Software Engineering Blog: October 2018

We all know that macOS has some very nice and useful widgets. In this post, I’ll show you how to use these widgets on your website.

We’re going to use a calculator widget for OS X provided by Donkeyneering. The name of this widget is PEMDAS. It is a simple calculator widget that also lets you work with equations, variables, different bases and many other functions. The widget looks like this:

The basic idea is that we will download this widget and edit the HTML file. Our HTML page will have a button and when the user clicks on a button; our widget will be shown. Then we will make this widget draggable and finally press the button again so that the user can close it when finished using the widget.

Let’s get started.

Download the widget from this link. http://www.donkeyengineering.com/pemdaswidget/

The widget will be downloaded in zip format. Please unzip it and you will be left with the widget file with .wdgt extension. Right click on this file and select show package contents. You will see the following files inside the widget.

These files basically contain bunch of JavaScript files, CSS file, images and an HTML file. You will get to see the widget in action if you open up the pemdas.html file. When you open the html file in a browser; you will just see the calculator widget.

We will edit this HTML file so that the widget gets shown/ hidden by pressing a button and also make it draggable so that it does not overlap any other elements present on your webpage.

Open the pemdas.html file in the code editor of your choice.

	<!DOCTYPE html>
	<html>
	<head>
	<title>PEMDAS</title>

	<!-- Widget Controllers -->
	<script type='text/javascript' src='controllers/interfaceController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDWidgetController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDFrontViewController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDKeypadViewController.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='controllers/PDHistoryViewController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDBackViewController.js' charset='utf-8'></script>

	<!-- Other Controllers -->
	<script type='text/javascript' src='controllers/PDPreferenceController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDUpdateController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDFormulaScrollerController.js' charset='utf-8'></script>
	<script type='text/javascript' src='controllers/PDQuickLookController.js' charset='utf-8'></script>

	<!-- Interface Classes -->
	<script type='text/javascript' src='classes/PDTextField.js' charset='utf-8'></script>
	<script type='text/javascript' src='classes/PDSmallerClasses.js' charset='utf-8'></script>
	<script type='text/javascript' src='classes/PDButton.js' charset='utf-8'></script>
	<script type='text/javascript' src='classes/PDPopUpButton.js' charset='utf-8'></script>
	<script type='text/javascript' src='classes/PDFunctionPadButton.js' charset='utf-8'></script>
	<script type='text/javascript' src='classes/PDAlertView.js' charset='utf-8'></script>


	<!-- Equation Controller -->
	<script type='text/javascript' src='equationController/PDEquationController.js' charset='utf-8'></script> <!-- S/B Good -->

	<!-- Manipulators -->
	<script type='text/javascript' src='equationController/core/PDEHasher.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='equationController/core/PDECalculator.js' charset='utf-8'></script> <!-- S/B Good -->

	<!-- Smaller Classes -->
	<script type='text/javascript' src='equationController/smallerClasses/PDBlock.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='equationController/smallerClasses/PDBlockInfo.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='equationController/smallerClasses/PDNumber.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='equationController/smallerClasses/PDResult.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='equationController/smallerClasses/PDPosition.js' charset='utf-8'></script> <!-- S/B Good -->
	<script type='text/javascript' src='equationController/smallerClasses/PDVariable.js' charset='utf-8'></script> <!-- S/B Good -->

	<!-- Number Formatter -->
	<script type='text/javascript' src='equationController/formatting/PDNumberFormatter.js' charset='utf-8'></script> <!-- S/B Good -->

	<!-- Apple Classes -->
	<script type='text/javascript' src='/System/Library/WidgetResources/AppleClasses/AppleScrollArea.js' charset='utf-8'></script>
	<script type='text/javascript' src='/System/Library/WidgetResources/AppleClasses/AppleScrollbar.js' charset='utf-8'></script>
	<script type='text/javascript' src='/System/Library/WidgetResources/AppleClasses/AppleAnimator.js' charset='utf-8'></script>

	<style type='text/css'>
	@import "images/mainstyle.css";
	</style>

	</head>

	<!-- -->

	<body onload="initWidget();" id='bodyElement' >

	<div id="front" style="position:absolute; top:0px; left:0px;">

	<input id="inputForClipboardCopy" type="text" style="position:absolute; overflow:hidden; height:20px; width:200px; top:-100px; left:0px;" value="">
	<div id='formulaStringSizingDiv' style='position:absolute; top:-100px; white-space:nowrap; display:inline; font-family:Helvetica, Arial, sans-serif; visibility:hidden;'></div>


