Problems rotating and scaling shapes

TonyRamirez

I created a shape by combining various primitives in a group. However the group's origin is in the top left of the group. There is no problem doing translations but rotation and scaling take place around the top left of the shape which (as far as I can figure) makes it difficult to rotate shapes around a more central point. Is there a way in Processing to redefine a shape's (or any other object's) local coordinates or apply a local transformation matrix?

TfGuy44

You're so close it hurts. Just translate your shape (-shape.width/2,-shape.height/2):

void setup(){
  size(400,400);
}

void draw(){
  background(0);
  translate(200,200);
  rotate(map(millis()%5000,0,5000,0,TWO_PI));
  translate(-20,-20);
  rect(0,0,40,40);
}

jeremydouglass

Is there a way in Processing to redefine a shape's (or any other object's) local coordinates or apply a local transformation matrix?

1. apply a local transformation matrix: https://processing.org/reference/translate_.html

   pushMatrix();
   translate(x,y);
   // draw under local transformation here
   popMatrix();
   

2. redefine a shape's local coordinates: https://processing.org/reference/PShape_translate_.html (note -- persistent and cumulative!)

   PShape s = createShape();
   s.beginDraw();
   s.translate(x,y);
   s.endDraw();