Tuesday, February 7, 2012

Creating a Flex AIR Screenshot app: Part 17

In this tutorial we will add the ability to select an area in our crop window.

First, go to the crop NavigatorContent container and put the existing cropHTML bitmap image object into a group and into a scroller. Set the scroller's width to {(contentBox.width>cropHTML.width+15)?(cropHTML.width+15):(contentBox.width)}. This expression will check whether the contentBox object's width extends the HTML object's width (with the scrollbar's 15 pixels). If it does, set the width of the scroller to HTML's width plus the scrollbar's width. Otherwise, set it to the width of contentBox. This will ensure that the scrollbars display properly.

Add 2 more objects to the group inside the scroller. These objects are SpriteVisualElement (we will use this as a drawing action), set its id to cropDraw and sizes to cropHTML's, and a Box object, set its alpha to 0, id to drawArea and size to cropHTML's size, also set its background to any color (doesn't matter which).

<s:NavigatorContent id="crop">
<s:VGroup width="{contentBox.width}" height="100%" gap="0" horizontalAlign="center">
<mx:HBox backgroundColor="#999999" width="100%" height="24" verticalScrollPolicy="off" verticalAlign="middle" paddingLeft="2">
<s:Button label="Back" click="{stack.selectedChild = loadpage;}" />
<s:Button label="Export selection" enabled="false" />
</mx:HBox>
<s:Scroller width="{(contentBox.width>cropHTML.width+15)?(cropHTML.width+15):(contentBox.width)}" height="{contentBox.height-24}">
<s:Group>
<s:BitmapImage id="cropHTML" />
<s:SpriteVisualElement id="cropDraw" width="{cropHTML.width}" height="{cropHTML.height}" />
<mx:Box width="{cropHTML.width}" height="{cropHTML.height}" alpha="0" id="drawArea" backgroundColor="#000000"/>
</s:Group>
</s:Scroller>
</s:VGroup>
</s:NavigatorContent>

Now I'll explain what we did. We added a drawing canvas over the bitmap image, so that we can draw a rectangle on it when needed. Over that layer, we created a Box object which covers all the area, but is invisible to the user. Thanks to it covering every pixel in the area, we can use it as the hit area for mouse events to handle drawing.

Go to the beginning of the script and declare these variables:

private var drawing:Boolean = false;
private var drawingRect:Array = [];

Go to changeState() function and add 3 event listeners. The events we're listening for are MOUSE_DOWN, MOUSE_UP and MOUSE_MOVE, the event handlers are drawDown, drawUp and drawMove respectively. Apply the first and the last of these event listeners to the drawArea object, and the MOUSE_UP one to the application:

private function changeState():void {
if (stack.selectedChild == loadpage) {
contentBox.setStyle("horizontalAlign", "center");
urlInput.text = urlString;
tempHTML.width = 1;
tempHTML.height = 1;
tempHTML.removeEventListener(Event.COMPLETE, onTempLoad);
tempHTML.htmlLoader.loadString("<html></html>");
}
if (stack.selectedChild == crop) {
maximize();
contentBox.setStyle("horizontalAlign", "left");
var bd:BitmapData = new BitmapData(tempHTML.width, tempHTML.height, false);
bd.draw(tempHTML);
var b:Bitmap = new Bitmap(bd, "auto", true);
cropHTML.source = b;
drawArea.addEventListener(MouseEvent.MOUSE_DOWN, drawDown);
addEventListener(MouseEvent.MOUSE_UP, drawUp);
drawArea.addEventListener(MouseEvent.MOUSE_MOVE, drawMove);
}
if (stack.selectedChild == screenshotsettings) {
screenSettings = [set2, set3, set4, set5, set6, set7];
contSize.text = "Full size (" + tempHTML.contentWidth + "x" + tempHTML.contentHeight + ")";
loadScreenshotSettings();
}
}

The drawingRect variable we've declared is supposed to store 4 values - x, y, width and height values of the selection rectangle.

