Thursday, February 23, 2012

Creating a Flex AIR Annotator app: Part 4

In this tutorial we will add some functionality to the existing tools.

First, find the toolbarStack viewstack object and add 1 more NavigatorContent to the beginning. Make it empty. Also, add a "change" event listener to the ViewStack, set its handler to a function caleld toolbarChange();

<mx:ViewStack id="toolbarStack" width="100%" height="100%" change="toolbarChange();">
<s:NavigatorContent>

</s:NavigatorContent>

We added this empty navigator content container so that no tool is selected when the application is launched. Because of this additional container, we need to move the indexes of other navigator content objects up when we call them. Find the IconButtons and in their click event handlers increase each index by 1. Also, set their enabled properties to buttonsEnabled. Finally, add a click event listener to the first IconButton, the handler is the importPicture() function:

<custom:IconButton icon="@Embed('../lib/new.png')" toolTip="New" enabled="{buttonsEnabled}" buttonMode="true" click="importPicture();" />
<custom:IconButton icon="@Embed('../lib/move.png')" toolTip="Move" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=1;" />
<custom:IconButton icon="@Embed('../lib/draw.png')" toolTip="Draw" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=2;" />
<custom:IconButton icon="@Embed('../lib/bubble.png')" toolTip="Annotation" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=3;" />
<custom:IconButton icon="@Embed('../lib/cut.png')" toolTip="Cut" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=4;" />
<custom:IconButton icon="@Embed('../lib/save.png')" toolTip="Save" enabled="{buttonsEnabled}" buttonMode="true" />

Declare the buttonsEnabled variable:

[Bindable]
private var buttonsEnabled:Boolean = false;

In stackChange(), set buttonsEnabled to true.

private function stackChange():void {
if (stack.selectedIndex == 1) {
imgHolder.source = new Bitmap(bitmapData);
drawArea.width = content.width;
drawArea.height = content.height;
drawGroup.width = content.width;
drawGroup.height = content.height;
buttonsEnabled = true;
}
}

Now all the tools are disabled on start, and enabled once an image is imported. Now let's make it so that the user can open a new picture even if there were pictures imported before that. Half of the job here is already done - we already call importPicure() when the New button is clicked, however, the content of the image holder does not update.

That's because the stackChange() function which handles that part of the process is not called (since the stack's selected index does not change). To fix this, add a line calling stackChange() in loadComplete() right before the selectedIndex of the stack is set.

private function loadComplete(evt:Event):void {
content = evt.target.content;
bitmapData = new BitmapData(content.width, content.height, false);
bitmapData.draw(content, new Matrix(), null, null, null, true);
stackChange(); // needed if selectedIndex was already 1 when the function was called
stack.selectedIndex = 1;
}

Now let's add another option to the Draw toolbar container. That option is the thickness of the line - create a Slider object, which is 2-way-bound to a variable called lineThickness, and calls a function updateLineExample() on change. Set the color picker's selected color to lineColor, using 2-way-binding as well. And just like with the slider, set the colorpicker's change event handler to updateLineExample().

Now, add a SpriteVisualElement object in that same HGroup. set its width to 40, height to 20 and id to lineExample. This will be the visual sample of what a line will look like with these settings.

<s:NavigatorContent>
<s:VGroup width="100%" height="44" top="4">
<s:Label fontSize="18" color="#333333">Selected: Draw</s:Label>
<s:HGroup>
<mx:ToggleButtonBar dataProvider="{toolbarToggle}" width="100" />
<mx:ColorPicker selectedColor="@{lineColor}" change="updateLineExample();" />
<mx:Slider minimum="1" maximum="15" change="updateLineExample();" value="@{lineThickness}" width="80" liveDragging="true"/>
<s:SpriteVisualElement width="40" height="20" id="lineExample"/>
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>

Declare the two variables:

[Bindable]
private var lineThickness:int = 5;
[Bindable]
private var lineColor:uint = 0xff0000;

And create a function called updateLineExample. Here we simply draw the line in that sprite object using the settings given.

private function updateLineExample():void{
lineExample.graphics.clear();
lineExample.graphics.lineStyle(lineThickness, lineColor);
lineExample.graphics.moveTo(10, 10);
lineExample.graphics.lineTo(30, 10);
}

The toolbarStack object has a change event listener, with a handler function toolbarChange. Let's create this function and add a conditional inside of it, checking if the selectedIndex of toolbarStack is 2 (the Draw options container), and if it is, call updateLineExample().

private function toolbarChange():void {
if (toolbarStack.selectedIndex == 2) {
updateLineExample();
}
}

And there we go!

Full code:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
   xmlns:s="library://ns.adobe.com/flex/spark"
   xmlns:mx="library://ns.adobe.com/flex/mx" 
   xmlns:custom="*"
   showStatusBar="false"
   creationComplete="init();" minWidth="700" minHeight="400"
   width="700" height="500">

