#include "l_bitmap.h"
L_LTIMGSFX_API L_INT L_AddShadowBitmap(pBitmap, uAngle, uThreshold, uFlags)
Adds shadows to the bitmap.
Pointer to the bitmap handle that references the bitmap on which to apply the effect.
Angle value indicating the direction of the light source producing the shadow. Possible values are:
Value | Meaning |
---|---|
SHADOW_E | [0] East |
SHADOW_NE | [1] Northeast |
SHADOW_N | [2] North |
SHADOW_NW | [3] Northwest |
SHADOW_W | [4] West |
SHADOW_SW | [5] Southwest |
SHADOW_S | [6] South |
SHADOW_SE | [7] Southeast |
Threshold value used to determine which pixels will be affected . Valid values range from 0 through 65535 for 64-bit, 48-bit and 16-bit grayscale images and from 0 through 4095 for 12-bit grayscale images. Otherwise, it is from 0 through 255. When uFlags
= COLOR_RGB, any component (R, G, or B) of a pixel with a value less than the uThreshold value is not affected. When uFlags
= COLOR_GRAY, any pixel where the master channel value is less than the uThreshold value is not affected.
Type of the shadow. Possible values are:
Value | Meaning |
---|---|
SHADOW_CLR_RGB | [0] Shadows are colored. |
SHADOW_CLR_GRAY | [1] Shadows are grayscale. |
Value | Meaning |
---|---|
SUCCESS | The function was successful. |
< 1 | An error occurred. Refer to Return Codes. |
This function applies a convolution matrix upon each color component and then combines the results in order to add shadows.
This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.
This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.
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.
To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.
In order to speed up widely used image processing filters in LEADTOOLS, the grayscale value (master channel) of a colored image is calculated using the following formulas:
#define CalcGrayValue(r, g, b) ((L_UCHAR)(((L_UCHAR) (((2 * (L_UINT) (r)) + (5 * (L_UINT) (g)) + (L_UINT) (b) + 4) / 8))))
#define CalcGrayValue16(r, g, b) ((L_UINT16) (((2 * (L_UINT32) (r)) + (5 * (L_UINT32) (g)) + (L_UINT32) (b) + 4) / 8))
#define CalcGrayValue32(r, g, b) ((L_UINT32) (((2 * (L_UINT32) (r)) + (5 * (L_UINT32) (g)) + (L_UINT32) (b) + 4) / 8))
Required DLLs and Libraries
Win32, x64.
L_INT AddShadowBitmapExample(L_VOID)
{
L_INT nRet;
BITMAPHANDLE LeadBitmap; /* Bitmap handle for the image */
/* Load a bitmap at its own bits per pixel */
nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
if(nRet !=SUCCESS)
return nRet;
/* Apply shadow effect to the image*/
nRet = L_AddShadowBitmap(&LeadBitmap, SHADOW_SE, 0, SHADOW_CLR_GRAY);
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;
}
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