get pixel colour from offscreen buffer

Programming Questions

h1n0t0r1

get pixel colour from offscreen buffer

in Programming Questions • 2 years ago

Hello everyone,

Im very new to processing and programming anything apart from BASIC and non linear languages like max/pd but am ready to make the leap.

I was wondering could anyone give me any pointers on how to get pixel colour data from an image loaded into an offscreen buffer so that it does not display. I though maybe i could also load an image to loadPixels without it displaying but have not found out how to do that yet either.

here is my messy first patch that probably contains a whole world of bad programming habits, any pointers would be great.

thanks for your time :)

PGraphics buffer;

PImage img;

PImage b;

void setup() {

size(800, 600);

buffer = createGraphics(800, 680, P3D);

b = loadImage("PROC01.gif");

image(b, 0, 0);

}

void draw() {

color cp = get(30, 20);

fill(cp);

rect(30, 20, 55, 55);

}

Replies(3)

calsign

Re: get pixel colour from offscreen buffer

2 years ago

To make the image draw to the PGraphics object, you simply call buffer.image(whatever ); instead of image(whatever );
That might help you out...
And then to get a pixel color from the offscreen buffer, use buffer.get(x , y ) which will return the color at (x, y).

fiveagon

Re: Re: get pixel colour from offscreen buffer

2 years ago

Totally this. Also, PImage and PGraphics share a lot of functions. For your example sketch, you don't even need an offscreen buffer.

void setup() {
size(800, 600);
b = loadImage("PROC01.gif");
}
void draw() {
color cp = b.get(30, 20);
fill(cp);
rect(30, 20, 55, 55);
}

h1n0t0r1

Re: get pixel colour from offscreen buffer

2 years ago

many many thanks to you both, wonderful help for a beginner .. it has really helped me understand where i was going right and wrong ... heavy on the wrong ;)

many thanks again

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