Monday, February 6, 2012

Creating a Flex AIR Screenshot app: Part 16

Today we'll start working on the Crop feature again.

I have decided to change the approach to the Crop functionality. Instead of displaying a live HTML page to the user on the crop page, we will load the page beforehand, take a screenshot of it and display only the screenshot.

Because of this, we will have to remove some of the already existing crop-related code. First of all go to the crop NavigatorContent container and remove 2 labels we have in the "toolbar". Remove the HTML object as well, replace it with a BitmapImage but call it cropHTML like before:

<s:NavigatorContent id="crop">
<s:VGroup width="100%" height="100%" gap="0">
<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:BitmapImage id="cropHTML" />
</s:VGroup>
</s:NavigatorContent>

Remove the onCropLoad() and onResize() functions, we won't need those anymore. Also remove the event listener for the RESIZE event from init().

Declare a new variable called screenGo:

private var screenGo:String;

Add a parameter for the goScreenshot() function, a string value. In the function, set screenGo to this value.

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));
}

I am doing this, because I am planning to use goScreenshot(), onTempLoad(), cancelLoading() functions and the screenshotloading page both for the screenshot and crop features, since most of the code is the same. I am using the parameter to be able to add individual code to the crop functionality.

Go to onTempLoad and add 2 conditionals. If screenGo is set to screenshot, set stack.selectedChild to screenshotsettings. If it is set to crop, check if the content dimensions exceed 4096x4096. If they do, throw an error message and return to loadpage. If everything is okay, create a timer for 1 second and set dimensions of the HTML object. The timer is needed to let the HTML object update before we take a screenshot of it. Once the timer has thrown a TIMER_COMPLETE event, go to the crop screen.

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;
}
}
}

Now, go to changeState(). In the "crop" conditional, create a bitmap screenshot of the html and apply it to the cropHTML BitmapImage object like this:

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;
}
if (stack.selectedChild == screenshotsettings) {
screenSettings = [set2, set3, set4, set5, set6, set7];
contSize.text = "Full size (" + tempHTML.contentWidth + "x" + tempHTML.contentHeight + ")";
loadScreenshotSettings();
}
}

Now go to the loadpage NavigatorContent container and set the screenshot button's click event handler to goScreenshot() with 'screenshot' as the string parameter, and the crop button's click event handler to goScreenshot() with 'crop' as the parameter.

<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>

And that's all for today's tutorial. Right now we can load a page and it displays its screenshot. There's still much to do. See you in next tutorial!

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.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 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;
}
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 + ")";
}
}
]]>
</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="100%" height="100%" gap="0">
<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:BitmapImage id="cropHTML" />
</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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