Creating a repeating background fill on a Spark Panel container in Flex 4

The following example shows how you can create a repeating tiled background fill on a Spark Panel container in Flex 4 by creating a custom skin, setting a BitmapFill on the background Rect and then set the skinClass style.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.

For more information on getting started with Flex 4 and Flash Builder 4, see the official Adobe Flex Team blog.

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/03/28/creating-a-repeating-background-fill-on-an-fxpanel-container-in-flex-gumbo/ -->
<s:Application name="Spark_Panel_skinClass_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx">
 
    <s:Panel id="panel"
            title="Spark Panel title"
            skinClass="skins.CustomPanelSkin"
            left="20" right="20" top="20" bottom="20">
        <s:RichText id="rchTxt"
                text="The quick brown fox jumps over the lazy dog."
                fontSize="72"
                left="10" right="10"
                top="10" bottom="10" />
    </s:Panel>
 
</s:Application>

The custom skin class, skins/CustomPanelSkin.mxml, is as follows:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/03/28/creating-a-repeating-background-fill-on-an-fxpanel-container-in-flex-gumbo/ -->
<s:SparkSkin name="CustomPanelSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:fb="http://ns.adobe.com/flashbuilder/2009"
        blendMode="normal"
        mouseEnabled="false"
        minWidth="131" minHeight="127"
        alpha.disabled="0.5" alpha.disabledWithControlBar="0.5">
    <!-- states -->
    <s:states>
        <s:State name="normal" />
        <s:State name="disabled" />
        <s:State name="normalWithControlBar" stateGroups="withControls" />
        <s:State name="disabledWithControlBar" stateGroups="withControls" />
    </s:states>
 
    <fx:Metadata>
        [HostComponent("spark.components.Panel")]
    </fx:Metadata>
 
    <fx:Script fb:purpose="styling">
        <![CDATA[
            /* Define the skin elements that should not be colorized.
            For panel, border and title background are skinned, but the content area and title text are not. */
            static private const exclusions:Array = ["background", "titleDisplay", "contentGroup", "controlBarGroup"];
 
            override public function get colorizeExclusions():Array {
                return exclusions;
            }
 
            override protected function initializationComplete():void {
                useChromeColor = true;
                super.initializationComplete();
            }
 
            override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void {
                if (getStyle("borderVisible") == true) {
                    border.visible = true;
                    background.left = background.top = background.right = background.bottom = 1;
                    contents.left = contents.top = contents.right = contents.bottom = 1;
                } else {
                    border.visible = false;
                    background.left = background.top = background.right = background.bottom = 0;
                    contents.left = contents.top = contents.right = contents.bottom = 0;
                }
 
                dropShadow.visible = getStyle("dropShadowVisible");
 
                var cr:Number = getStyle("cornerRadius");
                var withControls:Boolean = (currentState == "disabledWithControlBar" || currentState == "normalWithControlBar");
 
                if (cornerRadius != cr) {
                    cornerRadius = cr;
 
                    dropShadow.tlRadius = cornerRadius;
                    dropShadow.trRadius = cornerRadius;
                    dropShadow.blRadius = (withControls) ? cornerRadius : 0;
                    dropShadow.brRadius = (withControls) ? cornerRadius : 0;
 
                    setPartCornerRadii(topMaskRect, withControls);
                    setPartCornerRadii(border, withControls);
                    setPartCornerRadii(background, withControls);
                }
 
                if (bottomMaskRect) {
                    setPartCornerRadii(bottomMaskRect, withControls);
                }
 
                borderStroke.color = getStyle("borderColor");
                borderStroke.alpha = getStyle("borderAlpha");
 
                super.updateDisplayList(unscaledWidth, unscaledHeight);
            }
 
            private function setPartCornerRadii(target:Rect, includeBottom:Boolean):void {
                target.topLeftRadiusX = cornerRadius;
                target.topRightRadiusX = cornerRadius;
                target.bottomLeftRadiusX = includeBottom ? cornerRadius : 0;
                target.bottomRightRadiusX = includeBottom ? cornerRadius : 0;
            }
 
            private var cornerRadius:Number;
        ]]>
    </fx:Script>
 
    <!-- drop shadow can't be hittable so it stays sibling of other graphics -->
    <s:RectangularDropShadow id="dropShadow"
            blurX="20" blurY="20" alpha="0.32" distance="11"
            angle="90" color="#000000"
            left="0" top="0" right="0" bottom="0"/>
 
    <!-- drop shadow can't be hittable so all other graphics go in this group -->
    <s:Group left="0" right="0" top="0" bottom="0">
 
        <!-- top group mask -->
        <s:Group id="topGroupMask"
                left="1" top="1" right="1" bottom="1">
            <s:Rect id="topMaskRect"
                   left="0" top="0" right="0" bottom="0">
                <s:fill>
                    <s:SolidColor alpha="0"/>
                </s:fill>
            </s:Rect>
        </s:Group>
 
        <!-- bottom group mask -->
        <s:Group id="bottomGroupMask"
                left="1" top="1" right="1" bottom="1" 
                includeIn="normalWithControlBar, disabledWithControlBar">
            <s:Rect id="bottomMaskRect" left="0" top="0" right="0" bottom="0">
                <s:fill>
                    <s:SolidColor alpha="0"/>
                </s:fill>
            </s:Rect>
        </s:Group>
 
