L_LTIMGEFX_API L_INT L_AddBitmapNoise(pBitmap, uRange, uChannel, uFlags)
Adds random pixels to a bitmap, letting you specify the percentage of coverage and the color plane.
Pointer to the bitmap handle referencing the bitmap to process.
Percentage of coverage, expressed in tenths of a percent. Valid values are 0 to 1000.
Possible values are:
|CHANNEL_MASTER *|| All channels.|
|CHANNEL_RED|| Red channel only.|
|CHANNEL_GREEN|| Green channel only.|
|CHANNEL_BLUE|| Blue channel only.|
Reserved for future use. Must be 0.
|SUCCESS||The function was successful.|
|< 1||An error occurred. Refer to Return Codes.|
Use this function in order to add random noise to a bitmap.
Use the L_PerlinBitmap function to use a pseudo-random number generator in order to create a Perlin noise, and then procedurally transform that noise into a texture. Depending on the flags that are set, the texture can be saved as a bitmap by itself, or the texture can be combined with another bitmap. For more information, refer to Using the L_PerlinBitmap function.
Use the L_CloudsBitmap function in order to use Perlin equations to generate pseudo-random noise, and then procedurally transform that noise into a cloud-like texture. The L_CloudsBitmap function applies equations to the Perlin noise that are different than those used by the L_PerlinBitmap function.
To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.
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 signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.
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.
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, Linux.
For complete sample code, refer to the CHILD.C module of the DEMO example.
This example loads a bitmap and adds red noise to it.
BITMAPHANDLE LeadBitmap; /* Bitmap handle to hold the loaded image. */
/* Load the bitmap, keeping the bits per pixel of the file */
nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("sample2.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
/* Add red noise with 25 percent coverage */
nRet = L_AddBitmapNoise(&LeadBitmap, 250, CHANNEL_RED, 0);
nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL);
Medical Web Viewer .NET
.NET, Java, Android, and iOS/macOS Assemblies
C API/C++ Class Libraries