polargraphcontroller/DisplayMachine.pde

/**
  Polargraph controller
  Copyright Sandy Noble 2015.

  This file is part of Polargraph Controller.

  Polargraph Controller is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Polargraph Controller is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with Polargraph Controller.  If not, see <http://www.gnu.org/licenses/>.
    
  Requires the excellent ControlP5 GUI library available from http://www.sojamo.de/libraries/controlP5/.
  Requires the excellent Geomerative library available from http://www.ricardmarxer.com/geomerative/.
  
  This is an application for controlling a polargraph machine, communicating using ASCII command language over a serial link.

  sandy.noble@gmail.com
  http://www.polargraph.co.uk/
  https://github.com/euphy/polargraphcontroller
*/

class DisplayMachine extends Machine
{
  private Rectangle outline = null;
  private float scaling = 1.0;
  private Scaler scaler = null;
  private PVector offset = null;
  private float imageTransparency = 1.0;

  private Set<PVector> extractedPixels = new HashSet<PVector>(0);

  PImage scaledImage = null;
  
  private PVector currentPixel = null;

  public DisplayMachine(Machine m, PVector offset, float scaling)
  {
    // construct
    super(m.getWidth(), m.getHeight(), m.getMMPerRev(), m.getStepsPerRev());

    super.machineSize = m.machineSize;

    super.page = m.page;
    super.imageFrame = m.imageFrame;
    super.pictureFrame = m.pictureFrame;

    super.imageBitmap = m.imageBitmap;
    super.imageFilename = m.imageFilename;

    super.stepsPerRev = m.stepsPerRev;
    super.mmPerRev = m.mmPerRev;

    super.mmPerStep = m.mmPerStep;
    super.stepsPerMM = m.stepsPerMM;
    super.maxLength = m.maxLength;
    super.gridSize = m.gridSize;

    this.offset = offset;
    this.scaling = scaling;
    this.scaler = new Scaler(scaling, 100.0);

    this.outline = null;
  }

  public Rectangle getOutline()
  {
    outline = new Rectangle(offset, new PVector(sc(super.getWidth()), sc(super.getHeight())));
    return this.outline;
  }

  private Scaler getScaler()
  {
    if (scaler == null)
      this.scaler = new Scaler(getScaling(), getMMPerStep());
    return scaler;
  }

  public void setScale(float scale)
  {
    this.scaling = scale;
    this.scaler = new Scaler(scale, getMMPerStep());
  }
  public float getScaling()
  {
    return this.scaling;
  }
  public float sc(float val)
  {
    return getScaler().scale(val);
  }
  public void setOffset(PVector offset)
  {
    this.offset = offset;
  }
  public PVector getOffset()
  {
    return this.offset;
  }
  public void setImageTransparency(float trans)
  {
    this.imageTransparency = trans;
  }
  public int getImageTransparency()
  {
    float f = 255.0 * this.imageTransparency;
    f += 0.5;
    int result = (int) f;
    return result;
  }
  
  public PVector getCurrentPixel()
  {
    return this.currentPixel;
  }
  public void setCurrentPixel(PVector p)
  {
    this.currentPixel = p;
  }

  public void loadNewImageFromFilename(String filename)
  {
    super.loadImageFromFilename(filename);
    super.sizeImageFrameToImageAspectRatio();
    this.setExtractedPixels(new HashSet<PVector>(0));
  }

  public final int DROP_SHADOW_DISTANCE = 4;
  public String getZoomText()
  {
    NumberFormat nf = NumberFormat.getNumberInstance(Locale.UK);
    DecimalFormat df = (DecimalFormat)nf;  
    df.applyPattern("###");
    String zoom = df.format(scaling * 100) + "% zoom";
    return zoom;
  }

  public String getDimensionsAsText(Rectangle r)
  {
    return getDimensionsAsText(r.getSize());
  }
  public String getDimensionsAsText(PVector p)
  {
    String dim = inMM(p.x) + " x " + inMM(p.y) + "mm";
    return dim;
  }

  public void drawForSetup()
  {
    // work out the scaling factor.
    noStroke();
    // draw machine outline

