The Image widget

Author: Christian Mayer
Available since: 0.8.0 (2012)

Description

Adds an image to your visualization. Using the auto-refresh setting this widget can be used e.g. to show a camera picture.

Settings

For a general understanding of how the configuration files are structured and what elements and attributes are it is recommended to read this section first: Pages and structure of CometVisu.

The behaviour and appearance of the Image widget can be influenced by using certain attributes and elements. The following tables show the allowed attributes and elements and their possible values. The screenshots show, how both can be edited in the editor.

Attributes underlined by ….. are mandatory, all the others are optional and be omitted.

Allowed attributes in the Image-element

Element

Attribute

Name

Content

Description

image

src

URI

Complete path (URI) to the picture

width

dimension (number+unit)

Sets the width of the image. Format must be CSS (e.g. px, em, %).

height

dimension (number+unit)

Sets the height of the image. Format must be CSS (e.g. px, em, %).

widthfit

true or false

crop-top

dimension (number+unit)

Sets the top crop of the image. Format must be absolute CSS (e.g. px, em).

crop-bottom

dimension (number+unit)

Sets the bottom crop of the image. Format must be absolute CSS (e.g. px, em).

refresh

decimal

Sets the update rate for the picture in seconds

cachecontrol

full, force, weak or none

Set the cache control strategy for refresh.

flavour

string

Selection of a display variant. See also Flavour.

class

string

Add this value to the CSS class so that it can be formatted by a user provided style sheet.

align

left, right or center

placeholder

none, src, hide or exclude

Defined how to deal with the case when no image url is set

Valid values for cachecontrol are:

full Standard. By extending the URL with a timestamp a refresh is

ensured. Server support is required though.

force Using sophisticated methods an enforcement of the refresh is

attempted.

weak The URL will be extended by an anchor with timestamp. This will

work with most servers where full mode doesn’t work. But it requires the correct use of HTTP headers by the server as well as a correct reaction by the web browser.

none The URL will not be modified. A working refresh can be prevented

by caching.

../../../_images/en_config_widgets_image_index_editor_attributes.png

Attributes in the editor (simple view) [1]

Allowed child-elements and their attributes

Element

Attribute

Structure

Name

Content

Description

image
  • layout

colspan

decimal

Amount of columns this widget should be wide.

colspan-m

decimal

Overrules the amount of columns on a medium screen.

colspan-s

decimal

Overrules the amount of columns on a small screen.

rowspan

decimal

Amount of rows this widget should be high.

x

string

Horizontal position of the widget for 2D pages.

x-s

string

Horizontal position of the widget for 2D pages on a small screen.

x-m

string

Horizontal position of the widget for 2D pages on a medium screen.

y

string

Vertical position of the widget for 2D pages.

y-s

string

Vertical position of the widget for 2D pages on a small screen.

y-m

string

Vertical position of the widget for 2D pages on a medium screen.

z

string

Reserved for future use.

width

string

Width for the widget for 2D pages.

width-s

string

Width for the widget for 2D pages on a small screen.

width-m

string

Width for the widget for 2D pages on a medium screen.

scale

true or false

Enable/Disable scaling layout values relative to backdrop on 2d pages (default: true).

scale-s

true or false

Enable/Disable scaling layout values relative to backdrop on 2d pages on a small screen (default: true).

scale-m

true or false

Enable/Disable scaling layout values relative to backdrop on 2d pages on a medium screen (default: true).

Element

Attribute

Structure

Name

Content

Description

image
  • label

  • icon

name

string

Name of the icon registration.

type

string

flavour

string

Selection of a display variant. See also Flavour.

color

string

Color of the icon in CSS notation (e.g. #1188FF).

styling

string

Change the color of the displayed value depending on its value. See also Styling

class

string

Add this value to the CSS class so that it can be formatted by a user provided style sheet.

image
  • label

    • #text

string

Text to display a label for the widget.

Element

Attribute

Structure

Name

Content

Description

image
  • address

transform

string

Transformation of the bus system value to be shown.

mode

disable, read, write or readwrite

“disable” deactivates the communication, “read” will only fetch data from the backend, “write” will only write to it and an address with “readwrite” will be both, read from and written to.

variant

string

format-pos

decimal

Position for format string when multiple addresses are used.

selector

string

Only MQTT: JSON selector

qos

decimal

Only MQTT: QoS

retain

true or false

Only MQTT: retain flag

ignore-error

true or false

Only MQTT: ignore decode errors.

image
  • address

    • #text

string

The GA (like: 12/0/7) for KNX-backends, the item name for openHAB-backend or the MQTT topic

../../../_images/en_config_widgets_image_index_editor_elements.png

Elements in the editor

Examples

It is possible to manually edit the visu_config.xml and add an entry for the Image widget.

Caution

Make sure that you only use UTF-8 encoded characters by settings the encoding in your XML-editor to UTF-8 mode!

<image src="resource/icons/CometVisu_orange.png" width="45px" height="32px">
  <layout colspan="2"/>
</image>

Footnotes