Color System in Processing Paint-like Program - variables

Question

I am building a paint-like program in processing. I want to be able to adjust the r, g, and b values of the pen color. What I did is use the 'r' key to allow the user to change r. After hitting 'r' they use the '+' and '-' keys to adjust it. Then you hit 'd', and it finishes. '+' and '-' are already used for pen size so I had to do it this way. But when I run the code and hit r it freezes up and stops responding. Does anyone know what is wrong.
Here is the problematic part of the code:
if(key == 'r'){ // Activates if 'r' is pressed
actr = true; // Sets actr = to true
while (actr = true) { // Goes until actr is false
if (key == '=') { // Activates is '=' is pressed
r = r ++; // Increases r by one
}
if (key == '-'){ // Activates if '-' is pressed
r = r --; // Decreases r by one
}
if (key == 'd') { // Activates if 'd' is pressed
actr = false; // Sets actr = to false
}
}
}
Here is the full code: http://www.openprocessing.org/sketch/226658

Answer 1

You've got a few problems. First of all, look at this line:
while (actr = true) { // Goes until actr is false
You're not checking equality here, you're assigning the value of true to your actr variable, which will also evaluate to true. In other words, that will never be false. Instead, you should use:
while (actr == true) {
Or even better:
while (actr) {
However, even when you fix that, your while loop will still never exit. This is because you're busy waiting and blocking the program from continuing. This will prevent Processing from ever changing the key variable.
Instead of busy waiting, just keep track of which mode you're in, which determines what the + and - keys do. You could use a series of booleans:
boolean size = true;
boolean red = false;
boolean green = false;
boolean blue = false;
void keyPressed(){
if(key == 'r'){ // Activates if 'r' is pressed
if (key == '=') {
if(size){
x++;
}
else if(red){
r++;
}
}
else if (key == '-'){
if(size){
x++;
}
else if(red){
r++;
}
}
if (key == 'd') { // Activates if 'd' is pressed
size = true;
red = false;
blue = false;
green = false;
}
else if(key == 'r'){
size = false;
red = true;
blue = false;
green = false;
}
}
}
That's just one approach, and I didn't include all of the code, but that should be a better general idea than your busy waiting.