Quelle color_canvas.html Sprache: HTML

products/Sources/formale Sprachen/C/Firefox/dom/canvas/test/reftest/colors/color_canvas.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset=utf-8>
    <title>color_canvas.html</title>
  </head>
  
  <body>
    <form id=e_settings><fieldset><legend>Settings</legend>
      Width: <input id=e_width type=text value=100>
      <br>
      Height: <input id=e_height type=text value=100>
      <br>
      <fieldset><legend>Canvas Context</legend>
        Type: <select id=e_context>
          <option value=css selected>css</option>
          <option value=2d>2d</option>
          <option value=webgl>webgl</option>
          <option value=webgl2>webgl2</option>
        </select>
        <br>
        Options: <input id=e_options type=text value={}>
        <br>
        Colorspace: <input id=e_cspace type=text placeholder=srgb>
        <br>
        WebGL Format: <input id=e_webgl_format type=text placeholder=RGBA8>
      </fieldset>
      <br>
      Color: <input id=e_color type=text value='color(srgb 0 0.5 0)'>
      <br>
      <input id=e_publish type=button value=Publish>
      <input type=checkbox id=e_publish_omit_defaults checked><label for=e_publish_omit_defaults>Omit defaults</label>
      <hr>
    </fieldset></form>
    <div id=e_canvas_list><canvas></canvas></div>
    <script>
'use strict';

// -

function walk_nodes_depth_first(e, fn) {
  if (fn(e) === false) return; // Don't stop on `true`, or `undefined`!
  for (const c of e.childNodes) {
    walk_nodes_depth_first(c, fn);
  }
}

// -

// Click the canvas to toggle the settings pane.
e_canvas_list.addEventListener('click', () => {
  // Toggle display:none to hide/unhide.
  e_settings.hidden = !e_settings.hidden;
});

// Hide settings initially if there's a query string in the url.
if (window.location.search.startsWith('?')) {
  e_settings.hidden = true;
}

// -

// Imply .name from .id, because `new FormData` collects based on names.
walk_nodes_depth_first(e_settings, e => {
  if (e.id) {
    e.name = e.id;
    e._default_value = e.value;
  }
});

// -

const URL_PARAMS = new URLSearchParams(window.location.search);
URL_PARAMS.forEach((v,k) => {
  const e = window[k];
  if (!e) {
    if (k) {
      console.warn(`Unrecognized setting: ${k} = ${v}`);
    }
    return;
  }
  v = decode_url_v(k,v);
  e.value = v;
});

// -

globalThis.ASSERT = (() => {
  function toPrettyString(arg) {
    if (!arg) return ''+arg;

    if (arg.call) {
      let s = arg.toString();
      const RE_TRIVIAL_LAMBDA = /$ *$ *=> *(.*)/;
      const m = RE_TRIVIAL_LAMBDA.exec(s);
      if (m) {
        s = '`' + m[1] + '`';
      }
      return s;
    }
    if (arg.constructor == Array) {
      return `[${[].join.call(arg, ', ')}]`;
    }
    return JSON.stringify(arg);
  }

  /// new AssertArg(): Construct a wrapper for args to assert functions.
  function AssertArg(dict) {
    this.label = Object.keys(dict)[0];

    this.set = function(arg) {
      this.arg = arg;
      this.value = (arg && arg.call) ? arg.call() : arg;
      this.value = toPrettyString(this.value);
    };
    this.set(dict[this.label]);

    this.toString = function() {
      let ret = `${this.label} ${toPrettyString(this.arg)}`;
      if (this.arg.call) {
        ret += ` (${this.value})`;
      }
      return ret;
    }
  }

  const eq = (a,b) => a == b;
  const neq = (a,b) => a != b;

  const CMP_BY_NAME = {
    '==': eq,
    '!=': neq,
  };

  function IS(cmp, was, expected, _console) {
    _console = _console || console;

