Problem with size of reproduced full-size grabScreen screenshot?

@sdaau wrote:

Please consider the compilable minimal (non)working example below - based on examples/empty/emptyExample, standard Makefile and main.cpp, and then:

ofApp.h

#pragma once

#include "ofMain.h"
#define NUMLINES 100

class ofApp : public ofBaseApp{
  public:
    ofTrueTypeFont myfont;
    int state = 0;
    int lx[NUMLINES], ly[NUMLINES], ll[NUMLINES], lw[NUMLINES], lr[NUMLINES], lg[NUMLINES], lb[NUMLINES];
    unsigned int captFrame = 0;
    ofPoint captSize;
    ofImage imgCaptScreenshot;

    void setup();
    void update();
    void draw();

    void mousePressed(int x, int y, int button);
};

ofApp.cpp

#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup(){
  ofSetFrameRate(60);
  myfont.load("arial.ttf", 32);
  // data for random lines:
  int w = ofGetWidth(), h = ofGetHeight();
  for(int i=0; i<NUMLINES; i++) {
    lx[i] = (int) ofRandom(0, w);
    ly[i] = (int) ofRandom(0, h);
    ll[i] = (int) ofRandom(0, ((w>h) ? h/4 : w/4) );
    lw[i] = (int) ofRandom(1, 11);
    lr[i] = (int) ofRandom(0, 255);
    lg[i] = (int) ofRandom(0, 255);
    lb[i] = (int) ofRandom(0, 255);
  }
}

//--------------------------------------------------------------
void ofApp::update(){
  if (state == 1) { //draw nothing, just switch after a sec
    if (ofGetFrameNum() > captFrame + 60) {
      state = 2;
    }
  }
}

//--------------------------------------------------------------
void ofApp::draw(){
  if (state == 0) {
    ofBackgroundGradient(ofColor::blue, ofColor::violet);
    for(int i=0; i<NUMLINES; i++) {
      ofSetColor(lr[i], lg[i], lb[i]);
      ofSetLineWidth(lw[i]);
      ofDrawLine(lx[i], ly[i], lx[i]+ll[i], ly[i]+ll[i]);
    }
    ofSetColor(ofColor::yellow);
    myfont.drawString(" TESTING ", 100,100);
  }
  if (state == 1) { //draw nothing, just switches after a sec
  }
  if (state == 2) { // reproduce screenshot
    ofSetColor(ofColor::white); // set color to white
    imgCaptScreenshot.draw(0,0, captSize.x, captSize.y); //draw image (tinted white, i.e. untinted);
    //~ imgCaptScreenshot.draw(0,0, imgCaptScreenshot.getWidth(), imgCaptScreenshot.getHeight()); //same effect as previous command
  }
}

//--------------------------------------------------------------
void ofApp::mousePressed(int x, int y, int button){
  captFrame = ofGetFrameNum();
  captSize = ofPoint(ofGetWidth(), ofGetHeight());
  imgCaptScreenshot.grabScreen(0,0, captSize.x, captSize.y);
  ofLogNotice() << "::mousePressed " << captFrame << " " << captSize.x << " " << captSize.y ;
  state = 1;
}

In this application, first semi-random content is generated; upon mouse click, this content is captured into ofImage via grabScreen(), while an empty (gray) background is shown for about a second; after the one second is expired, then the captured screenshot is drawn back. The problem I have, is that the original content is rendered like this:

testScreenshot1.png1026x796 159 KB

... however, the reproduced screenshot is rendered like this:

testScreenshot2.png1026x796 72.2 KB

... which is clearly of the wrong size (or scale).

What am I doing wrong, and how can I reproduce a screenshot at exactly the same size and scale as the screen?

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