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alsa-scarlett-gui/src/widget-sample-rate.c
2025-02-21 04:08:35 +10:30

125 lines
3.0 KiB
C

// SPDX-FileCopyrightText: 2024-2025 Geoffrey D. Bennett <g@b4.vu>
// SPDX-License-Identifier: GPL-3.0-or-later
#include "gtkhelper.h"
#include "widget-boolean.h"
struct sample_rate {
struct alsa_card *card;
GtkWidget *button;
guint source;
char *path;
int sample_rate;
};
static void button_set_text(GtkWidget *button, int value) {
gtk_widget_remove_css_classes_by_prefix(button, "sample-rate-");
if (!value) {
gtk_button_set_label(GTK_BUTTON(button), "N/A");
return;
}
char *text;
if (value % 1000 == 0)
text = g_strdup_printf("%dkHz", value / 1000);
else
text = g_strdup_printf("%.1fkHz", value / 1000.0);
gtk_button_set_label(GTK_BUTTON(button), text);
g_free(text);
char *css_class = g_strdup_printf(
"sample-rate-%d", value
);
gtk_widget_add_css_class(button, css_class);
g_free(css_class);
}
// Read the sample rate from /proc/asound/cardN/stream0
// and return it as an integer
//
// Looking for a line containing:
// Momentary freq = 48000 Hz (0x6.0000)
static int get_sample_rate(struct sample_rate *data) {
if (!data->path)
return 0;
FILE *file = fopen(data->path, "r");
if (!file) {
perror("fopen /proc/asound/cardN/stream0");
return 0;
}
char *line = NULL;
size_t len = 0;
ssize_t read;
int sample_rate = 0;
while ((read = getline(&line, &len, file)) != -1) {
if (strstr(line, "Momentary freq = ")) {
char *start = strstr(line, "Momentary freq = ") + 17;
char *end = strstr(start, " Hz");
if (!start || !end)
continue;
*end = '\0';
sample_rate = atoi(start);
break;
}
}
free(line);
fclose(file);
return sample_rate;
}
static gboolean update_sample_rate(struct sample_rate *data) {
int sample_rate = get_sample_rate(data);
if (sample_rate != data->sample_rate) {
data->sample_rate = sample_rate;
button_set_text(data->button, sample_rate);
}
return G_SOURCE_CONTINUE;
}
static void on_destroy(struct sample_rate *data, GObject *widget) {
if (data->source)
g_source_remove(data->source);
g_free(data->path);
g_free(data);
}
GtkWidget *make_sample_rate_widget(
struct alsa_card *card
) {
struct sample_rate *data = g_malloc0(sizeof(struct sample_rate));
data->card = card;
data->button = gtk_toggle_button_new();
data->sample_rate = -1;
gtk_widget_set_sensitive(data->button, FALSE);
gtk_widget_add_css_class(data->button, "fixed");
gtk_widget_add_css_class(data->button, "sample-rate");
// can only update if it's a real card
if (card->num != SIMULATED_CARD_NUM) {
data->path = g_strdup_printf("/proc/asound/card%d/stream0", card->num);
data->source =
g_timeout_add_seconds(1, (GSourceFunc)update_sample_rate, data);
}
// initial update (will show "N/A" for simulated card)
update_sample_rate(data);
// cleanup when the button is destroyed
g_object_weak_ref(G_OBJECT(data->button), (GWeakNotify)on_destroy, data);
return data->button;
}