<fx:Script>
<![CDATA[
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.FocusDirection;
import flash.display.Loader;
import flash.events.Event;
import flash.filesystem.File;
import flash.filesystem.FileStream;
import flash.filters.DropShadowFilter;
import flash.geom.Matrix;
import flash.net.FileFilter;
import flash.net.URLRequest;
import flash.utils.ByteArray;
import mx.controls.Alert;
import flash.filesystem.FileMode;

private var bitmapData:BitmapData;
private var content:*;
[Bindable]
private var buttonsEnabled:Boolean = false;
[Bindable]
private var lineThickness:int = 5;
[Bindable]
private var lineColor:uint = 0xff0000;

private function init():void{
drawArea.filters = [new DropShadowFilter(4, 60, 0, 0.7, 10, 10, 1, 3)];
}

private function importPicture():void {
var file:File = new File();
var imageFilter:FileFilter = new FileFilter("Images", "*.jpg;*jpeg;*.gif;*.png");
file.browseForOpen("Import picture", [imageFilter]);
file.addEventListener(Event.SELECT, fileSelect);
}

private function fileSelect(evt:Event):void {
var file:File = evt.target as File;
var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadComplete);
loader.load(new URLRequest(file.url));
}

private function loadComplete(evt:Event):void {
content = evt.target.content;
bitmapData = new BitmapData(content.width, content.height, false);
bitmapData.draw(content, new Matrix(), null, null, null, true);
stackChange(); // needed if selectedIndex was already 1 when the function was called
stack.selectedIndex = 1;
}

private function stackChange():void {
if (stack.selectedIndex == 1) {
imgHolder.source = new Bitmap(bitmapData);
drawArea.width = content.width;
drawArea.height = content.height;
drawGroup.width = content.width;
drawGroup.height = content.height;
buttonsEnabled = true;
}
}

private function toolbarChange():void {
if (toolbarStack.selectedIndex == 2) {
updateLineExample();
}
}

private function updateLineExample():void{
lineExample.graphics.clear();
lineExample.graphics.lineStyle(lineThickness, lineColor);
lineExample.graphics.moveTo(10, 10);
lineExample.graphics.lineTo(30, 10);
}
]]>
</fx:Script>

<fx:Declarations>
<mx:ArrayCollection id="toolbarToggle">
<fx:Object icon="@Embed('../lib/ic_pen.png')" />
<fx:Object icon="@Embed('../lib/ic_ellipse.png')"/>
<fx:Object icon="@Embed('../lib/ic_rect.png')"/>
<fx:Object icon="@Embed('../lib/ic_line.png')"/>
</mx:ArrayCollection>
</fx:Declarations>

<s:VGroup width="100%" height="100%" gap="0">
<mx:HBox backgroundColor="#ccccdd" width="100%" height="52">
<custom:IconButton icon="@Embed('../lib/new.png')" toolTip="New" enabled="{buttonsEnabled}" buttonMode="true" click="importPicture();" />
<custom:IconButton icon="@Embed('../lib/move.png')" toolTip="Move" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=1;" />
<custom:IconButton icon="@Embed('../lib/draw.png')" toolTip="Draw" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=2;" />
<custom:IconButton icon="@Embed('../lib/bubble.png')" toolTip="Annotation" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=3;" />
<custom:IconButton icon="@Embed('../lib/cut.png')" toolTip="Cut" enabled="{buttonsEnabled}" buttonMode="true" click="toolbarStack.selectedIndex=4;" />
<custom:IconButton icon="@Embed('../lib/save.png')" toolTip="Save" enabled="{buttonsEnabled}" buttonMode="true" />
<mx:ViewStack id="toolbarStack" width="100%" height="100%" change="toolbarChange();">
<s:NavigatorContent>

</s:NavigatorContent>
<s:NavigatorContent>
<s:VGroup width="100%" height="44" top="4">
<s:Label fontSize="18" color="#333333">Selected: Move</s:Label>
<s:Label>Click and hold your mouse on annotations to move them.</s:Label>
</s:VGroup>
</s:NavigatorContent>
<s:NavigatorContent>
<s:VGroup width="100%" height="44" top="4">
<s:Label fontSize="18" color="#333333">Selected: Draw</s:Label>
<s:HGroup>
<mx:ToggleButtonBar dataProvider="{toolbarToggle}" width="100" />
<mx:ColorPicker selectedColor="@{lineColor}" change="updateLineExample();" />
<mx:Slider minimum="1" maximum="15" change="updateLineExample();" value="@{lineThickness}" width="80" liveDragging="true"/>
<s:SpriteVisualElement width="40" height="20" id="lineExample"/>
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>
<s:NavigatorContent>
<s:VGroup width="100%" height="44" top="4">
<s:Label fontSize="18" color="#333333">Selected: Annotation</s:Label>
<s:HGroup>
<s:TextInput width="180" text="Insert text here" />
<mx:ColorPicker />
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>
<s:NavigatorContent>
<s:VGroup width="100%" height="44" top="4">
<s:Label fontSize="18" color="#333333">Selected: Cut</s:Label>
<s:HGroup>
<s:Label>Select an area to crop.</s:Label>
<s:Button label="Crop selected area" />
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>
</mx:ViewStack>
</mx:HBox>
<mx:Canvas width="100%" height="100%" horizontalScrollPolicy="on" verticalScrollPolicy="on">
<mx:Box backgroundColor="#eeeeee" width="100%" height="100%" verticalAlign="middle" horizontalAlign="center" horizontalScrollPolicy="off" verticalScrollPolicy="off">
<mx:Box id="drawArea" backgroundColor="#ffffff" width="300" height="200" horizontalScrollPolicy="off" verticalScrollPolicy="off">
<mx:ViewStack id="stack" change="stackChange();">
<s:NavigatorContent>
<custom:BigButton icon="@Embed('../lib/folder.png')" subtext="Import picture" toolTip="Open file" enabled="true" buttonMode="true" bWidth="300" bHeight="200" click="importPicture();" />
</s:NavigatorContent>
<s:NavigatorContent>
<s:Group id="drawGroup">
<s:SpriteVisualElement id="drawSprite" width="100%" height="100%" />
</s:Group>
<mx:Image id="imgHolder" />
</s:NavigatorContent>
</mx:ViewStack>
</mx:Box>
</mx:Box>
</mx:Canvas>
</s:VGroup>

</s:WindowedApplication>

Thanks for reading!

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