draw_background(bgcolor, stroke) {
context.fillStyle = bgcolor;
context.strokeStyle = stroke;
context.rect(this.x, this.y, this.w, this.h);
context.fill();
context.stroke();
}
draw_text(fgcolor) {
context.fillStyle = fgcolor;
context.textAlign = "center";
context.textBaseline = "middle";
context.font = "30px sans-serif";
context.fillText(this.text, this.x + this.w / 2, this.y + this.h / 2);
}