    // drop shadow
    fill(80);
    rect(getOutline().getLeft()+DROP_SHADOW_DISTANCE, getOutline().getTop()+DROP_SHADOW_DISTANCE, getOutline().getWidth(), getOutline().getHeight());

    fill(getMachineColour());
    rect(getOutline().getLeft(), getOutline().getTop(), getOutline().getWidth(), getOutline().getHeight());
    text("machine " + getDimensionsAsText(getSize()) + " " + getZoomText(), getOutline().getLeft(), getOutline().getTop());

    if (displayingGuides)
    {
      // draw some guides
      stroke(getGuideColour());
      strokeWeight(1);
      // centre line
      line(getOutline().getLeft()+(getOutline().getWidth()/2), getOutline().getTop(), 
      getOutline().getLeft()+(getOutline().getWidth()/2), getOutline().getBottom());

      // page top line
      line(getOutline().getLeft(), getOutline().getTop()+sc(getHomePoint().y), 
      getOutline().getRight(), getOutline().getTop()+sc(getHomePoint().y));
    }

    // draw page
    fill(getPageColour());
    rect(getOutline().getLeft()+sc(getPage().getLeft()), 
    getOutline().getTop()+sc(getPage().getTop()), 
    sc(getPage().getWidth()), 
    sc(getPage().getHeight()));
    text("page " + getDimensionsAsText(getPage()), getOutline().getLeft()+sc(getPage().getLeft()), 
    getOutline().getTop()+sc(getPage().getTop()));
    fill(0);
    text("offset " + getDimensionsAsText(getPage().getPosition()), 
    getOutline().getLeft()+sc(getPage().getLeft()), 
    getOutline().getTop()+sc(getPage().getTop())+10);
    noFill();

    // draw home point
    noFill();
    strokeWeight(5);
    stroke(0, 128);
    PVector onScreen = scaleToScreen(inMM(getHomePoint()));
    ellipse(onScreen.x, onScreen.y, 15, 15);
    strokeWeight(2);
    stroke(255);
    ellipse(onScreen.x, onScreen.y, 15, 15);
    
    text("Home point", onScreen.x+ 15, onScreen.y-5);
    text(int(inMM(getHomePoint().x)+0.5) + ", " + int(inMM(getHomePoint().y)+0.5), onScreen.x+ 15, onScreen.y+15);


    if (displayingGuides 
      && getOutline().surrounds(getMouseVector())
      && currentMode != MODE_MOVE_IMAGE
      && mouseOverControls().isEmpty()
      )
    {  
      drawHangingStrings();
      drawLineLengthTexts();
      cursor(CROSS);
    }
    else
    {
      cursor(ARROW);
    }
  }

  public void drawLineLengthTexts()
  {
    PVector actual = inMM(asNativeCoords(inSteps(scaleToDisplayMachine(getMouseVector()))));
    PVector cart = scaleToDisplayMachine(getMouseVector());
    NumberFormat nf = NumberFormat.getNumberInstance(Locale.UK);
    DecimalFormat df = (DecimalFormat)nf;  
    df.applyPattern("###.#");

    text("Line 1: " + df.format(actual.x) + "mm", getDisplayMachine().getOutline().getLeft()+10, getDisplayMachine().getOutline().getTop()+18);
    text("Line 2: " + df.format(actual.y) + "mm", getDisplayMachine().getOutline().getLeft()+10, getDisplayMachine().getOutline().getTop()+28);

    text("X Position: " + df.format(cart.x) + "mm", getDisplayMachine().getOutline().getLeft()+10, getDisplayMachine().getOutline().getTop()+42);
    text("Y Position: " + df.format(cart.y) + "mm", getDisplayMachine().getOutline().getLeft()+10, getDisplayMachine().getOutline().getTop()+52);
  }

  public void draw()
  {
    // work out the scaling factor.
    noStroke();
    // draw machine outline

