This function adjusts the chrominance of a raster image.
Parameters
| Name | Explanation |
|---|---|
| SrcHandle | A structure containing the image handle and the
mask image handle member variables hImgBmh must be 1, 4, 8, 16, 24, or 32 bit images |
| SelectMode | Sets the method for selecting the area on the image that will be processed (0: Mask handle, 1: Total image, 2: Polygon, 3: Ellipse) |
| lpPoint | A structure defining coordinates for the points of
the polygonal area on the image. (This parameter is enabled when
SelectMode is 2)
In C++Builder, pass the pointer to the first element in the structure array. In Delphi, if Pt is an array of TPoint, then the arguments are returned in the first elements of the array Pt[0] |
| Points | The number of points defining the polygonal area on the image, i.e. the number of points in the lpPoint array (This parameter is enabled when SelectMode is 2). |
| Rect | A structure specifying the coordinates for the rectangle bounding the elliptical area on the image (This parameter is enabled when SelectMode is 3) |
| InOut | Determines whether the area inside the selected area will be processed or the area outside the selected area will be processed. Enabled for polygon and ellipse (SelectMode is 2 or 3). If False (0), the area outside the selected area is processed. If True (nonzero) the area inside the selected area is processed. |
| Level | Chrominance Level (-100 to 1000) |
| UserProc | The address of the user function (If not using the user function then set to 0) |
| Caption | Sets the text displayed in the title bar of the progress dialog box |
| Message | Sets the message displayed in the progress dialog box |
| Button | Sets the name of the button displayed in the progress dialog box |
Return Value
Returns the raster image handle if successful (1 bit image). Returns 0 if unsuccessful.
Explanation
The IKChroma function adjusts the chrominance of a raster image.
Chrominance refers to the color element of the image whereas Luminance refers to the brightness element. You can adjust the chrominance by using the Level parameter which can have a value ranging from -100 to 1000. When the Level parameter is 0, there is no change in the image color. As the level becomes negative, the colors in the image become less vivid. When the Level parameter reaches -100 the chrominance element is negated leaving only the Luminance element. This is grayscale. Conversely, as the Level parmeter increases from 0, the colors become more vivid.
Before executing this function, 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 SelectMode to 0. Then set the mask image handle in SrcHandle.
- To process the total image, set SelectMode to 1.
- To process the polygonal area on the image, set SelectMode to 2. Select the polygon by setting the appropriate coordinate values for the points of the polygon in the lpPoint structure. Then set the number of points defining the polygon in Points (must be 3 or more).
- To process an elliptical area on the image, set SelectMode to 3. Select the ellipse by setting the appropriate values for the bounding rectangle in the Rect structure.
For the lpPoint and Rect structure members, coordinate points are in pixel units. When SelectMode is set to a value other than 2, set a dummy array in lpPoint and set Points to 0. When SelectMode is set to a value other than 3, then set a dummy array in Rect.
For 1 , 4, or 8 bit images, regardless of whether the SelectMode parameter settings, the total image will be processed.
Note: the image handles passed to IKSELECT_IMAGE are NOT automatically freed after executing this function.
If the user function is set or if the Caption, Message, and Button parameters are blank then the Progress dialog box is not displayed. If the Progress dialog box is displayed, it indicates the percentage of the current process completed. For more information about the user function please refer to the Definition of User Function in the Ik10Effect.dll, Ik10EffectA.dll, Ik10Effect64.dll, Ik10Effect64A.dlll section.