Adds shadows to the bitmap.
#include "l_bitmap.h"
L_LTIMGSFX_API L_INT L_AddShadowBitmap(pBitmap, uAngle, uThreshold, uFlags)
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))
Shadow Function - Before
Shadow Function - After
View additional platform support for this Shadow function.
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("Master.jpg")), &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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