Iterating and managing ofPixels

ingyeoking13 · November 23, 2019, 2:20am

Hi

I’m struggling with ofPixels. accessing pixels and change r,g,b information. my source is following.

ofImage image;
ofPixels pixs;

void ofApp::setup() {

	ofSetFrameRate(60);
	ofSetWindowTitle("openFrameworks");

	ofBackground(239);
	ofSetLineWidth(2);
	ofEnableDepthTest();
	image.load("angelinaDanilova.jpg");
	ofSetWindowShape(image.getWidth(), image.getHeight());

}

//--------------------------------------------------------------
void ofApp::update() {
	pixs = image.getPixelsRef();
	for (ui i = 0; i < pixs.getHeight(); i++)
	{
		for (ui j = 0; j < pixs.getWidth(); j++)
		{
			ui idx = i * image.getWidth() + j;
			ofColor pix = pixs[idx];

//			pix.r = pix.r;//(pix.r / 255) * 255;
//			pix.g = pix.g;//(pix.g / 255) * 255;
//			pix.b = pix.b;//(pix.b / 255) * 255;

			pixs.setColor(idx, pix); //<-- pixs.setColor(i, j,pix), pis.setColor(j, i, pix)?
		}
	}
}

//--------------------------------------------------------------
void ofApp::draw() {

	ofTexture data;
	data.loadData(pixs);
	data.draw(0, 0);

}

//--------------------------------------------------------------
int main() {

	ofSetupOpenGL(720, 720, OF_WINDOW);
	ofRunApp(new ofApp());
}

following image is result.

her head is missing…
I tried with pix.setColor(i, j, pixs), pix.setColor(j, i, pixs)… but failed.
I need help. thanks.

ofpixel · November 23, 2019, 2:07pm

Make it simple

What happens if you only do

pixs = image.getPixels();

Without the rest below (cause it is at the moment redundant).

Maybe try with specifying the format. GL_RGBA or GL_RGB in both loads.
Just out of curiosity. Add this in the setup.

ofDisableAlphaBlending();
ofDisableArbTex();

ingyeoking13 · November 24, 2019, 2:04pm

Hi, @ofpixel. I tried with your solution. but the result is same.
your second suggestion that use format GL_RGBA. I tried with ofFbo but failed.
following is my source.

#include "ofApp.h"
using ui = unsigned int;


ofImage image;
ofPixels pixs;

void ofApp::setup() {
	ofDisableArbTex();
	ofDisableAlphaBlending();

	ofSetFrameRate(60);
	ofSetWindowTitle("openFrameworks");

	ofBackground(239);
	image.load("angelinaDanilova.jpg");
	ofSetWindowShape(image.getHeight(), image.getWidth());

}

//--------------------------------------------------------------
void ofApp::update() {
	pixs = image.getPixels();
	for (ui i = 0; i < pixs.getHeight(); i++)
	{
		for (ui j = 0; j < pixs.getWidth(); j++)
		{
			ui idx = i * image.getWidth() + j;
			ofColor pix = pixs[idx];

			pix.r = pix.r;//(pix.r / 255) * 255;
			pix.g = pix.g;//(pix.g / 255) * 255;
			pix.b = pix.b;//(pix.b / 255) * 255;

			pixs.setColor(idx, pix);
		}
	}
}

//--------------------------------------------------------------
void ofApp::draw() {
	ofFbo fbo;
	fbo.allocate(image.getWidth(), image.getHeight(), GL_RGBA);
	fbo.begin();

	ofTexture data;
	data.loadData(pixs);
	data.draw(0, 0);

	fbo.end();
	fbo.draw(0, 0);
}

//--------------------------------------------------------------
int main() {

	ofSetupOpenGL(720, 720, OF_WINDOW);
	ofRunApp(new ofApp());
}

but the result is same… sorry…

ingyeoking13 · November 26, 2019, 3:58pm

solved.

I was trying to write a code that manages ofPixels. but I found similar article at this site. I could same operator with image object. and now I know that what was problem. the problem was idx (variable) that my cord calculate. it does not matched coordinate (x, y) of Image.

I achieved writing more readable code. following is my source. and also result.

#include "ofApp.h"
using ui = unsigned int;

ofImage image;

void ofApp::setup() {

	ofSetFrameRate(60);
	ofSetWindowTitle("openFrameworks");

	ofBackground(239);
	image.load("angelinaDanilova.jpg");
	ofSetWindowShape(image.getHeight(), image.getWidth());

}

//--------------------------------------------------------------
void ofApp::update() {
	for (ui i = 0; i < image.getHeight(); i++)
	{
		for (ui j = 0; j < image.getWidth(); j++)
		{
			ofColor col = image.getColor(j, i);

			col.r = round(((double)col.r)/ 255) * 255;
			col.g = round(((double)col.g)/ 255) * 255; 
			col.b = round(((double)col.b)/ 255) * 255;

			image.setColor(j, i, col);
		}
	}
	image.update();
}

//--------------------------------------------------------------
void ofApp::draw() {
	image.draw(0, 0);
}

//--------------------------------------------------------------
int main() {

	ofSetupOpenGL(720, 720, OF_WINDOW);
	ofRunApp(new ofApp());
}