sclass ScaledDiagram {
  settable int w = 600;
  settable int h = 400;
  settable int horizontalMargin = 10;
  settable int verticalMargin = 10;
  
  settable DoubleRange horizontalRange;
  settable DoubleRange verticalRange;

  // Ranges in pixels that we can paint in (image size minus margins)
  DoubleRange xRange() { ret doubleRange(horizontalMargin, w-horizontalMargin); }
  DoubleRange yRange() { ret doubleRange(h-verticalMargin, verticalMargin); }
  
  double xToScreen(double x) { ret transformBetweenDoubleRanges(x, horizontalRange(), xRange()); }
  double yToScreen(double y) { ret transformBetweenDoubleRanges(y, verticalRange(), yRange()); }
  
  int xToScreen_int(double x) { ret iround(xToScreen(x)); }
  int yToScreen_int(double y) { ret iround(yToScreen(y)); }
  
  double xFromScreen(double x) { ret transformBetweenDoubleRanges(x, xRange(), horizontalRange()); }
  double yFromScreen(double y) { ret transformBetweenDoubleRanges(y, yRange(), verticalRange()); }
  
  public int getWidth() { ret w; }
  public int getHeight() { ret h; }
  
  bool hasScale() { ret horizontalRange != null && verticalRange != null; }
}

Began life as a copy of #1036145