    _console.assert(was.call, '`was.call` not defined.');
    was = new AssertArg({was});
    expected = new AssertArg({expected});

    const fn_cmp = CMP_BY_NAME[cmp] || cmp;

    _console.assert(fn_cmp(was.value, expected.value), `${toPrettyString(was.arg)} => ${was.value} not ${cmp} ${expected}`);
    if (was.value != expected.value) {
    } else if (globalThis.ASSERT && globalThis.ASSERT.verbose) {
      const maybe_cmp_str = (cmp == '==') ? '' : ` ${was.value} ${cmp}`;
      _console.log(`${toPrettyString(was.arg)} => ${maybe_cmp_str}${expected}`);
    }
  }

  // -

  const MOCK_CONSOLE = {
    _asserts: [],
    assert: function(expr, ...args) {
      if (!expr) {
        this._asserts.push(args);
      }
    },
    log: function(...args) {
      // Don't record.
    },
  };

  // -
  // Test `==`

  IS('==', () => 1, 1, MOCK_CONSOLE);
  console.assert(MOCK_CONSOLE._asserts.length == 0, MOCK_CONSOLE._asserts);
  MOCK_CONSOLE._asserts = [];

  IS('==', () => 2, 2, MOCK_CONSOLE);
  console.assert(MOCK_CONSOLE._asserts.length == 0, MOCK_CONSOLE._asserts);
  MOCK_CONSOLE._asserts = [];

  IS('==', () => 5, () => 3, MOCK_CONSOLE);
  console.assert(MOCK_CONSOLE._asserts.length == 1, MOCK_CONSOLE._asserts);
  MOCK_CONSOLE._asserts = [];

  IS('==', () => [1,2], () => [1,2], MOCK_CONSOLE);
  console.assert(MOCK_CONSOLE._asserts.length == 0, MOCK_CONSOLE._asserts);
  MOCK_CONSOLE._asserts = [];

  // -
  // Test `!=`

  IS('!=', () => [1,2,5], () => [1,2,3], MOCK_CONSOLE);
  console.assert(MOCK_CONSOLE._asserts.length == 0, MOCK_CONSOLE._asserts);
  MOCK_CONSOLE._asserts = [];

  // -

  const ret = {
    verbose: false,
    IS,
  };
  ret.EQ = (was,expected) => ret.IS('==', was, expected);
  ret.NEQ = (was,expected) => ret.IS('!=', was, expected);
  ret.EEQ = (was,expected) => ret.IS('===', was, expected);
  ret.NEEQ = (was,expected) => ret.IS('!==', was, expected);
  ret.TRUE = was => ret.EQ(was, true);
  ret.FALSE = was => ret.EQ(was, false);
  ret.NULL = was => ret.EEQ(was, null);
  return ret;
})();

// -

function parse_css_rgb(str) {
  //          rgb  (R      ,G      ,B             /A         )
  const m = /rgba?$([^,]+),([^,]+),([^/)]+)(?: *\/([^)]+))?$/.exec(str);
  if (!m) throw str;
  const rgba = m.slice(1,1+4).map((s,i) => {
    if (s === undefined && i == 3) {
      s = '1'; // Alpha defaults to 1.
    }
    s = s.trim();
    let v = parseFloat(s);
    if (s.endsWith('%')) {
      v /= 100;
    } else {
      if (i < 3) { // r,g,b but not a!
        v /= 255;
      }
    }
    return v;
  });
  return rgba;
}
ASSERT.EQ(() => parse_css_rgb('rgb(255,255,255)'), [1,1,1,1]);
ASSERT.EQ(() => parse_css_rgb('rgba(255,255,255)'), [1,1,1,1]);
ASSERT.EQ(() => parse_css_rgb('rgb(255,255,255)'), [1,1,1,1]);
ASSERT.EQ(() => parse_css_rgb('rgba(255,255,255)'), [1,1,1,1]);
ASSERT.EQ(() => parse_css_rgb('rgb(20,40,60)'), () => [20/255, 40/255, 60/255, 1]);
ASSERT.EQ(() => parse_css_rgb('rgb(20,40,60 / 0.5)'), () => [20/255, 40/255, 60/255, 0.5]);
ASSERT.EQ(() => parse_css_rgb('rgb(20,40,60 / 0)'), () => [20/255, 40/255, 60/255, 0]);

