mirror of
https://github.com/Michaelangel007/apple2_hgr_font_tutorial.git
synced 2024-12-01 02:49:58 +00:00
56 lines
2.0 KiB
HTML
56 lines
2.0 KiB
HTML
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<html>
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<head>
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<script>
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function byte2hex$( byte )
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{
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return ("0" + byte.toString(16)).toUpperCase().substr(-2)
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}
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function OnLoad()
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{
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var image = document.getElementById( "Apple2eFont7x8" );
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var canvas = document.createElement( "canvas" );
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var context = canvas.getContext( "2d" );
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canvas.width = image.width;
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canvas.height = image.height;
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context.drawImage( image, 0, 0 );
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var CW = 7, CH = 8; // Cell Width Height
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var address = 0x6000, pixel, rgba, lines = "";
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for( var ty = 0; ty < image.height/CH; ++ty )
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{
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for( var tx = 0; tx < image.width/CW; ++tx )
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{
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var text = "";
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for( var y = 0; y < CH; ++y )
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{
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var hex = 0, mask = 0x1;
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for( var x = 0; x < CW; ++x, mask <<= 1 )
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{
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pixel = context.getImageData( tx*CW+x, ty*CH+y, 1, 1 );
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rgba = pixel.data;
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hex += rgba[0] ? mask : 0; // assume R=G=B
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}
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text += byte2hex$( hex ) + " ";
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}
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var c = (16*ty)+tx, d = String.fromCharCode( c );
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if (c < 32) d = "^" + String.fromCharCode( c + 0x40 );
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text += "; " + d + "\n";
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lines += "" + address.toString(16).toUpperCase() + ":" + text;
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address += 8;
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}
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}
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console.log( lines );
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var pre = document.getElementById( "hexdump" );
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pre.innerHTML = lines;
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}
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</script>
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</head>
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<body onload="OnLoad()">
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<img id="Apple2eFont7x8" src="Apple2eFont7x8.png">
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<hr>
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<pre id="hexdump"></pre>
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</body>
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</html>
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