Processing 1.0 - Processing Discourse - Drawing text into an image buffer

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Index › Programming Questions & Help › Programs › Drawing text into an image buffer

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Drawing text into an image buffer (Read 843 times)

zai

Drawing text into an image buffer
Apr 18^th, 2006, 4:55am

In short, I want to use the shapes and areas defined by a dynamic text string as a mask, or in the future as points in a physics model. Since you can't use text() to draw into a particular PImage, the only way within Processing I can think of is drawing to the main screen, saving those pixels, and then covering the screen up again with background().

If it comes to it I can look up on using a text renderer for Java, but I'm just wondering if anyone has a simple solution. Thanks!

mark hill

Re: Drawing text into an image buffer
Reply #1 - Apr 18^th, 2006, 8:51am

try:

Code:




PGraphics drawing;
 
void setup() {
  size(400, 300, P3D);

  drawing = createGraphics(width,height,P3D,null);
  drawing.defaults();
}
 



 
void draw()
{
 background (255);
 image(drawing, 0 ,0);  
 
 drawing.fill(mouseX);
 drawing.ellipse(mouseX,mouseY,20,20);
  
}

mark hill

Re: Drawing text into an image buffer
Reply #2 - Apr 18^th, 2006, 8:59am

Although this is more in tune with your request, but I'm a bit unsure what's happening (as are others) with the fill on the mask.

Code:




PGraphics drawing;
 
void setup() {
  size(400, 300, P3D);

  drawing = createGraphics(width,height,P3D,null);
  drawing.defaults();
  
  PGraphics drawingMask = createGraphics(width,height,P3D,null);
  drawingMask.defaults();
  drawingMask.background(0);
  drawing.mask(drawingMask);
}
 



 
void draw()
{
 background (255);
 image(drawing, 0 ,0);  
 
 drawing.fill(mouseX,0);
 drawing.stroke(mouseX);
 drawing.ellipse(mouseX,mouseY,20,20);
  
}

zai

Re: Drawing text into an image buffer
Reply #3 - Apr 18^th, 2006, 9:46am

Thanks for the PGraphics tip. I decided to dig into the Processing source for the first time and I think I found an answer in the form of PFont.images, which seems to contain the glyphs of each character.

But looking further, there are a bunch of methods in the PGraphics involving the placing and drawing of glyphs ... so perhaps I'll extend PGraphics and make a version of
protected void textCharScreenImpl(PImage glyph, int xx, int yy, int w0, int h0)

where it draws to a to a pixel buffer rather than the screen.
PImage.setBuffer(PImage new_buffer) ... etc.

Going down that route, it would just beg for making it another textMode (textMode == IMAGE_BUFFER ?) such that i can simply reuse the textLinePlacedImpl(), textCharImpl() functions ... the problem is that I don't need those features at all. Would it be helpful at all for others if I implemented it that way?

zai YaBB Newbies Offline Posts: 25	Re: Drawing text into an image buffer Reply #4 - Apr 18^th, 2006, 9:49am correction: instead of a new textMode it would probably be a PGraphics-wide drawMode(BUFFER), but that's probably confusing.

Ricard

Re: Drawing text into an image buffer
Reply #5 - Apr 18^th, 2006, 10:45am

I think the best approach would be to make a new method text(PGraphics g, ...) which also takes as input a PGraphics. That would avoid having to change modes and not knowing to what buffer it's drawing.

It's the approach I used in the geomerative library. This library might be of your interest if you are dealing with fonts.
link to geomerative

It's still alpha and the API might change, but right now I don't have the time to spend on it.

fry YaBB Moderator Offline Posts: 2623 mass, usa	Re: Drawing text into an image buffer Reply #6 - Apr 18^th, 2006, 3:41pm the PGraphics method mentioned by mark is the way you want to go. PFont.images isn't guaranteed to work in the future. the PGraphics objects subclass PImage specifically so that you can draw into them and later draw the PGraphics back to the screen as an image.

zai YaBB Newbies Offline Posts: 25	Re: Drawing text into an image buffer Reply #7 - Apr 18^th, 2006, 4:58pm Thanks Ricard, Fry. Your geomerative library looks like it may be very useful to me (as a plus, we use the same naming scheme) ... I'll check it out and let you know.

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