openFrameworks: When ofSetLineWidth is greater than 0 the corners don't line up. This script lines up the corner of the rectangle based on the Line Width.

gistfile1.cpp

void ofFrameRect(ofRectangle r, float lw, bool innerStroke = true) {
    ofNoFill();
    ofSetLineWidth(lw);
    lw = ((innerStroke) ? -1 : 1) * lw / 2;
    ofLine(r.x, r.y, r.x + r.width, r.y);
    ofLine(r.x + r.width + lw, r.y, r.x + r.width + lw, r.y + r.height);
    ofLine(r.x + r.width + lw, r.y + r.height + lw, r.x, r.y + r.height + lw);
    ofLine(r.x + lw, r.y + r.height, r.x + lw, r.y + lw);
}