Question

I have 2 functions(js) in a webpage for attaching an image to a canvas element:

 function attachImage(tile, x, y)
    {
      base_image = new Image();
      base_image.src = 'Images/tiles/'+(tile-1)+'.png';
      base_image.onload = function(){
        context.drawImage(base_image, 32*x,32*y);
      }
    }

and i literally copy and pasted it and duplicated it for another canvas

  function attachImage2(tile2, x2, y2)
    {
        base_image2 = new Image();
        base_image2.src = 'Images/tiles/'+(tile2-1)+'.png';
        base_image2.onLoad = function(){
            context2.drawImage(base_image2, 32*x2,32*y2);
      }
    }

On firefox, if i make one onload and the other onLoad, then it works fine. but no matter what i do for chrome, it doesn’t load the images properly.

edit: here is and image comparison between firefox and chrome:

FIREFOX: https://i.stack.imgur.com/l5sMt.jpg

CHROME: https://i.stack.imgur.com/u12H6.jpg

Answer 1

You should use the onload (lowercase).

Some general notes

• When you need local variables use var.
• You should set the onload before actually setting the src because otherwise (for cached) images the onload might not get called.
• Since your methods do the same thing, you should use only one, and pass the context as a parameter

So

<script>
var canvas = document.getElementById('map');
context = canvas.getContext('2d');

var canvas2 = document.getElementById('map2');
context2 = canvas2.getContext('2d');

function attachImage(tile, x, y, canvasContext)
{
  var base_image = new Image();
  base_image.onload = function(){
    canvasContext.drawImage(base_image, 32*x,32*y);
  }
  base_image.src = 'Images/tiles/'+(tile-1)+'.png';
}
</script>

and you should not create a script tag for each call

<?php
echo("<script>");
for($tr = 0; $tr < count($mapArray)-1; $tr++) {
    for($tc = 0; $tc < count($mapArray[$tr])-1; $tc++) {
        $tile = $mapArray[$tr][$tc];
        echo "attachImage(" . $tile . "," . $tc . "," . $tr . ",context);";
    }
}

for($tr = 0; $tr < count($mapArrayy)-1; $tr++) {
    for($tc = 0; $tc < count($mapArrayy[$tr])-1; $tc++) {
        if($mapArrayy[$tr][$tc]!=0){
            echo "attachImage(" . $mapArrayy[$tr][$tc]. "," . $tc . "," . $tr . ",context2);";
        }
    }
}
echo("</script>");
?>