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main.js
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// *************************************************
// * Utils
// *************************************************
const base64 = function(buffer) {
const bytes = new Uint8Array(buffer);
const chars = [];
for (let i = 0; i < bytes.byteLength; ++i) {
chars[i] = String.fromCharCode(bytes[i]);
}
return btoa(chars.join(''));
};
// has_font takes a font name and returns true if the font is available to the browser.
// The function signature is not immediately clear from the line of code that follows
// this comment, as the function is constructed as a closure returned by calling an
// anonymous function.
// has_font signature:
// boolean has_font(string name);
const has_font = function() {
// First check if document.fonts.check is available and works as expected.
// As of 2020/08/04, document.fonts.check does not work on Firefox:
// https://bugzilla.mozilla.org/show_bug.cgi?id=1252821
let fonts_api_available = false;
try {
const fake_status = document.fonts.check('12px font_name_that_does_not_exist');
const monospace_status = document.fonts.check('12px monospace');
fonts_api_available = !fake_status && monospace_status;
} catch {}
// If document.fonts.check is not viable (or returns false, per comment below),
// use an approach that checks for font availability by 1) creating a <span>
// with the specified font, using a generic font as a fallback, and seeing if
// the width or height differs from a <span> constructed with the generic font.
// Generic fonts from: https://www.w3.org/TR/CSS2/fonts.html#generic-font-families
const generic_fonts = ['serif', 'sans-serif', 'cursive', 'fantasy', 'monospace'];
const string = 'The quick brown fox jumps over the lazy dog';
const body = document.body;
const span = document.createElement('span');
span.style.fontSize = '72px';
span.innerHTML = string;
const width_lookup = {};
const height_lookup = {};
for (const generic_font of generic_fonts) {
span.style.fontFamily = generic_font;
body.appendChild(span);
width_lookup[generic_font] = span.offsetWidth;
height_lookup[generic_font] = span.offsetHeight;
body.removeChild(span);
}
function closure(font) {
if (generic_fonts.includes(font))
return true;
// As of 2020/08/04, document.fonts.check('12px courier') returns false
// on Chrome on Ubuntu, even when the font is available. Only rely on this
// approach when the API worked as expected above, and check() returns true.
if (fonts_api_available && document.fonts.check('12px ' + font))
return true;
for (const generic_font of generic_fonts) {
span.style.fontFamily = font + ', ' + generic_font;
body.appendChild(span);
const matched = span.offsetWidth !== width_lookup[generic_font]
|| span.offsetHeight !== height_lookup[generic_font];
body.removeChild(span);
if (matched) return true;
}
return false;
}
return closure;
}();
// *************************************************
// * Core
// *************************************************
// Multiple of size to determine padding in pixels.