// -

function parse_css_color(str) {
  //         color (  srgb     R        G        B           /A         )
  const m = /color$ *([^ ]+) +([^ ]+) +([^ ]+) +([^/)]+)(?:\/([^)]+))?$/.exec(str);
  if (!m) {
    return ['srgb', ...parse_css_rgb(str)];
  }

  const cspace = m[1].trim();
  let has_extreme_colors = false;
  const rgba = m.slice(2, 2+4).map((s,i) => {
    if (s === undefined && i == 3) {
      s = '1'; // Alpha defaults to 1.
    }
    s = s.trim();
    let v = parseFloat(s);
    if (s.endsWith('%')) {
      v /= 100;
    }
    if (v < 0 || v > 1) {
      has_extreme_colors = true;
    }
    return v;
  });
  if (has_extreme_colors) {
    console.warn(`parse_css_color('${str}') has colors outside [0.0,1.0]: ${JSON.stringify(rgba)}`);
  }
  return [cspace, ...rgba];
}
ASSERT.EQ(() => parse_css_color('rgb(255,255,255)'), ['srgb',1,1,1,1]);
ASSERT.EQ(() => parse_css_color('rgb(20,40,60 / 0.5)'), () => ['srgb', 20/255, 40/255, 60/255, 0.5]);
ASSERT.EQ(() => parse_css_color('color(srgb 1 0 1 /0.3)'), ['srgb',1,0,1,0.3]);
ASSERT.EQ(() => parse_css_color('color(display-p3 1 0% 100%/ 30%)'), ['display-p3',1,0,1,0.3]);

// -

class CssColor {
  constructor(cspace, r,g,b,a=1) {
    this.cspace = cspace;
    this.rgba = [this.r, this.g, this.b, this.a] = [r,g,b,a];
    this.rgb = this.rgba.slice(0,3);
    this.tuple = [this.cspace, ...this.rgba];
  }

  toString() {
    return `color(${this.cspace} ${this.rgb.join(' ')} / ${this.a})`;
  }
};
CssColor.parse = function(str) {
  return new CssColor(...parse_css_color(str));
}

{
  let STR;
  // Test round-trip.
  STR = 'color(display-p3 1 0 1 / 0.3)';
  ASSERT.EQ(() => CssColor.parse(STR).toString(), STR);

  // Test round-trip normalization
  ASSERT.EQ(() => CssColor.parse('color( display-p3 1 0 1/30% )').toString(), 'color(display-p3 1 0 1 / 0.3)');
}

// -

function redraw() {
  while (e_canvas_list.firstChild) {
    e_canvas_list.removeChild(e_canvas_list.firstChild);
  }

  const c = make_canvas(e_color.value.trim());
  c.style.border = '4px solid black';
  e_canvas_list.appendChild(c);
}

function fill_canvas_rect(context /*: CanvasRenderingContext | WebGLRenderingContext*/, css_color, rect=null) {
  rect = rect || {left: 0, top: 0, w: context.canvas.width, h: context.canvas.height};

  const is_c2d = ('fillRect' in context);
  if (is_c2d) {
    const c2d = context;
    c2d.fillStyle = css_color;
    c2d.fillRect(rect.left, rect.top, rect.w, rect.h);
    return;
  }

  const is_webgl = ('drawArrays' in context);
  if (is_webgl) {
    const gl = context;
    console.assert(context.canvas.width == gl.drawingBufferWidth, context.canvas.width, '!=', gl.drawingBufferWidth);
    console.assert(context.canvas.height == gl.drawingBufferHeight, context.canvas.height, '!=', gl.drawingBufferHeight);

