image.lzx

<library>
<!--- image represents an image that can be loaded at runtime, either by specifying a URL directly or by binding to data-->
    <class name="image">
        <!--- an optional prefix URL to load from. If specified, the url will be appended to this prefix.-->
        <attribute name="prefix" value="" type="string"/>
        <!--- The URL to load the image from.  May be set directly on this attribute or indirectly by specifying a datapath for this tag. -->
        <attribute name="src" value="" type="string"/>
        <!--- The last URL loaded by this image tag.  Used to prevent the same URL from loading twice.  
              @keywords readonly-->
        <attribute name="lastloaded" value="" type="string"/>
        <!--- If true, the same URL will be reloaded.  If false, the same URL will not load multiple times.  -->
        <attribute name="forcereload" value="false" type="boolean"/>

        <!--- @keywords private -->
        <method name="applyData" args="d">
            if (d != null) this.setAttribute('src', d);
        </method>

        <event name="onsrc"/>

        <handler name="onsrc" method="loadNow"/>

        <!--- Loads an image in response to the src attribute being set.  Should not be called directly - setAttribute('src' ...) should be used instead. 
              @keywords private -->
        <method name="loadNow" args="img">
         
            // don't reload the same thing unless we're told to
            var url = this.prefix + img;
            if (this.forcereload || this.lastloaded != url) {
                this.lastloaded = url;
                this.setSource( url );
            }
        
        </method>

        <!--- Loads the image on init.
              @keywords private -->
        <method name="init">
        
            super.init();
            if (this.src != '' && this.src != null)
                this.loadNow(this.src);
        
        </method>

        <doc>
          <tag name="shortdesc"><text>A way to import images</text></tag>
          <text>
            <example title="image">
            <canvas debug="true">
                <dataset name="imagedata">
                    <image url="http://www.openlaszlo.org/images/horses/horse-1-sm.jpg"/>
                </dataset>
            
                <wrappinglayout/>
                <image src="http://www.openlaszlo.org/images/horses/horse-1-sm.jpg"/>
                <image datapath="imagedata:/image/@url"/>
                <image prefix="http://www.openlaszlo.org/images/horses/" src="horse-1-sm.jpg"/>
                <image src="http://www.openlaszlo.org/images/horses/horse-1-sm.jpg"/>
                <image>
                    <text>Click me</text>
                    <handler name="onclick">
                        this.setAttribute('src', 'http://www.openlaszlo.org/images/horses/horse-1-sm.jpg');
                    </handler>
                </image>
                <image forcereload="true">
                    <text>Click me to reload</text>
                    <handler name="onclick">
                        this.setAttribute('src', 'http://www.openlaszlo.org/images/horses/horse-1-sm.jpg');
                    </handler>
                </image>
            </canvas>
            </example>
          </text>
        </doc>
    </class>
</library>
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