Image Cursor in Tuio Code - processing

Question

I'm looking to make an external image cursor to track the fiducial codes in tuio for my graffiti wall. Since I need background to not be run constantly in void draw(), the image cursor leaves a trail of the image around the stage. Anyone know how I can stop it from doing this without placing background in void draw()?
This is my code;
// background(255);
textFont(font, 18*scale_factor);
float obj_size = object_size*scale_factor;
float cur_size = cursor_size*scale_factor;
Vector tuioObjectList = tuioClient.getTuioObjects();
for (int i=0;i<tuioObjectList.size();i++) {
TuioObject tobj = (TuioObject)tuioObjectList.elementAt(i);
stroke(0);
fill(0);
//pushMatrix();
//translate(tobj.getScreenX(width),tobj.getScreenY(height));
//rotate(tobj.getAngle());
image(spray,10,10);
//rect(-obj_size/2,-obj_size/2,obj_size,obj_size);
// popMatrix();
if (mp == true)
{
if (tobj.getSymbolID()==66) {
fill(#FF00FF);
noStroke();
tint(255,127);
ellipse(tobj.getScreenX(width), tobj.getScreenY(height), 50, 50);
fill(#FF00FF);
text(""+tobj.getSymbolID(), tobj.getScreenX(width), tobj.getScreenY(height));
}
if (tobj.getSymbolID()==23) {
fill(#0000FF);
noStroke();
tint(255,127);
ellipse(tobj.getScreenX(width), tobj.getScreenY(height), 50, 50);
fill(#0000FF);
text(""+tobj.getSymbolID(), tobj.getScreenX(width), tobj.getScreenY(height));
}
if (tobj.getSymbolID()==22) {
fill(#00FF00);
noStroke();
tint(255,127);
ellipse(tobj.getScreenX(width), tobj.getScreenY(height), 50, 50);
fill(#00FF00);
text(""+tobj.getSymbolID(), tobj.getScreenX(width), tobj.getScreenY(height));
}
}
}
Vector tuioCursorList = tuioClient.getTuioCursors();
for (int i=0;i<tuioCursorList.size();i++) {
TuioCursor tcur = (TuioCursor)tuioCursorList.elementAt(i);
Vector pointList = tcur.getPath();
if (pointList.size()>0) {
stroke(0, 0, 255);
TuioPoint start_point = (TuioPoint)pointList.firstElement();
;
for (int j=0;j<pointList.size();j++) {
TuioPoint end_point = (TuioPoint)pointList.elementAt(j);
line(start_point.getScreenX(width), start_point.getScreenY(height), end_point.getScreenX(width), end_point.getScreenY(height));
start_point = end_point;
}
stroke(192, 192, 192);
fill(192, 192, 192);
ellipse( tcur.getScreenX(width), tcur.getScreenY(height), cur_size, cur_size);
fill(0);
text(""+ tcur.getCursorID(), tcur.getScreenX(width)-5, tcur.getScreenY(height)+5);
}
}
}
void mousePressed () {
bDrawFullSize = true;
mp = true;
player.play();
if (mouseX > x && mouseX < x+w && mouseY > y && mouseY < y+h) {
button = !button;
}
}
/*if(mousePressed) {
if(mouseX>x && mouseX <x+w && mouseY>y && mouseY <y+h){
image(stencil1,200,100,FULL_SIZE, FULL_SIZE);
}
else
{
if(mouseX>x && mouseX <x+w && mouseY>y && mouseY <y+h){
image(stencil2,200,100,FULL_SIZE, FULL_SIZE);
}
}
}
}*/
void mouseReleased() {
mp = false;
player.close();
//since close closes the file, we need to load the sound effect again.
player = minim.loadFile("spray_close.wav");
}
void mouseDragged() {
drag = true;
}
// these callback methods are called whenever a TUIO event occurs
// called when an object is added to the scene
void addTuioObject(TuioObject tobj) {
println("add object "+tobj.getSymbolID()+" ("+tobj.getSessionID()+") "+tobj.getX()+" "+tobj.getY()+" "+tobj.getAngle());
}
// called when an object is removed from the scene
void removeTuioObject(TuioObject tobj) {
println("remove object "+tobj.getSymbolID()+" ("+tobj.getSessionID()+")");
}
// called when an object is moved
void updateTuioObject (TuioObject tobj) {
println("update object "+tobj.getSymbolID()+" ("+tobj.getSessionID()+") "+tobj.getX()+" "+tobj.getY()+" "+tobj.getAngle()
+" "+tobj.getMotionSpeed()+" "+tobj.getRotationSpeed()+" "+tobj.getMotionAccel()+" "+tobj.getRotationAccel());
}
// called when a cursor is added to the scene
void addTuioCursor(TuioCursor tcur) {
println("add cursor "+tcur.getCursorID()+" ("+tcur.getSessionID()+ ") " +tcur.getX()+" "+tcur.getY());
}
// called when a cursor is moved
void updateTuioCursor (TuioCursor tcur) {
println("update cursor "+tcur.getCursorID()+" ("+tcur.getSessionID()+ ") " +tcur.getX()+" "+tcur.getY()
+" "+tcur.getMotionSpeed()+" "+tcur.getMotionAccel());
}
// called when a cursor is removed from the scene
void removeTuioCursor(TuioCursor tcur) {
println("remove cursor "+tcur.getCursorID()+" ("+tcur.getSessionID()+")");
}
// called after each message bundle
// representing the end of an image frame
void refresh(TuioTime bundleTime) {
redraw();
}
void keyPressed() {
endRecord();
background(bg1);
bDrawFullSize = false;
button = false;
}

Answer 1

Maybe using layers, draw your cursor and/or the other stuff in different layers. Erase one layer and not other as you need, display all them in draw. This is usually done with PGraphics objects. Search processing + layers to see samples. Here and/or in processing forum
something like this:
EDIT: Actually I think that the way to do it is to move all non refreshing draw to a PGraphics and do refresh draw with background(), where you can draw refreshing stuff without a trail. I changed the code to reflect that.
PGraphics l1;
void setup() {
size(200, 200);
l1 = createGraphics(200, 200, JAVA2D);
background(255);
noStroke();
}
void draw() {
background(255);
l1.beginDraw();
l1.fill(255, 0, 255);
l1.noStroke();
if (frameCount%100 == 0) {
l1.rect(random(width), random(height), 20, 20);
}
l1.endDraw();
image(l1, 0, 0);
fill(230);
ellipse(mouseX, mouseY, 30, 30);
}