static int heightForWidth(int w, int h, int newWidth) {
  ret iround(newWidth*doubleRatio(h, w));
}

static int heightForWidth(BufferedImage img, int newWidth) {
  ret heightForWidth(img.getWidth(), img.getHeight(), newWidth);
}

static int heightForWidth(int newWidth, BufferedImage img) {
  ret heightForWidth(img, newWidth);
}

static int heightForWidth(WidthAndHeight img, int newWidth) {
  ret heightForWidth(img.getWidth(), img.getHeight(), newWidth);
}