Syntax
Visual Basic
C#
Managed Extensions for C++
C++/CLI
Members
| Member | Value | Description |
|---|---|---|
| Decim_1x1_1x1_1x1 | 0 | For each Y sample, one Cb sample and one Cr sample are stored. |
| Decim_1x2_1x1_1x1 | 2 | For each vertical pair of Y samples, one Cb sample and one Cr sample are stored. |
| Decim_1x4_1x1_1x1 | 8 | For each four vertical Y samples, one Cb sample and one Cr sample are stored. |
| Decim_1x4_1x2_1x2 | 10 | For each four vertical Y samples, two vertical Cb samples and two vertical Cr samples are stored. |
| Decim_2x1_1x1_1x1 | 1 | For each horizontal pair of Y samples, one Cb sample and one Cr sample are stored. |
| Decim_2x2_1x1_1x1 | 3 | For each four (two horizontal by two vertical) Y samples, one Cb sample and one Cr sample are stored. |
| Decim_2x2_2x1_2x1 | 4 | For each four (two horizontal by two vertical) Y samples, two horizontal Cb samples and two horizontal Cr samples are stored. |
| Decim_2x4_1x1_1x1 | 6 | For each eight (two horizontal by four vertical) Y samples, one Cb sample and one Cr sample are stored. |
| Decim_4x1_1x1_1x1 | 7 | For each four horizontal Y samples, one Cb sample and one Cr sample are stored. |
| Decim_4x1_2x1_2x1 | 9 | For each four horizontal Y samples, two horizontal Cb samples and two horizontal Cr samples are stored. |
| Decim_4x2_1x1_1x1 | 5 | For each eight (four horizontal by two vertical) Y samples, one Cb sample and one Cr sample are stored. |
| Decim_4x4_2x2_2x2 | 11 | For each 16 (four horizontal by four vertical) Y samples, four (two horizontal by two vertical) Cb samples and four (two horizontal by two vertical) Cr samples are stored. |
Remarks
The format of these ImageGear decimation constants is: Decim_(H1)x(V1)_(H2)x(V2)_(H3)x(V3),
where Hi, Vi = horizontal and vertical decimation values for the i-channel.
The following is a simple example of decimation. For a more detailed definition, please see the JPEG Specification.
A decimation setting of Decim_4x2_1x1_1x1 would yield the following results:
As shown, 8 Y components in the source image have yielded one Cb and one Cr component. In general, this setting will reduce the quality of the compression, unless the image has many continuous tone areas.
Maximum quality can be reached using a value of Decim_1x1_1x1_1x1.
Maximum compression ratio can be reached with a value of Decim_4x4_2x2_2x2.
The ImageGear default decimation value is: Decim_2x2_1x1_1x1.
Inheritance Hierarchy
System.Object
System.ValueType
System.Enum
ImageGear.Formats.JPG.ImGearDecimationTypes