	<!-- TOP BAR -->
	<div id='formulaBarContainer'>
	<div id="formulaBarLeft"></div>
	<div id="formulaBarMiddle"></div>
	<div id="formulaBarRight"></div>

	<!-- CLEAR, DELETE BUTTONS -->
	<img id='deleteButton' src="images/buttons/deletebutton_off.png" alt="Delete">
	<img id='clearButton' src="images/buttons/clearbutton_off.png" alt="Clear">


	<!-- Variable Quick Look (note this gets positioned underneath the formula div) -->
	<canvas id='quickLookCanvas' width="250" height="50"></canvas>
	<div id='quickLookTextDiv'></div>

	<!-- Answer Div -->
	<div id="answerDiv">0</div>

	</div>

	<!-- Formula and Cursor Divs-->

	<textarea id="formulaTextArea" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"></textarea>


	<!-- MAIN BODY -->

	<div id="mainBodyContainer">

	<!-- BODY LEFT/RIGHT SHADOWS -->
	<div id="bodyLeftShadow"></div>
	<div id="bodyRightShadow"></div>

	<!-- HISTORY/VARIABLE VIEW -->
	<div id="historyViewDiv">

	<!-- Variable List -->
	<div id='variableCacheContainerDiv'>
	<div id="variableCacheParentDiv">
	<div id="variableCacheDiv" class="formulaCacheFont">
	<div class='variableCacheVariableHeader' style='padding-top:1px;'>Constants</div>
	<div id='variableCacheConstantsDiv' style='display:block;'></div>
	<div class='variableCacheVariableHeader'>Auto-Defined</div>
	<div id='variableCacheAutoDefinedDiv' style='display:block;'></div>
	<div class='variableCacheVariableHeader'>Defined</div>
	<div id='variableCacheDefinedDiv' style='display:block;'></div>
	</div>
	</div>
	<div id='variableCacheScrollBar'></div>
	</div>

	<!-- History View -->
	<div id="formulaCacheContainerDiv">
	<div id="formulaCacheParentDiv">
	<div id="formulaCacheDiv"></div>
	</div>
	<div id="formulaCacheScrollBar"></div>
	</div>

	<!-- Divider -->
	<div id='variableFormulaCacheResizeDiv'>
	<div id='variableFormulaCacheResizeVerticalBar'></div>
	</div>

	</div>


	<!-- KEYPAD VIEW -->
	<div id="keypadViewDiv">

	<!-- FUNCTION PAD CONTAINER -->

	<div class='keypadLight' style='width:122px; left:0px;'>

	<div id="padButtonDiv1" class="fPButtonContainer fPCol1 fPRow1"><div class='fPShifterSup' style='margin-left:3px;'>x<sup>-1</sup></div></div>
	<div id="padButtonDiv2" class="fPButtonContainer fPCol2 fPRow1"><div class='fPShifterSup' style='margin-left:2px;'>x<sup>2</sup></div></div>
	<div id="padButtonDiv3" class="fPButtonContainer fPCol3 fPRow1"><div class='fPShifter'>sqrt</div></div>

	<div id="padButtonDiv4" class="fPButtonContainer fPCol1 fPRow2"><div class='fPShifter'>sin</div></div>
	<div id="padButtonDiv5" class="fPButtonContainer fPCol2 fPRow2"><div class='fPShifter'>cos</div></div>
	<div id="padButtonDiv6" class="fPButtonContainer fPCol3 fPRow2"><div class='fPShifter'>tan</div></div>

	<div id="padButtonDiv7" class="fPButtonContainer fPCol1 fPRow3"><div class='fPShifterSup' style='margin-left:4px;'>sin<sup>-1</sup></div></div>
	<div id="padButtonDiv8" class="fPButtonContainer fPCol2 fPRow3"><div class='fPShifterSup' style='margin-left:4px;'>cos<sup>-1</sup></div></div>
	<div id="padButtonDiv9" class="fPButtonContainer fPCol3 fPRow3"><div class='fPShifterSup' style='margin-left:4px;'>tan<sup>-1</sup></div></div>

