Image

The Image control is a CygNet-aware single-value control 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). Canvas does not support animated .gifs, or animated .svgs. 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.
• The control optionally can be hidden if the associated point tag is invalid.
• In the Canvas Native view 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.
• In the CygNet TWC web view a context menu is available with access to CygNet point and alarm data, including current value details, alarm acknowledgment, alarm summary, and trending point data on a quick chart. The TWC context menu also supports adding any CygNet point presented in the main web view to an ad hoc chart.

This control is supported in the Canvas Native view and the CygNet TWC web view.

Scalable Vector Graphics (.svg) in Thin Web Client

While Canvas and the Image control support .svg file types, we have observed that not all .svg files are compatible with web browsers. If you select an .svg file that is supported in Canvas, but not in a web browser, it may not display correctly in the CygNet TWC web view. We recommend opening the .svg file in a web browser to check that it opens and displays correctly. If it does, then it should be supported by the CygNet TWC web view.

Image Example

The following image shows an image control.

Sample Image control image changes as point state changes

Property Inheritance

Property Inheritance

Property inheritance, or sending and receiving, is a widely used concept in Canvas. The application supports an explicit relationship between screens, objects, and controls, where certain property values, such as facilities and SiteService details, 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 facility and SiteService. Depending on how you have your screens, objects, and controls configured, the facility and SiteService may be received from any one of the following sources:

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

Broadcasting

Screens and objects support an additional notification option to broadcast their facility and SiteService selection changes to other open screens. If configured, a <Broadcast> option is available to source the screen's facility and SiteService 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