YCCLevelVariant (ImageKit Control/ Effect Method)

This method increases (or decreases) the YCrCb values of a raster image. This method is recommended when using scripting languages and other programs that require variant types

[Visual Basic] [ Boolean = ]imagekitcontrolname.Effect.YCCLevelVariant(x As Long, y As Long, Points As Long, Yb As Long, Cr As Long, Cb As Long)

Parameters

Name	Explanation
x	An array of x coordinate values defining points of a polygonal area on the image. (in pixels) *
y	An array of y coordinate values defining points of a polygonal area on the image. (in pixels) *
Yb	Sets the shift in the Y component (luminance) of the YCrCb value (from-255 to 255)
Cr	Sets the shift in the Cr component (chrominance) of the YCrCb value (from-255 to 255)
Cb	Sets the shift in the Cb component (chrominance) of the YCrCb value (from-255 to 255)
* The arguments are returned in the first elements of the arrays x and y

Return Value

Returns True (nonzero) if successful, otherwise returns False (0).

Explanation

The YCCLevelVariant method increases or decreases the YCrCb values in a raster image. Y represents luminance, Cr and Cb represent chrominance. As the values of the Yb, Cr, or Cb parameters increase, the image becomes brighter. As those values decrease, the image becomes darker. If the Yb, Cr, or Cb parameters are 0, the image is not altered.

To execute the YCCLevelVariant method, set the image handle of the image in the ImageHandle property or the Layer(LayerNo).ImageHandle property. The YCCLevelVariant method supports 1, 4, 8, 16, 24, and 32 bit images.

Before executing the YCCLevelVariant method, you must set the area on the image that will be affected. There are 4 ways to do this.

To use a mask image, set the SelectMode property to 0. Set the mask image handle in the MaskImageHandle property
To process the total image, set the SelectMode property to 1
To process the polygonal area on the image, set the SelectMode property to 2. Select the polygon by setting the appropriate coordinate values for the points of the polygon in two arrays, one array for the x coordinate values and one array for the y coordinate values. The pass these arrays to the x and y arguments of the YCCLevelVariant method. The number of points defining the polygon must be 3 or more
To process an elliptical area on the image, set the SelectMode property to 3. Select the ellipse by setting the appropriate values for the bounding rectangle in the RectLeft, RectTop, RectRight, and RectBottom properties

When the SelectMode property is set to values other than 2 (ikEffectPolygon), please set dummy arrays in the x and y parameters.
When the SelectMode property is set to 2 or 3, the appropriate value must be set in the InOut property. When a 1, 4, or 8 bit image is processed, the total image will be processed regardless of the value set in the SelectMode property.

If successful the resulting raster image data is set in the LayerNo property (the ImageHandle property or the Layer(LayerNo).ImageHandle property. If unsuccessful, 0 is returned.

When the Caption, Message, and ButtonName properties are blank, the progress dialog box will not be displayed. When the progress dialog box is displayed, the percentage that the processing has completed will be shown in the dialog box.

Also see the YCCLevel method.