGQuality
It will also apply to:
◼IEN: When
IEN_Compression is ioJPEG
◼PDF: When
PDF_Compression is ioPDF_JPEG
◼SVG: When
SVG_ImageCompression is ioJPEG
It does
NOT set:
◼PNG_Compression
◼DICOM_J2000Rate
◼J2000_Rate
Note:
◼To set lossless compression (HDP and WebP), enable
Lossless
◼See JPEG Quality comparisons at:
JPEG_Quality
Default: 0.8 (Specified by
IOParamDefaults().JPEG_Quality / 100)
ImageEnView1.IO.Params.ImageQuality := 0.7;
ImageEnView1.IO.SaveToFile( 'D:\image.hdp' );
Heif Size Comparisons
ImageEnView1.IO.LoadFromFile( 'D:\Alpha.png' ); // Original PNG - 335KB

ImageEnView1.IO.Params.ImageQuality := 1.0;
ImageEnView1.IO.SaveToFile( 'D:\image100.Heif' ); // 85KB

ImageEnView1.IO.Params.ImageQuality := 0.9;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image90.Heif' ); // 68KB

ImageEnView1.IO.Params.ImageQuality := 0.7;
ImageEnView1.IO.SaveToFile( 'D:\image70.Heif' ); // 40KB

ImageEnView1.IO.Params.ImageQuality := 0.5;
ImageEnView1.IO.SaveToFile( 'D:\image50.Heif' ); // 21KB

ImageEnView1.IO.Params.ImageQuality := 0.2;
ImageEnView1.IO.SaveToFile( 'D:\image20.Heif' ); // 7KB

ImageEnView1.IO.Params.ImageQuality := 0.01;
ImageEnView1.IO.SaveToFile( 'D:\image01.Heif' ); // 3KB

WebP Size Comparisons
ImageEnView1.IO.LoadFromFile( 'D:\Alpha.png' ); // Original PNG - 335KB

ImageEnView1.IO.Params.Lossless := True;
ImageEnView1.IO.SaveToFile( 'D:\imageLossless.WebP' ); // 143KB (Lossless)

ImageEnView1.IO.Params.ImageQuality := 1.0;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image100.WebP' ); // 62KB

ImageEnView1.IO.Params.ImageQuality := 0.9;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image90.WebP' ); // 38KB

ImageEnView1.IO.Params.ImageQuality := 0.7;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image70.WebP' ); // 26KB

ImageEnView1.IO.Params.ImageQuality := 0.5;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image50.WebP' ); // 23KB

ImageEnView1.IO.Params.ImageQuality := 0.2;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image20.WebP' ); // 20KB

ImageEnView1.IO.Params.ImageQuality := 0.01;
ImageEnView1.IO.Params.Lossless := False;
ImageEnView1.IO.SaveToFile( 'D:\image01.WebP' ); // 17KB

See Also
◼Lossless