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Index › Programming Questions & Help › Syntax Questions › gradient question

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gradient question (Read 477 times)

klive

gradient question
May 13^th, 2009, 5:41pm

hi board

i'm trying to make a line that fades in and out at the ends... i don't understand why this piece of code doesn't do the trick!

int iii = 1;

void setup(){
size(600, 400);
background(0);
frameRate(30);
}

void draw(){
background(0);
strokeWeight(0.5);

for (int i = 0; i < mouseY; i = i + 1){
for (int ii = 0; ii < 255; ii = ii + iii){
if(ii == 255){
iii = -1;}
stroke(ii);}
point(10, i);
}
}

please give me some tips!

Cedric YaBB Moderator Offline Posts: 1838	Re: gradient question Reply #1 - May 13^th, 2009, 6:04pm didnt take a closer look at it. Btw i ii and iii is confusing... just use some other letters or numbers. you can at least add a gradient from the top if you change stroke to stroke(i); cause right now you count it up up to 255 before it "reaches" the point, so thats why its always white.
	twitter.com/CedricKiefer

klive

Re: gradient question
Reply #2 - May 13^th, 2009, 6:20pm

yes i tried stroke(i); it worked fine but i need a separate int that fades in from zero to 255 and out to zero again.

so now the code is already at 255 when it reaches the point(), making every single point white, right?

how would i make the program draw points forming a line, changing the stroke color value each time a new point is drawn?

thanks for any suggestions!

blindfish

Re: gradient question
Reply #3 - May 14^th, 2009, 2:06am

I'm still not sure I understand what you're trying to achieve. The following code gives two possible options.

Code:

int grey;
void setup(){
 size(600, 500);
 background(0);
 frameRate(30);
}

void draw(){
 background(0);
 strokeWeight(0.5);

// Will work up to height = 255*2
for (int i = 0; i < mouseY; i++){
    if(i<255) {
     stroke(i);
    }
    else {
     grey = 255 - (i-255);
     stroke(grey);
    }
   point(10, i);
}

// Fades in to the height of the window
for (int i = 0; i < mouseY; i++){
    float input = i;
    grey = 255 - round(((height-input)/height) * 255);
    println(grey);
    stroke(grey);
    point(20,i);
}
    
}

If you want the line to fade in and out then you might want to look at passing the value of (height-input)/height [from the second for loop] to sin and tweak it as necessary to get the shade of grey you need at each point...

Where is the what if the what is in why?

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