//    fill(80);
//    rect(getOutline().getLeft()+DROP_SHADOW_DISTANCE, getOutline().getTop()+DROP_SHADOW_DISTANCE, getOutline().getWidth(), getOutline().getHeight());

    fill(getMachineColour());
    rect(getOutline().getLeft(), getOutline().getTop(), getOutline().getWidth(), getOutline().getHeight());



    if (displayingGuides)
    {
      // draw some guides
      stroke(getGuideColour());
      strokeWeight(1);
      // centre line
      line(getOutline().getLeft()+(getOutline().getWidth()/2), getOutline().getTop(), 
      getOutline().getLeft()+(getOutline().getWidth()/2), getOutline().getBottom());

      // page top line
      line(getOutline().getLeft(), getOutline().getTop()+sc(getHomePoint().y), 
      getOutline().getRight(), getOutline().getTop()+sc(getHomePoint().y));
    }

    // draw page
    fill(getPageColour());
    rect(getOutline().getLeft()+sc(getPage().getLeft()), 
    getOutline().getTop()+sc(getPage().getTop()), 
    sc(getPage().getWidth()), 
    sc(getPage().getHeight()));
    text("page " + getDimensionsAsText(getPage()), getOutline().getLeft()+sc(getPage().getLeft()), 
    getOutline().getTop()+sc(getPage().getTop())-3);
    noFill();



    // draw actual image
    if (displayingImage && imageIsReady())
    {
      float ox = getOutline().getLeft()+sc(getImageFrame().getLeft());
      float oy = getOutline().getTop()+sc(getImageFrame().getTop());
      float w = sc(getImageFrame().getWidth());
      float h = sc(getImageFrame().getHeight());
      tint(255, getImageTransparency());
      image(getImage(), ox, oy, w, h);
      noTint();
      strokeWeight(1);
      stroke(150, 150, 150, 40);
      rect(ox, oy, w-1, h-1);
      fill(150, 150, 150, 40);
      text("image", ox, oy-3);
      noFill();
    }
    
    stroke(getBackgroundColour(),150);
    strokeWeight(3);
    noFill();
    rect(getOutline().getLeft()-2, getOutline().getTop()-2, getOutline().getWidth()+3, getOutline().getHeight()+3);

    stroke(getMachineColour(),150);
    strokeWeight(3);
    noFill();
    rect(getOutline().getLeft()+sc(getPage().getLeft())-2, 
    getOutline().getTop()+sc(getPage().getTop())-2, 
    sc(getPage().getWidth())+4, 
    sc(getPage().getHeight())+4);



    if (displayingSelectedCentres)
    {
      drawExtractedPixelCentres();
    }
    if (displayingDensityPreview)
    {
      drawExtractedPixelDensities();
    }
    if (displayingGuides)
    {
      drawPictureFrame();
    }

    if (displayingVector && getVectorShape() != null)
    {
      displayVectorImage();
    }

    if (displayingGuides 
      && getOutline().surrounds(getMouseVector())
      && currentMode != MODE_MOVE_IMAGE
      && mouseOverControls().isEmpty()
      )
    {
      drawHangingStrings();
      drawRows();
      cursor(CROSS);
    }
    else
    {
      cursor(ARROW);
    }
  }
  
  public void drawForTrace()
  {
    // work out the scaling factor.
    noStroke();
    // draw machine outline
    
//    liveImage = trace_buildLiveImage();
    // draw actual image

//    if (drawingLiveVideo)
//    {
//      displayLiveVideo();
//    }
    
    if (drawingTraceShape && traceShape != null)
    {
      displaytraceShape();
    }
    else
    {
      
