ImageGear for .NET
RemoveChannel Method
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ImageGear21.Core Assembly > ImageGear.Processing Namespace > ImGearRasterProcessing Class : RemoveChannel Method




page
Page to remove channel.
channelNumber
Position of the channel to be removed.

Glossary Item Box

Removes the specified channel from the page's DIB and shifts remaining channels without transforming pixel data.

Syntax

 
Visual Basic
C#
Managed Extensions for C++
C++/CLI
 
 

Parameters

page
Page to remove channel.
channelNumber
Position of the channel to be removed.

Remarks

channelNumber can be within the [0..ChannelCount-1] range.

Color Space is changed as follows:

  • If page has more than one Extra channel, color space is unchanged.
  • If page has one Extra channel, ExtraMask is cleared.
  • If page has Alpha channel and no Extra channels, AlphaMask and PremultAlphaMask are cleared.
  • If page has only color channels, color space is changed to Unknown, and all remaining channels are considered Extra channels.

Example

C#Copy Code
// Separate image into separate images for each channel.
ImGearChannelRef[] igChannelRef = ImGearRasterProcessing.SeparateChannels(igRasterPage);
// Remove the alpha channel from an RGBA image.
ImGearRasterProcessing.RemoveChannel(igRasterPage, 3);
// Save the page out without the alpha channel.
using (FileStream localFile = new FileStream("withoutalpha.jpg", FileMode.Create))
{
    ImGearFileFormats.SavePage(igRasterPage,localFile, 0, ImGearSavingModes.OVERWRITE, ImGearSavingFormats.JPG);
}
//Set the colorspace to RGBA again.
ImGearRasterProcessing.ConvertColorSpace(
    igRasterPage, new ImGearColorSpace(ImGearColorSpaceIDs.RGBA));
// Add the alpha channel back to the image.
ImGearRasterProcessing.InsertChannel(igRasterPage, 3, igChannelRef[3]);
// Remove the alpha channel added by the colorspace conversion.
ImGearRasterProcessing.RemoveChannel(igRasterPage, 4);
Visual BasicCopy Code
' Separate image into separate images for each channel.
Dim igChannelRef As ImGearChannelRef() = ImGearRasterProcessing.SeparateChannels(igRasterPage)
' Remove the alpha channel from an RGBA image.
ImGearRasterProcessing.RemoveChannel(igRasterPage, 3)
' Save the page out without the alpha channel.
Using localFile As New FileStream("withoutalpha.jpg", FileMode.Create)
    ImGearFileFormats.SavePage(igRasterPage, localFile, 0, ImGearSavingModes.OVERWRITE, ImGearSavingFormats.JPG)
End Using
'Set the colorspace to RGBA again.
ImGearRasterProcessing.ConvertColorSpace(igRasterPage, New ImGearColorSpace(ImGearColorSpaceIDs.RGBA))
' Add the alpha channel back to the image.
ImGearRasterProcessing.InsertChannel(igRasterPage, 3, igChannelRef(3))
' Remove the alpha channel added by the colorspace conversion.
ImGearRasterProcessing.RemoveChannel(igRasterPage, 4)

See Also

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