Frequency Readout

The most easy way to show the frequency readout is to use a text rather than an image.

gboolean front_panel(GtkWidget *widget, GdkEventExpose *event, gpointer data)
{
    int x, y, width, height;
    double color, barlength;
    x = event->area.x;
    y = event->area.y;
    width = event->area.width;
    height = event->area.height;
    cairo_t *cr = gdk_cairo_create(widget->window);
    cairo_rectangle(cr, x, y, width, height);
    cairo_clip(cr);
    barlength = (s_meter/255.0) * (width-20);
    color = 0.0;
    for(int i=0; i<barlength; i+=10) {
     if((i/10)%10 == 0) cairo_set_source_rgb(cr, 0x33/256.0, 0x66/256.0, 0x99/256.0);
     else cairo_set_source_rgb(cr, color, 1.0-color, 0.1);
     cairo_rectangle(cr, x+10+i, y+10, 10, height-20);
     color += 0.020;
     if(color > 1.0) color = 0.0;
     cairo_fill(cr);
    }
    char string[128];
    sprintf(string,"%12.3f",freq_show/1000.0);
    cairo_set_source_rgb(cr, 1.0, 0.0, 0.0);
    cairo_select_font_face(cr, "FreeSans", CAIRO_FONT_SLANT_ITALIC, CAIRO_FONT_WEIGHT_NORMAL);
    cairo_set_font_size(cr, 46.0);
    cairo_move_to(cr, width-270.0, height-8.0);
    cairo_show_text(cr, string);
    cairo_set_source_rgb(cr,0,0,0);
    cairo_destroy(cr);
    return FALSE;
}

This code is very dirty, but it works. The first half is for the S-meter, and the latter half for the Frequency Display.