Table of Contents

Class FormatConverter

Namespace
SharpDX.WIC
Assembly
SharpDX.Direct2D1.dll
[Guid("00000301-a8f2-4877-ba0a-fd2b6645fb94")]
public class FormatConverter : BitmapSource
Inheritance
FormatConverter
Inherited Members

Constructors

FormatConverter(FormatConverterInfo)

Initializes a new instance of the FormatConverter class.

public FormatConverter(FormatConverterInfo converterInfo)

Parameters

converterInfo FormatConverterInfo

The converter info.

FormatConverter(ImagingFactory)

Initializes a new instance of the FormatConverter class.

public FormatConverter(ImagingFactory factory)

Parameters

factory ImagingFactory

The factory.

FormatConverter(nint) 

public FormatConverter(nint nativePtr)

Parameters

nativePtr nint

Methods

CanConvert(Guid, Guid)

Determines if the source pixel format can be converted to the destination pixel format.

public RawBool CanConvert(Guid srcPixelFormat, Guid dstPixelFormat)

Parameters

srcPixelFormat Guid

The source pixel format.

dstPixelFormat Guid

The destionation pixel format.

Returns

RawBool

A reference that receives a value indicating whether the source pixel format can be converted to the destination pixel format.

Initialize(BitmapSource, Guid)

Initializes this instance with the specified bitmap source and format

public void Initialize(BitmapSource sourceRef, Guid dstFormat)

Parameters

sourceRef BitmapSource

The source ref.

dstFormat Guid

The destination format.

Initialize(BitmapSource, Guid, BitmapDitherType, Palette, double, BitmapPaletteType)

Initializes the format converter.

public void Initialize(BitmapSource sourceRef, Guid dstFormat, BitmapDitherType dither, Palette paletteRef, double alphaThresholdPercent, BitmapPaletteType paletteTranslate)

Parameters

sourceRef BitmapSource

The input bitmap to convert

dstFormat Guid

The destination pixel format Guid.

dither BitmapDitherType

The BitmapDitherType used for conversion.

paletteRef Palette

The palette to use for conversion.

alphaThresholdPercent double

The alpha threshold to use for conversion.

paletteTranslate BitmapPaletteType

The palette translation type to use for conversion.

Remarks

If you do not have a predefined palette, you must first create one. Use InitializeFromBitmap to create the palette object, then pass it in along with your other parameters.

dither, pIPalette, alphaThresholdPercent, and paletteTranslate are used to mitigate color loss when converting to a reduced bit-depth format. For conversions that do not need these settings, the following parameters values should be used: dither set to WICBitmapDitherTypeNone, pIPalette set to null, alphaThresholdPercent set to 0.0f, and paletteTranslate set to WICBitmapPaletteTypeCustom.

The basic algorithm involved when using an ordered dither requires a fixed palette, found in the BitmapPaletteType enumeration, in a specific order. Often, the actual palette provided for the output may have a different ordering or some slight variation in the actual colors. This is the case when using the Microsoft?Windows palette which has slight differences among versions of Windows. To provide for this, a palette and a palette translation are given to the format converter. The pIPalette is the actual destination palette to be used and the paletteTranslate is a fixed palette. Once the conversion is complete, the colors are mapped from the fixed palette to the actual colors in pIPalette using a nearest color matching algorithm.

If colors in pIPalette do not closely match those in paletteTranslate, the mapping may produce undesireable results.

WICBitmapDitherTypeOrdered4x4 can be useful in format conversions from 8-bit formats to 5- or 6-bit formats as there is no way to accurately convert color data.

WICBitmapDitherTypeErrorDiffusion selects the error diffusion algorithm and may be used with any palette. If an arbitrary palette is provided, WICBitmapPaletteCustom should be passed in as the paletteTranslate. Error diffusion often provides superior results compared to the ordered dithering algorithms especially when combined with the optimized palette generation functionality on the Palette.

When converting a bitmap which has an alpha channel, such as a Portable Network Graphics (PNG), to 8bpp, the alpha channel is normally ignored. Any pixels which were transparent in the original bitmap show up as black in the final output because both transparent and black have pixel values of zero in the respective formats.

Some 8bpp content can contains an alpha color; for instance, the Graphics Interchange Format (GIF) format allows for a single palette entry to be used as a transparent color. For this type of content, alphaThresholdPercent specifies what percentage of transparency should map to the transparent color. Because the alpha value is directly proportional to the opacity (not transparency) of a pixel, the alphaThresholdPercent indicates what level of opacity is mapped to the fully transparent color. For instance, 9.8% implies that any pixel with an alpha value of less than 25 will be mapped to the transparent color. A value of 100% maps all pixels which are not fully opaque to the transparent color. Note that the palette should provide a transparent color. If it does not, the 'transparent' color will be the one closest to zero - often black.

Operators

explicit operator FormatConverter(nint) 

public static explicit operator FormatConverter(nint nativePtr)

Parameters

nativePtr nint

Returns

FormatConverter