Exam 70-480 topic 3 question 35 discussion

Actual exam question from Microsoft's 70-480

Question #: 35
Topic #: 3

HOTSPOT -
You develop an interactive scalable vector graphics (SVG) application. You write the following HTML markup that makes a rectangle rotate:

You need to control the speed of the rotating rectangle.
How should you complete the relevant code? (To answer, select the appropriate option from each drop-down list in the answer area.)
Hot Area:

Show Suggested Answer

Suggested Answer:

Note:
* What is SVG?
SVG stands for Scalable Vector Graphics
SVG is used to define vector-based graphics for the Web
SVG defines the graphics in XML format
SVG graphics do NOT lose any quality if they are zoomed or resized
Every element and every attribute in SVG files can be animated

SVG is a W3C recommendation -
* Example:
<script>
/* CONSTANTS */
var initialTheta = 0; // The initial rotation angle, in degrees. var thetaDelta = 0.3; // The amount to rotate the square every "delay" milliseconds, in degrees. var delay = 10; // The delay between animation stills, in milliseconds. Affects animation smoothness. var angularLimit = 90; // The maximum number of degrees to rotate the square.

/*
Note that it will take the square (angularLimit/thetaDelta)*delay milliseconds to rotate an angularLimit number of degrees. For example, (90/0.3)*10 = 3000 ms (or 3 seconds) to rotate the square 90 degrees.
*/

/* GLOBALS */
var theSquare; // Will contain a reference to the square element, as well as other things. var timer; // Contains the setInterval() object, used to stop the animation.

function init()
/*
Assumes that this function is called after the page loads.
*/
{
theSquare = document.getElementById("mySquare"); // Set this custom property after the page loads. theSquare.currentTheta = initialTheta; // The initial rotation angle to use when the animation starts, stored in timer = setInterval(doAnim, delay); // Call the doAnim() function every "delay" milliseconds until "timer" is cleared.
}

function doAnim()
/*
This function is called by setInterval() every "delay" milliseconds.
*/
{
if (theSquare.currentTheta > angularLimit)
{
clearInterval(timer); // The square has rotated enough, instruct the browser to stop calling the doAnim() function. return; // No point in continuing; stop now.
}

theSquare.setAttribute("transform", "rotate(" + theSquare.currentTheta + ")"); // Rotate the square by a small amount. theSquare.currentTheta += thetaDelta; // Increase the angle that the square will be rotated to, by a small amount.
}
</script>
</head>

by Joshua at Nov. 12, 2019, 8:22 p.m.

Comments

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Joshua

Highly Voted 5 years, 8 months ago

you would use document.getElementById("mySquare");

upvoted 8 times

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Bennyseems

Highly Voted 5 years, 4 months ago

Kyrylx is nearly there, but it should be: document.getElementById("mySquare"); as others have said. https://www.w3schools.com/code/tryit.asp?filename=GCDVRWT2KSRO

upvoted 5 times

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ichbin

Most Recent 5 years, 4 months ago

What is correct here in the end?

upvoted 1 times

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KyryIx

5 years, 5 months ago

var squareShape; var myTimer; function startAnimation(){ squareShape = mySquare; //squareShape = document.getElementById("mySquare"); squareShape.currentTheta = 0; //myTimer = speed.value; //myTimer = myTimer.interval( speed.value ); //myTimer = setTimer( animateImage, speed.value ); //myTimer = new timer( animateImage, speed.value ); myTimer = setInterval( animateImage, speed.value ); animateImage(); } function animateImage(){ squareShape.setAttribute( "transform", "rotate(" + squareShape.currentTheta + ")" ); squareShape.currentTheta += 0.1; }

upvoted 3 times

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Joshua

5 years, 7 months ago

Think the other two are wrong too. It should be rotate

upvoted 4 times

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Etnic

5 years, 8 months ago

agreee document.getElementById("mySquare");

upvoted 3 times

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