const PADDING_FACTOR = 0.5;
const BASE_PALETTE = [
0x000000, 0x800000, 0x008000, 0x808000, 0x000080, 0x800080, 0x008080, 0xc0c0c0,
0x808080, 0xff0000, 0x00ff00, 0xffff00, 0x0000ff, 0xff00ff, 0x00ffff, 0xffffff,
0x000000, 0x00005f, 0x000087, 0x0000af, 0x0000d7, 0x0000ff, 0x005f00, 0x005f5f,
0x005f87, 0x005faf, 0x005fd7, 0x005fff, 0x008700, 0x00875f, 0x008787, 0x0087af,
0x0087d7, 0x0087ff, 0x00af00, 0x00af5f, 0x00af87, 0x00afaf, 0x00afd7, 0x00afff,
0x00d700, 0x00d75f, 0x00d787, 0x00d7af, 0x00d7d7, 0x00d7ff, 0x00ff00, 0x00ff5f,
0x00ff87, 0x00ffaf, 0x00ffd7, 0x00ffff, 0x5f0000, 0x5f005f, 0x5f0087, 0x5f00af,
0x5f00d7, 0x5f00ff, 0x5f5f00, 0x5f5f5f, 0x5f5f87, 0x5f5faf, 0x5f5fd7, 0x5f5fff,
0x5f8700, 0x5f875f, 0x5f8787, 0x5f87af, 0x5f87d7, 0x5f87ff, 0x5faf00, 0x5faf5f,
0x5faf87, 0x5fafaf, 0x5fafd7, 0x5fafff, 0x5fd700, 0x5fd75f, 0x5fd787, 0x5fd7af,
0x5fd7d7, 0x5fd7ff, 0x5fff00, 0x5fff5f, 0x5fff87, 0x5fffaf, 0x5fffd7, 0x5fffff,
0x870000, 0x87005f, 0x870087, 0x8700af, 0x8700d7, 0x8700ff, 0x875f00, 0x875f5f,
0x875f87, 0x875faf, 0x875fd7, 0x875fff, 0x878700, 0x87875f, 0x878787, 0x8787af,
0x8787d7, 0x8787ff, 0x87af00, 0x87af5f, 0x87af87, 0x87afaf, 0x87afd7, 0x87afff,
0x87d700, 0x87d75f, 0x87d787, 0x87d7af, 0x87d7d7, 0x87d7ff, 0x87ff00, 0x87ff5f,
0x87ff87, 0x87ffaf, 0x87ffd7, 0x87ffff, 0xaf0000, 0xaf005f, 0xaf0087, 0xaf00af,
0xaf00d7, 0xaf00ff, 0xaf5f00, 0xaf5f5f, 0xaf5f87, 0xaf5faf, 0xaf5fd7, 0xaf5fff,
0xaf8700, 0xaf875f, 0xaf8787, 0xaf87af, 0xaf87d7, 0xaf87ff, 0xafaf00, 0xafaf5f,
0xafaf87, 0xafafaf, 0xafafd7, 0xafafff, 0xafd700, 0xafd75f, 0xafd787, 0xafd7af,
0xafd7d7, 0xafd7ff, 0xafff00, 0xafff5f, 0xafff87, 0xafffaf, 0xafffd7, 0xafffff,
0xd70000, 0xd7005f, 0xd70087, 0xd700af, 0xd700d7, 0xd700ff, 0xd75f00, 0xd75f5f,
0xd75f87, 0xd75faf, 0xd75fd7, 0xd75fff, 0xd78700, 0xd7875f, 0xd78787, 0xd787af,
0xd787d7, 0xd787ff, 0xd7af00, 0xd7af5f, 0xd7af87, 0xd7afaf, 0xd7afd7, 0xd7afff,
0xd7d700, 0xd7d75f, 0xd7d787, 0xd7d7af, 0xd7d7d7, 0xd7d7ff, 0xd7ff00, 0xd7ff5f,
0xd7ff87, 0xd7ffaf, 0xd7ffd7, 0xd7ffff, 0xff0000, 0xff005f, 0xff0087, 0xff00af,
0xff00d7, 0xff00ff, 0xff5f00, 0xff5f5f, 0xff5f87, 0xff5faf, 0xff5fd7, 0xff5fff,
0xff8700, 0xff875f, 0xff8787, 0xff87af, 0xff87d7, 0xff87ff, 0xffaf00, 0xffaf5f,
0xffaf87, 0xffafaf, 0xffafd7, 0xffafff, 0xffd700, 0xffd75f, 0xffd787, 0xffd7af,
0xffd7d7, 0xffd7ff, 0xffff00, 0xffff5f, 0xffff87, 0xffffaf, 0xffffd7, 0xffffff,
0x080808, 0x121212, 0x1c1c1c, 0x262626, 0x303030, 0x3a3a3a, 0x444444, 0x4e4e4e,
0x585858, 0x626262, 0x6c6c6c, 0x767676, 0x808080, 0x8a8a8a, 0x949494, 0x9e9e9e,
0xa8a8a8, 0xb2b2b2, 0xbcbcbc, 0xc6c6c6, 0xd0d0d0, 0xdadada, 0xe4e4e4, 0xeeeeee,
];
// Some themes are from VS code, with the VS-specific themes excluded.
// These include:
// abyss, dark, high contrast, kimbie dark, light, monokai, monokai dimmed,
// quiet light, red, solarized dark, solarized light, tomorrow night blue
// Data are from the corresponding JSON files
// * E.g., https://github.com/microsoft/vscode/blob/master/extensions/
// theme-abyss/themes/abyss-color-theme.json
// * ANSI colors are from the 'terminal.*' settings.
