const int major_tick_y1 = text_height + ValueMargin * 2;
const int tick_y2 = height();
const int minor_tick_y1 = (major_tick_y1 + tick_y2) / 2;
const int major_tick_y1 = text_height + ValueMargin * 2;
const int tick_y2 = height();
const int minor_tick_y1 = (major_tick_y1 + tick_y2) / 2;