class SAPO.Component.CanvasScrollable
Authors:
jose.p.dias AT co.sapo.pt
Version:
0.1 requires SAPO.Dom.Event The function of this component is to mimic the behavior of a scrollable view using just canvas elements. This is an abstraction for large canvas (especially useful for managed draws). TODOs: - test/give example of applyRendererDeltas = false - test/correct when renderer's dimensions change during view lifetime - support an option for drags not to redraw on every mousemove (timer-based)
Since:
February 2012
Defined in Component/CanvasScrollable/0.1/lib.js

Constructor Summary
_init (String|DomElement container, Object options)

Function Summary
deltaScroll (Number dx, Number dy)
- increments the scroll. fixes parameters out of bounds.
Number[2] getDimensions()
- returns the container's dimensions.
Number[2] getMaxScroll()
- returns the max scroll.
Number[2] getScroll()
- returns the current scroll.
redraw()
redraws the view. internally asks the renderer to update itself.
scroll (Number x, Number y)
- updates the scroll. fixes parameters out of bounds.

Constructor Details

constructor _init

_init(String|DomElement container, Object options)
Parameters:
container - the container where the view is to be created (that is, a canvas element).
options
  • Number[2] dims - dimensions of the scrollable view, in pixels.
  • Object renderer - an object with a defined API. getDimensions(), getCanvas and redraw(delta, visibleWindow). see samples for usage.
  • [ String scrollbarsVisible ] - one of ['none', 'horizontal', 'vertical', 'both', 'auto']. defaults to 'auto'
  • [ Number scrollbarLength ] - length of the visible scrolls, in pixels. defaults to 12.
  • [ String scrollbarFill ] - the canvas style to apply to the scrollbars. defaults to rgba(0, 0, 0, 0.5).
  • [ Number wheelDelta ] - the scroll to apply when the mouse wheel is pressed, in pixels. defaults to 10.
  • [ Boolean applyRendererDeltas ] - if true (default), the component applies the scroll, otherwise it's up to the renderer to simulate it.

Function Details

function deltaScroll

deltaScroll(Number dx, Number dy)
- increments the scroll. fixes parameters out of bounds.
Parameters:
dx - scroll delta to apply to the X coordinate, in pixels
dy - scroll delta to apply to the Y coordinate, in pixels

function getDimensions

Number[2] getDimensions()
- returns the container's dimensions.

function getMaxScroll

Number[2] getMaxScroll()
- returns the max scroll.

function getScroll

Number[2] getScroll()
- returns the current scroll.

function redraw

redraw()
redraws the view. internally asks the renderer to update itself.

function scroll

scroll(Number x, Number y)
- updates the scroll. fixes parameters out of bounds.
Parameters:
x - scroll position to apply in the X coordinate, in pixels
y - scroll position to apply in the Y coordinate, in pixels
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