	<div id="padButtonDiv10" class="fPButtonContainer fPCol1 fPRow4"><div class='fPShifterSup'>10<sup>x</sup></div></div>
	<div id="padButtonDiv11" class="fPButtonContainer fPCol2 fPRow4"><div class='fPShifter'>log</div></div>
	<div id="padButtonDiv12" class="fPButtonContainer fPCol3 fPRow4"><div class='fPShifter'>ans</div></div>

	<div id="padButtonDiv13" class="fPButtonContainer fPCol1 fPRow5"><div class='fPShifterSup'>e<sup>x</sup></div></div>
	<div id="padButtonDiv14" class="fPButtonContainer fPCol2 fPRow5"><div class='fPShifter'>ln</div></div>
	<div id="padButtonDiv15" class="fPButtonContainer fPCol3 fPRow5"><div class='fPShifter'>%</div></div>

	</div>

	<div class='keypadBorder' style='left:122px;'></div>


	<!-- NUMBER PAD CONTAINER -->

	<div class='keypadLight' style='width:111px; left:123px;'>

	<div id="padButtonDiv16" class="nPButtonContainer nPCol1 nPRow1"><div class='nPShifter'>7</div></div>
	<div id="padButtonDiv17" class="nPButtonContainer nPCol2 nPRow1"><div class='nPShifter'>8</div></div>
	<div id="padButtonDiv18" class="nPButtonContainer nPCol3 nPRow1"><div class='nPShifter'>9</div></div>

	<div id="padButtonDiv19" class="nPButtonContainer nPCol1 nPRow2"><div class='nPShifter'>4</div></div>
	<div id="padButtonDiv20" class="nPButtonContainer nPCol2 nPRow2"><div class='nPShifter'>5</div></div>
	<div id="padButtonDiv21" class="nPButtonContainer nPCol3 nPRow2"><div class='nPShifter'>6</div></div>

	<div id="padButtonDiv22" class="nPButtonContainer nPCol1 nPRow3"><div class='nPShifter'>1</div></div>
	<div id="padButtonDiv23" class="nPButtonContainer nPCol2 nPRow3"><div class='nPShifter'>2</div></div>
	<div id="padButtonDiv24" class="nPButtonContainer nPCol3 nPRow3"><div class='nPShifter'>3</div></div>

	<div id="padButtonDiv25" class="nPButtonContainer nPCol1 nPRow4"><div class='nPShifter'>0</div></div>
	<div id="padButtonDiv26" class="nPButtonContainer nPCol2 nPRow4"><div id='padRadixCharacter' class='nPShifter'>.</div></div>
	<div id="padButtonDiv27" class="nPButtonContainer nPCol3 nPRow4"><div class='nPShifter'>π</div></div>

	</div>

	<div class='keypadBorder' style='left:234px;' ></div>


	<!-- OPERATOR CONTAINER -->

	<div class='keypadLight' style='left:235px; width:70px;' >

	<div id="padButtonDiv28" class="oPButtonContainer oPCol1 nPRow1">÷</div> <!-- division -->
	<div id="padButtonDiv29" class="oPButtonContainer oPCol2a nPRow1 oPSmallText"><div style='margin-top:1px;'>(</div></div> <!-- left parethesis -->
	<div id="padButtonDiv30" class="oPButtonContainer oPCol2b nPRow1 oPSmallText"><div style='margin-top:1px;'>)</div></div> <!-- right parethesis -->

	<div id="padButtonDiv31" class="oPButtonContainer oPCol1 nPRow2">×</div> <!-- multiplication -->
	<div id="padButtonDiv32" class="oPButtonContainer oPCol2 nPRow2 oPSmallText"><div style='margin-top:2px;'>%</div></div> <!-- percent -->

	<div id="padButtonDiv33" class="oPButtonContainer oPCol1 nPRow3">−</div> <!-- subtraction -->
	<div id="padButtonDiv34" class="oPButtonContainer oPCol2 nPRow3"><div style='margin-top:5px;'>⌃</div></div> <!-- exponent -->

	<div id="padButtonDiv35" class="oPButtonContainer oPCol1 nPRow4">+</div> <!-- plus -->
	<div id="padButtonDiv36" class="oPButtonContainer oPCol2 nPRow4">=</div> <!-- equals -->


	</div>

	</div>

	<!-- ALERT VIEW CONTAINER -->
	<div id='alertViewContainer'>
	<div id='alertViewMessageBody'></div>
	<div id='alertButtonLeft' class='alertButtonGray'></div>
	<div id='alertButtonMiddle' class='alertButtonRed'></div>
	<div id='alertButtonRight' class='alertButtonBlue'></div>
	</div>

