Problems with textWidth

Programming Questions

Automata

in Programming Questions • 2 months ago

Hi there,

I'm new to processing and have been playing with it for a few days. I'm trying to prepare some code so individual letter in a frase disperse and return on pressing a button (everything is already working). But I'm having problems with textWith() giving me an NullPointerException, for no apparent reason. I've searched around but it seems that my problem is different. Nay ideas? here's part of the code (as you can see I'm creating a string as a list of characters using references):

class PFrase {
PFrase next;
PVector location;
PVector origin;
PVector velocity;
PFont font;
char letter;
int size =100;
boolean mode = true;
PFrase(String str, float x, float y, PFont f) {
letter = str.charAt(0);
font = f;
location = new PVector(x, y);
origin = new PVector(x, y);
velocity = new PVector(random(-5, 5), random(-5, 5));
if (str.length()>1) {
next = new PFrase(str.substring(1), x+textWidth(letter), y,f); //the problem here
}
}
}

Replies(4)

dimkir

Re: Problems with textWidth

2 months ago

when your sketch starts running, the "current font" is UNDEFINED. Meaning that you sketch doesn't know which font (or at least size) you want to use. So in order for textWidth() to work, you need first to init font

void setup()
{
// You can init font like this, as shown in the reference for textWidth()
// {@link http://processing.org/reference/textWidth_.html}
textSize(22);
// or create font and set it as current font.
PFont ff = createFont("Arial", 32);
textFont(ff);
PFrase p = new PFrase("stroka", 7 , 8 , ff);
}
void draw(){
}

Automata

Re: Problems with textWidth

2 months ago

Ah!!, thanks. I did create the font and passed it as reference when creating the object, but you are right, the textSize was undefined!

dimkir

Re: Problems with textWidth

2 months ago

when you created font, and passed it as reference you just reassigned it to another variable, but never used it. You can create as many fonts with createFont() or loadFont() but until you call "textFont(myfontname)" processing never knows about your font. So until you call textFont() inside of your PFrase() constructor, processing won't be taking your font into account. Probably the measures you're getting now are measures of some default font NOT the one you're loading. If you try loading some narrow font (like ArialNarrow) then you may start seeing discrepancies in text width.

Automata

Re: Problems with textWidth

2 months ago

I did notice that. Thanks.

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