#include "l_bitmap.h"
L_LTIMGCLR_API L_INT L_ColorThresholdBitmap (pBitmap, uColorSpace, pCompData, uFlags)
Using any one of eight color spaces, resets those bitmaps pixel component values that fall inside or outside of a specified range.
Pointer to the bitmap handle that references the bitmap on which to apply the effect.
Color space which the threshold is based on. Possible values are
Value | Meaning |
---|---|
CLTH_RGB_SPACE | [0x00000000] RGB color space |
CLTH_HSV_SPACE | [0x00000001] HSV color space |
CLTH_HLS_SPACE | [0x00000002] HLS color space |
CLTH_XYZ_SPACE | [0x00000003] XYZ color space |
CLTH_YCrCb_SPACE | [0x00000004] YCrCb color space |
CLTH_YUV_SPACE | [0x00000005] YUV color space |
CLTH_LAB_SPACE | [0x00000006] LAB color space |
CLTH_CMY_SPACE | [0x00000007] CMY color space |
Pointer to an array of 3 COMPDATA structures that contains the parameters used to compare and modify each component.
Reserved for future use. Must be 0.
Value | Meaning |
---|---|
SUCCESS | The function was successful. |
< 1 | An error occurred. Refer to Return Codes. |
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 is similar to the L_ConvertColorSpace function but provides greater flexibility by allowing the specification of a range and different options for handling those values that fall outside of the range. Please note that every color space component may have a different range.
Color Component | Range for 8-bit components | Range for 16-bit components |
---|---|---|
RGB | ||
R | 0 - 255 | 0 - 65535 |
G | 0 - 255 | 0 - 65535 |
B | 0 - 255 | 0 - 65535 |
HSV | ||
H | 0 - 360 | 0 - 36000 |
S | 0 - 100 | 0 - 10000 |
V | 0 - 255 | 0 - 65535 |
HLS | ||
H | 0 - 360 | 0 - 36000 |
L | 0 - 255 | 0 - 65535 |
S | 0 - 100 | 0 - 10000 |
XYZ | ||
X | 0 - 255 | 0 - 65535 |
Y | 0 - 255 | 0 - 65535 |
Z | 0 - 255 | 0 - 65535 |
YCrCb | ||
Y | 0 - 255 | 0 - 65535 |
Cr | -128 - 127 | -32768 - 32767 |
Cb | -128 - 127 | -32768 - 32767 |
YUV | ||
Y | 0 - 255 | 0 - 65535 |
U | -112 - 111 | -28567 - 28566 |
V | -138 - 137 | -35337 - 35336 |
LAB | ||
L | 0 - 100 | 0 - 10000 |
A | -128 - 127 | -32768 - 32767 |
B | -128 - 127 | -32768 - 32767 |
CMY | ||
C | 0 - 255 | 0 - 65535 |
M | 0 - 255 | 0 - 65535 |
Y | 0 - 255 | 0 - 65535 |
This function works as follows:
b. If CLTH_VALUE_MAX is passed, the rejected pixel/component is set to 255.
c. If CLTH_VALUE_CLAMP is passed, components less that nMin go to 0 and components greater than nMax go to 255. This would work only with the CLTH_MOD_CHANNEL and CLTH_TYP_BANDPASS flag.
This function works for 1, 2, 3, 8,16, 24, 32, 48 and 64-bit color bitmaps and can support regions for 24 and 48-bit bitmaps. If a 24 or 48-bit bitmap has a region the effect will be applied on the region only.
One structure is used for each color component. The order is considered to be the same as in the CLTH_xxx_SPACE name. For example, for CLTH_RGB_SPACE:
The pCompData[0].uStructSize must be set to sizeof(COMPDATA) before calling this function. For an array of structures, only the first structure in the array needs to have uStructSize member set.
To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.
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.
Required DLLs and Libraries
Win32, x64, Linux.
L_INT ColorThresholdBitmapExample(L_VOID)
{
L_INT nRet;
BITMAPHANDLE LeadBitmap; /* Bitmap handle for the image */
COMPDATA pCompData[3];
L_INT nI;
/* Load a bitmap at its own bits per pixel */
nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image1.jpg")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
if(nRet !=SUCCESS)
return nRet;
pCompData[0].uStructSize = sizeof(COMPDATA);
for (nI = 0; nI < 3; nI++)
{
pCompData[nI].nMinRange = 128;
pCompData[nI].nMaxRange = 255;
pCompData[nI].uFlags = 0;
}
/* Apply color Threshold effect on the image*/
nRet = L_ColorThresholdBitmap(&LeadBitmap, CLTH_RGB_SPACE, pCompData, 0);
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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