Scaling/flipping PGraphics

G_D

I am trying to get two copies of a PGraphics - one displayed normally, the other flipped. I then want to convert my PGraphics to a PImage. I've got the following, but the second image isn't flipped...

  PGraphics g;
  g = createGraphics(width, height, P3D);
  g.beginDraw();
  g.image(srcImg, 0, 0);
  g.endDraw();
  PImage output = g.get();

  PGraphics g2; 
  g2 = createGraphics(width, height, P3D);
  g2.beginDraw();
  g2.image(srcImg, 0, 0);
  g2.scale(-1,1);
  g2.endDraw();
  PImage output2 = g2.get();

GoToLoop

AFaIK scale(), just like fill() and textSize(), isn't retroactive.
That is, it doesn't affect previous drawings: /:)
https://Processing.org/reference/scale_.html

G_D

Well, I am sure I did have .scale() working at some point to flip PGraphics. Just can't remember how I made it work.

TfGuy44

You probably set the scale before you drew your image. You might also need to translate(width,0); in there. You would want to do that translate first. Then change the scale. Then draw the image.

G_D

Thanks TfGuy44. Works like a charm. I ended up with:

  PGraphics g;
  g = createGraphics(width, height, P3D);
  g.beginDraw();
  g.pushMatrix();
  g.scale(1, -1);
  g.translate(0, -g.height);
  g.image(img, 0, 0);
  g.popMatrix();
  g.endDraw();
  PImage output = g.get();