euglena/src/Ellipse.java

import processing.core.*;
import static processing.core.PApplet.*;


class Ellipse {

    float centerX, centerY, width, height;
    int color, brushSize;
    boolean visible;

    private boolean centerPointComplete, widthComplete;

    Ellipse(int color, int penWidth) {
        this.color = color;
        this.brushSize = penWidth;
        this.visible = false;

        this.centerPointComplete = false;
        this.widthComplete = false;
    }

    Ellipse(float centerX, float centerY, float width, float height, int color, int penWidth) {
        this.centerX = centerX;
        this.centerY = centerY;
        this.width = width;
        this.height = height;
        this.color = color;
        this.brushSize = penWidth;
        this.visible = true;

        this.centerPointComplete = true;
        this.widthComplete = true;
    }

    ProjectorCommand makeProjectorCommand() {
        return (ProjectorApplet p) -> {
            if (!visible) {
                //done drawing already
                return true;
            }

            float old_strokeWeight = p.g.strokeWeight;
            int old_strokeColor = p.g.strokeColor;

            p.ellipseMode(CENTER);
            p.strokeWeight(brushSize);
            p.stroke(color);
            p.noFill();

            p.ellipse(p.convertXCoord(centerX), p.convertYCoord(centerY),
                      p.convertXDistance(width), p.convertYDistance(height));

            p.strokeWeight(old_strokeWeight);
            p.stroke(old_strokeColor);
            return true;
        };
    }

    ClickGetter makeClickGetter(ProjectorApplet p){
        return (int x, int y) -> {
            if (!centerPointComplete){
                centerX = x;
                centerY = y;
                centerPointComplete = true;
                return false;

            } else if (!widthComplete) {
                width = abs(centerX - x) * 2;
                widthComplete = true;
                return false;

            } else {
                height = abs(centerY - y) * 2;
                visible = true;

                p.commandQueue.add(makeProjectorCommand());
                return true;
            }
        };
    }
}