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) * |
| Points | The number of points defining the polygonal area on the image. |
| spx | An array of YCrCb values defining the x coordinates of points on the YCCSpline curve. (from 0 to 255) ** |
| spy | An array of YCrCb values defining the y coordinates of points on the YCCSpline curve. (from 0 to 255) ** |
| spPoints | The number of (spx, spy) coordinates in the array (from 3 to 10) |
| Yb | Affects the Y component (luminance) of the YCrCb value (False(0): does not affect the Y component, True( nonzero): affects the Y component) |
| Cr | Affects the Cr component (chrominance) of the YCrCb value (False(0): does not affect the Cr component, True( nonzero): affects the Cr component) |
| Cb | Affects the Cb component (chrominance) of the YCrCb value (False(0): does not affect the Cb component, True( nonzero): affects the Cb component) |
| * In Visual C++, pass the pointer to the first
element in the x and y arrays. In Visual Basic, the arguments are returned in the first elements of the arrays x(0) and y(0). ** Use the Spx and Spy arrays in the same way as the x and y arrays explained above. |
|
Return Value
Returns True (nonzero) if successful, otherwise returns False (0).
Explanation
The YCCSpline method uses a spline function to modify the
YCrCb values of a raster image. A spline function is a method of
interpolating values that lay in between data points. In other
words it produces a smooth curve from a limited set of points.
The YCCSpline method allows you to define the relationship
between the input YCrCb values in the original image and output
YCrCb values in the newly created image. You do this by specifying
a set of coordinate points where the input YCrCb values are the x
coordinates and the output YCrCb values are the y coordinates.
These coordinate points are stored in arrays and passed to the
YCCSpline method through the spx and spy parameters. The YCCSpline
method then interpolates a "smooth" curve from these coordinate
points. The graphic representation of this relationship between
input YCrCb and output YCrCb values is known as the YCCSpline
curve. A sample YCCSpline curve is shown in the diagram below:
In the above diagram, the Cr default YCCSpline curve represents no
change between input YCrCb values and output YCrCb values. In this
case, the newly created image is exactly the same as the orginal
image. The red YCCSpline curve represents an increase in contrast
between the original image and the newly created image. It was
generated from the following points:
Point (spx
values,spy values)
-----------------------------------------------------
Point
A (0,0)
Point
B (64,32)
Point
C (128,128)
Point
D (192,160)
Point
E (255,255)
At the midpoint of the Yb YCCSpline curve, the input YCrCb value of
128 equals the output YCrCb value of 128. At points below the
midpoint, however, the output YCrCb values are lower than the input
YCrCb values. This means that dark colors become darker.
Conversely, at points above the midpoint, output YCrCb values are
higher than input YCrCb values. This means that light colors become
lighter. This particular YCCSpline curve therefore increases the
contrast of the image.
An YCCSpline curve that decreases contrast could be defined with
the following points:
Point (spx
values,spy values)
----------------------------------------------------
Point
A (0,0)
Point
B (64, 96)
Point
C (128,128)
Point
D (225, 192)
Point
E (255,255)
To execute the YCCSpline method, set the image handle of the
image in the ImageHandle
property or the Layer(LayerNo).ImageHandle
property. The YCCSpline method supports 1, 4, 8, 16, 24, and
32 bit images.
Before executing the YCCSpline 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 YCCSpline 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 and set the Points
parameter to 0.
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.
For scripting languages and other programs that require variant
types, please refer to the YCCSplineVariant method.