Using the ImageSnapshot class to capture images as JPEGs or PNGs in Flex 3

The following example shows how you can use the ImageSnapshot class to capture images as JPEGs or PNGs by setting the encoder parameter in the ImageSnapshot class’s static captureImage() method in Flex 3.

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/12/07/using-the-imagesnapshot-class-to-capture-images-as-jpegs-or-pngs-in-flex-3/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.graphics.ImageSnapshot;
            import mx.graphics.codec.*;

            private const jpgEnc:JPEGEncoder = new JPEGEncoder();
            private const pngEnc:PNGEncoder = new PNGEncoder();

            private function captureImg(imgEnc:IImageEncoder):void {
                var ohSnap:ImageSnapshot;
                ohSnap = ImageSnapshot.captureImage(img, 0, imgEnc);
                textArea.text = ImageSnapshot.encodeImageAsBase64(ohSnap);
            }
        ]]>
    </mx:Script>

    <mx:ApplicationControlBar dock="true">
        <mx:ToggleButtonBar id="toggleButtonBar"
                itemClick="captureImg(event.item.data);">
            <mx:dataProvider>
                <mx:Array>
                    <mx:Object label="Capture as JPEG" data="{jpgEnc}" />
                    <mx:Object label="Capture as PNG" data="{pngEnc}" />
                </mx:Array>
            </mx:dataProvider>
        </mx:ToggleButtonBar>
    </mx:ApplicationControlBar>

    <mx:Image id="img"
            source="@Embed('images/flex_logo.jpg')" />

    <mx:TextArea id="textArea"
            editable="false"
            width="320"
            height="160" />

</mx:Application>

View source is enabled in the following example.

7 thoughts on “Using the ImageSnapshot class to capture images as JPEGs or PNGs in Flex 3

  1. Hi Peter,

    Thats a great example , but can we create the vice-verca of that means creating image from this binary data.

    Thanks,
    Tony

  2. hi! Is this the quickest way to create a png from a Flex component? I am trying to create a button such as “view PNG” and have my flex chart opened in a web-browser window as a png.

    any ideas

  3. I’m trying to do this in flash using flash develop but publishing through adobe ide. I should be able to use the base64 methods since I imported the swc which has them, it compiles telling me that it can find the signatures but I get the following runtime error, im using a path to the library like C:\work\myproject\libs\as3core and in that location there is the swc as3corelib.swc

    Class mx.utils::Base64Encoder could not be found.
    thanks for any help

  4. Does anyone know of an issue where you use this to take a snapshot then all event listeners applied to the MovieClip you just took a snapshot of now no longer has the event listeners active?
    I am using ImageSnapshot like this…
    snap_image = ImageSnapshot.captureImage(txtContainer, 300, new PNGEncoder());
    ResponseString = ImageSnapshot.encodeImageAsBase64(snap_image);

    txtContainer is a movieClip that contains some dynamically created objects and it has eventListeners for roll over, out and click. Those no longer work after the snapshot is taken even when I try to reapply the listeners.
    Any tips?

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