        <!-- layer 1: border -->
        <s:Rect id="border"
                left="0" right="0" top="0" bottom="0" >
            <s:stroke>
                <s:SolidColorStroke id="borderStroke" weight="1" />
            </s:stroke>
        </s:Rect>
 
        <!-- layer 2: background fill -->
        <!--- Defines the appearance of the PanelSkin class's background. -->
        <s:Rect id="background"
                left="1" top="1" right="1" bottom="1">
            <s:fill>
                <s:BitmapFill id="backgroundFill" source="@Embed('skins/pattern_149.gif')" fillMode="repeat" />
            </s:fill>
        </s:Rect>
 
        <!-- layer 3: contents -->
        <!--- Contains the vertical stack of titlebar content and controlbar. -->
        <s:Group id="contents"
                left="1" right="1" top="1" bottom="1">
            <s:layout>
                <s:VerticalLayout gap="0" horizontalAlign="justify" />
            </s:layout>
 
            <s:Group id="topGroup" mask="{topGroupMask}">
 
                <!-- layer 0: title bar fill -->
                <s:Rect id="tbFill"
                        left="0" right="0" top="0" bottom="1">
                    <s:fill>
                        <s:LinearGradient rotation="90">
                            <s:GradientEntry color="0xE2E2E2" />
                            <s:GradientEntry color="0xD9D9D9" />
                        </s:LinearGradient>
                    </s:fill>
                </s:Rect>
 
                <!-- layer 1: title bar highlight -->
                <s:Rect id="tbHilite"
                        left="0" right="0" top="0" bottom="0">
                    <s:stroke>
                        <s:LinearGradientStroke rotation="90" weight="1">
                            <s:GradientEntry color="0xEAEAEA" />
                            <s:GradientEntry color="0xD9D9D9" />
                        </s:LinearGradientStroke>
                    </s:stroke>
                </s:Rect>
 
                <!-- layer 2: title bar divider -->
                <s:Rect id="tbDiv"
                        left="0" right="0" height="1" bottom="0">
                    <s:fill>
                        <s:SolidColor color="0xC0C0C0" />
                    </s:fill>
                </s:Rect>
 
                <!-- layer 3: text -->
                <s:Label id="titleDisplay"
                        maxDisplayedLines="1"
                        left="9" right="3" top="1" bottom="0" minHeight="30"
                        verticalAlign="middle" fontWeight="bold">
                </s:Label>
            </s:Group>
 
            <!--
            Note: setting the minimum size to 0 here so that changes to the host component's
            size will not be thwarted by this skin part's minimum size.   This is a compromise,
            more about it here: http://bugs.adobe.com/jira/browse/SDK-21143
            -->
            <s:Group id="contentGroup"
                    width="100%" height="100%" minWidth="0" minHeight="0">
            </s:Group>
 
            <s:Group id="bottomGroup" minWidth="0" minHeight="0"
                     includeIn="normalWithControlBar, disabledWithControlBar" >
 
                <s:Group left="0" right="0" top="0" bottom="0" mask="{bottomGroupMask}">
 
                    <!-- layer 0: control bar divider line -->
                    <s:Rect left="0" right="0" top="0" height="1" alpha="0.22">
                        <s:fill>
                            <s:SolidColor color="0x000000" />
                        </s:fill>
                    </s:Rect>
 
                    <!-- layer 1: control bar highlight -->
                    <s:Rect left="0" right="0" top="1" bottom="0">
                        <s:stroke>
                            <s:LinearGradientStroke rotation="90" weight="1">
                                <s:GradientEntry color="0xE5E5E5" />
                                <s:GradientEntry color="0xD8D8D8" />
                            </s:LinearGradientStroke>
                        </s:stroke>
                    </s:Rect>
 
                    <!-- layer 2: control bar fill -->
                    <s:Rect left="1" right="1" top="2" bottom="1">
                        <s:fill>
                            <s:LinearGradient rotation="90">
                                <s:GradientEntry color="0xDADADA" />
                                <s:GradientEntry color="0xC5C5C5" />
                            </s:LinearGradient>
                        </s:fill>
                    </s:Rect>
                </s:Group>
                <!-- layer 3: control bar -->
                <s:Group id="controlBarGroup"
                         left="0" right="0" top="1" bottom="1" minWidth="0" minHeight="0">
                    <s:layout>
                        <s:HorizontalLayout paddingLeft="10" paddingRight="10" paddingTop="7" paddingBottom="7" gap="10" />
                    </s:layout>
                </s:Group>
            </s:Group>
        </s:Group>
    </s:Group>
</s:SparkSkin>

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View source is enabled in the following example.

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This entry is based on a beta version of the Flex 4 SDK and therefore is very likely to change as development of the Flex SDK continues. The API can (and will) change causing examples to possibly not compile in newer versions of the Flex 4 SDK.

One thought on “Creating a repeating background fill on a Spark Panel container in Flex 4

  1. Every time I see an Image background fill example with Spark it’s an embed:

    How do I fill with an image dynamically pulled from a web URL? In Flex 3.5 this was pretty easy.

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