    }
  }
  
//  public void displayLiveVideo()
//  {
//    // draw actual image, maximum size
//    if (processedLiveImage != null)
//    {
//      // origin - top left of the corner
//      float ox = getPanel(PANEL_NAME_WEBCAM).getOutline().getRight()+7;
//      float oy = getPanel(PANEL_NAME_GENERAL).getOutline().getTop();
//      
//      // calculate size to display at.
//      float aspectRatio = (rotateWebcamImage) ? 480.0/640.0 : 640.0/480.0; // rotated, remember
//      float h = height - getPanel(PANEL_NAME_GENERAL).getOutline().getTop() -10;
//      float w = h * (480.0/640.0);
////      println("height: " + h + ", width: " + w);
////      println("origin x: " + ox + ", y: " + oy);
//      
//      if (rotateWebcamImage) 
//      {
//        float t = h;
//        h = w;
//        w = t;
//      }
//      
//      //stroke(255);
//      rect(ox,oy,w,h);
//
//      tint(255, getImageTransparency());
//      if (rotateWebcamImage)
//      {
//        translate(ox, oy);
//        rotate(radians(270));
//        image(processedLiveImage, -w, 0, w, h);
//        image(liveImage, -w, (w-(w/4))+10, w/4, h/4);
////        stroke(0,255,0);
////        ellipse(0,0,80,40);
////        stroke(0,0,255);
////        ellipse(-w,0,80,40);
//        rotate(radians(-270));
//        translate(-ox, -oy);
//      }
//      else
//      {
//        translate(ox, oy);
//        image(processedLiveImage, 0, 0, h, w);
//        image(liveImage, h-(h/4), w+10, h/4, w/4);
//        translate(-ox, -oy);
//      }
//      noTint();
//      noFill();
//    }
//  }
  
  public void displaytraceShape()
  {
    strokeWeight(1);
    
    if (captureShape != null)
    {
      //displaytraceShapeAtFullSize(traceShape, false, color(150,150,150));
      displaytraceShapeAtFullSize(captureShape, true, color(0,0,0));
    }
    else
    {
      displaytraceShapeAtFullSize(traceShape, false, color(255,255,255));
    }
  }
  
  public void displaytraceShapeAtFullSize(RShape vec, boolean illustrateSequence, Integer colour)
  {
    RG.ignoreStyles();
    // work out scaling to make it full size on the screen
    float aspectRatio = vec.getWidth()/vec.getHeight(); // rotated, remember
    float h = height - getPanel(PANEL_NAME_GENERAL).getOutline().getTop() -10;
    float w = h * aspectRatio;
    float scaler = h / vec.getWidth();
    if (rotateWebcamImage)
      scaler =  h / vec.getHeight();
    PVector position = new PVector(getPanel(PANEL_NAME_TRACE).getOutline().getRight()+7, getPanel(PANEL_NAME_GENERAL).getOutline().getTop());

    noFill();
    RPoint[][] pointPaths = vec.getPointsInPaths();
    if (illustrateSequence)
      pointPaths = sortPathsCentreFirst(vec, pathLengthHighPassCutoff);
    
    if (pointPaths != null)
    {
      float incPerPath = 0.0;
      if (illustrateSequence)
        incPerPath = 255.0 / (float) pointPaths.length;

      for(int i = 0; i<pointPaths.length; i++)
      {
        float col = (float)i * incPerPath;
//        if (pointPaths[i].length >= pathLengthHighPassCutoff)
//        {
          if (pointPaths[i] != null) 
          {
            if (illustrateSequence)
              stroke((int)col, (int)col, (int)col, 128);
            else
              stroke(colour);
              
            beginShape();
            for (int j = 0; j<pointPaths[i].length; j++)
            {
              PVector p = new PVector(pointPaths[i][j].x, pointPaths[i][j].y);
              p = PVector.mult(p, scaler);
              p = PVector.add(p, position);
              vertex(p.x, p.y);
            }
            endShape();
//          }
        }
      }
    }
    noFill();
  }
  
  public void displayVectorImage()
  {
    displayVectorImage(getVectorShape(), vectorScaling/100, getVectorPosition(), color(0,0,0), true);
    
    if (captureShape != null)
    {
      float scaling = inMM(getPictureFrame().getWidth()) / captureShape.getWidth();
      PVector position = new PVector(inMM(getPictureFrame().getPosition().x), inMM(getPictureFrame().getPosition().y) + (captureShape.getHeight() * scaling));
      displayVectorImage(captureShape, 
        scaling, 
        position, 
        color(0,200,0), true);
    }
  }
  
  public void displayVectorImage(RShape vec, float scaling, PVector position, int strokeColour, boolean drawCentroid)
  {
    PVector centroid = new PVector(vec.width/2, vec.height/2);
    centroid = PVector.mult(centroid, (vectorScaling/100));
    centroid = PVector.add(centroid, getVectorPosition());
    centroid = scaleToScreen(centroid);

