How do I rotate one image that is on top of a second background image?

VSCode

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– index.html code:

<!DOCTYPE html>
<html>
    <head>
       <meta charset="UTF-8">
       <meta name="viewport", content="width=device-width, initial-scale=1.0">
       <link rel="stylesheet" href="image.css">
    </head>
    <body>
        <div id="canvasContainer">
            <canvas id="canvas" width="900" height="520"></canvas>
            </div>
        <script src="image.js"></script>
    </body>
</html>

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– image.js code:

const cCanvas = document.getElementById('canvas');
cCanvas.width = 600;
cCanvas.height = 300;
const cContext = cCanvas.getContext('2d');
const cBackgroundImage = new Image();
const cBackgroundWidth = cCanvas.width;
let lBackgroundHeight; 
const cCarImage = new Image();
const cCarImageWidth = 40; 
const cCarImageHeight = 100; 
let lCarImageX; 
let lCarImageY; 
document.addEventListener('DOMContentLoaded', (ev) => 
    {
        cBackgroundImage.onload = function () {
            cCarImage.onload = function () 
            {
              const cAspectRatio = cBackgroundImage.naturalWidth / cBackgroundImage.naturalHeight;
              lBackgroundHeight = cCanvas.height = cBackgroundWidth / cAspectRatio; 
              lCarImageX = cBackgroundWidth / 2 - cCarImageWidth / 2; 
              lCarImageY = lBackgroundHeight - cCarImageHeight; 
              cContext.drawImage(cBackgroundImage, 0, 0, cBackgroundWidth, lBackgroundHeight); 
              cContext.drawImage(cCarImage, lCarImageX, lCarImageY, cCarImageWidth, cCarImageHeight);
            }
            cCarImage.src = "Car.jpg"; 
        }
        cBackgroundImage.src = "Streets.jpg";
    }
)
document.body.addEventListener("keydown", e =>{
  e.preventDefault();
  switch(e.key){
    case 'ArrowUp':
      lCarImageY -= 10;
      break;
    case 'ArrowDown':
      lCarImageY += 10;
      break;
    case 'ArrowLeft':
      lCarImageX -= 10;
      break;
    case 'ArrowRight':
      lCarImageX += 10;
      break;
  }
    render();
})
function render(){
  cContext.clearRect(0, 0, cCanvas.width, cCanvas.height);
  cContext.drawImage(cBackgroundImage, 0, 0, cBackgroundWidth, lBackgroundHeight); 
  cContext.drawImage(cCarImage, lCarImageX, lCarImageY, cCarImageWidth, cCarImageHeight);
}

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– This code puts a car on a street background. The arrow keys move the car on the street.

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I want the car to also turn 90 degrees when the keyboard letter “l” is entered.

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– This was added to < body > html:

<div style="margin: 8px">
    <img id="CarRotate" src="Car.jpg" />
    </div>

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– In image.js, this

const cCarImage = new Image();

was replaced with this.

// const cCarImage = new Image();
const cCarImage = document.getElementById('CarRotate');

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– Two lines of code were deleted

document.addEventListener('DOMContentLoaded', (ev) => 
    {
        cBackgroundImage.onload = function () {
            // cCarImage.onload = function () 
            {
              ... 
            }
            // cCarImage.src = "Car.jpg"; 
        }
        cBackgroundImage.src = "Streets.jpg";
    }
)

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– This was added to switch(e.key)

case 'l':
  cCarImage.style.transform = 'rotate(90deg)';
  break;     

================================

– Unfortunately, this displays “two” cars on the street. One car is moved by the arrows. The other car rotates.

What do I change to combine the movements into one car?

Streets.jpg => https://snipboard.io/4YgDaf.jpg

Car.jpg => https://snipboard.io/ptkWjJ.jpg

1 Like

See https://stackoverflow.com/questions/77182626/how-do-i-rotate-one-image-that-is-on-top-of-a-second-background-image.

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