How to move an image around with arrow keys javascript
Date : March 29 2020, 07:55 AM
To fix the issue you can do I can't figure out what your game is about, and so don't know what to do with that code. However, since you mentioned you were having trouble with movement, I wrote a quick JavaScript movement engine just for you, complete with acceleration and deceleration. Use the arrow keys to move. The following code represents a complete HTML document, so copy and paste it into a blank text file and save as .html. And make sure you have a 10x10 image called '1.png' in the same folder as the file. <html>
<head>
<script type='text/javascript'>
// movement vars
var xpos = 100;
var ypos = 100;
var xspeed = 1;
var yspeed = 0;
var maxSpeed = 5;
// boundary
var minx = 0;
var miny = 0;
var maxx = 490; // 10 pixels for character's width
var maxy = 490; // 10 pixels for character's width
// controller vars
var upPressed = 0;
var downPressed = 0;
var leftPressed = 0;
var rightPressed = 0;
function slowDownX()
{
if (xspeed > 0)
xspeed = xspeed - 1;
if (xspeed < 0)
xspeed = xspeed + 1;
}
function slowDownY()
{
if (yspeed > 0)
yspeed = yspeed - 1;
if (yspeed < 0)
yspeed = yspeed + 1;
}
function gameLoop()
{
// change position based on speed
xpos = Math.min(Math.max(xpos + xspeed,minx),maxx);
ypos = Math.min(Math.max(ypos + yspeed,miny),maxy);
// or, without boundaries:
// xpos = xpos + xspeed;
// ypos = ypos + yspeed;
// change actual position
document.getElementById('character').style.left = xpos;
document.getElementById('character').style.top = ypos;
// change speed based on keyboard events
if (upPressed == 1)
yspeed = Math.max(yspeed - 1,-1*maxSpeed);
if (downPressed == 1)
yspeed = Math.min(yspeed + 1,1*maxSpeed)
if (rightPressed == 1)
xspeed = Math.min(xspeed + 1,1*maxSpeed);
if (leftPressed == 1)
xspeed = Math.max(xspeed - 1,-1*maxSpeed);
// deceleration
if (upPressed == 0 && downPressed == 0)
slowDownY();
if (leftPressed == 0 && rightPressed == 0)
slowDownX();
// loop
setTimeout("gameLoop()",10);
}
function keyDown(e)
{
var code = e.keyCode ? e.keyCode : e.which;
if (code == 38)
upPressed = 1;
if (code == 40)
downPressed = 1;
if (code == 37)
leftPressed = 1;
if (code == 39)
rightPressed = 1;
}
function keyUp(e)
{
var code = e.keyCode ? e.keyCode : e.which;
if (code == 38)
upPressed = 0;
if (code == 40)
downPressed = 0;
if (code == 37)
leftPressed = 0;
if (code == 39)
rightPressed = 0;
}
</script>
</head>
<body onload="gameLoop()" onkeydown="keyDown(event)" onkeyup="keyUp(event)" bgcolor='gray'>
<!-- The Level -->
<div style='width:500;height:500;position:absolute;left:0;top:0;background:black;'>
</div>
<!-- The Character -->
<img id='character' src='1.png' style='position:absolute;left:100;top:100;height:10;width:10;'/>
</body>
</html>
|
JavaScript move an image with arrow keys
Date : March 29 2020, 07:55 AM
may help you . I've seen lots of people ask similar questions here, but none of them seem to work for me. I have an img, with the id 'character'. I want it to move left on left click and right on right click. This is the code I have: , Why not use jQuery? $("body").keydown(function(e) {
var max = $('body').width();
var min = 0;
var move_amt = 10;
var position = $("#my_image").offset();
if(e.which == 37) { // left
var new_left = ((position.left-move_amt < min) ? min : position.left-move_amt);
$("#my_image").offset({ left: new_left})
}
else if(e.which == 39) { // right
var new_left = ((position.left+move_amt > max) ? max : position.left+move_amt);
$("#my_image").offset({ left: new_left})
}
});
|
How to move an object using arrow keys using javascript
Date : March 29 2020, 07:55 AM
This might help you Going through with the code gdros and yourself provided: Fiddle: https://jsfiddle.net/k3akqz3c/1/// Basic variables
var canvas;
var context;
var rectX = 10;
var rectY = 10;
// Set canvas context
window.onload = function() {
canvas = document.getElementById("myCanvas");
context = canvas.getContext("2d");
}
function fillRect() {
context.beginPath();
context.fillStyle = "#ffffff";
context.fillRect(0, 0, 1000 + canvas.width, 1000 + canvas.height);
context.beginPath();
context.fillStyle = "#666666";
// Check if the rect isn't out of bounds, if so: place it back.
if (rectX < 0) {
rectX = 0;
} else if (rectX > 250) {
rectX = 250;
}
if (rectY < 0) {
rectY = 0;
} else if (rectX > 100) {
rectX = 100;
}
context.fillRect(rectX, rectY, 50, 50);
}
function onkeydown(e) {
if (e.keyCode == 39) {
rectX++;
} //right arrow
else if (e.keyCode == 37) {
rectX--;
} //left arrow
else if (e.keyCode == 38) {
rectY--;
} //up arrow
else if (e.keyCode == 40) {
rectY++;
} //down arrow
fillRect();
}
window.addEventListener("keydown", onkeydown);
|
Multiple contentEditable, unable to move carret to end of span with arrow keys
Date : March 29 2020, 07:55 AM
around this issue It seems like a browser bug. It is only happening in Firefox for me, however, adding any amount of padding to the spans seems to correct the issue: span[contentEditable] { padding: 1px; }
|
how to move a image with arrow keys and get id of behind div in javascript?
Date : March 29 2020, 07:55 AM
Hope this helps Following up to my comments above, document.elementFromPoint only gets the top most element - mozilla docs, which here is the image itself, so use a work around like setting display:none or pointer-events:none to the image to make the box as the top most elem and get the box Id. Then reset the value back.
|
Boards Message :
Related QUESTIONS :