virtual L_INT LBitmap::ColorThreshold (uColorSpace, pCompData, uFlags = 0)
Using any one of eight color spaces, resets those bitmaps pixel component values that fall inside or outside of a specified range.
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 is similar to the LBuffer::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:
For every pixel, the following operations are performed: Each component is compared with the nMinRange and nMaxRange ranges of the appropriate COMPDATA structure.
If it is inside the range, the component is considered to have "passed" the test.
If it is outside the range, the component has been rejected". The CLTH_TYP_BANDREJECT flag inverts this by making "rejected" components "passed" and viceversa.
If CLTH_MOD_CHANNEL is set, the components are modified independently. If CLTH_MOD_ALL has been passed, the pixel is rejected by the test if any component is rejected. If the pixel/component is rejected, then:
a. If CLTH_VALUE_MIN is passed, the rejected pixel/component is set to 0.
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 LBase::EnableStatusCallback.
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.
Win32, x64.
L_INT LBitmap__ColorThresholdExample(LBitmap *pLeadBitmap)
{
COMPDATA pCompData[3];
L_INT nI;
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*/
return pLeadBitmap->ColorThreshold(CLTH_RGB_SPACE, pCompData);
}
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