// ------------------------------------------------------------------
private void eraseUserStuff(Graphics g, int fX, int fY, int n) {
if (n == 0) {
canvasVector.plotVector(backgroundColor, tailPosX, tailPosY, userPosX, userPosY, g);
}
canvasEquation.plotEquation(g, forceName, units, backgroundColor, fX, fY, n);
}
// ------------------------------------------------------------------
// initialize the canvas contents or judge the user's mouse events and respond
public void paint(Graphics g) {
// if forceNumber < 0 and !mUp: do nothing until mUp
// if forceNumber < 0 and mUp (click): start the forces
if (forceNumber < 0 && mUp) {
fInit = true;
mDown = false;
// next line added 4/17/08 (correction for case of zero force true answer)
mUp = false;
forceNumber = 0;
forceName = forceNames[forceNumber];
userPosX = tailPosX;
userPosY = tailPosY;
numTries = 0;
messageCanvas.notifyMouseClick(blinkerStrings[forceNumber]);
// create the force equation and vector objects
canvasEquation = new CanvasEquation(g);
canvasVector = new CanvasVector(g);
}
// if mouseDown and all forces finished: do end game
if (mDown && (forceNumber == maxForceNumber + 1)) {
endGame("OK", cgiScript, problemNo, mouseUpsString);
}
// if mouseDown or mouseDrag and really a force:
// erase user's old vector & eqn, update position
if ((mDown || mDrag) && (forceNumber >= 0) && (forceNumber <= maxForceNumber)) {
messageCanvas.notifyMouseDown(blinkerStrings[forceNumber]);
eraseUserStuff(g, forceX[0], forceY[0], 0);
if (numEquations == 2) {
eraseUserStuff(g, forceX[1], forceY[1], 1);
}
userPosX = newUserPosX;
userPosY = newUserPosY;
}
// if browserPaint or forceInit or mouseDown or mouseDrag and really a force:
// plot fixed & user's new stuff
if ((ifBrowserPaint || fInit || mDown || mDrag)
&& (forceNumber >= 0)
&& (forceNumber <= maxForceNumber)) {
// redraw the userCanvas bounding box and the apparatus
g.setColor(Color.black);
g.drawRect(0, 0, userFrameX, userFrameY);
problemSelector.drawUserApparatus(g);
// draw the user's previously-done correct vectors
if (forceNumber > 0) {
drawDoneVectors(forceNumber - 1, g);
}
// draw the user's new vector and equation
canvasVector.plotVector(tailPosX, tailPosY, userPosX, userPosY, g);
forceX[0] = p2fX(userPosX, userPosY);
forceY[0] = p2fY(userPosX, userPosY);
canvasEquation.plotEquation(g, forceName, units, forceX[0], forceY[0], 0);
if (numEquations == 2) {
forceX[1] = (int) Math.round(cost * forceX[0] - sint * forceY[0]);
forceY[1] = (int) Math.round(sint * forceX[0] + cost * forceY[0]);
canvasEquation.plotEquation(g, forceName, units, forceX[1], forceY[1], 1);
}
// get ready up for new input
fInit = mDown = mDrag = false;
if (ifBrowserPaint) {
ifBrowserPaint = false;
}
}
// if mouseUp, evaluate the user's answer
if (mUp && (forceNumber >= 0) && (forceNumber < numForces)) {
// keep track of the mouse ups
String leftStr = "";
String rightStr = "";
String midStr = mouseUpsString.substring(forceNumber, forceNumber + 1);
if (forceNumber > 0) {
leftStr = mouseUpsString.substring(0, forceNumber);
}
if (forceNumber < numForces - 1) {
rightStr = mouseUpsString.substring(forceNumber + 1, numForces);
}
int numTries = Integer.parseInt(midStr);
numTries++;
if (numTries <= 9) {
midStr = Integer.toString(numTries);
} else {
midStr = "9";
}
mouseUpsString = leftStr + midStr + rightStr;
// if correct, cycle to the next force or to the trailer message
int matchIndex = matchForceComps[forceNumber] - 1;
int depX = Math.abs(forceX[matchIndex] - truAnsX[forceNumber][matchIndex]);
int depY = Math.abs(forceY[matchIndex] - truAnsY[forceNumber][matchIndex]);
if ((depX <= forceTolerance) && (depY <= forceTolerance)) {
// erase the user's stuff
for (int n = 0; n <= numEquations - 1; n++) {
eraseUserStuff(g, forceX[n], forceY[n], n);
}
// draw the apparatus
problemSelector.drawUserApparatus(g);
// draw the set of correctly done vectors
drawDoneVectors(forceNumber, g);
// notify the resultsCanvas of the user's correctly drawn force
boolean ifResultsDone = false;
if (forceNumber == maxForceNumber) {
ifResultsDone = true;
}
resultsCanvas.notifyMouseUpOk(
ifResultsDone,
forceNumber,
forceNames,
units,
truAnsX,
truAnsY,
resultsSpacingStrings,
numEquations,
numForces);
// cycle the force or do the end game
if (forceNumber < maxForceNumber) {
forceNumber++;
numTries = 0;
forceName = forceNames[forceNumber];
userPosX = tailPosX;
userPosY = tailPosY;
forceX[0] = forceY[0] = forceX[1] = forceY[1] = 0;
// draw the equation and message for the *next* force
for (int n = 0; n <= numEquations - 1; n++) {
canvasEquation.plotEquation(g, forceName, units, forceX[n], forceY[n], n);
}
// notify the messageCanvas that there is a new force
messageCanvas.notifyMouseUpOk(blinkerStrings[forceNumber]);
} else {
g.setColor(userTrailerColor);
g.drawString(userTrailer, userTrailerPosX, userTrailerPosY);
// notify the messageCanvas that we are all done
messageCanvas.notifyMouseUpOk("done");
forceNumber++;
}
}
// if not correct and mode > 1, check # of tries
else {
if (problemMode > 1 && numTries >= maxTriesEachForce) {
endGame("notOK", cgiScript, problemNo, mouseUpsString);
}
}
fInit = mUp = mDown = false;
}
}