L_HalfToneBitmap
#include "l_bitmap.h"
L_INT EXT_FUNCTION L_HalfToneBitmap(pBitmap, uType, nAngle, uDim, hList)
pBITMAPHANDLE pBitmap; |
/* Pointer to the bitmap handle */ |
L_UINT uType; |
/* Type of halftoning to do */ |
L_INT32 nAngle; |
/* Angle of rotation */ |
L_UINT uDim; |
/* Size of the grain */ |
HBITMAPLIST hList; |
/* Handle to the list of bitmaps */ |
Converts a 1-, 4-, 8-, 16-, 24-, or 32-bit bitmap to a halftoned bitmap, with a specified pattern rotation. A halftoned bitmap is a 1-bit bitmap that has been dithered for black and white printing or display.
Parameter |
Description |
|
pBitmap |
Pointer to the bitmap handle referencing the bitmap to be converted. |
|
uType |
Value that indicates the type of halftoning to perform. Possible values are: |
|
|
Value |
Meaning |
|
HT_PRINT |
[0x0000] Halftone for printing |
|
HT_VIEW |
[0x0001] Halftone for display |
|
HT_RECT |
[0x0002] Rectangular halftone |
|
HT_CIRC |
[0x0003] Circular halftone |
|
HT_ELLIPS |
[0x0004] Elliptical halftone |
|
HT_RAND |
[0x0005] Random halftone |
|
HT_LINEAR |
[0x0006] Linear halftone |
|
HT_USERDEF |
[0x0007] User defined halftone |
nAngle |
The angle of rotation, expressed in hundredths of degrees. A value of 0 produces a horizontal halftone pattern. This parameter specifies the number of degrees to change the pattern. Positive values rotate the pattern clockwise; negative values rotate the pattern counterclockwise. This value is ignored if the selected halftone pattern is HT_RECT, HT_CIRC or HT_RAND or HT_USERDEF. |
|
uDim |
Value that indicates the size of the grain. This value is ignored if the selected halftone pattern is HT_VIEW or HT_PRINT. If the pattern is not HT_VIEW or HT_PRINT, uDim should be >= 1. If this parameter is < 1 this function will return ERROR_INV_PARAMETER (-13). |
|
hList |
Handle to the list of bitmaps that will be used in half toning if the HT_USERDEF option is selected. |
Returns
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
For the HT_USERDEF option, the number of bitmaps in the list must be at least equal to (uDim * uDim + 1). Bitmaps with higher indexes correspond to higher intensity values.
This function can process the whole image or a region of the image.
This function does not support 12 and 16-bit grayscale and 48 and 64-bit color images.
To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.
This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.
Required DLLs and Libraries
LTIMG For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application. |
Platforms
Windows 95 / 98 / Me, Windows 2000 / XP.
See Also
Example
BITMAPHANDLE LeadBitmap; /* Bitmap handle for the image */
HBITMAPLIST hList;
/* Load a bitmap at its own bits per pixel */
L_LoadBitmap (TEXT("image3.cmp"), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
/* fill hList by at least 26 bitmaps*/
/* Halftone the bitmap */
L_HalfToneBitmap(&LeadBitmap, HT_USERDEF,0, 5, hList);