    RPoint[][] pointPaths = vec.getPointsInPaths();
    RG.ignoreStyles();
    strokeWeight(1);
    if (pointPaths != null)
    {
      for(int i = 0; i<pointPaths.length; i++)
      {
        if (pointPaths[i] != null) 
        {
          boolean inShape = false;
          for (int j = 0; j<pointPaths[i].length; j++)
          {
            PVector p = new PVector(pointPaths[i][j].x, pointPaths[i][j].y);
            p = PVector.mult(p, scaling);
            p = PVector.add(p, position);
            if (getPictureFrame().surrounds(inSteps(p)))
            {
              if (!inShape) 
              {
                beginShape();
                inShape = true;
              }
              p = scaleToScreen(p);
              stroke(strokeColour);
              vertex(p.x, p.y);
//              ellipse(p.x, p.y, 3, 3);
            }
            else
            {
              if (inShape) 
              {
                endShape();
                inShape = false;
              }
            }
          }
          if (inShape) endShape();
        }
      }
      if (drawCentroid)
      {
        // draw spot at centre
        fill(255,0,0,128);
        ellipse(centroid.x, centroid.y, 20,20);
        noFill();
      }
    }
  }


  // this scales a value from the screen to be a position on the machine
  /**  Given a point on-screen, this works out where on the 
   actual machine it refers to.
   */
  public PVector scaleToDisplayMachine(PVector screen)
  {
    // offset
    float x = screen.x - getOffset().x;
    float y = screen.y - getOffset().y;

    // transform
    float scalingFactor = 1.0/getScaling();
    x = scalingFactor * x;
    y = scalingFactor * y;

    // and out
    PVector mach = new PVector(x, y);
    return mach;
  }

  /** This works out the position, on-screen of a specific point on the machine.
   Both values are cartesian coordinates.
   */
  public PVector scaleToScreen(PVector mach)
  {
    // transform
    float x = mach.x * scaling;
    float y = mach.y * scaling;

    // offset
    x = x + getOffset().x;
    y = y + getOffset().y;

    // and out!
    PVector screen = new PVector(x, y);
    return screen;
  }

  // converts a cartesian coord into a native one
  public PVector convertToNative(PVector cart)
  {
    // width of machine in mm
    float width = inMM(super.getWidth());

    // work out distances
    float a = dist(0, 0, cart.x, cart.y);
    float b = dist(width, 0, cart.x, cart.y);

    // and out
    PVector nativeMM = new PVector(a, b);
    return nativeMM;
  }

  void drawPictureFrame()
  {
    strokeWeight(1);

    PVector topLeft = scaleToScreen(inMM(getPictureFrame().getTopLeft()));
    PVector botRight = scaleToScreen(inMM(getPictureFrame().getBotRight()));

    stroke (getFrameColour());

    // top left    
    line(topLeft.x-4, topLeft.y, topLeft.x-10, topLeft.y);
    line(topLeft.x, topLeft.y-4, topLeft.x, topLeft.y-10);

    // top right
    line(botRight.x+4, topLeft.y, botRight.x+10, topLeft.y);
    line(botRight.x, topLeft.y-4, botRight.x, topLeft.y-10);

    // bot right
    line(botRight.x+4, botRight.y, botRight.x+10, botRight.y);
    line(botRight.x, botRight.y+4, botRight.x, botRight.y+10);

    // bot left
    line(topLeft.x-4, botRight.y, topLeft.x-10, botRight.y);
    line(topLeft.x, botRight.y+4, topLeft.x, botRight.y+10);

    stroke(255);


    //    float width = inMM(getPictureFrame().getBotRight().x - getPictureFrame().getTopLeft().x);
    //    println("width: "+ width);
  }


  public void drawHangingStrings()
  {
    // hanging strings
    strokeWeight(4);
    stroke(255, 255, 255, 64);
    line(getOutline().getLeft(), getOutline().getTop(), mouseX, mouseY);
    line(getOutline().getRight(), getOutline().getTop(), mouseX, mouseY);
  }

  /**  This draws on screen, showing an arc highlighting the row that the mouse
   is on.
   */
  public void drawRows()
  {
    PVector mVect = getMouseVector();