// * background is from 'editor.background'
// * foreground is from 'editor.foreground' when available
// otherwise #333333 for light themes, #CCCCCC for dark themes,
// and #FFFFFF for high contrast themes
// * cursor is from 'editorCursor.foreground' when available
// otherwise use the same value used for foreground
// * cursorAccent is the same value used for background
// * selection is from 'editor.selectionBackground' when available
// (excluding alpha channel)
// otherwise #000040 for light themes, #FFFF40 for dark themes,
// and #FFFF80 for high contrast themes
// Some themes are contributions from pull requests:
// gruvbox dark, gruvbox light (PR #5)
const THEMES = {
abyss: {
black: '#111111', red: '#ff9da4', green: '#d1f1a9', yellow: '#ffeead',
blue: '#bbdaff', purple: '#ebbbff', cyan: '#99ffff', white: '#cccccc',
brightBlack: '#333333', brightRed: '#ff7882', brightGreen: '#b8f171', brightYellow: '#ffe580',
brightBlue: '#80baff', brightPurple: '#d778ff', brightCyan: '#78ffff', brightWhite: '#ffffff',
background: '#000c18', foreground: '#6688cc', cursor: '#ddbb88', cursorAccent: '#000c18',
selection: '#770811',
},
dark: {
background: '#1e1e1e', foreground: '#d4d4d4', cursor: '#d4d4d4', cursorAccent: '#1e1e1e',
selection: '#ffff40',
},
gruvbox_dark: {
black: '#282828', red: '#cc241d', green: '#98971a', yellow: '#d79921',
blue: '#458588', purple: '#b16286', cyan: '#689d6a', white: '#a89984',
brightBlack: '#928374', brightRed: '#fb4934', brightGreen: '#b8bb26', brightYellow: '#fabd2f',
brightBlue: '#83a598', brightPurple: '#d3869b', brightCyan: '#8ec07c', brightWhite: '#ebdbb2',
background: '#282828', foreground: '#ebdbb2', cursor: '#ebdbb2', cursorAccent: '#002451',
selection: '#003f8e',
},
gruvbox_light: {
black: '#fbf1c7', red: '#cc241d', green: '#98971a', yellow: '#d79921',
blue: '#458588', purple: '#b16286', cyan: '#689d6a', white: '#a89984',
brightBlack: '#928374', brightRed: '#fb4934', brightGreen: '#b8bb26', brightYellow: '#fabd2f',
brightBlue: '#83a598', brightPurple: '#d3869b', brightCyan: '#8ec07c', brightWhite: '#ebdbb2',
background: '#fbf1c7', foreground: '#3c3836', cursor: '#002451', cursorAccent: '#ebdbb2',
selection: '#a89984',
},
high_contrast: {
background: '#000000', foreground: '#ffffff', cursor: '#ffffff', cursorAccent: '#000000',
selection: '#ffff80',
},
kimbie_dark: {
background: '#221a0f', foreground: '#d3af86', cursor: '#d3af86', cursorAccent: '#221a0f',
selection: '#84613d',
},
light: {
background: '#ffffff', foreground: '#000000', cursor: '#000000', cursorAccent: '#ffffff',
selection: '#000040',
},
monokai: {
black: '#333333', red: '#c4265e', green: '#86b42b', yellow: '#b3b42b',
blue: '#6a7ec8', purple: '#8c6bc8', cyan: '#56adbc', white: '#e3e3dd',
brightBlack: '#666666', brightRed: '#f92672', brightGreen: '#a6e22e', brightYellow: '#e2e22e',
brightBlue: '#819aff', brightPurple: '#ae81ff', brightCyan: '#66d9ef', brightWhite: '#f8f8f2',
background: '#272822', foreground: '#f8f8f2', cursor: '#f8f8f0', cursorAccent: '#272822',
selection: '#878b91',
},
monokai_dimmed: {
white: '#ffffff',
background: '#1e1e1e', foreground: '#c5c8c6', cursor: '#c07020', cursorAccent: '#1e1e1e',
selection: '#676b71',
},
quiet_light: {
background: '#f5f5f5', foreground: '#333333', cursor: '#54494b', cursorAccent: '#f5f5f5',
selection: '#c9d0d9',
},
red: {
background: '#390000', foreground: '#f8f8f8', cursor: '#970000', cursorAccent: '#390000',
selection: '#750000',
},
solarized_dark: {
black: '#073642', red: '#dc322f', green: '#859900', yellow: '#b58900',
blue: '#268bd2', purple: '#d33682', cyan: '#2aa198', white: '#eee8d5',
brightBlack: '#586e75', brightRed: '#cb4b16', brightGreen: '#586e75', brightYellow: '#657b83',
brightBlue: '#839496', brightPurple: '#6c71c4', brightCyan: '#93a1a1', brightWhite: '#fdf6e3',
background: '#002b36', foreground: '#cccccc', cursor: '#d30102', cursorAccent: '#002b36',
selection: '#274642',
},
solarized_light: {
black: '#073642', red: '#dc322f', green: '#859900', yellow: '#b58900',
blue: '#268bd2', purple: '#d33682', cyan: '#2aa198', white: '#eee8d5',
brightBlack: '#586e75', brightRed: '#cb4b16', brightGreen: '#586e75', brightYellow: '#657b83',
brightBlue: '#839496', brightPurple: '#6c71c4', brightCyan: '#93a1a1', brightWhite: '#eee8d5',
background: '#fdf6e3', foreground: '#333333', cursor: '#657b83', cursorAccent: '#fdf6e3',
selection: '#eee8d5',
},
tomorrow_night_blue: {
black: '#111111', red: '#ff9da4', green: '#d1f1a9', yellow: '#ffeead',
blue: '#bbdaff', purple: '#ebbbff', cyan: '#99ffff', white: '#cccccc',
brightBlack: '#333333', brightRed: '#ff7882', brightGreen: '#b8f171', brightYellow: '#ffe580',
brightBlue: '#80baff', brightPurple: '#d778ff', brightCyan: '#78ffff', brightWhite: '#ffffff',
background: '#002451', foreground: '#ffffff', cursor: '#ffffff', cursorAccent: '#002451',
selection: '#003f8e',
},
};
const FONT_CANDIDATES = function() {
// WARN: Checking for font availability (with either document.fonts.check or using
// the DOM) is slow on some browsers/platforms (e.g., around 30ms per font when
// experimenting on Chrome on Linux for the first call, and negligible latency
// for subsequent calls with the same font). Keep this list small to reduce the
// latency.
