1 /* Copyright (C) 2001-2017 Peter Selinger.
2 This file is part of Potrace. It is free software and it is covered
3 by the GNU General Public License. See the file COPYING for details. */
4
5 /* operations on potrace_progress_t objects, which are defined in
6 potracelib.h. Note: the code attempts to minimize runtime overhead
7 when no progress monitoring was requested. It also tries to
8 minimize excessive progress calculations beneath the "epsilon"
9 threshold. */
10
11 #ifndef PROGRESS_H
12 #define PROGRESS_H
13
14 /* structure to hold progress bar callback data */
15 struct progress_s {
16 void (*callback)(double progress, void *privdata); /* callback fn */
17 void *data; /* callback function's private data */
18 double min, max; /* desired range of progress, e.g. 0.0 to 1.0 */
19 double epsilon; /* granularity: can skip smaller increments */
20 double b; /* upper limit of subrange in superrange units */
21 double d_prev; /* previous value of d */
22 };
23 typedef struct progress_s progress_t;
24
25 /* notify given progress object of current progress. Note that d is
26 given in the 0.0-1.0 range, which will be scaled and translated to
27 the progress object's range. */
progress_update(double d,progress_t * prog)28 static inline void progress_update(double d, progress_t *prog) {
29 double d_scaled;
30
31 if (prog != NULL && prog->callback != NULL) {
32 d_scaled = prog->min * (1-d) + prog->max * d;
33 if (d == 1.0 || d_scaled >= prog->d_prev + prog->epsilon) {
34 prog->callback(prog->min * (1-d) + prog->max * d, prog->data);
35 prog->d_prev = d_scaled;
36 }
37 }
38 }
39
40 /* start a subrange of the given progress object. The range is
41 narrowed to [a..b], relative to 0.0-1.0 coordinates. If new range
42 is below granularity threshold, disable further subdivisions. */
progress_subrange_start(double a,double b,const progress_t * prog,progress_t * sub)43 static inline void progress_subrange_start(double a, double b, const progress_t *prog, progress_t *sub) {
44 double min, max;
45
46 if (prog == NULL || prog->callback == NULL) {
47 sub->callback = NULL;
48 return;
49 }
50
51 min = prog->min * (1-a) + prog->max * a;
52 max = prog->min * (1-b) + prog->max * b;
53
54 if (max - min < prog->epsilon) {
55 sub->callback = NULL; /* no further progress info in subrange */
56 sub->b = b;
57 return;
58 }
59 sub->callback = prog->callback;
60 sub->data = prog->data;
61 sub->epsilon = prog->epsilon;
62 sub->min = min;
63 sub->max = max;
64 sub->d_prev = prog->d_prev;
65 return;
66 }
67
progress_subrange_end(progress_t * prog,progress_t * sub)68 static inline void progress_subrange_end(progress_t *prog, progress_t *sub) {
69 if (prog != NULL && prog->callback != NULL) {
70 if (sub->callback == NULL) {
71 progress_update(sub->b, prog);
72 } else {
73 prog->d_prev = sub->d_prev;
74 }
75 }
76 }
77
78 #endif /* PROGRESS_H */
79
80