L_HalfToneBitmap (original) (raw)

Summary

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.

Syntax

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_HalfToneBitmap(pBitmap, uType, nAngle, uDim, hList, uFlags)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to be converted.

L_UINT uType

Value that indicates the type of halftoning to perform. Possible values are:

L_INT32 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.

L_UINT 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).

HBITMAPLIST hList

Handle to the list of bitmaps that will be used in half toning if the HT_USERDEF option is selected.

L_UINT32 uFlags

Reserved for future use. Must be 0.

Returns

Comments

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.

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 supports 32-bit grayscale images.

Halftone Function - Before

Halftone Function - After

View additional platform support for this Halftone function.

Required DLLs and Libraries

• LTIMGCOR
• 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

Win32, x64, Linux.

See Also

Functions

• L_DefaultDithering
• L_GrayScaleBitmap
• L_GrayScaleBitmapExt
• L_DlgHalftone
• L_AutoColorLevelBitmap
• L_ColorLevelBitmap
• L_CorrelationBitmap
• L_GrayScaleToDuotone
• L_GrayScaleToMultitone
• L_HolesRemovalBitmapRgn
• L_SelectiveColorBitmap
• L_SkeletonBitmap

Topics

• Raster Image Functions: Doing Color Expansion or Reduction
• Color Halftone and Halftone Images

Example

L_INT HalfToneBitmapExample(L_VOID) { L_INT nRet; BITMAPHANDLE LeadBitmap; /* Bitmap handle for the image */ BITMAPHANDLE TmpBitmap; /* Temporary bitmap for building the list */ HBITMAPLIST hList; L_INT i; /* Load a bitmap at its own bits per pixel */ nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("sample5.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); if (nRet != SUCCESS) return nRet; nRet = L_CreateBitmapList(&hList); if (nRet != SUCCESS) return nRet; for (i = 0; i <= 36; ++i) { nRet = L_CopyBitmap(&TmpBitmap, &LeadBitmap, sizeof(BITMAPHANDLE)); if (nRet != SUCCESS) return nRet; /* Rotate, using the transparent color as the fill color */ nRet = L_RotateBitmap(&TmpBitmap, 1000 * i, 0, RGB(0, 0, 0)); if (nRet != SUCCESS) return nRet; nRet = L_InsertBitmapListItem(hList, (L_UINT)-1, &TmpBitmap); if (nRet != SUCCESS) return nRet; } /* fill hList by at least 26 bitmaps*/ /* Halftone the bitmap */ nRet = L_HalfToneBitmap(&LeadBitmap, HT_USERDEF, 0, 5, hList, 0); if (nRet != SUCCESS) return nRet; nRet = L_DestroyBitmapList(hList); if (nRet != SUCCESS) return nRet; nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); if (nRet != SUCCESS) return nRet; //free bitmap if (LeadBitmap.Flags.Allocated) L_FreeBitmap(&LeadBitmap); return SUCCESS; }