// The list of monospace fonts was primarily constructed by checking which fonts from
// https://en.wikipedia.org/wiki/List_of_typefaces#Monospace
// are available on Ubuntu, Windows, or Mac.
// Fonts listed on Wikipedia:
// andale mono, arial monospaced, bitstream vera, consolas, courier, courier new,
// dejavu sans mono, droid sans mono, everson mono, fira mono, fira code, fixed,
// fixedsys, hyperfont, ibm plex mono, inconsolata, letter gothic, liberation mono,
// lucida console, lucida sans typewriter, lucida typewriter, menlo, micr, monaco,
// monospace, ms gothic, ms mincho, nimbus mono l, ocr-a, ocr-b, pragmatapro,
// prestige, prestige elite, profont, proggy clean, proggy square, proggy small,
// proggy tiny, roboto mono, simhei, simsun, source code pro, terminal, ubuntu mono,
// vera sans mono
let set = new Set();
let ubuntu_fonts = [
'courier new', 'dejavu sans mono', 'liberation mono', 'monospace', 'ms gothic',
'simhei', 'simsun', 'ubuntu mono'
];
ubuntu_fonts.forEach(set.add, set);
let windows_fonts = [
'consolas', 'courier', 'courier new', 'lucida console', 'lucida sans typewriter',
'monospace', 'ms gothic simsun'
];
windows_fonts.forEach(set.add, set);
let mac_fonts = [
'andale mono', 'courier', 'courier new', 'dejavu sans mono', 'menlo', 'monaco',
'monospace'
];
mac_fonts.forEach(set.add, set);
// Also add two monospace fonts from /system/fonts on Android. Specifying these makes
// them available from Firefox for Android, but not Chrome for Android.
let android_fonts = ['cutive mono', 'droid sans mono'];
android_fonts.forEach(set.add, set);
// Lastly, make sure that the generic 'monospace' font is available.
set.add('monospace');
let fonts = Array.from(set);
fonts.sort();
return fonts;
}();
// Converts a color string (e.g., 003f8e) to its corresponding integer.
const int = function(string) {
const r = parseInt(string.substring(1, 3), 16);
const g = parseInt(string.substring(3, 5), 16);
const b = parseInt(string.substring(5, 7), 16);
return (r << 16) + (g << 8) + b;
};
// Calculates the squared distance between two hex colors.
const distance2 = function(color1, color2) {
const r1 = color1 >> 16;
const g1 = (color1 & 0x00ff00) >> 8;
const b1 = color1 & 0x0000ff;
const r2 = color2 >> 16;
const g2 = (color2 & 0x00ff00) >> 8;
const b2 = color2 & 0x0000ff;
return Math.pow(r1 - r2, 2) + Math.pow(g1 - g2, 2) + Math.pow(b1 - b2, 2)
};
// Returns the index of the color in haystack that is closest to needle.
// 'exclude' is an optional argument specifying a Set() of indices to skip in the haystack.
const closest = function(needle, haystack, exclude) {
let min = Infinity;
let idx = -1;
for (let i = 0; i < haystack.length; ++i) {
if (exclude && exclude.has(idx)) continue;
const candidate = haystack[i];
const dist = distance2(needle, candidate);
if (dist >= min) continue;
min = dist;
idx = i;
}
return idx;
};
// Returns a palette that contains the required set of colors. Required colors are
// included in the palette by replacing close colors in the BASE_PALETTE.
const get_palette = function(required) {
const palette = [...BASE_PALETTE];
const req = Array.from(new Set(required)).slice(0, palette.length);
const exclude = new Set();
for (const color of req) {
let idx = closest(color, palette, exclude);
exclude.add(idx);
palette[idx] = color;
}
return palette;
};
// Given a set of pixels, quantize each to the index of the nearest
// pixel in the specified palette.
const quantize = function(pixels, palette) {
const color_code = {};
for (let i = 0; i < palette.length; ++i) {
color_code[palette[i]] = i;
}
const colors = Array.from(new Set(pixels));
for (let i = 0; i < colors.length; ++i) {
const color = colors[i];
if (color in color_code) continue;
// Find the closest color
color_code[color] = closest(color, BASE_PALETTE);
}
const indexed_pixels = [];
for (let i = 0; i < pixels.length; ++i) {
indexed_pixels[i] = color_code[pixels[i]];
}
return indexed_pixels;
};
const header_palette_theme = function(header_palette) {
let colors = header_palette.split(':');
if (colors.length === 8)
colors = colors.concat(colors);
const theme = {
black: colors[0],
red: colors[1],
green: colors[2],
yellow: colors[3],
blue: colors[4],
purple: colors[5],
cyan: colors[6],
white: colors[7],
brightBlack: colors[8],
brightRed: colors[9],
brightGreen: colors[10],
brightYellow: colors[11],
brightBlue: colors[12],
brightPurple: colors[13],
brightCyan: colors[14],
brightWhite: colors[15],
};
return theme;
};
// Extract frames from the asciinema cast file events.
