[Reprinted] Some Macros in opencv

Some Macros in opencv

 

Address: http://blog.csdn.net/wqvbjhc/archive/2010/04/17/5496632.aspx

 

Cv_funcname defines the variable cvfuncname to store the function name. It is used to report the function with an error when an error occurs.

_ File _ macro in C language, which is often used in cv_error. It indicates the source file name of the faulty function.

_ Line _ macro in C language, which is often used in cv_error to indicate the error location.

In cxerror. h

View plaincopy to clipboardprint?
/* Cv_funcname macro defines icvfuncname constant which is used by cv_error macro */
# Ifdef cv_no_func_names
# Define cv_funcname (name)
# Define cvfuncname ""
# Else
# Define cv_funcname (name )/
Static char cvfuncname [] = Name
# Endif
/*
Cv_error macro unconditionally raises error with passed code and message.
After raising error, control will be transferred to the exit label.
*/
# Define cv_error (Code, MSG )/
{/
Cverror (CODE), cvfuncname, MSG, _ file __, _ line __);/
Exit ;/
}
/* Cv_funcname macro defines icvfuncname constant which is used by cv_error macro */
# Ifdef cv_no_func_names
# Define cv_funcname (name)
# Define cvfuncname ""
# Else
# Define cv_funcname (name )/
Static char cvfuncname [] = Name
# Endif
/*
Cv_error macro unconditionally raises error with passed code and message.
After raising error, control will be transferred to the exit label.
*/
# Define cv_error (Code, MSG )/
{/
Cverror (CODE), cvfuncname, MSG, _ file __, _ line __);/
Exit ;/
}
 

2.

_ Begin _ and _ end _ are used together. When an error occurs, exit

In cxerror. h

# DEFINE _ begin __{
# DEFINE _ end _ goto exit; exit :;}
# DEFINE _ cleanup __
# Define exit goto exit

Add a semicolon after _ begin _ and _ end _ in the Code:

Because _ begin __; is equivalent to {;, where semicolon (;) is an empty statement, it is reasonable, but do not use. _ end _ as well.

View plaincopy to clipboardprint?
Int I;
;
;
Int B;
Int I;
;
;
Int B;

This syntax is correct.

3.

Cv_cn_max 64 // The maximum number of channels is 64

Cv_depth_max = 8 = (1000) // The maximum depth is 8.

Cv_mat_type_mask 11111111 // 511

Cv_mat_type (flags) & cv_mat_depth_mask) // flags and flags must be flags, but flags must be between 0 and 511.

Cv_mat_depth_mask = 7 = (0111) // bit deep mask to ensure the maximum value is 8 (the remaining number)

Cv_mat_cn_mask = (111111,000) // mask

Cv_mat_cn

Cv_mat_depth: Obtain the depth. The depth ranges from 8 to 0 ~ 7

Cv_elem_size = number of channels x depth = number of channels> X = number of bytes per pixel

Cv_maketype (depth, CN) (cv_mat_depth (depth) + (CN)-1) <cv_cn_shift) // shifts the cn-1 three places left (that is, multiply by 8) and then add to depth

In cxtypes. h

View plaincopy to clipboardprint?
/* 0x3a50 = 11 10 10 01 01 00 ~ Array of log2 (sizeof (arr_type_elem ))*/
# Define cv_elem_size (type )/
(Cv_mat_cn (type) <(sizeof (size_t)/4 + 1) * 16384 | 0x3a50)> cv_mat_depth (type) * 2) & 3 ))
# Define cv_cn_max 64
# Define cv_mat_cn_mask (cv_cn_max-1) <cv_cn_shift)
# Define cv_mat_cn (flags) & cv_mat_cn_mask)> cv_cn_shift) + 1)
# Define cv_mat_depth (flags) & cv_mat_depth_mask)
# Define cv_mat_depth_mask (cv_depth_max-1)
# Define cv_cn_shift 3
# Define cv_depth_max (1 <cv_cn_shift)