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