const extract_frames = function(events) {
const frames = [{time: 0.0, data: ''}];
for (let i = 0; i < events.length; ++i) {
const [time, type, data] = events[i];
if (type !== 'o') continue;
frames.push({
time: time,
data: data,
});
}
// Add a delay field.
for (let i = 1; i < frames.length; ++i) {
frames[i - 1].delay = frames[i].time - frames[i - 1].time;
}
frames[frames.length - 1].delay = 0.0;
return frames;
};
// Merge frames that are less than a hundredth of a second.
// The reasons for this are 1) to satisfy GIF specs, 2) speed
// processing time, and 3) allow for more accurate playback
// speed (it seems that times less than .01 second playback
// for longer than they're supposed to, probably due to GIF
// specs).
const merge_frames = function(frames) {
if (frames.length === 0) return frames;
frames.reverse();
const merged = [];
while (frames.length > 0) {
merged.push(frames.pop());
while (merged[merged.length - 1].delay < .01 && frames.length > 0) {
const short = merged[merged.length - 1];
const addition = frames.pop();
short.data += addition.data;
short.delay += addition.delay;
}
}
return merged;
};
// Parse a cast file. Return an object with a header and a list of events.
// Includes error-checking.
const parse_cast = function(cast) {
const lines = cast.split(/\r?\n/);
if (lines.length === 0) throw Error('Invalid file.');
let header = null;
try {
header = JSON.parse(lines[0]); // throws a SyntaxError
} catch(e) {
throw Error('Error parsing JSON.');
}
if (header.version !== 2) throw Error('gifcast only supports asciinema cast version 2.');
const events = [];
for (let i = 1; i < lines.length; ++i) {
const line = lines[i];
if (!line) continue;
try {
events.push(JSON.parse(line));
} catch(e) {
throw Error('Error parsing JSON.');
}
}
const output = {header: header, events: events};
return output;
};
// asciicast file format (version 2) is specified at:
// https://github.com/asciinema/asciinema/blob/develop/doc/asciicast-v2.md
const TermRunner = function(parent, options, cast) {
// Callback before term running
this.oninit = function() {};
// Callback for each step of term running
this.onstep = function(state) {};
// Callback after successful term running
this.onsuccess = function() {};
// Callback after failed term running
this.onerror = function(message) {};
const run = () => {
let header, events;
try {
({header, events} = parse_cast(cast));
} catch(e) {
this.onerror(e.message);
return;
}
let frames = merge_frames(extract_frames(events));
// Writing text to the xterm.js terminal is asynchronous.
// To workaround this, iteration is conducted with the
// onRender callback. Each time the terminal is rendered,
// the GIF is updated, and another frame (more text) is pushed
// for processing. Iteration starts with the initial onRender
// that is called when the terminal is opened.
const theme = JSON.parse(JSON.stringify(THEMES[options.theme] || {}));
if (options.theme === 'none' && 'theme' in header) {
// It appears that there is no way to set cursor, cursorAccent, and selection
// in the asciicast file format (version 2).
const header_theme = header.theme;
if ('fg' in header_theme) theme.foreground = header_theme.fg;
if ('bg' in header_theme) theme.background = header_theme.bg;
if ('palette' in header_theme)
Object.assign(theme, header_palette_theme(header_theme.palette));
}
// xtermjs scales the canvas depending on devicePixelRatio. Adjust for this so
// that the generated GIF size is independent of devicePixelRatio.
const font_size = options.size / window.devicePixelRatio; // non-integer values seems to work
const cols = header.width;
const rows = header.height;
const config = {
cols: cols,
rows: rows,
cursorBlink: false,
allowTransparency: false,
theme: theme,
fontSize: font_size,
rendererType: 'canvas',
minimumContrastRatio: options.contrast_gain,
fontFamily: options.font + ', monospace',
};
// Cursor can possibly be 'none', which is not a valid setting for xtermjs.
if (['bar', 'block', 'underline'].includes(options.cursor))
config.cursorStyle = options.cursor;
const term = new Terminal(config);
term.loadAddon(new CanvasAddon.CanvasAddon());
// 'idx' is the index of the frame being processed. Frames are written to
// the terminal at the end of process(), except for the initial frame, which
// is written at the beginning to start the process.
let idx = 0;
const process = () => {
// Don't process if there is more buffered data to write.
if (term._core._writeBuffer._writeBuffer.length > 0) {
term.write(''); // trigger another rendering
return;
}
const text_canvas = parent.getElementsByClassName('xterm-text-layer')[0];
const cursor_canvas = parent.getElementsByClassName('xterm-cursor-layer')[0];
if (text_canvas.height !== cursor_canvas.height
|| text_canvas.width !== cursor_canvas.width) {
// The code assumes that the text canvas and cursor canvas are the same size.