In the drawDown() function, set drawing to true, set values for drawingRect and call a function called drawRectangle().

private function drawDown(evt:MouseEvent):void {
drawing = true;
drawingRect = [evt.target.mouseX, evt.target.mouseY, 0, 0];
drawRectangle();
}

In drawUp(), set drawing to false:

private function drawUp(evt:MouseEvent):void{
drawing = false;
}

In drawMove(), check for the drawing variable's value and if it is set to true, set values for the width and height values in drawingRect array. Call drawRectangle():

private function drawMove(evt:MouseEvent):void{
if (drawing) {
drawingRect[2] = evt.target.mouseX - drawingRect[0];
drawingRect[3] = evt.target.mouseY - drawingRect[1];
drawRectangle();
}
}

The drawRectangle() function draws the frame like this:

private function drawRectangle():void{
cropDraw.graphics.clear();
cropDraw.graphics.lineStyle(1, 0xff0000);
cropDraw.graphics.beginFill(0x00ff00, 0.15);
cropDraw.graphics.drawRect(drawingRect[0], drawingRect[1], drawingRect[2], drawingRect[3]);
cropDraw.graphics.endFill();
}

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:custom="*"
                       xmlns:mx="library://ns.adobe.com/flex/mx" showStatusBar="false"
   width="550" height="600" creationComplete="init();">
   
   
<fx:Declarations>
<mx:ArrayCollection id="headerTitles">
<fx:Object step="Step one:" description="load a web page." />
<fx:Object step="Loading..." description="please wait." />
<fx:Object step="Step two:" description="set your export preferences." />
<fx:Object step="Step two:" description="select the area you wish to crop." />
<fx:Object step="Step three:" description="set your export preferences for the cropped image." />
<fx:Object step="Exporting:" description="please wait." />
</mx:ArrayCollection>
</fx:Declarations>

<fx:Style>
@namespace s "library://ns.adobe.com/flex/spark";
@namespace mx "library://ns.adobe.com/flex/mx";

.descriptionText{
fontSize: 24;
color: #fff;
}

.descriptionText2{
fontSize: 16;
color: #fff;
}

.settingText{
fontSize: 16;
color: #fff;
}

#headStep{
fontSize: 30;
fontWeight: bold;
color: #ffffbb;
}

#headDesc{
fontSize: 30;
color: #ffffff;
}
</fx:Style>

<fx:Script>
<![CDATA[
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.events.TimerEvent;
import flash.filesystem.File;
import flash.filesystem.FileStream;
import flash.geom.Point;
import flash.geom.Rectangle;
import flash.net.URLRequest;
import flash.utils.ByteArray;
import flash.utils.Timer;
import mx.controls.HTML;
import mx.core.FlexHTMLLoader;
import mx.events.FlexNativeWindowBoundsEvent;
import mx.controls.Alert;
import mx.events.ResizeEvent;
import mx.graphics.codec.IImageEncoder;
import mx.graphics.codec.JPEGEncoder;
import mx.graphics.codec.PNGEncoder;
import mx.graphics.ImageSnapshot;
import spark.primitives.BitmapImage;
import flash.filesystem.FileMode;
import mx.managers.PopUpManager;

[Bindable]
private var urlString:String;
private var tempHTML:HTML = new HTML();

private var preferences:SharedObject = SharedObject.getLocal("kirshotPreferences");
[Bindable]
private var pref_screensizes:Array;
[Bindable]
private var pref_format:String;
[Bindable]
private var pref_quality:int;
[Bindable]
private var pref_folder:Boolean;
[Bindable]
private var pref_destination:String;
[Bindable]
private var exportText:String;
private var screenGo:String;
private var drawing:Boolean = false;
private var drawingRect:Array = [];

private var screenSettings:Array;

private function init():void {
//preferences.data.firsttime = null;

// Set preferences if loaded for the first time
if (preferences.data.firsttime == null) {
preferences.data.firsttime = true;
preferences.data.screensizes = [ 
{ checked:true },
{ checked:true, w:1280, h:1024 },
{ checked:true, w:1280, h:800 },
{ checked:true, w:1024, h:768 },
{ checked:false, w:"", h:"" },
{ checked:false, w:"", h:"" },
{ checked:false, w:"", h:"" } ];
preferences.data.format = "JPEG";
preferences.data.quality = 100;
preferences.data.folder = true;
preferences.data.destination = File.documentsDirectory.nativePath;
preferences.flush();
}

