TK.MeterBase

new MeterBase(optionsopt)

TK.MeterBase is a base class to build different meters such as TK.LevelMeter from. TK.MeterBase uses TK.Gradient and contains a TK.Scale widget. TK.MeterBase inherits all options from TK.Scale.

Note that the two options format_labels and scale_base have different names here.

Note that level meters with high update frequencies can be very demanding when it comes to rendering performance. These performance requirements can be reduced by increasing the segment size using the segment option. Using a segment, the different level meter positions are reduced. This widget will take advantage of that by avoiding rendering those changes to the meter level, which fall into the same segment.

Parameters:
Name Type Attributes Default Description
options Object <optional>
 { }

An object containing initial options.
Properties:
Name Type Attributes Default Description
options.layout String <optional>
 "left"

A string describing the layout of the meter. Possible values are "left", "right", "top" and "bottom". "left" and "right" are vertical layouts, where the meter is on the left or right of the scale, respectively. Similarly, "top" and "bottom" are horizontal layouts in which the meter is at the top or the bottom, respectively.
options.segment Integer <optional>
 1

Segment size. Pixel positions of the meter level are rounded to multiples of this size. This can be used to give the level meter a LED effect and to reduce processor load.
options.value Number <optional>
 0

Level value.
options.base Number <optional>
 false

The base value of the meter. If set to false, the base will coincide with the minimum value options.min. The meter level is drawn starting from the base to the value.
options.label Number <optional>
 0

Value to be displayed on the label.
options.format_label function <optional>
 TK.FORMAT("%.2f")

Function for formatting the label.
options.show_label Boolean <optional>
 false

If set to true a label is displayed.
options.title Number <optional>
 false

The title of the TK.MeterBase. Set to false to hide it.
options.show_scale Boolean <optional>
 true

Set to false to hide the scale.
options.scale_base Number | Boolean <optional>
 false

Base of the meter scale, see TK.Scale for more information.
options.show_labels Boolean <optional>
 true

If true, display labels on the scale.
options.format_labels function <optional>
 TK.FORMAT("%.2f")

Function for formatting the scale labels. This is passed to TK.Scale as option labels.
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Extends

Members

_bar :HTMLDivElement

The DIV element containing the masks and drawing the background. Has class toolkit-bar.

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_canvas :HTMLCanvas

The canvas element drawing the mask. Has class toolkit-mask.

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element :HTMLDivElement

The main DIV container. Has class toolkit-meter-base.

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label :TK.Label

The TK.Label displaying the label.

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scale :TK.Scale

The TK.Scale of the meter.

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title :TK.Label

The TK.Label displaying the title. Has class toolkit-title.

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Methods inherited from TK.Widget

add_child(child)

Registers a widget as a child widget. This method is used to build up the widget tree. It does not modify the DOM tree.

add_children(a)

Registers an array of widgets as children.

all_children()

Returns an array of all children.

enable_draw()

Schedules this widget for drawing.

force_hide()

This is an alias for hide, which may be overloaded. See TK.Container for an example.

force_show()

This is an alias for hide, which may be overloaded. See TK.Container for an example.

get_style()

Returns the computed style of this widgets DOM element.

hidden()

Returns the current hidden status.

hide()

Make the widget hidden. This does not modify the DOM, instead it will stop rendering this widget. Options changed after calling hide will only be rendered (i.e. applied to the DOM) when the widget is made visible again using TK.Widget#show.

remove_child(child)

Removes a child widget. Note that this method only modifies the widget tree and does not change the DOM.

remove_children(a)

Removes an array of children.

set(key, value)

Sets an option.

set_style()

Sets a CSS style property in this widgets DOM element.

show()

Make the widget visible. This does not modify the DOM, instead it will only schedule the widget for rendering.

toggle_hidden()

TK.Toggle the hidden status. This is equivalent to calling hide() or show(), depending on the current hidden status of this widget.

visible_children()

Returns an array of all visible children.

widgetize()

Set the DOM elements of this widgets. This method is usually only used internally. Basically it means to add the id from options and set a basic CSS class. If delegate is true, basic events will be delegated from the element to the widget instance if classify is true, CSS functions will be bound to the widget instance.

Methods inherited from TK.Base

add_event(event, func, prevent, stop)

Register an event handler.

add_events(events, func)

Add multiple event handlers at once, either as dedicated event handlers or a list of event descriptors with a single handler function.

delegate_events(element) → {HTMLElement}

Delegates all occuring DOM events of a specific DOM node to the widget. This way the widget fires e.g. a click event if someone clicks on the given DOM node.

destroy()

Destroys all event handlers and the options object.

fire_event(event, …args)

Fires an event.

fire_events(events)

Fires several events.

get(key)

Get the value of an option.

has_event_listeners(event) → {boolean}

Test if the event descriptor has some handler functions in the queue.

remove_event(event, fun)

Removes the given function from the event queue. If it is a native DOM event, it removes the DOM event listener as well.

remove_events(events, func)

Remove multiple event handlers at once, either as dedicated event handlers or a list of event descriptors with a single handler function.

set_options(optionsopt)

Merges a new options object into the existing one, including deep copies of objects. If an option key begins with the string "on" it is considered as event handler. In this case the value should be the handler function for the event with the corresponding name without the first "on" characters.

userset(key, value)

Sets an option by user interaction. Emits the userset event. The userset event can be cancelled (if an event handler returns false), in which case the option is not set. Returns true if the option was set, false otherwise. If the option was set, it will emit a useraction event.

Events

basechanged

Is fired when the base value changed. The argument is the actual base value.

Parameters:
Name Type Description
base number

The value of the base.
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labelchanged

Is fired when the label changed. The argument is the actual label value.

Parameters:
Name Type Description
label string

The label of the TK.MeterBase.
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titlechanged

Is fired when the title changed. The argument is the actual title.

Parameters:
Name Type Description
title string

The title of the TK.MeterBase.
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valuechanged

Is fired when the value changed. The argument is the actual value.

Parameters:
Name Type Description
value number

The value of the TK.MeterBase.
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Events inherited from TK.Widget

GenericDOMEvents

Generic DOM events. Please refer to W3Schools for further details.

classified

Is fired when a widget is classified.

destroy

Is fired when a widget is destroyed.

doubleclick

Is fired after a double click appeared. Set dblclick to 0 to disable click event handling.

hide

The hide event is emitted when a widget is hidden and is not rendered anymore. This happens both with browser visibility changes and also internally when using layout widgets such as TK.Pager.

initialized

Is fired when a widget is initialized.

redraw

Is fired when a redraw is executed.

resize

The resize event is emitted whenever a widget is being resized. This event can be used to e.g. measure its new size. Note that some widgets do internal adjustments after the resize event. If that is relevant, the TK.Widget#resized event can be used, instead.

resized

The resized event is emitted after each rendering frame, which was triggered by a resize event.

set

The set event is emitted when an option was set using the TK.Widget#set method. The arguments are the option name and its new value.

Note that this happens both for user interaction and programmatical option changes.

show

The show event is emitted when a widget is shown and is being rendered. This is the counterpart to TK.Widget#hide.

stylized

Is fired when a widget is stylized.

visibility

Is fired when the visibility state changes. The first argument is the visibility state, which is either true or false.

widgetize

Is fired when a widget is widgetized.

Events inherited from TK.Base

delegated

Is fired when an element is delegated.

set_[option]

Is fired when an option is set.