this.onerror('Canvas size mismatch.');
return;
}
const padding = Math.ceil(PADDING_FACTOR * options.size);
const px_per_row = text_canvas.height / rows;
const px_per_col = text_canvas.width / cols;
const shaved_rows = rows - options.shave.top - options.shave.bottom;
if (shaved_rows <= 0) {
let msg = 'Not enough rows.';
if (options.shave.top > 0 || options.shave.bottom > 0)
msg += ' Try to decrease the shave quantities.';
this.onerror(msg);
return;
}
const shaved_cols = cols - options.shave.left - options.shave.right;
if (shaved_cols <= 0) {
let msg = 'Not enough columns.';
if (options.shave.left > 0 || options.shave.right > 0)
msg += ' Try to decrease the shave quantities.';
this.onerror(msg);
return;
}
const width = shaved_cols * px_per_col;
const height = shaved_rows * px_per_row;
const canvas = parent.ownerDocument.createElement('canvas');
const padded_width = width + 2 * padding;
const padded_height = height + 2 * padding;
canvas.width = padded_width;
canvas.height = padded_height;
const context = canvas.getContext('2d');
context.fillStyle = theme.background;
context.fillRect(0, 0, padded_width, padded_height);
const source_x = options.shave.left * px_per_col;
const source_y = options.shave.top * px_per_row;
context.drawImage(
text_canvas,
source_x, source_y, width, height,
padding, padding, width, height);
if (options.cursor !== 'none') {
context.drawImage(
cursor_canvas,
source_x, source_y, width, height,
padding, padding, width, height);
}
const state = {
idx: idx,
delay: frames[idx].delay,
num_frames: frames.length,
canvas: canvas,
config: config
}
this.onstep(state);
if (idx >= frames.length - 1) {
this.onsuccess();
setTimeout(function() {
term.dispose();
});
return;
}
term.write(frames[++idx].data);
};
term.onRender(process);
term.open(parent);
// Monkey patch the xterm.js renderer (see CursorRenderLayer.ts) so that calls to
// _renderBlurCursor become calls to _renderBlockCursor. This prevents an unfocused
// cursor.
const cursor_render_layer = term._core._renderService._renderer._renderLayers[3];
const patchable = cursor_render_layer._canvas.className === 'xterm-cursor-layer'
&& '_renderBlurCursor' in cursor_render_layer
&& '_renderBlockCursor' in cursor_render_layer;
if (!patchable) {
term.dispose();
this.onerror('Unsupported version of xterm.js.');
return;
}
cursor_render_layer._renderBlurCursor = cursor_render_layer._renderBlockCursor;
// Set <textarea readonly> so that a screen keyboard doesn't pop-up on mobile devices.
const textareas = parent.getElementsByTagName('textarea');
for (let i = 0; i < textareas.length; ++i) {
textareas[i].readOnly = true;
}
// Have to focus to get the cursor to show up (even a blurred cursor won't show up without
// this).
term.focus();
term.write(frames[0].data);
};
this.run = function() {
// Utilize the event loop message queue with setTimeout to process oninit first.
setTimeout(this.oninit);
setTimeout(run);
};
};
const GifRenderer = function(parent, options, cast) {
// Callback before running
this.oninit = function() {};
// Callback for each progress update
this.onprogress = function(percent) {};
// Callback after successful GIF generated
this.onsuccess = function(data_url) {};
// Callback after failure
this.onerror = function(message) {};
const run = () => {
const term_runner = new TermRunner(parent, options, cast);
const bytes = [];
// This is initialized later, when we have the actual dimensions available.
let gif = null;
// This is initialized later, when we have the colors. If a theme was already
// selected, we'd know the colors here. But when theme=none, it's possible for
// colors to be specified in the cast header, which hasn't been parsed yet.
let palette = null;
term_runner.oninit = this.oninit;
term_runner.onstep = (state) => {
const context = state.canvas.getContext('2d');
const width = state.canvas.width;
const height = state.canvas.height;
const data = context.getImageData(0, 0, width, height).data;
const pixels = [];
for (let i = 0; i < width * height; ++i) {
const r = data[i * 4];
const g = data[i * 4 + 1];
const b = data[i * 4 + 2];
const color = (r << 16) + (g << 8) + b;
pixels[i] = color;
}
if (palette === null) {
const required = [];
for (const value of Object.values(state.config.theme)) {
required.push(int(value));
}
palette = get_palette(required);
}
const indexed_pixels = quantize(pixels, palette);
let delay = state.delay;
if (gif === null) {
// Set 'loop' to 0 to continuously loop. Set 'loop' to
// undefined to not loop. Set 'loop' to N to loop N times.