    // scale it to  find out the coordinates on the machine that the mouse is pointing at.
    mVect = scaleToDisplayMachine(mVect);
    // convert it to the native coordinates system
    mVect = convertToNative(mVect);
    // snap it to the grid
    mVect = snapToGrid(mVect, getGridSize());
    // scale it back to find out how to represent this on-screen
    mVect = scaleToScreen(mVect);

    // and finally, because scaleToScreen also allows for the machine position (offset), subtract it.
    mVect.sub(getOffset());

    float rowThickness = inMM(getGridSize()) * getScaling();
    rowThickness = (rowThickness < 1.0) ? 1.0 : rowThickness;
    strokeWeight(rowThickness);
    stroke(150, 200, 255, 50);
    strokeCap(SQUARE);

    float dia = mVect.x*2;
    arc(getOutline().getLeft(), getOutline().getTop(), dia, dia, 0, 1.57079633);

    dia = mVect.y*2;
    arc(getOutline().getRight(), getOutline().getTop(), dia, dia, 1.57079633, 3.14159266);
    
  }

  void drawExtractedPixelCentres()
  {
    for (PVector cartesianPos : getExtractedPixels())
    {
      // scale em, danno.
      PVector scaledPos = scaleToScreen(cartesianPos);
      strokeWeight(1);
      stroke(255, 0, 0, 128);
      noFill();
      line(scaledPos.x-1, scaledPos.y-1, scaledPos.x+1, scaledPos.y+1);
      line(scaledPos.x-1, scaledPos.y+1, scaledPos.x+1, scaledPos.y-1);
    }
  }

  void drawExtractedPixelDensities()
  {

    float pixelSize = inMM(getGridSize()) * getScaling();
    pixelSize = (pixelSize < 1.0) ? 1.0 : pixelSize;

    pixelSize = pixelSize * getPixelScalingOverGridSize();

    if (getExtractedPixels() != null)
    {
      for (PVector cartesianPos : getExtractedPixels())
      {
        if ((cartesianPos.z <= pixelExtractBrightThreshold) && (cartesianPos.z >= pixelExtractDarkThreshold))
        {
          // scale em, danno.
          PVector scaledPos = scaleToScreen(cartesianPos);
          noStroke();
          
          // Posterize the density value
          int reduced = int(map(cartesianPos.z, 1, 255, 1, densityPreviewPosterize)+0.5);
          int brightness = int(map(reduced, 1, densityPreviewPosterize, 1, 255));
          
          fill(brightness);
          switch (getDensityPreviewStyle())
          {
            case DENSITY_PREVIEW_ROUND: 
              previewRoundPixel(scaledPos, pixelSize);
              break;
            case DENSITY_PREVIEW_ROUND_SIZE:
              fill(0);
              previewRoundPixel(scaledPos, map(brightness, 1, densityPreviewPosterize, pixelSize, 1));
              break;
            case DENSITY_PREVIEW_DIAMOND:
              previewDiamondPixel(scaledPos, pixelSize, pixelSize, brightness);
              break;
            case DENSITY_PREVIEW_NATIVE:
              previewNativePixel(scaledPos, pixelSize, brightness);
              break; 
            case DENSITY_PREVIEW_NATIVE_SIZE:
              previewNativePixel(scaledPos, map(brightness, 1, densityPreviewPosterize, pixelSize, 1), 50);
              break; 
            case DENSITY_PREVIEW_NATIVE_ARC:
              previewRoundPixel(scaledPos, pixelSize*0.8);
              previewNativeArcPixel(scaledPos, pixelSize, brightness);
              break; 
            default:
              previewRoundPixel(scaledPos, pixelSize);
              break;
          }
        }
      }
    }
    noFill();
  }
  
  void previewDiamondPixel(PVector pos, float wide, float high, float brightness)
  {
    wide*=1.4;
    high*=1.4;
    // shall I try and draw a diamond here instead? OK! I'll do it! Ha!
    float halfWidth = wide / 2.0;
    float halfHeight = high / 2.0;
    fill(0,0,0, 255-brightness);
    quad(pos.x, pos.y-halfHeight, pos.x+halfWidth, pos.y, pos.x, pos.y+halfHeight, pos.x-halfWidth, pos.y);
    
