The gauge graphic displays one value on a circular dial.
The gGauge is a class and contains, apart from the constructor, two functions: dDefine and draw.
Temporary minimum and maximum values are noticed with a green and red dot.
On the same screen, an histogram and a gauge display
Parameters are very close to those of Histogram.
void dDefine( defines an histogram graphic with the following parameters:
Serial_LCD * lcd0, LCD to which the button belongs, with &myLCD,
uint16_t x0, uint16_t y0, point x0, y0,
uint16_t dx, uint16_t dy, x-width dx and y-height dy,
float valueMin, float valueMax, minimal and maximal values.
Optional parameters with default values
uint16_t memory=8, keeps max and min memory for 8 periods. 0 means no memory.
uint16_t grid=8, divides the value axis into 8 areas with 8+1=3 dots. 0 means no grid.
uint16_t backColour=blackColour, self-contained
void draw(float value, String sValue=""); updates the graphic with value and displays sValue if provided.