let gopts_loop;
if (typeof options.play_count === 'number'
&& !Number.isFinite(options.play_count))
gopts_loop = 0
else if (options.play_count === 1)
gopts_loop = undefined;
else if (options.play_count > 1)
gopts_loop = options.play_count - 1;
else
throw Error('Invalid play count.');
const gopts = {palette: palette, loop: gopts_loop};
gif = new GifWriter(bytes, width, height, gopts);
}
// omggif expects centi-seconds
const gif_delay = delay * 100;
const opts = {delay: gif_delay};
gif.addFrame(0, 0, width, height, indexed_pixels, opts);
const percent = 100.0 * (state.idx + 1) / state.num_frames;
this.onprogress(percent);
};
term_runner.onsuccess = () => {
const b64 = base64(bytes);
const data_url = 'data:image/gif;base64,' + b64;
this.onsuccess(data_url);
};
term_runner.onerror = this.onerror;
term_runner.run(cast);
};
this.run = function() {
// Utilize the event loop message queue with setTimeout to process oninit first.
setTimeout(this.oninit);
setTimeout(run);
};
};
const PngRenderer = function(parent, options, cast) {
// Callback before running
this.oninit = function() {};
// Callback for each progress update
this.onprogress = function(percent) {};
// Callback after successful PNG generated
this.onsuccess = function(data_url, width, height) {};
// Callback after failure
this.onerror = function(message) {};
const run = () => {
const term_runner = new TermRunner(parent, options, cast);
term_runner.oninit = this.oninit;
let last_state = null;
term_runner.onstep = (state) => {
last_state = state;
const percent = 100.0 * (state.idx + 1) / state.num_frames;
this.onprogress(percent);
};
term_runner.onsuccess = () => {
const width = last_state.canvas.width;
const height = last_state.canvas.height;
const data_url = last_state.canvas.toDataURL('image/png');
this.onsuccess(data_url, width, height);
};
term_runner.onerror = this.onerror;
term_runner.run(cast);
};
this.run = function() {
// Utilize the event loop message queue with setTimeout to process oninit first.
setTimeout(this.oninit);
setTimeout(run);
};
};
// *************************************************
// * DOM Manipulation
// *************************************************
// Creates a DOM element, attached to the document, for running a terminal.
// This should be removed with remove_terminal_element().
const create_terminal_element = function() {
const terminal = document.createElement('div');
document.body.appendChild(terminal);
// The following settings make the terminal invisible and not
// affect the layout of the page. 'display: none' does not work
// since the terminal does not get rendered.
terminal.style.position = 'fixed';
terminal.style.bottom = '0';
terminal.style.right = '0';
terminal.style.opacity = '0';
terminal.style.zIndex = '-1';
return terminal;
};
const remove_terminal_element = function(terminal) {
terminal.parentElement.removeChild(terminal);
};
const get_options = function() {
const size = Number.parseInt(document.getElementById('size').value);
const contrast_gain = Number.parseInt(
document.getElementById('contrast_gain').value);
const cursor = document.getElementById('cursor').value;
let font = document.getElementById('font').value;
if (!font) {
font = 'monospace';
}
const play_count = Number.parseInt(document.getElementById('play_count').value);
const shave = {};
for (const pos of ['top', 'left', 'bottom', 'right']) {
shave[pos] = Number.parseInt(document.getElementById('shave_' + pos).value);
}
const theme = document.getElementById('theme').value;
const options = {
size: size,
contrast_gain: contrast_gain,
cursor: cursor,
font: font,
play_count: play_count,
shave: shave,
theme: theme,
};
return options;
};
// Using a <fieldset> provides a way to enable and disable all form inputs
// and buttons together.
const enable_fieldset = function(enabled) {
if (enabled === undefined) enabled = true;
document.getElementById('fieldset').disabled = !enabled;
};
const enable_render_button = function(enabled) {
if (enabled === undefined) enabled = true;
document.getElementById('render_button').disabled = !enabled;
};
// Used for updating progress, with a specification for the delay in
// milliseconds (to prevent rapid updates).
const ProgressSetter = function(delay = 200) {
let last_set_time = null;
this.set = (percent) => {
const time = new Date().getTime();
if (percent !== 100.0 || last_set_time !== null) {
const diff = time - last_set_time;
if (diff < delay) return;
}
const string = percent.toFixed(1);
document.getElementById('progress').value = string;
const progress_text = string + '%';
document.getElementById('progress_text').innerText = progress_text;
last_set_time = time;
}
};
const show_loading = function() {
const loading = document.getElementById('loading');
loading.style.visibility = 'visible';
loading.scrollIntoView();
};
const hide_loading = function() {
document.getElementById('loading').style.visibility = null;
};
const ImgModal = function(parent) {
const SRC = 'data:,';
const ESC_KEY = 'Escape';
const HIDDEN_STYLE = 'none';
const SHOWN_STYLE = 'initial';
const doc = parent.ownerDocument;
const span = doc.createElement('span');
span.id = 'close';
span.innerHTML = '×';
parent.appendChild(span);
const div = doc.createElement('div');
div.id = 'modal_inner';
parent.appendChild(div);
const img = doc.createElement('img');
img.id = 'img';
div.appendChild(img);
this.show = function(src) {
img.src = src;
parent.style.display = SHOWN_STYLE;
};
this.hide = function() {
img.src = SRC;
parent.style.display = HIDDEN_STYLE;
};
span.onclick = () => {
this.hide();
};
parent.onclick = () => {
this.hide();
};
img.onclick = function(event) {
// Prevent the click from being passed to the modal element.
