ImageGear v26.5 - Updated
ImageGear.Core Assembly / ImageGear.Processing Namespace / ImGearProcessing Class / CreateThumbnail Method
Source image from which the thumbnail is created.
Width of the thumbnail.
Height of the thumbnail.
Interpolation options.
Example




In This Topic
    CreateThumbnail Method
    In This Topic
    Creates a thumbnail image according to the specified dimensions.
    Syntax
    'Declaration
     
    Public Shared Function CreateThumbnail( _
       ByVal page As ImGearPage, _
       ByVal width As Integer, _
       ByVal height As Integer, _
       ByVal options As ImGearInterpolationOptions _
    ) As ImGearPage
    'Usage
     
    Dim page As ImGearPage
    Dim width As Integer
    Dim height As Integer
    Dim options As ImGearInterpolationOptions
    Dim value As ImGearPage
     
    value = ImGearProcessing.CreateThumbnail(page, width, height, options)
    public static ImGearPage CreateThumbnail( 
       ImGearPage page,
       int width,
       int height,
       ImGearInterpolationOptions options
    )
    public: static ImGearPage* CreateThumbnail( 
       ImGearPage* page,
       int width,
       int height,
       ImGearInterpolationOptions* options
    ) 
    public:
    static ImGearPage^ CreateThumbnail( 
       ImGearPage^ page,
       int width,
       int height,
       ImGearInterpolationOptions^ options
    ) 

    Parameters

    page
    Source image from which the thumbnail is created.
    width
    Width of the thumbnail.
    height
    Height of the thumbnail.
    options
    Interpolation options.

    Return Value

    New thumbnail image.
    Remarks
    This method processes all channels of the image.

    Interpolation options depend on the color space and bit depth of the image. Grayscale, PreserveBlack and PreserveWhite interpolations are applicable only to 1 bit images.

    Average and Bilinear interpolations are not applicable to 1 bit images nor to images having a non-gray palette. Also, Bilinear interpolation cannot be applied to the images if one of the dimensions is decreased.

    Use ImGearProcessingVerifier.CanApplyCreateThumbnail method to check whether the operation can be performed.

    Example
    // Creates a thumbnail 100 pixels wide maintaining aspect ratio.
    
    // Determine appropriate height.
    int newHeight = 100 * igPage.DIB.Height / igPage.DIB.Width;
    
    // Set default interpolation to none.
    ImGearInterpolations igInterpolations = ImGearInterpolations.NONE;
    
    // If the image is 1-bit and larger than 100x100, use grayscale interpolation.
    if (igPage is ImGearRasterPage &&
        1 == igPage.DIB.BitDepth &&
        igPage.DIB.Width >= 100 &&
        igPage.DIB.Height >= 100)
    {
        igInterpolations = ImGearInterpolations.GRAYSCALE;
    }
    
    // Create the thumbnail using the default options for the chosen interpolation.
    ImGearPage igPageThumbnail = ImGearProcessing.CreateThumbnail(igPage, 100, newHeight,
        ImGearInterpolationOptions.GetDefault(igInterpolations));
    ' Creates a thumbnail 100 pixels wide maintaining aspect ratio.
    
    ' Determine appropriate height.
    Dim newHeight As Integer = 100 * igPage.DIB.Height / igPage.DIB.Width
    
    ' Set default interpolation to none.
    Dim igInterpolations As ImGearInterpolations = ImGearInterpolations.NONE
    
    ' If the image is 1-bit and larger than 100x100, use grayscale interpolation.
    If TypeOf igPage Is ImGearRasterPage AndAlso 1 = igPage.DIB.BitDepth AndAlso _
     igPage.DIB.Width >= 100 AndAlso igPage.DIB.Height >= 100 Then
        igInterpolations = ImGearInterpolations.GRAYSCALE
    End If
    
    ' Create the thumbnail using the default options for the chosen interpolation.
    Dim igPageThumbnail As ImGearPage
    igPageThumbnail = ImGearProcessing.CreateThumbnail(igPage, 100, newHeight, _
     ImGearInterpolationOptions.GetDefault(igInterpolations))
    See Also