	</div>

	<!-- BOTTOM BAR -->

	<div id="bottomBarContainer">

	<!-- BOTTOM BAR BACKGROUNDS -->
	<div id="bottomBarLeft"></div>
	<div id="bottomBarMiddle"></div>
	<div id="bottomBarRight"></div>
	<div id="bottomBarTopBorder"></div>

	<!-- BOTTOM BAR CONTENT -->
	<div id="bottomBarNumberFormattingOptionLabel" class="bottomBarComboBoxFont bottomBarPopUpButtonLarge">Float</div>
	<select id="bottomBarNumberFormattingOption">
	<option value='1' selected>Float</option>
	<option value='2'>Scientific</option>
	<option value='3'>Engineering</option>
	<option value='4'>Percent</option>
	<option value='5'>Binary</option>
	<option value='6'>Octal</option>
	<option value='7'>Hexadecimal</option>
	</select>

	<div id='bottomBarDegreesRadiansOptionLabel' class="bottomBarComboBoxFont bottomBarPopUpButton">Radians</div>
	<select id="bottomBarDegreesRadiansOption">
	<option value='1' selected>Radians</option>
	<option value='0'>Degrees</option>
	</select>

	<img id='expandButton' src="images/buttons/expandbutton_off.png" alt="Enable or Disable Mini Mode">
	<img id='keypadHistoryButton' src="images/buttons/historybutton_off.png" alt="Switch between Keypad and History View">
	<img id='infoButton' src="images/buttons/infobutton_off.png" alt="Widget Info">

	<img id='resizeButton' src='images/buttons/resize.png' alt=''>

	</div>

	<div id='pasteHelperDiv' style='position:absolute; display:none;'></div>

	</div>

	<div id='back' class='widgetBack'>

	<div id='backGeneralButton'></div> <!--left:22px; -->
	<div id='backFormattingButton'></div> <!--left:111px; -->
	<!-- <div id='backConstantsButton' style='left:216px; width:80px;'></div> -->

	<div id="backPEMDASLogo">PEMDAS<span class="backVersionNumber">Version 3.1</span></div>

	<div id='supportButton'></div>
	<div id='doneButton'></div>


	<!-- Next are all the containers -->

	<!-- General items -->
	<div id='backGeneralContainer' class='backContainer' style='display:block;'>

	<div id='modulusCheckBoxButtonLabel' style='text-align:right; width:186px; position:absolute; left:0px; top:38px;' class='backOptionLabel'>Use % as Modulus:</div>
	<div id='updatesCheckBoxButtonLabel' style='text-align:right; width:186px; position:absolute; left:0px; top:69px;' class='backOptionLabel'>Check for Updates:</div>
	<img id='modulusCheckBoxButton' src='images/buttons/checkbox.png' class='checkBoxButton' style='position:absolute; left:188px; top:34px;' alt=''>
	<img id='updatesCheckBoxButton' src='images/buttons/checkbox.png' class='checkBoxButton' style='position:absolute; left:188px; top:65px;' alt=''>

	<div id='updateAvailabilityLabel' style='text-align:left; width:170px; position:absolute; left:65px; top:89px;' class='backOptionLabelSmall handCursor'></div>

	</div>

	<!-- Formatting items -->
	<div id='backFormattingContainer' class='backContainer' style='display:none;'>

	<div style='position:absolute; top:14px; left:10px; text-align:right; width:162px;' class='backOptionLabel'>Number Display:</div>

	<div id='widgetBackSigfigDecimalComboOptionLabel' class='popUpButtonLarge backOptionLabel'>Auto</div> <!--Note the classname gets overriden in the backviewcontroller file -->
	<select id="widgetBackSigfigDecimalComboOption">
	<optgroup label="Auto Formatting">
	<option value='0' selected>Auto</option>
	</optgroup>
	<optgroup label="Limit Decimals Places">
	<option value='11'>0</option>
	<option value='12'>1</option>
	<option value='13'>2</option>
	<option value='14'>3</option>
	<option value='15'>4</option>
	<option value='16'>5</option>
	<option value='17'>6</option>
	<option value='18'>7</option>
	<option value='19'>8</option>
	<option value='20'>9</option>
	<option value='21'>10</option>
	</optgroup>
	<optgroup label="Limit Significant Figures">
	<option value='1'>1</option>
	<option value='2'>2</option>
	<option value='3'>3</option>
	<option value='4'>4</option>
	<option value='5'>5</option>
	<option value='6'>6</option>
	<option value='7'>7</option>
	<option value='8'>8</option>
	<option value='9'>9</option>
	<option value='10'>10</option>
	</optgroup>
	</select>