// Set preferences loaded from local storage
pref_screensizes = preferences.data.screensizes;
pref_format = preferences.data.format;
pref_quality = preferences.data.quality;
pref_folder = preferences.data.folder;
pref_destination = preferences.data.destination;

addElement(tempHTML);
removeElement(tempHTML);
}

private function doBrowse():void{
var file:File = new File();
file.addEventListener(Event.SELECT, browseSelect);
file.browseForOpen("Load a webpage");

function browseSelect(evt:Event):void {
urlInput.text = file.nativePath;
}
}

private function goScreenshot(screen:String):void {
screenGo = screen;
stack.selectedChild = screenshotloading;
urlString = urlInput.text;

addElement(tempHTML);
tempHTML.htmlLoader.useCache = false;
tempHTML.horizontalScrollPolicy = "off";
tempHTML.verticalScrollPolicy = "off";
tempHTML.visible = false;
tempHTML.addEventListener(Event.COMPLETE, onTempLoad);
tempHTML.htmlLoader.load(new URLRequest(urlString));
}

private function onTempLoad(evt:Event):void {
tempHTML.removeEventListener(Event.COMPLETE, onTempLoad);
if(screenGo=="screenshot"){
stack.selectedChild = screenshotsettings;
}
if (screenGo == "crop") {
if(tempHTML.contentWidth <= 4096 && tempHTML.contentHeight <= 4096){
var t:Timer = new Timer(1000, 1);
t.addEventListener(TimerEvent.TIMER_COMPLETE, tComplete);
t.start();
tempHTML.width = tempHTML.contentWidth;
tempHTML.height = tempHTML.contentHeight;
function tComplete(evt:TimerEvent):void {
stack.selectedChild = crop;
}
}else {
Alert.show("Dimensions of a screenshot cannot exceed 4096 pixels.", "Sorry...");
stack.selectedChild = loadpage;
}
}
}

private function cancelLoading():void {
tempHTML.removeEventListener(Event.COMPLETE, onTempLoad);
tempHTML.cancelLoad();
stack.selectedChild = loadpage;
removeElement(tempHTML);
}

private function screenshotBack():void {
saveScreenshotSettings();
stack.selectedChild = loadpage;
removeElement(tempHTML);
}

private function changeState():void {
if (stack.selectedChild == loadpage) {
contentBox.setStyle("horizontalAlign", "center");
urlInput.text = urlString;
tempHTML.width = 1;
tempHTML.height = 1;
tempHTML.removeEventListener(Event.COMPLETE, onTempLoad);
tempHTML.htmlLoader.loadString("<html></html>");
}
if (stack.selectedChild == crop) {
maximize();
contentBox.setStyle("horizontalAlign", "left");
var bd:BitmapData = new BitmapData(tempHTML.width, tempHTML.height, false);
bd.draw(tempHTML);
var b:Bitmap = new Bitmap(bd, "auto", true);
cropHTML.source = b;
drawArea.addEventListener(MouseEvent.MOUSE_DOWN, drawDown);
addEventListener(MouseEvent.MOUSE_UP, drawUp);
drawArea.addEventListener(MouseEvent.MOUSE_MOVE, drawMove);
}
if (stack.selectedChild == screenshotsettings) {
screenSettings = [set2, set3, set4, set5, set6, set7];
contSize.text = "Full size (" + tempHTML.contentWidth + "x" + tempHTML.contentHeight + ")";
loadScreenshotSettings();
}
}

private function loadScreenshotSettings():void {
set1checkbox.selected = pref_screensizes[0].checked;

for (var i:int = 0; i < screenSettings.length; i++) {
screenSettings[i].checked = pref_screensizes[i + 1].checked;
screenSettings[i].w = pref_screensizes[i + 1].w;
screenSettings[i].h = pref_screensizes[i + 1].h;
}

