I've got some code that's been modified, and I tried to specify some OpenType fonts to produce the output, but when I do that, it doesn't use those fonts; it only uses one of them.

Even worse, when saving to PDF, it doesn't use any of those fonts and doesn't retain the spacing I see in the on-screen output.

Any ideas for a solution?

Okay, but it's mostly in Spanish:

int nro_linea = 2;
int nro_espacio = 0;

PFont font, font1, font2, font3, font4;
String par_actual = "";               // valor actual del escaneo del texto
String[] lines;                       // lineas del texto escaneado
String[] str_ayuda;
int arrastrando = -1;

int pares_totales = 0;
float k_total;


int espacio_abajo;
int espacio_arriba;
int espacio_derecha;
int espacio_izquierda;
String layout_actual = "standard";
String visual_mode = "lineal";
int burbujas_maximas = 49;
int burbujas_graficadas = 0;

Ball[] balls = new Ball[0];
float grav = 1.40;                    // Gravedad
float b = 0.85;                       // Rebote
float f = 0.90;                       // Friccion

color ColorLineasGrales = color(200);
color ColorAcento = color(255, 102, 0);
color ColorAcentoCompanion = color(255, 180, 0);

int lapso_refresh = 1;               // cada cuantos frames se renueva la info del listado
int timer_interno = 0;
boolean resorte_activado = false;
boolean show_info = false;
boolean llenar_burbujas = false;
boolean hay_gravedad = false;
boolean mostrar_ayuda = false;
boolean mostrando_ayuda = false;

//added
boolean record=false;



void setup() {

 size(1024, 725);
 background(255);
 smooth();
 loop();  

 /* font=createFont("Arial-Black",18);
 font1=createFont("ArialMT",25);
 font2=createFont("Arial-BoldMT",18);
 font3=createFont("Arial-BoldMT",14);*/
 font=createFont ("Gotham-Black",20);
 font1-createFont ("Gotham-Medium",18);
 font2=createFont ("Gotham-Bold",18);
 font3=createFont ("Gotham-Bold",14);
 font4=createFont("TimesNewRomanPSMT",18);

With the current fonts referenced, it it should be using Gotham-Black for the on-screen output, unless the frequency of the word changes, at which point it should use a different, smaller font.

But it appears to only use one of the fonts, and that would be Gotham-Medium. And even after doing that, use the command to save the output to a PDF file results in characters that aren't in that font, and don't retain the spacing of the original on-screen results. It appears instead to use Arial for the PDF, which is completely wrong.

I need to fix that problem so I can render correctly on-screen and capture accurate results in the PDF that match the on-screen representation.

No, I didn't read that, because I'm not really a programmer. I started with some code that somebody sent me and I had some modifications made, keeping the option to Save to PDF.

I didn't list all the code because it is more than 6000 characters and would not fit. I could email it to you if you send me your email address in a private message.

As I wrote, we need relevant code. Perhaps you can use http://pastebin.com to show it.
Also, the names of the fonts look odd, what system do you have Have you tried the snippet given at PFont.list() to see the font names to use

I don't like public questions going to the private sphere, as I am not the only one able to solve issues (or having time to work on it).
So we wait to see the code. And the answers to my questions...

You need to give the URL of the paste.
And please, try the PFont.list snippet in the PDE to answer my question.