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Make spectrum display nicer by plotting continuous lines between samples

This commit is contained in:
Andreas Eversberg 2017-05-31 08:35:13 +02:00
parent e0534db15c
commit aef4cf0997
1 changed files with 80 additions and 13 deletions
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93
src/common/display_wave.c
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@ -105,11 +105,11 @@ void display_wave_limit_scroll(int on)
*
* theoretical example: HEIGHT = 3 allows 5 steps
*
* Line 0: -_
* Line 1: -_
* Line 2: -
* Line 0: '.
* Line 1: '.
* Line 2: '
*
* HEIGHT is odd, so the center line's char is '-' (otherwise '_')
* HEIGHT is odd, so the center line's char is ''' (otherwise '.')
* (HEIGHT - 1) / 2 = 1, so the center line is drawn in line 1
*
* y is in range of 0..4, so these are 5 steps, where 2 is the
@ -120,7 +120,8 @@ void display_wave(sender_t *sender, sample_t *samples, int length, double range)
dispwav_t *disp = &sender->dispwav;
int pos, max;
sample_t *buffer;
int i, j, k, y;
int i, j, k, s, e;
double last, current, next;
int color = 9; /* default color */
int center_line;
char center_char;
@ -133,20 +134,20 @@ void display_wave(sender_t *sender, sample_t *samples, int length, double range)
/* at what line we draw our zero-line and what character we use */
center_line = (HEIGHT - 1) >> 1;
center_char = (HEIGHT & 1) ? '-' : '_';
center_char = (HEIGHT & 1) ? '\'' : '.';
pos = disp->interval_pos;
max = disp->interval_max;
buffer = disp->buffer;
for (i = 0; i < length; i++) {
if (pos >= width) {
if (pos >= width + 2) {
if (++pos == max)
pos = 0;
continue;
}
buffer[pos++] = samples[i];
if (pos == width) {
if (pos == width + 2) {
memset(&screen, ' ', sizeof(screen));
for (j = 0; j < width; j++) {
/* Input value is scaled to range -1 .. 1 and then substracted from 1,
@ -156,10 +157,76 @@ void display_wave(sender_t *sender, sample_t *samples, int length, double range)
* We always use odd number of steps, so there will be a center between
* values.
*/
y = round((1.0 - buffer[j] / range) * (double)(HEIGHT - 1));
/* only display level, if it is in range */
if (y >= 0 && y < HEIGHT * 2 - 1)
screen[y >> 1][j] = (y & 1) ? '_' : '-';
last = (1.0 - buffer[j] / range) * (double)(HEIGHT - 1);
current = (1.0 - buffer[j + 1] / range) * (double)(HEIGHT - 1);
next = (1.0 - buffer[j + 2] / range) * (double)(HEIGHT - 1);
/* calculate start and end for vertical line
* if the current value is a peak (above or below last AND next point),
* round this peak point to become one end of the vertical line.
* the other end is rounded up or down, so the end of the line will
* not overlap with the ends of the surrounding lines.
*/
if (last > current) {
if (next > current) {
/* current point is a peak up */
s = round(current);
/* use lowest neighbor point and end is half way */
if (last > next)
e = floor((last + current) / 2.0);
else
e = floor((next + current) / 2.0);
/* end point must not be above start point */
if (e < s)
e = s;
} else {
/* current point is a transition upwards */
s = ceil((next + current) / 2.0);
e = floor((last + current) / 2.0);
/* end point must not be above start point */
if (e < s)
s = e = round(current);
}
} else {
if (next <= current) {
/* current point is a peak down */
e = round(current);
/* use heighes neighbor point and start is half way */
if (last <= next)
s = ceil((last + current) / 2.0);
else
s = ceil((next + current) / 2.0);
/* start point must not be below end point */
if (s > e)
s = e;
} else {
/* current point is a transition downwards */
s = ceil((last + current) / 2.0);
e = floor((next + current) / 2.0);
/* start point must not be below end point */
if (s > e)
s = e = round(current);
}
}
/* only draw line, if it is in range */
if (e >= 0 && s < HEIGHT * 2 - 1) {
/* clip */
if (s < 0)
s = 0;
if (e >= HEIGHT * 2 - 1)
e = HEIGHT * 2 - 1;
/* plot start and end point */
if ((s & 1))
screen[s >> 1][j] = '.';
else if (e != s)
screen[s >> 1][j] = '|';
if (!(e & 1))
screen[e >> 1][j] = '\'';
else if (e != s)
screen[e >> 1][j] = '|';
/* plot line between start and end point */
for (k = (s >> 1) + 1; k < (e >> 1); k++)
screen[k][j] = '|';
}
}
sprintf(screen[0], "(chan %d", sender->kanal);
*strchr(screen[0], '\0') = ')';
@ -175,7 +242,7 @@ void display_wave(sender_t *sender, sample_t *samples, int length, double range)
printf("\033[0;34m");
}
putchar(center_char);
} else if (screen[j][k] == '-' || screen[j][k] == '_') {
} else if (screen[j][k] == '\'' || screen[j][k] == '.' || screen[j][k] == '|') {
/* green scope curve */
if (color != 2) {
color = 2;