  }
  
  void previewNativePixel(PVector pos, float size, float brightness)
  {
    float half = size / 2.0;
    
    // arcs from the left-hand corner
    float distFromPointA = getOutline().getTopLeft().dist(pos);
    float distFromPointB = getOutline().getTopRight().dist(pos);

    List<PVector> int1 = findIntersections(getOutline().getLeft(), distFromPointA-half, getOutline().getRight(), distFromPointB-half, size);
    List<PVector> int2 = findIntersections(getOutline().getLeft(), distFromPointA+half, getOutline().getRight(), distFromPointB-half, size);
    
    if (!int1.isEmpty() && !int2.isEmpty()) {
      fill(0,0,0, 255-brightness);
      beginShape();
  
      // plot out the vertexes    
      vertex(int1.get(0).x, int1.get(0).y);
      vertex(int2.get(0).x, int2.get(0).y);
      vertex(int2.get(1).x, int2.get(1).y);
      vertex(int1.get(1).x, int1.get(1).y);
      vertex(int1.get(0).x, int1.get(0).y);
      endShape();
    }
  }

  void previewNativeArcPixel(PVector pos, float size, float brightness)
  {
    float half = size / 2.0;
//    fill(0,0,0, 255-brightness);
    beginShape();
    
    // arcs from the left-hand corner
    float distFromPointA = getOutline().getTopLeft().dist(pos);
    float distFromPointB = getOutline().getTopRight().dist(pos);

    List<PVector> int1 = findIntersections(getOutline().getLeft(), distFromPointA-half, getOutline().getRight(), distFromPointB-half, size);
    List<PVector> int2 = findIntersections(getOutline().getLeft(), distFromPointA+half, getOutline().getRight(), distFromPointB-half, size);

    // plot out the vertexes    
    noFill();
    stroke(0,0,0, 255-brightness);
    
    float i1Angle1 = atan2(int1.get(0).y-getOutline().getTop(), int1.get(0).x-getOutline().getLeft());
    float i1Angle2 = atan2(int1.get(1).y-getOutline().getTop(), int1.get(1).x-getOutline().getLeft());
    arc(getOutline().getLeft(), getOutline().getTop(), (distFromPointA-half)*2, (distFromPointA-half)*2, i1Angle1, i1Angle2);

    i1Angle1 = atan2(int2.get(0).y-getOutline().getTop(), int2.get(0).x-getOutline().getLeft());
    i1Angle2 = atan2(int2.get(1).y-getOutline().getTop(), int2.get(1).x-getOutline().getLeft());
    arc(getOutline().getLeft(), getOutline().getTop(), (distFromPointA+half)*2, (distFromPointA+half)*2, i1Angle1, i1Angle2);

    i1Angle1 = atan2( int1.get(0).y-getOutline().getTop(), int1.get(0).x-getOutline().getRight());
    i1Angle2 = atan2( int2.get(0).y-getOutline().getTop(), int2.get(0).x-getOutline().getRight());
    arc(getOutline().getRight(), getOutline().getTop(), (distFromPointB-half)*2, (distFromPointB-half)*2, i1Angle2, i1Angle1);

    i1Angle1 = atan2( int1.get(1).y-getOutline().getTop(), int1.get(1).x-getOutline().getRight());
    i1Angle2 = atan2( int2.get(1).y-getOutline().getTop(), int2.get(1).x-getOutline().getRight());
    arc(getOutline().getRight(), getOutline().getTop(), (distFromPointB+half)*2, (distFromPointB+half)*2, i1Angle2, i1Angle1);

    
    endShape();
  }
  
  
        

  void previewRoundPixel(PVector pos, float dia)
  {
     ellipse(pos.x, pos.y, dia*1.1, dia*1.1);
  }
  
  // compute and draw intersections
  /**
  circle1 = c1x is the centre, and r1 is the radius of the arc to be drawn.
  circle2 = c2x, r2 describe the arc that is used to calculate the start and 
  end point of the drawn arc.
  
  circle3 = c2x, r3 is calculated by adding size to r2.
  
  The drawn arc should start at the intersection with the circle1, 
  and end at the intersection with circle3.
  
