apple2js/js/ui/printer.js
Ian Flanigan f991833d68
Add a "Clear" button to clear the printer paper (#35)
Before, the printer "paper" would just keep accumulating changes. Now
the `printer-modal` dialog has a "clear" button that will the paper.
2020-10-11 08:48:16 -07:00

72 lines
2.3 KiB
JavaScript

/* Copyright 2010-2019 Will Scullin <scullin@scullinsteel.com>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
/**
* Printer UI. The "paper" is bound to the element selected by the input.
*
* Every line that is output to the printer is added as a <div> to the paper.
* The high bit of all characters is stripped and only visible characters are
* added to the output. The following characters receive special treatment:
*
* * `EOT` (ASCII 4): deletes last character
* * `HT` (ASCII 9): replaced with 8 spaces
* * `LF` (ASCII 10): silently removed
* * `CR` (ASCII 13): a newline and carriage return
*
* @param {string} el The selector of the element on which to bind the "paper".
*/
export default function Printer(el) {
var paper = document.querySelector(el);
var _lineBuffer = '';
var _line;
function newLine() {
_line = document.createElement('div');
_line.classList.add('line');
_line.innerText = _lineBuffer;
paper.append(_line);
_lineBuffer = '';
}
newLine();
return {
putChar: function(val) {
var ascii = val & 0x7f;
var visible = val >= 0x20;
var c = String.fromCharCode(ascii);
if (c === '\r') {
newLine();
} else if (c === '\n') {
// eat for now
} else if (c === '\t') {
_lineBuffer += ' ';
} else if (ascii === 0x04) {
_lineBuffer = _lineBuffer.slice(0, -1);
} else if (visible) {
_lineBuffer += c;
}
_line.innerText = _lineBuffer;
},
clear: function() {
_lineBuffer = '';
paper.innerHTML = "";
newLine();
},
hasPrintout: function() {
return paper.text.length;
}
};
}