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CreateAlphaImage Method

Summary

Creates a grayscale image from this RasterImage alpha channel data.

Syntax

Java

Objective-C

WinRT C#

C++

public RasterImage CreateAlphaImage()

Public Function CreateAlphaImage() As Leadtools.RasterImage

public Leadtools.RasterImage CreateAlphaImage()

- (nullable LTRasterImage *)createAlphaImage:(NSError **)error

public RasterImage createAlphaImage()

 function Leadtools.RasterImage.CreateAlphaImage()

public: 
Leadtools.RasterImage^ CreateAlphaImage();

Return Value

The newly create image, which contains the source image alpha channel data.

Remarks

Only 16-bit, 32-bit, and 64-bit images can have an alpha channel. If the source image has another color resolution, the result is an image filled with zeros.

Typically, the alpha channel contains a mask that is used for transparency.

For more information, refer to Implementing Transparency.

For more information, refer to Grayscale Images.

For more information, refer to Saving A Region.

Example

Silverlight C#

Silverlight VB

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Dicom; 
using Leadtools.Drawing; 
using Leadtools.Controls; 
using LeadtoolsExamples.Common; 
using Leadtools.Svg; 
 
public void CreateAlphaImageExample() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
   // Load the image, at 16 bit per pixel. 
   RasterImage image = codecs.Load(Path.Combine(ImagesPath.Path, "IMAGE1.CMP"), 16, CodecsLoadByteOrder.Bgr, 1, 1); 
 
   // Specify a rectangle to define the region. 
   LeadRect ellipseRectangle = new LeadRect(image.Width / 8, image.Height / 8, image.Width / 2, image.Height / 2); 
 
   // Create an elliptical region in the AlphaImage. 
   image.AddEllipseToRegion(null, ellipseRectangle, RasterRegionCombineMode.Set); 
 
   // Create a mask image from the region. 
   RasterImage alphaImage = image.CreateMaskFromRegion(); 
 
   // Update the alpha channel in the main image. 
   image.SetAlphaImage(alphaImage); 
 
   // Save the image at 16 bits per pixel to keep the alpha channel. 
   codecs.Save(image, Path.Combine(ImagesPath.Path, "TestAlpha.TIF"), RasterImageFormat.Tif, 24, 1, 1, 1, CodecsSavePageMode.Overwrite); 
 
   // Load the bitmap that we just saved and get its alpha channel. 
   image = codecs.Load(Path.Combine(ImagesPath.Path, "TestAlpha.TIF"), 16, CodecsLoadByteOrder.Bgr, 1, 1); 
 
   alphaImage = image.CreateAlphaImage(); 
 
   // Use the AlphaBitmap as a mask to set the region in the MainBitmap. 
   image.AddMaskToRegion(null, alphaImage, RasterRegionCombineMode.Set); 
 
   image.Dispose(); 
   codecs.Dispose(); 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Controls 
Imports Leadtools.Dicom 
Imports Leadtools.Drawing 
Imports Leadtools.Svg 
 
Public Sub CreateAlphaImageExample() 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   ' Load the image, at 16 bit per pixel. 
   Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"), 16, CodecsLoadByteOrder.Bgr, 1, 1) 
 
   ' Specify a rectangle to define the region. 
   Dim EllipseRectangle As LeadRect = New LeadRect(image.Width \ 8, image.Height \ 8, image.Width \ 2, image.Height \ 2) 
 
   ' Create an elliptical region in the AlphaImage. 
   image.AddEllipseToRegion(Nothing, EllipseRectangle, RasterRegionCombineMode.Set) 
 
   ' Create a mask image from the region. 
   Dim alphaImage As RasterImage = image.CreateMaskFromRegion() 
 
   ' Update the alpha channel in the main image. 
   image.SetAlphaImage(alphaImage) 
 
   ' Save the image at 16 bits per pixel to keep the alpha channel. 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "TestAlpha.TIF"), RasterImageFormat.Tif, 24, 1, 1, 1, CodecsSavePageMode.Overwrite) 
 
   ' Load the bitmap that we just saved and get its alpha channel. 
   image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "TestAlpha.TIF"), 16, CodecsLoadByteOrder.Bgr, 1, 1) 
 
   alphaImage = image.CreateAlphaImage() 
 
   ' Use the AlphaBitmap as a mask to set the region in the MainBitmap. 
   image.AddMaskToRegion(Nothing, alphaImage, RasterRegionCombineMode.Set) 
 
   image.Dispose() 
   codecs.Dispose() 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Dicom; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Examples; 
using Leadtools.Windows.Media; 
 
public void CreateAlphaImageExample(RasterImage image, Stream destStream) 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   // Specify a rectangle to define the region. 
   LeadRect EllipseRectangle = new LeadRect(image.Width / 8, image.Height / 8, image.Width / 2, image.Height / 2); 
 
   // Create a region in the AlphaImage. 
   image.AddRectangleToRegion(null, EllipseRectangle, RasterRegionCombineMode.Set); 
 
   // Create a mask image from the region. 
   RasterImage alphaImage = image.CreateMaskFromRegion(); 
 
   // Update the alpha channel in the main image. 
   image.SetAlphaImage(alphaImage); 
 
   // Save the image at 16 bits per pixel to keep the alpha channel. 
   codecs.Save(image, destStream, RasterImageFormat.Tif, 24, 1, 1, 1, CodecsSavePageMode.Overwrite); 
 
   // Load the bitmap that we just saved and get its alpha channel. 
   image = codecs.Load(destStream, 16, CodecsLoadByteOrder.Bgr, 1, 1); 
 
   alphaImage = image.CreateAlphaImage(); 
 
   // Use the AlphaBitmap as a mask to set the region in the MainBitmap. 
   image.AddMaskToRegion(null, alphaImage, RasterRegionCombineMode.Set); 
 
   image.Dispose(); 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Dicom 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Windows.Media 
 
Public Sub CreateAlphaImageExample(ByVal image As RasterImage, ByVal destStream As Stream) 
   Dim codecs As RasterCodecs = New RasterCodecs() 
 
   ' Specify a rectangle to define the region. 
   Dim EllipseRectangle As LeadRect = New LeadRect(image.Width / 8, image.Height / 8, image.Width / 2, image.Height / 2) 
 
   ' Create a region in the AlphaImage. 
   image.AddRectangleToRegion(Nothing, EllipseRectangle, RasterRegionCombineMode.Set) 
 
   ' Create a mask image from the region. 
   Dim alphaImage As RasterImage = image.CreateMaskFromRegion() 
 
   ' Update the alpha channel in the main image. 
   image.SetAlphaImage(alphaImage) 
 
   ' Save the image at 16 bits per pixel to keep the alpha channel. 
   codecs.Save(image, destStream, RasterImageFormat.Tif, 24, 1, 1, 1, CodecsSavePageMode.Overwrite) 
 
   ' Load the bitmap that we just saved and get its alpha channel. 
   image = codecs.Load(destStream, 16, CodecsLoadByteOrder.Bgr, 1, 1) 
 
   alphaImage = image.CreateAlphaImage() 
 
   ' Use the AlphaBitmap as a mask to set the region in the MainBitmap. 
   image.AddMaskToRegion(Nothing, alphaImage, RasterRegionCombineMode.Set) 
 
   image.Dispose() 
End Sub

Requirements

Target Platforms

Reference

RasterImage Class

RasterImage Members

Help Version 19.0.2017.10.27