﻿ Flags for the LBitmap::ApplyMathLogic Function - Raster imaging C++ Class Library Help

# Flags for the LBitmap::ApplyMathLogic Function

The following flags indicate the channel that will be used:

 Value Meaning CHANNEL_MASTER * [0x00000000] All channels. CHANNEL_RED [0x00000001] Red channel only. CHANNEL_GREEN [0x00000002] Green channel only. CHANNEL_BLUE [0x00000003] Blue channel only.

### Calculating Master Channel Values

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)) ````

The following flags indicate how to treat the color value:

 Value Meaning AML_VALUE_NOP [0x00000000] No change. AML_VALUE_NOT [0x00000010] Invert the color, resulting in its complement. AML_VALUE_0 [0x00000020] Change all bits to 0. AML_VALUE_1 [0x00000030] Change all bits to 1.

The following flags indicate the mathematical operation to use. The operations are performed between each component (R, G and B) and nFactor:

 Value Meaning AML_OP_AND [0x00000000] Combine each pixel component value and nFactor using a bitwise AND (&). (pixel = pixel & nFactor) AML_OP_OR [0x00000100] Combine each pixel component value and nFactor using a bitwise OR (|). (pixel = pixel | nFactor) AML_OP_XOR [0x00000200] Combine each pixel component value and nFactor using a bitwise XOR (^). (pixel = pixel ^ nFactor) AML_OP_ADD [0x00000300] Add pixel component value to the nFactor clamping the result to the maximum allowed pixel value. (pixel = min(pixel + nFactor, MAX_PIXEL_VALUE) ) AML_OP_SUBFACT [0x00000400] Subtract each pixel component value from the nFactor, clamping the result to the allowed pixel range. (pixel = min(max(nFactor - pixel, MIN_PIXEL_VALUE), MAX_PIXEL_VALUE) ) AML_OP_SUBVALUE [0x00000500] Subtract nFactor from each pixel component value, clamping the result to the allowed pixel range. (pixel = min(max(pixel nFactor), MIN_PIXEL_VALUE, MAX_PIXEL_VALUE) ) AML_OP_ABSDIF [0x00000600] Calculate the absolute difference between nFactor and each pixel component value. (pixel = abs(pixel nFactor)) AML_OP_MUL [0x00000700] Multiply each pixel component value by nFactor/100. (pixel = pixel * nFactor / 100) AML_OP_DIVFACT [0x00000800] Divide each pixel component value by nFactor/100. An error will be returned if nFactor = 0. (pixel = pixel * 100 / nFactor) AML_OP_DIVVALUE [0x00000900] Divide nFactor by each pixel values. If the pixel values are 0, the result set to maximum allowed pixel value. (pixel = pixel ? min(nFactor / pixel, MAX_PIXEL_VALUE) : MAX_PIXEL_VALUE) AML_OP_AVG [0x00000A00] Use the average of the each pixel component value and nFactor. (pixel = (pixel+nFactor) / 2). AML_OP_MIN [0x00000B00] Use the lesser of the pixel component values and nFactor: (pixel = min(pixel, nFactor) ) AML_OP_MAX [0x00000C00] Use the greater of the pixel component values and nFactor: (pixel = max(pixel, nFactor) )

The way MIN_PIXEL_VALUE and MAX_PIXEL_VALUE are calculated depends on the bits per pixel and whether the bitmap is signed or unsigned:

If the bitmap is unsigned (most common):

• MAX_PIXEL_VALUE will be : 255 (8-bit), 4095 (12-bit) or 65535 (16-bit)
• MIN_PIXEL_VALUE = 0

If the bitmap is signed (rare case):

• MAX_PIXEL_VALUE will be : 127 (8-bit), 2047 (12-bit) or 32767 (16-bit)
• MIN_PIXEL_VALUE will be -128 (8-bit), -2048 (12-bit) or -32768 (16-bit)

The following flags indicate how to treat the output value:

 Value Meaning AML_RES_NOP [0x00000000] No change. AML_RES_NOT [0x00001000] Invert the color, resulting in its complement. AML_RES_0 [0x00002000] Change all bits to 0. AML_RES_1 [0x00003000] Change all bits to 1.

For uFlags equal to AML_OP_AND, AML_OP_OR, AML_OP_XOR, AML_OP_ADD, AML_OP_MIN, AML_OP_MUL, AML_OP_MAX, AML_OP_DIVVALUE , or AML_OP_SUBVALUE, the valid range for nFactor is from MIN_PIXEL_VALUE to MAX_PIXEL_VALUE.

For uFlags equal to AML_OP_SUBFACT, AML_OP_DIF, AML_OP_AVG, the valid range for nFactor is from (2 * MIN_PIXEL_VALUE) to (2 * MAX_PIXEL_VALUE).

Help Version 20.0.2018.10.16