Class: Scrollbar

Blockly.Scrollbar

class   static

Class for a pure SVG scrollbar. This technique offers a scrollbar that is guaranteed to work, but may not look or behave like the system's scrollbars.

Constructor

Scrollbar

new Scrollbar(workspace, horizontal, opt_pair, opt_class, opt_margin)

Parameter
workspace	Workspace to bind the scrollbar to. Value must not be null.
horizontal	True if horizontal, false if vertical.
opt_pair	Optional True if scrollbar is part of a horiz/vert pair.
opt_class	Optional A class to be applied to this scrollbar.
opt_margin	Optional The margin to apply to this scrollbar.

Properties

DEFAULT_SCROLLBAR_MARGIN

constant   package   static

number

Default margin around the scrollbar (between the scrollbar and the edge of the viewport in pixels).

scrollbarThickness

static

Width of vertical scrollbar or height of horizontal scrollbar in CSS pixels. Scrollbars should be larger on touch devices.

outerSvg_

non-null Element

position

package

Blockly.utils.Coordinate

The upper left corner of the scrollbar's SVG group in CSS pixels relative to the scrollbar's origin. This is usually relative to the injection div origin.

ratio

package

nullable number

The ratio of handle position offset to workspace content displacement.

svgHandle_

non-null Element

Methods

dispose

dispose()

Dispose of this scrollbar. Unlink from all DOM elements to prevent memory leaks.

getRatio_

package

getRatio_() returns number

Helper to calculate the ratio of handle position to scrollbar view size.

Returns

number Ratio.

isVisible

isVisible() returns boolean

Is the scrollbar visible. Non-paired scrollbars disappear when they aren't needed.

Returns

boolean True if visible.

resize

resize(opt_metrics)

Recalculate the scrollbar's location and its length.

Parameter
opt_metrics	Optional Blockly.utils.Metrics A data structure of from the describing all the required dimensions. If not provided, it will be fetched from the host object.

resizeContentHorizontal

resizeContentHorizontal(hostMetrics)

Recalculate a horizontal scrollbar's location within its path and length. This should be called when the contents of the workspace have changed.

Parameter
hostMetrics	Blockly.utils.Metrics A data structure describing all the required dimensions, possibly fetched from the host object. Value must not be null.

resizeContentVertical

resizeContentVertical(hostMetrics)

Recalculate a vertical scrollbar's location within its path and length. This should be called when the contents of the workspace have changed.

Parameter
hostMetrics	Blockly.utils.Metrics A data structure describing all the required dimensions, possibly fetched from the host object. Value must not be null.

resizeViewHorizontal

resizeViewHorizontal(hostMetrics)

Recalculate a horizontal scrollbar's location on the screen and path length. This should be called when the layout or size of the window has changed.

Parameter
hostMetrics	Blockly.utils.Metrics A data structure describing all the required dimensions, possibly fetched from the host object. Value must not be null.

resizeViewVertical

resizeViewVertical(hostMetrics)

Recalculate a vertical scrollbar's location on the screen and path length. This should be called when the layout or size of the window has changed.

Parameter
hostMetrics	Blockly.utils.Metrics A data structure describing all the required dimensions, possibly fetched from the host object. Value must not be null.

set

set(value, updateMetrics)

Set the scrollbar handle's position.

Parameter
value	number The content displacement, relative to the view in pixels.
updateMetrics	Optional boolean Whether to update metrics on this set call. Defaults to true.

setContainerVisible

setContainerVisible(visible)

Set whether the scrollbar's container is visible and update display accordingly if visibility has changed.

Parameter
visible	boolean Whether the container is visible

setHandlePosition

setHandlePosition(newPosition)

Set the offset of the scrollbar's handle from the scrollbar's position, and change the SVG attribute accordingly.

Parameter
newPosition	number The new scrollbar handle offset in CSS pixels.

setOrigin

setOrigin(x, y)

Record the origin of the workspace that the scrollbar is in, in pixels relative to the injection div origin. This is for times when the scrollbar is used in an object whose origin isn't the same as the main workspace (e.g. in a flyout.)

Parameter
x	number The x coordinate of the scrollbar's origin, in CSS pixels.
y	number The y coordinate of the scrollbar's origin, in CSS pixels.

setPosition

package

setPosition(x, y)

Set the position of the scrollbar's SVG group in CSS pixels relative to the scrollbar's origin. This sets the scrollbar's location within the workspace.

Parameter
x	number The new x coordinate.
y	number The new y coordinate.

setVisible

setVisible(visible)

Set whether the scrollbar is visible. Only applies to non-paired scrollbars.

Parameter
visible	boolean True if visible.

updateDisplay_

updateDisplay_()

Update visibility of scrollbar based on whether it thinks it should be visible and whether its containing workspace is visible. We cannot rely on the containing workspace being hidden to hide us because it is not necessarily our parent in the DOM.