Quick, Draw! example for openFrameworks

ofApp.cpp

#include "ofApp.h"
#include <fstream>

void ofApp::setup(){
    ofBackground(255);
    ofSetColor(0);
    ofNoFill();
    ofSetBackgroundAuto(false);

    //select file
    string inputFile = "face.ndjson";
    ifstream input(ofToDataPath(inputFile), ifstream::in);
    
    //read JSON data line by line
    ofxJSONElement jsonElement;
    Json::Reader reader;
    string currentLine;
    while(getline(input, currentLine)) {
        reader.parse(currentLine, jsonElement);
        drawDataJson.push_back(jsonElement);
    }
    cout << "Done : read " << drawDataJson.size() << " drawings!"<< endl;

    objNum = int(ofRandom(drawDataJson.size()));
    strokeNum = 0;
    vertexNum = 0;
}

void ofApp::update(){
}

void ofApp::draw(){
    ofSetLineWidth(2.0);
    ofPushMatrix();
    ofTranslate(ofGetWidth()/2-128, ofGetHeight()/2-128);
    ofBeginShape();
    for (int i = 0; i < vertexNum; i++) {
        int x = drawDataJson[objNum]["drawing"][strokeNum][0][i].asInt();
        int y = drawDataJson[objNum]["drawing"][strokeNum][1][i].asInt();
        ofVertex(x, y);
    }
    ofEndShape();
    ofPopMatrix();
    vertexNum++;
    if (vertexNum > drawDataJson[objNum]["drawing"][strokeNum][0].size()) {
        vertexNum = 0;
        strokeNum++;
        if (strokeNum > drawDataJson[objNum]["drawing"].size()-1) {
            vertexNum = 0;
            strokeNum = 0;
            objNum = int(ofRandom(drawDataJson.size()));
            sleep(1);
            ofBackground(255);
        }
    }
}

ofApp.h

#pragma once

#include "ofMain.h"
#include "ofxJSON.h"

class ofApp : public ofBaseApp{
    
public:
    void setup();
    void update();
    void draw();
    
    vector<ofxJSONElement> drawDataJson;
    int vertexNum;
    int objNum;
    int strokeNum;
};