event.stopPropagation();
};
doc.addEventListener('keyup', (event) => {
if (event.key === ESC_KEY && parent.style.display === SHOWN_STYLE) {
this.hide();
}
});
};
const modal = new ImgModal(document.getElementById('modal'));
// A cache is used in order to prevent the rendering logic from running when an
// image was created and we can reuse it.
const Cache = function() {
let valid = false;
let data = null;
this.valid = function() {
return valid;
};
this.invalidate = function() {
valid = false;
};
this.set = function(value) {
valid = true;
data = value;
};
this.get = function() {
return valid ? data : null;
};
};
const cache = new Cache();
// Set callback to invalidate state when any option is changed.
document.getElementById('options').onchange = function(e) {
cache.invalidate();
};
// Populate the font dropdown menu and font examples.
FONT_CANDIDATES.forEach((font) => {
const font_dropdown = document.getElementById('font');
const font_examples = document.getElementById('font_examples');
const num_candidates = FONT_CANDIDATES.length;
// Checking for font availability can be slow. Use an asynchronous callback
// for each font so that the UI is not blocked. The ordering is maintained
// since Javascript event loop events are processed in FIFO order.
setTimeout(() => {
if (has_font(font)) {
// Add a dropdown option.
const option = document.createElement('option');
option.text = font;
if (font === 'monospace')
option.selected = true;
font_dropdown.appendChild(option);
// Add an example.
const row = document.createElement('tr');
const key = document.createElement('td');
key.innerText = font;
const val = document.createElement('td');
val.style.fontFamily = font;
val.innerText = 'The quick brown fox jumps over the lazy dog';
row.appendChild(key);
row.appendChild(val);
row.appendChild(val);
font_examples.getElementsByTagName('tbody')[0].appendChild(row);
}
// Enable dropdown after processing the last candidate.
if (num_candidates > 0 && font === FONT_CANDIDATES[num_candidates - 1]) {
font_dropdown.removeChild(document.getElementById('initial_font'));
font_dropdown.disabled = false;
}
}, 0);
});
// Populate the theme dropdown menu.
{
const theme_element = document.getElementById('theme');
const themes = Object.keys(THEMES);
themes.push('none');
const value_and_text = [];
for (let i = 0; i < themes.length; ++i) {
value_and_text.push({
value: themes[i],
text: themes[i].replace(/_/g, ' ')
});
}
value_and_text.sort((a, b) => {
return a.text.localeCompare(b.text);
});
for (let i = 0; i < value_and_text.length; ++i) {
const {value, text} = value_and_text[i];
const option = document.createElement('option');
option.value = value;
option.text = text;
if (value === 'none')
option.selected = true;
theme_element.appendChild(option);
}
}
// Populate the theme preview grid.
{
const preview_cast = function(name, light) {
const lines = [
'{"version": 2, "width": 24, "height": 9}',
`[0.00, "o", "\\u001b[m\\u001b[3${light ? 8 : 7}m// ${name}\\u001b[m\\r\\n"]`,
'[0.00, "o", "\\u001b[m\\r\\n"]',
'[0.00, "o", "\\u001b[m\\u001b[35m#include \\u001b[m\\u001b[31m<stdio.h>\\u001b[m\\r\\n"]',
'[0.00, "o", "\\u001b[m\\r\\n"]',
'[0.00, "o", "\\u001b[m\\u001b[32mint\\u001b[m main(\\u001b[32mvoid\\u001b[m) {\\r\\n"]',
'[0.00, "o", "\\u001b[m printf(\\u001b[31m\\"hello \\"\\u001b[m);\\r\\n"]',
'[0.00, "o", "\\u001b[m printf(\\u001b[31m\\"world\\u001b[m\\u001b[35m\\\\n"]',
'[0.00, "o", "\\u001b[m\\u001b[31m\\"\\u001b[m);\\r\\n"]',
'[0.00, "o", "\\u001b[m \\u001b[33mreturn\\u001b[m \\u001b[31m0\\u001b[m;\\r\\n"]',
'[0.00, "o", "\\u001b[m}"]'
]
return lines.join('\n');
};
let generated = false;
document.getElementById('theme_grid_link').ontoggle = function(e) {
if (e.target.open && !generated) {
generated = true;