Enum JpegXRAlphaDataDiscardOption

Namespace

PaintDotNet.Imaging

Assembly

PaintDotNet.Windows.dll

Sets the amount of alpha frequency data to discard during a compressed domain transcode.

public enum JpegXRAlphaDataDiscardOption

Fields

None = 0

No image frequency data is discarded.

FlexBits = 1

The FlexBits are discarded, making an arbitrary reduction of the quality of the planar alpha channel for the transcoded image without changing the effective resolution. The exact file size reduction or the specific quality reduction depends on numerous factors and cannot be specified or predicted.

HighPass = 2

The HighPass frequency data band is discarded (which also includes the FlexBits), effectively reducing the resolution of the transcoded image planar alpha channel by a factor of 4 in both dimensions. The actual dimensions of the transcoded image remain the same, but the image loses all planar alpha channel detail in each 4x4 block of pixels. Therefore, the transcoded image should be down-sampled accordingly whenever it is decoded. Typically, you should set this value only when you set the ImageDataDiscard propertyto the same value.

HighPassAndFlexBits = 3

Both the HighPass and LowPass frequency data bands are discarded (which also includes the FlexBits), effectively reducing the resolution of the transcoded image by a factor of 16 in both dimensions. The actual dimensions of the transcoded image remain the same, but the image loses all detail in each 16x16 macroblock of pixels. Therefore, the transcoded image should be down-sampled accordingly whenever it is decoded. Typically, you should set this value only when you set the ImageDataDiscard property to the same value.

All = 4

The Alpha channel is completely discarded. The pixel format of the transcoded image is changed to reflect the removal of the alpha channel.