if (pref_format == "JPEG") {
screenRadioJPEG.selected = true;
} else {
screenRadioPNG.selected = true;
}
}

private function saveScreenshotSettings():void {
pref_screensizes[0].checked = set1checkbox.selected;

for (var i:int = 0; i < screenSettings.length; i++) {
pref_screensizes[i + 1].checked = screenSettings[i].checked;
pref_screensizes[i + 1].w = screenSettings[i].w;
pref_screensizes[i + 1].h = screenSettings[i].h;
}

if (screenRadioJPEG.selected == true) {
pref_format == "JPEG";
} else {
pref_format == "PNG";
}

preferences.data.screensizes = pref_screensizes;
preferences.data.format = pref_format;
preferences.data.quality = pref_quality;
preferences.data.folder = pref_folder;
preferences.data.destination = pref_destination;
preferences.flush();
}

private function formatChange(newformat:String):void {
pref_format = newformat;
}

private function startExportScreenshot():void {
var canExport:Boolean = true;

for (var i:int = 0; i < screenSettings.length; i++) {
if (screenSettings[i].checked && ((screenSettings[i].w == "" || screenSettings[i].w == 0) || (screenSettings[i].h == "" || screenSettings[i].h == 0))) {
canExport = false;
}
}

if (canExport) {
if ((pref_folder && folderField.text != "") || !pref_folder) {
saveScreenshotSettings();
exportScreen();
}else {
Alert.show("Folder name should not be blank!", "Oops...");
}
}else {
Alert.show("One or more selected screen sizes are not entered or are invalid!", "Oops...");
}
}

private function screenshotDestination():void {
var newDestination:File = new File(pref_destination);
newDestination.browseForDirectory("Select directory");
newDestination.addEventListener(Event.SELECT, destinationSelect);

function destinationSelect(evt:Event):void {
pref_destination = newDestination.nativePath;
}
}

private function exportScreen():void {
var encoder:IImageEncoder;
var bd:BitmapData;
var byteArray:ByteArray;
var folderName:String = (pref_folder)?(folderField.text):("");
var fileName:String;
var file:File;
var fileStream:FileStream;
var screensToExport:Array = [];
stack.selectedChild = export;

if (pref_format == "JPEG") {
encoder = new JPEGEncoder(pref_quality);
}
if (pref_format == "PNG") {
encoder = new PNGEncoder();
}

// add full-size screen to array if checked
if (pref_screensizes[0].checked) {
screensToExport = [ { w:tempHTML.contentWidth, h: tempHTML.contentHeight, full:true} ];
}

// add the rest screens to array if checked
for (var i:int = 0; i < screenSettings.length; i++) {
if (pref_screensizes[i + 1].checked) {
screensToExport.push( { w: pref_screensizes[i + 1].w, h:pref_screensizes[i + 1].h } );
}
}

// if nothing is checked, go to first page and stop code
if (screensToExport.length == 0) {
removeElement(tempHTML);
stack.selectedChild = loadpage;
return;
}

// create a timer that repeats itself as many times as many items there are in the array
var timer:Timer = new Timer(2000, screensToExport.length);
timer.addEventListener(TimerEvent.TIMER, onTimer);
// set sizes to the first size of the array
if (screensToExport[0].full) {
tempHTML.horizontalScrollPolicy = "off";
tempHTML.verticalScrollPolicy = "off";
}else {
tempHTML.horizontalScrollPolicy = "auto";
tempHTML.verticalScrollPolicy = "auto";
}
if(screensToExport[0].h <= 4096 && screensToExport[0].w <= 4096){
tempHTML.height = screensToExport[0].h;
tempHTML.width = screensToExport[0].w;
}
updateExportText(screensToExport[0].w, screensToExport[0].h, 1, screensToExport.length);
timer.start();

