function drawChar(line, col, ch) {
    if (line < 0 || line >= LINES || col < 0 || col >= COLUMNS)
        return;
    //
    // attributes
    const a = line * COLUMNS + col
    const attr = makeAttribute(my.ink, my.paper)
    displayColours[a] = attr
    //
    // index of the first byte of the character in the character set
    const chAt = (ch.charCodeAt(0) - 0x20) * CHARSIZE
    //
    // copy pixel data
    for (let i = 0; i < CHARSIZE; i++) {
        const at = (line * CHARSIZE + i) * COLUMNS + col
        displayPixels[at] = CHARSET[chAt + i]
    }
} //                                                                    drawChar

/** drawChar():
 *  Draws a single character at the specified line and column.
 *
 *  @param [line]  Line number, a number from 0 to LINES-1.
 *                 The starting line is at the top of the display.
 *
 *  @param [col]   Column number, a number from 0 to COLUMNS-1.
 *                 The starting column is at the left of the display.
 *
 *  @param [ch]    The character to draw, as a string.
 *                 Only the first character of the string is used.
 */
Draws a single character at the specified line and column.

@param [line]  Line number, a number from 0 to LINES-1.
The starting line is at the top of the display.

@param [col]   Column number, a number from 0 to COLUMNS-1.
The starting column is at the left of the display.

@param [ch]    The character to draw, as a string.
Only the first character of the string is used.
Draws a single character at the specified line and column . @param [ line ] Line number a number from 0 to LINES - 1 . The starting line is at the top of the display . @param [ col ] Column number a number from 0 to COLUMNS - 1 . The starting column is at the left of the display . @param [ ch ] The character to draw as a string . Only the first character of the string is used .
function drawChar(line, col, ch) {
    if (line < 0 || line >= LINES || col < 0 || col >= COLUMNS)
        return;
    const a = line * COLUMNS + col
    const attr = makeAttribute(my.ink, my.paper)
    displayColours[a] = attr
    const chAt = (ch.charCodeAt(0) - 0x20) * CHARSIZE
    for (let i = 0; i < CHARSIZE; i++) {
        const at = (line * CHARSIZE + i) * COLUMNS + col
        displayPixels[at] = CHARSET[chAt + i]
    }
} 
function drawChar ( line , col , ch ) { if ( line < 0 || line >= LINES || col < 0 || col >= COLUMNS ) return ; const a = line * COLUMNS + col const attr = makeAttribute ( my . ink , my . paper ) displayColours [ a ] = attr const chAt = ( ch . charCodeAt ( 0 ) - 0x20 ) * CHARSIZE for ( let i = 0 ; i < CHARSIZE ; i ++ ) { const at = ( line * CHARSIZE + i ) * COLUMNS + col displayPixels [ at ] = CHARSET [ chAt + i ] } }
drawChar():
  Draws a single character at the specified line and column.
drawChar () : Draws a single character at the specified line and column .
//
 // attributes
 //
 // index of the first byte of the character in the character set
 //
 // copy pixel data
 //                                                                    drawChar