	<div id='thousandsSeparatorsCheckBoxButtonLabel' style='position:absolute; top:40px; left:10px; text-align:right; width:162px;' class='backOptionLabel'>Use Thousands Separators:</div>
	<img id='thousandsSeparatorsCheckBoxButton' src='images/buttons/checkbox.png' class='checkBoxButton' style='position:absolute; left:173px; top:36px;' alt=''>

	<!-- Thousands Separator Character -->
	<div style='position:absolute; top:66px; left:10px; text-align:right; width:162px;' class='backOptionLabel'>Thousands Separator:</div>
	<div id='widgetBackThousandsSeparatorCharacterOptionLabel' class='popUpButton backOptionLabel'></div>
	<select id="widgetBackThousandsSeparatorCharacterOption">
	<option value='0' id='widgetBackThousandsSeparatorCharacterComma' selected>,</option>
	<option value='1'>Space</option>
	<option value='2'>'</option>
	</select>

	<!-- Multiplication symbol -->
	<div style='position:absolute; top:92px; left:10px; text-align:right; width:162px;' class='backOptionLabel'>Multiplication Symbol:</div>
	<div id='widgetBackMultiplicationSymbolOptionLabel' class='popUpButton backOptionLabel'>*</div>
	<select id="widgetBackMultiplicationSymbolOption">
	<option value='0' selected>*</option>
	<option value='1'>⋅</option>
	</select>

	<div style='position:absolute; top:118px; left:10px; text-align:right; width:162px;' class='backOptionLabel'>Decimal Separator:</div>
	<div id='widgetBackDecimalSeparatorOptionLabel' class='popUpButton backOptionLabel'>Auto</div>
	<select id="widgetBackDecimalSeparatorOption">
	<option value='0' selected>Auto</option>
	<option value='1'>.</option>
	<option value='2'>,</option>
	</select>

	</div>

	</div>

	<div id="consoleDiv" style="" class="consolefont"></div>

	</body>
	</html>

view raw pemdas.html hosted with ❤ by GitHub

You will see all the Classes and Controller files written in JavaScript to implement this calculator widget in the head section. The head section also imports a CSS file that styles the calculator.

Let’s go ahead and add a button to this page. We will code in such a way that when user loads this html page; only the button should be shown. And when the user clicks on that button our calculator widget will get shown. We will write some JavaScript to show/ hide this widget on button click. Finally, we will use some jQuery to make this widget draggable.

The changes in the code is as follows:

	<head>
	<!-- jQuery Library -->
	<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
	<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
	</head>

	<body onload="initWidget();" id='bodyElement' >

	<input type="button" id="btn" style="position:absolute; top:50%; left:50%" name="answer" value="Show Calculator" onclick="showDiv()" />

	<div id="front" style="position:absolute; top:0px; left:0px; display: none;">

	<!-- Show/ Hide Calculator -->
	<script>
	function showDiv() {
	var x = document.getElementById('front');
	if (x.style.display === "none") {
	x.style.display = "block";
	btn.value = "Hide Calculator";
	} else {
	x.style.display = "none";
	btn.value = "Show Calculator";
	}
	}
	</script>

	<!-- To make the widget draggable -->
	<script>
	$( function() {
	$( "#front" ).draggable({ containment: "window", scroll: false, cursor: "move"});
	} );
	</script>

	<div id='formulaStringSizingDiv' style='position:absolute; top:-100px; white-space:nowrap; display:inline; font-family:Helvetica, Arial, sans-serif; visibility:hidden;'></div>

view raw pemdas1.html hosted with ❤ by GitHub

As you can see above, we have added jQuery library so that we can use draggable method to make our widget draggable. Inside the body we have added a button with the value ‘Show calculator’ and written script for the same. Notice that the display is changed to none so that the calculator does not get shown by default. The script compares the display and if it is none then it changes to block and our calculator will be shown. Also, the button value changes to ‘Hide Calculator’.

We have then implemented the jQuery draggable method to make our calculator widget move within the window. Notice that div with id inputForClipboardCopy has been removed. Please make the above changes to your code and you will get to see the final output below.

You can find the full code for this blog post here.

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