function onTimer(evt:TimerEvent):void {
// do export for the current size
if(screensToExport[timer.currentCount-1].h <= 4096 && screensToExport[timer.currentCount-1].w <= 4096){
timer.stop();
doExport();
timer.start();
}else {
Alert.show("Cannot export " + screensToExport[timer.currentCount-1].w + "x" + screensToExport[timer.currentCount-1].h + " - dimensions of a screenshot cannot extend 4096.","Sorry");
}
// change the size if this was not the last size in the array
if (timer.currentCount != screensToExport.length) {
tempHTML.horizontalScrollPolicy = "auto";
tempHTML.verticalScrollPolicy = "auto";
if(screensToExport[timer.currentCount].h <= 4096 && screensToExport[timer.currentCount].w <= 4096){
tempHTML.height = screensToExport[timer.currentCount].h;
tempHTML.width = screensToExport[timer.currentCount].w;
}
updateExportText(screensToExport[timer.currentCount].w, screensToExport[timer.currentCount].h, timer.currentCount+1, screensToExport.length);
}else {
// if it was the last size in the array, return to first page
timer.stop();
removeElement(tempHTML);
stack.selectedChild = loadpage;
}
}

function doExport():void {
bd = new BitmapData(tempHTML.width, tempHTML.height, false);
bd.draw(tempHTML, null, null, null, null, true);
byteArray = encoder.encode(bd);
fileName = pref_destination + File.separator + folderName + File.separator + tempHTML.width + "x" + tempHTML.height + "." + pref_format;
file = new File(fileName);
fileStream = new FileStream();
fileStream.open(file, FileMode.WRITE);
fileStream.writeBytes(byteArray);
fileStream.close();
}

function updateExportText(w:int, h:int, current:int, total:int):void {
exportText = "Exporting " + w + "x" + h + "." + pref_format + " (" + current + "/" + total + ")";
}
}

private function drawDown(evt:MouseEvent):void {
drawing = true;
drawingRect = [evt.target.mouseX, evt.target.mouseY, 0, 0];
drawRectangle();
}

private function drawUp(evt:MouseEvent):void{
drawing = false;
}

private function drawMove(evt:MouseEvent):void{
if (drawing) {
drawingRect[2] = evt.target.mouseX - drawingRect[0];
drawingRect[3] = evt.target.mouseY - drawingRect[1];
drawRectangle();
}
}

private function drawRectangle():void{
cropDraw.graphics.clear();
cropDraw.graphics.lineStyle(1, 0xff0000);
cropDraw.graphics.beginFill(0x00ff00, 0.15);
cropDraw.graphics.drawRect(drawingRect[0], drawingRect[1], drawingRect[2], drawingRect[3]);
cropDraw.graphics.endFill();
}
]]>
</fx:Script>
   
<s:VGroup width="100%" height="100%" gap="0">
<mx:HBox backgroundColor="#333333" height="46" width="100%" paddingTop="10" paddingLeft="10">
<s:Label id="headStep" text="{headerTitles.getItemAt(stack.selectedIndex).step}" />
<s:Label id="headDesc" text="{headerTitles.getItemAt(stack.selectedIndex).description}" />
</mx:HBox>
<mx:Box backgroundColor="#666666" width="100%" height="100%" id="contentBox" horizontalAlign="center">
<mx:ViewStack id="stack" change="changeState();">
<s:NavigatorContent id="loadpage">
<s:VGroup width="100%" horizontalAlign="center" paddingTop="20">
<s:Label styleName="descriptionText">Enter the link to the page:</s:Label>
<s:HGroup>
<s:TextInput width="250" id="urlInput" text="http://" /><s:Button label="Browse local..." click="doBrowse();" />
</s:HGroup>
<s:HGroup>
<custom:ImageButton img="@Embed('../lib/b_screenshot.png')" over="@Embed('../lib/b_screenshot_over.png')" toolTip="Take screenshots" click="goScreenshot('screenshot');" buttonMode="true" enabled="{urlInput.text!=''}" />
<custom:ImageButton img="@Embed('../lib/b_cut.png')" over="@Embed('../lib/b_cut_over.png')" toolTip="Crop area" click="goScreenshot('crop');" buttonMode="true" enabled="{urlInput.text!=''}" />
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>

