1IM_READMASK(3) Library Functions Manual IM_READMASK(3)
2
6 im_create_dmask, im_create_imask, im_create_dmaskv, im_create_imaskv,
7 im_dup_dmask, im_dup_imask, im_free_dmask, im_free_imask,
8 im_print_imask, im_print_dmask, im_read_dmask, im_read_imask,
9 im_scale_dmask, im_write_dmask, im_write_imask - operations on double
10 or int masks
11
13 #include <vips/vips.h>
14 DOUBLEMASK *im_create_dmask( name, xs, ys )
16 char *name;
17 int xs, ys;
18 INTMASK *im_create_imask( name, xs, ys )
20 char *name;
21 int xs, ys;
22 DOUBLEMASK *im_create_dmaskv( name, xs, ys, ... )
24 char *name;
25 int xs, ys;
26 INTMASK *im_create_imaskv( name, xs, ys, ... )
28 char *name;
29 int xs, ys;
30 DOUBLEMASK *im_dup_dmask( m, name )
32 DOUBLEMASK *m;
33 char *name;
34 INTMASK *im_dup_imask( m, name )
36 INTMASK *m;
37 char *name;
38 void im_free_dmask( mask )
40 DOUBLEMASK *mask;
41 void im_free_imask( mask )
43 INTMASK *mask;
44 DOUBLEMASK *im_read_dmask( name )
46 char *name;
47 INTMASK *im_read_imask( name )
49 char *name;
50 void im_print_dmask( mask )
52 DOUBLEMASK *mask;
53 void im_print_imask( mask )
55 INTMASK *mask;
56 INTMASK im_scale_dmask( mask, name )
58 DOUBLEMASK *mask;
59 char *name
60 int im_write_imask( m )
62 INTMASK *m;
63 int im_write_imask_name( m, name )
65 INTMASK *m;
66 char *name;
67 int im_write_dmask_name( m, name )
69 DOUBLEMASK *m;
70 char *name;
71
74 Masks are (see <vips/vips.h>):
75 typedef struct { typedef struct {
77 int xsize; int xsize;
78 int ysize; int ysize;
79 int scale; double scale;
80 int offset; double offset;
81 int *coeff; double *coeff;
82 char *filename; char *filename;
83 } INTMASK ; } DOUBLEMASK ;
84 By mask files have the following structure:
86 x y [scale] [offset]
88 a11 a12 ... a1y
89 a21 a22 ... a2y]
90 ... ... ... ...
91 ax1 ax2 ... axy
92 The mask sizes x and y are always integer whereas all the remaining
94 coefficients are either int for INTMASK and double for the DOUBLEMASK.
95 All numbers are written in ASCII, for convenience. scale and offset are
96 always optional. If missing, they default to 1 and 0 respectively. This
97 laxity makes mask files useful for matrix operations, see im_matinv(3),
98 etc.
99 im_create_dmask() returns an DOUBLEMASK with the filename xsize and
101 ysize set to name xs and ys respectively. The function allocates mem‐
102 ory for the coefficients which are all initialised to zero. In case of
103 error the function returns NULL.
104 im_create_dmaskv() operates exactly as im_create_dmask(), except that
106 the mask is initialised by the parameters following the width and
107 height. These parameters must all be doubles. For example:
108 DOUBLEMASK *m = im_create_dmaskv( "untitled", 3, 3,
110 1.0, 0.0, 0.0,
111 0.0, 1.0, 0.0,
112 0.0, 0.0, 1.0 );
113 creates an identity matrix.
115 im_create_imask() returns an INTMASK with the filename xsize and ysize
117 set to name xs and ys respectively. The function allocates memory for
118 the coefficients which are all initialised to zero. In case of error
119 the function returns NULL.
120 im_create_imaskv() operates exactly as im_create_imask(), except that
122 the mask is initialised by the parameters following the width and
123 height. These parameters must all be ints. For example:
124 INTMASK *m = im_create_imaskv( "untitled", 3, 3,
126 1, 0, 0,
127 0, 1, 0,
128 0, 0, 1 );
129 creates an identity matrix.
131 im_dup_dmask() duplicates the DOUBLEMASK mask pointed by m and returns
133 a pointer to the new mask. The filename member of the returned mask is
134 set to the entered name. The function returns either a DOUBLEMASK
135 pointer or NULL on error.
136 im_dup_imask() duplicates the INTMASK mask pointed by m and returns a
138 pointer to the new mask. The filename member of the returned mask is
139 set to the entered name. The function returns either an INTMASK
140 pointer or NULL on error.
141 im_free_dmask() frees the memory allocated for the DOUBLEMASK mask.
143 im_free_imask() frees the memory allocated for the INTMASK mask.
145 im_print_dmask() prints at the sterr the DOUBLEMASK pointed by mask.
147 im_print_imask() prints at the sterr the INTMASK pointed by mask.
149 im_read_dmask() opens the argument name and reads the mask into a DOU‐
151 BLEMASK structure. The function returns a pointer to an DOUBLEMASK or
152 NULL on error.
153 im_read_imask() opens the argument name and reads the mask into a INT‐
155 MASK structure. If the input file has non-integer coefficients then
156 the function im_read_dmask() should be used instead. There is a built-
157 in checking for all mask members. If the mask has coefficients which
158 are integers or they are floats with the decimal part equal to zero,
159 the function reads the mask properly and puts the resultant coeffi‐
160 cients in a valid INTMASK. The function returns a pointer to an INT‐
161 MASK or NULL on error.
162 im_scale_dmask() returns an INTMASK of the DOUBLE MASK m. The maximum
164 value of the DOUBLEMASK is scaled to 100 in the returned mask. The
165 scale member of the INTMASK is scaled accordingly to the scale member
166 of m. The function returns a pointer to an INTMASK or NULL on error.
167 im_write_imask() writes the INTMASK pointed by m to the filename member
169 of m. The function checks whether the filename is valid and it expects
170 only an INTMASK. The function returns 0 on success and -1 on error.
171 For writing a DOUBLEMASK use im_write_dmask() instead.
172 im_write_imask_name() operates as im_write_imask(), but the mask is
174 written to the named file.
175 im_write_dmask() writes the DOUBLEMASK pointed by m to the filename
177 member of m. The function checks whether the filename is valid and it
178 expects only an DOUBLEMASK. The mask is written in a file with the
179 format given above. The function uses fprintf with the conversion
180 character %g, to write the non integer mask coefficients. It returns 0
181 on success and -1 on error.
182 im_write_dmask_name() operates as im_write_dmask(), but the mask is
184 written to the named file.
185
188 im_lindetect(3), im_compass(3), im_conv(3), im_matinv(3).
189
191 N. Dessipris
192
194 N. Dessipris - 02/05/1991
195 2 May 1991 IM_READMASK(3)