  The clever bits of this are nicked off http://processing.org/discourse/beta/num_1223494826.html
  */
  List<PVector> findIntersections(float c1x, float r1, float c2x, float r2, float pixelSize)
  {
    float c1y = getOutline().getTop();
    float c2y = getOutline().getTop();
    float d=getOutline().getWidth(); // distance between centers
    float base1, h1, base2, h2; // auxiliary distances
    //  p, middle point between q1 and q2
    // q1 dn q2 intersection points
    float p1x,p1y,p2x,p2y, q1x,q1y,q2x,q2y; 
  
    if(d<abs(r1-r2) || d>r1+r2)
    {
      println("C1 and C2 do not intersect");
      return new ArrayList();
    }
    else if(d==r1+r2)
    { // outside each other, intersect in one point
      return new ArrayList();
    }
    else
    {
      // intersect in two points
      base1 = (r1*r1-r2*r2+d*d) / (2*d);
      h1 = sqrt(r1*r1-base1*base1);
  
      p1x = c1x+base1*(c2x-c1x)/d;
      p1y = c1y+base1*(c2y-c1y)/d;
      q1x=abs(p1x-h1*(c2y-c1y)/d);
      q1y=abs(p1y+h1*(c2x-c1x)/d);

      float r3 = r2+pixelSize;
      base2 = (r1*r1-r3*r3+d*d) / (2*d);
      h2 = sqrt(r1*r1-base2*base2);
  
      p2x = c1x+base2*(c2x-c1x)/d;
      p2y = c1y+base2*(c2y-c1y)/d;
      q2x=abs(p2x-h2*(c2y-c1y)/d);
      q2y=abs(p2y+h2*(c2x-c1x)/d);

      List<PVector> l = new ArrayList<PVector>(2);
      l.add(new PVector(q1x, q1y));
      l.add(new PVector(q2x, q2y));
      return l;
     }
  }
  
  color getPixelAtScreenCoords(PVector pos)
  {
    pos = scaleToDisplayMachine(pos);
    pos = inSteps(pos);
    float scalingFactor = getImage().width / getImageFrame().getWidth();
    color col = super.getPixelAtMachineCoords(pos, scalingFactor);
    return col;
  }

  Set<PVector> getExtractedPixels()
  {
    return this.extractedPixels;
  }
  void setExtractedPixels(Set<PVector> p)
  {
    this.extractedPixels = p;
  }

  /* This will return a list of pixels that are included in the area in the 
   parameter.  All coordinates are for the screen.
   */
  Set<PVector> getPixelsPositionsFromArea(PVector p, PVector s, float rowSize)
  {
    extractPixelsFromArea(p, s, rowSize, 0.0);
    return getExtractedPixels();
  }

  public void extractPixelsFromArea(PVector p, PVector s, float rowSize, float sampleSize)
  {
    // get the native positions from the superclass
    Set<PVector> nativePositions = super.getPixelsPositionsFromArea(inSteps(p), inSteps(s), rowSize, sampleSize);

    // work out the cartesian positions
    Set<PVector> cartesianPositions = new HashSet<PVector>(nativePositions.size());
    for (PVector nativePos : nativePositions)
    {
      // convert to cartesian
      PVector displayPos = super.asCartesianCoords(nativePos);
      displayPos = inMM(displayPos);
      displayPos.z = nativePos.z;
      cartesianPositions.add(displayPos);
    }
    setExtractedPixels(cartesianPositions);
  }


  public Set<PVector> extractNativePixelsFromArea(PVector p, PVector s, float rowSize, float sampleSize)
  {
    // get the native positions from the superclass
    Set<PVector> nativePositions = super.getPixelsPositionsFromArea(inSteps(p), inSteps(s), rowSize, sampleSize);
    return nativePositions;
  }

  protected PVector snapToGrid(PVector loose, float rowSize)
  {
    PVector snapped = inSteps(loose);
    snapped = super.snapToGrid(snapped, rowSize);
    snapped = inMM(snapped);
    return snapped;
  }
  
  public boolean pixelsCanBeExtracted()
  {
    if (super.getImage() == null)
      return false;
    else
      return true;
  }
}