Apple-2-SW/apple2_hgr_font_tutorial
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Added image_2_hex.html

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michaelangel007 2016-01-09 19:21:26 -08:00
parent 89d7e9fe4d
commit 37d2dbab18
1 changed files with 55 additions and 0 deletions
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image_2_hex.html Normal file
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<html>
<head>
<script>
function byte2hex$( byte )
{
return ("0" + byte.toString(16)).toUpperCase().substr(-2)
}
function OnLoad()
{
var image = document.getElementById( "Apple2eFont7x8" );
var canvas = document.createElement( "canvas" );
var context = canvas.getContext( "2d" );
canvas.width = image.width;
canvas.height = image.height;
context.drawImage( image, 0, 0 );
var CW = 7, CH = 8; // Cell Width Height
var address = 0x6000, pixel, rgba, lines = "";
for( var ty = 0; ty < image.height/CH; ++ty )
{
for( var tx = 0; tx < image.width/CW; ++tx )
{
var text = "";
for( var y = 0; y < CH; ++y )
{
var hex = 0, mask = 0x1;
for( var x = 0; x < CW; ++x, mask <<= 1 )
{
pixel = context.getImageData( tx*CW+x, ty*CH+y, 1, 1 );
rgba = pixel.data;
hex += rgba[0] ? mask : 0; // assume R=G=B
}
text += byte2hex$( hex ) + " ";
}
var c = (16*ty)+tx, d = String.fromCharCode( c );
if (c < 32) d = "^" + String.fromCharCode( c + 0x40 );
text += "; " + d + "\n";
lines += "" + address.toString(16).toUpperCase() + ":" + text;
address += 8;
}
}
console.log( lines );
var pre = document.getElementById( "hexdump" );
pre.innerHTML = lines;
}
</script>
</head>
<body onload="OnLoad()">
<img id="Apple2eFont7x8" src="Apple2eFont7x8.png">
<hr>
<pre id="hexdump"></pre>
</body>
</html>