<s:NavigatorContent id="screenshotloading">
<s:VGroup width="100%" horizontalAlign="center" paddingTop="20">
<s:Label styleName="descriptionText">The page is being loaded...</s:Label>
<s:Button label="Cancel" click="cancelLoading();" />
</s:VGroup>
</s:NavigatorContent>

<s:NavigatorContent id="screenshotsettings">
<s:VGroup width="100%" horizontalAlign="center" paddingTop="20">
<s:Label styleName="descriptionText2">Select screenshot screen sizes:</s:Label>
<s:SkinnableContainer backgroundColor="#999999" width="310" height="18" >
<s:CheckBox toolTip="Use this screen size" x="4" id="set1checkbox" />
<s:Label id="contSize" styleName="settingText" x="22" y="3" />
</s:SkinnableContainer>
<custom:ScreenSetting id="set2" />
<custom:ScreenSetting id="set3" />
<custom:ScreenSetting id="set4" />
<custom:ScreenSetting id="set5" />
<custom:ScreenSetting id="set6" />
<custom:ScreenSetting id="set7" />

<s:Label/>

<s:Label styleName="descriptionText2">Export as:</s:Label>
<s:HGroup>
<s:RadioButton id="screenRadioJPEG" label="JPEG" groupName="screenshotFormat" change="formatChange('JPEG');" styleName="descriptionText2" /> 
<s:RadioButton id="screenRadioPNG" label="PNG" groupName="screenshotFormat" change="formatChange('PNG');" styleName="descriptionText2" /> 
</s:HGroup>
<s:Label styleName="descriptionText2">Quality:</s:Label>
<s:HSlider id="screenQualitySlider" width="310" minimum="1" maximum="100" liveDragging="true" enabled="{pref_format=='JPEG'}" value="@{pref_quality}" />

<s:Label/>

<s:Label styleName="descriptionText2">Export destination:</s:Label>
<s:HGroup width="310">
<s:TextInput editable="false" width="100%" toolTip="Destination" text="{pref_destination}" />
<s:Button label="Browse" click="screenshotDestination();" />
</s:HGroup>
<s:CheckBox id="folderCheckbox" label="Create new folder with exported images" styleName="descriptionText2" selected="@{pref_folder}" />
<s:TextInput id="folderField" width="100%" toolTip="Folder name" maxChars="200" enabled="{folderCheckbox.selected}" restrict="a-zA-Z0-9._-=+" />
<s:HGroup>
<s:Button label="Back" click="screenshotBack();" />
<s:Button label="Export" click="startExportScreenshot();" />
</s:HGroup>
</s:VGroup>
</s:NavigatorContent>

<s:NavigatorContent id="crop">
<s:VGroup width="{contentBox.width}" height="100%" gap="0" horizontalAlign="center">
<mx:HBox backgroundColor="#999999" width="100%" height="24" verticalScrollPolicy="off" verticalAlign="middle" paddingLeft="2">
<s:Button label="Back" click="{stack.selectedChild = loadpage;}" />
<s:Button label="Export selection" enabled="false" />
</mx:HBox>
<s:Scroller width="{(contentBox.width>cropHTML.width+15)?(cropHTML.width+15):(contentBox.width)}" height="{contentBox.height-24}">
<s:Group>
<s:BitmapImage id="cropHTML" />
<s:SpriteVisualElement id="cropDraw" width="{cropHTML.width}" height="{cropHTML.height}" />
<mx:Box width="{cropHTML.width}" height="{cropHTML.height}" alpha="0" id="drawArea" backgroundColor="#000000"/>
</s:Group>
</s:Scroller>
</s:VGroup>
</s:NavigatorContent>

<s:NavigatorContent id="cropsettings">

</s:NavigatorContent>

<s:NavigatorContent id="export">
<s:VGroup width="100%" horizontalAlign="center" paddingTop="20">
<s:Label styleName="descriptionText" text="{exportText}" />
</s:VGroup>
</s:NavigatorContent>
</mx:ViewStack>
</mx:Box>
</s:VGroup>

</s:WindowedApplication>

Thanks for reading!

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