Linear Gauge Widget (LinearGauge.class)

The Linear Gauge Widget uses two images (a background image and a pointer image) to create a custom "linear gauge". A byte (or word) returned from a function call is the input. The pointer travels linearly on the background image and is positioned based upon the value of the byte (or word) returned from an href function call. The height and width dimensions of the background image determine whether the pointer travels horizontally or vertically. By default, the longer dimension establishes the path that the pointer travels. Optionally, the orientation can be specified if it is desired to have the pointer travel the shorter dimension. It is possible to use a pointerImage that contains transparent components.

Linear Gauge Parameter Attributes:

Parameter="invisible" value="CHECKED" or "UNCHECKED" — Specifies if the Linear Gauge is to start out invisible or not. If the attribute is not present, then by default the Linear Gauge is visible. If the Linear Gauge starts out invisible, the only way to make it visible again is via the IWC method reappear().

Parameter="backgroundImage" value="image" — Image used as the linear background image. Image dimensions must be exactly the same as the dimensions of the Linear Gauge Widget. Image file must be of type .GIF, .JPG, or .PNG.

Parameter="href" value="function" — The function called to retrieve the widget input. See Appendix B for all available functions for the Linear Gauge widget. The function is called at an update frequency specified by the updateFreq attribute.

Parameter="max" value="number" — Maximum value returned from the href function; must be greater than min. If the function returns a byte, the range is 1 - 255 (0x01 - 0xFF). If the function returns a word, the range is 1 - 65535 (0x01 - 0xFFFF).

Parameter="min" value="number" — Minimum value returned from the href function; must be less than max. If the function returns a byte, the range is 0 - 254 (0x00 - 0xFE). If the function returns a word, the range is 0 - 65534 (0x00 - 0xFFFE).

Parameter="minAt" value=""LEFT" or "RIGHT" or "TOP" or "BOTTOM"" — Determines where the minimum value of the linear gauge is located. When the minimum value is returned, the pointer is located at the minAt location. As the value increases, the pointer travels the length of the linear background image until the maximum value is reached and the pointer is then located at the opposite extreme of the minAt location. Default values are LEFT for horizontal linear gauges and BOTTOM for vertical linear gauges. The options are:

• LEFT — The pointer value increases from left to right. (horizontal linear gauge only)
• RIGHT — The pointer value increases from right to left. (horizontal linear gauge only)
• TOP — The pointer value increases from top to bottom. (vertical linear gauge only)
• BOTTOM — The pointer value increases from bottom to top. (vertical linear gauge only)

Parameter="pointerImage" value="image" — Image used as the pointer which travels across the linear background image. Image file must be of type .GIF, .JPG, or .PNG.

Parameter="updateFreq" value ="number," — Specifies the href function call frequency (specified in seconds, with a single floating-point number). The range is 0.00 - 655.35. A value of 0.00 means update never.

Parameter="updateDelay" value ="number" — Specifies the delay time from when the page is loaded until the first href function call (specified in seconds, with a single floating-point number). The range is 0.00 - 655.35. If the second number is not specified, then the delay time defaults to the value of updateFreq.

Parameter="waitForInit" value="CHECKED" or "UNCHECKED" — Specifies if the Linear Gauge pointer will wait for valid data before being displayed on the linearImage. If CHECKED, the Linear Gauge pointer will not display until valid data is received. If UNCHECKED, or the attribute is not present, the Linear Gauge pointer starts at the minAt location until the first packet of data is received.

Optional Linear Gauge Parameter Attributes:

Parameter="orientation" value="HORIZONTAL" or "VERTICAL" — Specifies if the pointer icon is to travel horizontally or vertically. The orientation
parameter will override the orientation determined by the height and width dimensions.

Parameter="pointerOffset" value="number" — Specifies the number of pixels from the center of the channel the handle is located. If a vertical slider, positive numbers shift the handle to the right and negative numbers shift it to the left. If a horizontal slider, positive numbers shift the handle to the bottom and negative numbers shift it to the top. [The range is -100 through 100].