GdPicture image identifier.
Output parameter. Array of 256 entries containing the red channel histogram data.
Example





In This Topic
GdPicture14 Namespace / GdPictureImaging Class / HistogramGetRed Method

HistogramGetRed Method (GdPictureImaging)

In This Topic
Computes the red channel histogram of a GdPicture image.
Syntax
'Declaration

 


Public Function HistogramGetRed( _

   ByVal ImageID As Integer, _

   ByRef Data() As Integer _

) As GdPictureStatus
public GdPictureStatus HistogramGetRed( 

   int ImageID,

   ref int[] Data

)
public function HistogramGetRed( 

    ImageID: Integer;

   var  Data: Integerarray of

): GdPictureStatus; 
public function HistogramGetRed( 

   ImageID : int,

   Data : int[]

) : GdPictureStatus;
public: GdPictureStatus HistogramGetRed( 

   int ImageID,

   ref int[]* Data

) 
public:

GdPictureStatus HistogramGetRed( 

   int ImageID,

   array<int>^% Data

)

Parameters

ImageID
GdPicture image identifier.
Data
Output parameter. Array of 256 entries containing the red channel histogram data.

Return Value

A member of the GdPictureStatus enumeration.
Example
Getting the red channel histogram of a jpeg image and creating an image representing this histogram. 
using (GdPictureImaging gdpictureImaging = new GdPictureImaging())

{

    int imageID = gdpictureImaging.CreateGdPictureImageFromFile("image.jpg", false);

 

    // Get the red channel histogram and the image dimensions.

    int[] histo = new int[256];

    gdpictureImaging.HistogramGetRed(imageID, ref histo);

    int count = gdpictureImaging.GetWidth(imageID) * gdpictureImaging.GetHeight(imageID);

 

    gdpictureImaging.ReleaseGdPictureImage(imageID);

 

    // Create an image representing the histogram. 

    // The image has the same width as the histogram and its height is 1000.                

    int histogramID = gdpictureImaging.CreateNewGdPictureImage(256, 1000, 24, Color.White);

    for (int i = 0; i < 256; i++)

    {

        int value = histo[i] * 1000 / count;

        for (int j = 0; j < value; j++)

        {

            gdpictureImaging.PixelSetColor(histogramID, i, j, Color.Red);

        }

    }

 

    gdpictureImaging.SaveAsPNG(histogramID, "histo.png");

    gdpictureImaging.ReleaseGdPictureImage(histogramID);

}
See Also

Reference

GdPictureImaging Class
GdPictureImaging Members