cobalt/skins/FocusSkin.as

////////////////////////////////////////////////////////////////////////////////
//
//  ADOBE SYSTEMS INCORPORATED
//  Copyright 2009 Adobe Systems Incorporated
//  All Rights Reserved.
//
//  NOTICE: Adobe permits you to use, modify, and distribute this file
//  in accordance with the terms of the license agreement accompanying it.
//
////////////////////////////////////////////////////////////////////////////////

package cobalt.skins
{

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.IBitmapDrawable;
import flash.events.Event;
import flash.filters.GlowFilter;
import flash.geom.ColorTransform;
import flash.geom.Matrix;
import flash.geom.Point;
import flash.geom.Rectangle;

import mx.core.UIComponent;
import mx.core.mx_internal;

import spark.components.supportClasses.SkinnableComponent;

/**
 *  Focus skins for Spark components.
 *
 *  @langversion 3.0
 *  @playerversion Flash 10
 *  @playerversion AIR 1.5
 *  @productversion Flex 4
 */
public class FocusSkin extends UIComponent
{
    //--------------------------------------------------------------------------
    //
    //  Class constants
    //
    //--------------------------------------------------------------------------

    // TODO: Make this a style property?
    private const FOCUS_THICKNESS:int = 2;

    //--------------------------------------------------------------------------
    //
    //  Class variables
    //
    //--------------------------------------------------------------------------

    private static var colorTransform:ColorTransform = new ColorTransform(
                1.01, 1.01, 1.01, 2);
    private static var glowFilter:GlowFilter = new GlowFilter(
                0x70B2EE, 0.85, 5, 5, 3, 1, false, true);
    private static var rect:Rectangle = new Rectangle();;
    private static var filterPt:Point = new Point();

    //--------------------------------------------------------------------------
    //
    //  Constructor
    //
    //--------------------------------------------------------------------------

    /**
     * Constructor.
     */
    public function FocusSkin()
    {
        super();
    }

    //--------------------------------------------------------------------------
    //
    //  Variables
    //
    //--------------------------------------------------------------------------

    /**
     *  Bitmap capture of the focused component. This bitmap includes a glow
     *  filter that shows the focus glow.
     *
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
    private var bitmap:Bitmap;

    /**
     *  @private
     */
    private var _focusObject:SkinnableComponent;

    /**
     *  Object to draw focus around.  If null, uses focusManager.getFocus();
     *
     *  @langversion 3.0
     *  @playerversion Flash 10
     *  @playerversion AIR 1.5
     *  @productversion Flex 4
     */
	public function get focusObject():SkinnableComponent
	{
	    return _focusObject;
	}

	public function set focusObject(value:SkinnableComponent):void
	{
	    _focusObject = value;

        // Add an "updateComplete" listener to the skin so we can redraw
        // whenever the skin is drawn.
        if (_focusObject.skin)
            _focusObject.skin.addEventListener("updateComplete",
                    skin_updateCompleteHandler, false, 0, true);
	}

    //--------------------------------------------------------------------------
    //
    //  Overridden methods
    //
    //--------------------------------------------------------------------------

    override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
    {
        // Early exit if we don't have a focus manager
        if (!focusManager)
            return;

        // Grab a bitmap of the focused object
        if (!focusObject)
			focusObject = focusManager.getFocus() as SkinnableComponent;

        var bitmapData:BitmapData = new BitmapData(
                    focusObject.width + (FOCUS_THICKNESS * 2),
                    focusObject.height + (FOCUS_THICKNESS * 2), true, 0);
        var m:Matrix = new Matrix();

        // If the focus object already has a focus skin, make sure it is hidden.
        if (focusObject.mx_internal::focusObj)
            focusObject.mx_internal::focusObj.visible = false;

        // Temporary solution for focus drawing on CheckBox and RadioButton components.
        // Hide the label before drawing the focus.
        // TODO: Figure out a better solution.
        var hidLabelElement:Boolean = false;
        if ((weakIsCheck(focusObject, "spark.components::CheckBox") ||
             weakIsCheck(focusObject, "spark.components::RadioButton"))
             && Object(focusObject).labelDisplay)
        {
            Object(focusObject).labelDisplay.displayObject.visible = false;
            hidLabelElement = true;
        }

        m.tx = FOCUS_THICKNESS;
        m.ty = FOCUS_THICKNESS;
        bitmapData.draw(focusObject as IBitmapDrawable, m);

        // Show the focus skin, if needed.
        if (focusObject.mx_internal::focusObj)
            focusObject.mx_internal::focusObj.visible = true;

        // Show the label, if needed.
        if (hidLabelElement)
            Object(focusObject).labelDisplay.displayObject.visible = true;

        // Special case for Scroller - fill the entire rect.
        // TODO: Figure out a better solution.
        if (weakIsCheck(focusObject, "spark.components::Scroller"))
        {
            rect.x = rect.y = FOCUS_THICKNESS;
            rect.width = focusObject.width;
            rect.height = focusObject.height;
            bitmapData.fillRect(rect, 0xFFFFFFFF);
        }

        // Transform the color to remove the transparency. The GlowFilter has the "knockout" property
        // set to true, which removes this image from the final display, leaving only the outer glow.
        rect.x = rect.y = FOCUS_THICKNESS;
        rect.width = focusObject.width;
        rect.height = focusObject.height;
        bitmapData.colorTransform(rect, colorTransform);

        // Apply the glow filter
        rect.x = rect.y = 0;
        rect.width = bitmapData.width;
        rect.height = bitmapData.height;
        // If the focusObject has an errorString, use "errorColor" instead of "focusColor"
        if (focusObject.errorString != null && focusObject.errorString != "")
        {
            glowFilter.color = focusObject.getStyle("errorColor");
        }
        else
        {
            glowFilter.color = focusObject.getStyle("focusColor");
        }
        bitmapData.applyFilter(bitmapData, rect, filterPt, glowFilter);

        if (!bitmap)
        {
            bitmap = new Bitmap();
            addChild(bitmap);
            bitmap.x = bitmap.y = -FOCUS_THICKNESS;
        }

        bitmap.bitmapData = bitmapData;
    }

    private static var classDefCache:Object = {};

    /**
     *  @private
     */
    private function weakIsCheck(obj:Object, className:String):Boolean
    {
        if (!(className in classDefCache))
        {
            var classObj:Class = Class(systemManager.getDefinitionByName(className));

            classDefCache[className] = classObj;
        }

        if (!classDefCache[className])
            return false;

        return obj is classDefCache[className];
    }

    private function skin_updateCompleteHandler(event:Event):void
    {
        // We need to redraw whenever the focus object skin redraws.
        invalidateDisplayList();
    }
}
}