Image

The Image control is a CygNet-aware tool that can be used to display raster (bitmap) and vector images on your screens. Supported image file formats include bitmap (.bmp), portable network graphics (.png), jpeg (.jpg and .jpeg), graphics interchange format (.gif) and scalable vector graphics (.svg). The control can display a static image or a CygNet-aware image or icon, which can be configured to change based on the point state or alarm condition of the associated point. The Image control will be hidden if the configured point is in a point state that doesn’t match any configured images for the control. The control will then update to display the configured image if the point enters a state matching the point scheme, point type, and point state. If no default or custom point state image is specified, a missing image icon () is displayed at design and run mode. The size of the image can be set independently from the size of the control, so that a smaller image can be displayed in a nominal case and a larger, different image in the case of an alarm. Several other configurable properties are supported, including:

• The control can be configured with a valid point configuration but prevented from retrieving any CygNet data, allowing the display of static text while still allowing CygNet data context available from script.
• Date, time, and value formatting for the text displayed on the control is supported.
• The mouse cursor that appears when the mouse hovers over the control is configurable.
• Font sizing, text styling, and text weighting are also configurable.
• This control supports tooltips, which can be displayed as tokenized text, a Canvas object, or the tooltip can be scripted to retrieve and display values for related points or CygNet notes.
• A context menu is available at runtime with access to CygNet point and alarm data, including alarm acknowledgment, current and history values, point and facility configuration, and trending point data on a default chart. Custom context menu items can be scripted allowing customized control behavior.
• The control can be hidden if the associated point is invalid.

The image control does not support animated .gifs, or animated .svgs, at this time.

Image Example

The following image shows an image control.

Sample Image control image changes as point state changes

Property Inheritance

Property Inheritance

Property inheritance is a widely used concept in Canvas. The application supports an explicit relationship between screens, objects, and controls, where certain property values, such as SiteService and facility tags, are passed from one element to another via an inheritance framework. Screens, objects, and controls can be configured as property senders or property receivers and provide configuration options where you can explicitly define the source of the SiteService and facility. Depending on how you have your screens, objects, and controls set up, the SiteService and facility may come from any one of the following sources:

• from itself — indicated by selecting <Self> and then explicitly configuring the property
• inherited from the screen — indicated by selecting Screen, which is always present as a sender
• inherited from another control — indicated by selecting the Name of the sending control

Broadcasting

Screens and objects support an additional notification option to broadcast their SiteService and facility selection changes to other open screens running in the Canvas or Canvas View application. If configured, a <Broadcast> option is available to source the screen's SiteService and facility properties from another open screen.

For example, a text tool can be configured to get its facility from the screen and the screen can be configured to get its facility from a tag chooser. Or Screen_A might source its facility from Screen_B, which gets its facility from a tag chooser.

Receiver or Sender

The image control supports property inheritance as a receiver of its SiteService and facility:

Receive from		Send to
SiteService	Facility	SiteService	Facility
self screen	self screen other controls	none	none

The image control does not send its SiteService or facility to other controls.

Related Topics