Color testing

Programming Questions

David Wil..

in Programming Questions • 2 years ago

Hi all,

Can anyone help me with a simple way of switching a boolean if the mouse pointer is over the colour #CCCCCC for example - I've searched and not found anything and could really use the help...?

cheers

Dave

Replies(6)

Psysoul

Re: Color testing

2 years ago

I guess there is no simple solution.

What is the thing the mouse will be over? You can get mouseX and mouseY and the object position that might be grey...so check if 1, mouse is over the object, 2, object is grey.

David Wil..

Re: Color testing

2 years ago

Thanks, that might be the way forward I suppose - the mouse would be over a PShape, i thought perhaps there might be a way to do it with the dist() function.

Perhaps not?

blindfish

The forum being a bit weird today :(

See get() for a method of getting the colour under the mouse (though note comment about pixels[] being faster).

Also see my recent demo:

http://www.openprocessing.org/visuals/?visualID=15910

anchnk

Re: Color testing

2 years ago

Here's a snippet :

void setup() {
size(200, 200);
background(255);
noStroke();
fill(#CCCCCC);
rect(20, 40, 10, 10);
fill(#0EDAFF);
rect(60, 80, 40, 20);
}
void draw() {
if(isMouseOver(#CCCCCC)) {
println("mouse is over color #CCCCCC");
}
else if(isMouseOver(#0EDAFF)) {
println("mouse is over color #EE00FF");
}
}
boolean isMouseOver(color c) {
// If processing pixels array is null (we didn't call loadPixels yet)
// call loadPixels() to fill processing pixels array
if(pixels == null) {
loadPixels();
return false;
}
else { // Otherwise, if we already get pixels in memory
// check if mouse over pixel's color is equal to the given color
if(pixels[(mouseY*width) + mouseX] == c) {
return true;
}
else {
return false;
}
}
}

blindfish

Re: Re: Color testing

2 years ago

Note that you'll need to call loadPixels() every time the contents of the screen change (e.g. if your shape is moving around):

int x=60;
int vx = 1;
void setup() {
size(200, 200);
noStroke();
}
void draw() {
background(0);
fill(#CCCCCC);
rect(20, 40, 10, 10);
fill(#0EDAFF);
rect(x, 60, 40, 20);
x+=vx;
if(x+40>width || x<0) {
vx*=-1;
}
if(isMouseOver(#CCCCCC)) {
println("mouse is over color #CCCCCC");
}
else if(isMouseOver(#0EDAFF)) {
println("mouse is over color #EE00FF");
}
}
boolean isMouseOver(color c) {
loadPixels();
// you can return the result of the calculation directly here
// instead of using a condition ;)
return pixels[(mouseY*width) + mouseX] == c;
}

David Wil..

Re: Color testing

2 years ago

Great, Thanks for the help! this defintely gives me some options...

D.

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