    gl.enable(gl.SCISSOR_TEST);
    gl.disable(gl.DEPTH_TEST);
    const bottom = rect.top + rect.h; // in y-down c2d coords
    gl.scissor(rect.left, context.canvas.height - bottom, rect.w, rect.h);

    const canvas_cspace = context.drawingBufferColorSpace || 'srgb';
    if (css_color.cspace != canvas_cspace) {
      console.warn(`Ignoring mismatched color vs webgl canvas cspace: ${css_color.cspace} vs ${canvas_cspace}`);
    }
    gl.clearColor(...css_color.rgba);
    gl.clear(gl.COLOR_BUFFER_BIT);
    return;
  }

  console.error('Unhandled context kind:', context);
}

window.e_canvas = null;

function make_canvas(css_color) {
  css_color = CssColor.parse(css_color);

  // `e_width` and e_friends are elements (by id) that we added to the raw HTML above.
  // `e_width` is an old shorthand for `window.e_width || document.getElementById('e_width')`.
  const W = parseInt(e_width.value);
  const H = parseInt(e_height.value);
  if (e_context.value == 'css') {
    e_canvas = document.createElement('div');
    e_canvas.style.width = `${W}px`;
    e_canvas.style.height = `${H}px`;
    e_canvas.style.backgroundColor = css_color;
    return e_canvas;
  }
  e_canvas = document.createElement('canvas');
  e_canvas.width = W;
  e_canvas.height = H;

  let requested_options = JSON.parse(e_options.value);
  requested_options.colorSpace = e_cspace.value || undefined;

  const context = e_canvas.getContext(e_context.value, requested_options);
  if (requested_options.colorSpace) {
    if (!context.drawingBufferColorSpace) {
      console.warn(`${context.constructor.name}.drawingBufferColorSpace not supported by browser.`);
    } else {
      context.drawingBufferColorSpace = requested_options.colorSpace;
    }
  }

  if (e_webgl_format.value) {
    if (!context.drawingBufferStorage) {
      console.warn(`${context.constructor.name}.drawingBufferStorage not supported by browser.`);
    } else {
      context.drawingBufferStorage(W, H, context[e_webgl_format.value]);
    }
  }

  let actual_options;
  if (!context.getContextAttributes) {
    console.warn(`${canvas.constructor.name}.getContextAttributes not supported by browser.`);
    actual_options = requested_options;
  } else {
    actual_options = context.getContextAttributes();
  }

  // -

  fill_canvas_rect(context, css_color);

  return e_canvas;
}

e_settings.addEventListener('change', async () => {
  redraw();
  const e_updated = document.createElement('i');
  e_updated.textContent = '(Updated!)';
  document.body.appendChild(e_updated);
  await new Promise(go => setTimeout(go, 1000));
  document.body.removeChild(e_updated);
});
redraw();

// -

function encode_url_v(k,v) {
  if (k == 'e_color') {
    v = v.replaceAll(' ', ',');
  }
  console.assert(!v.includes(' '), v);
  return v
}
function decode_url_v(k,v) {
  console.assert(!v.includes(' '), v);
  if (k == 'e_color') {
    v = v.replaceAll(',', ' ');
  }
  return v
}
ASSERT.EQ(() => decode_url_v('e_color', encode_url_v('e_color', 'color(srgb 1 0 0)')), 'color(srgb 1 0 0)')

e_publish.addEventListener('click', () => {
  const fd = new FormData(e_settings);
  let settings = [];
  for (let [k,v] of fd) {
    const e = window[k];
    if (e_publish_omit_defaults.checked && v == e._default_value) continue;

    v = encode_url_v(k,v);
    settings.push(`${k}=${v}`);
  }
  settings = settings.join('&');
  if (!settings) {
    settings = '='; // Empty key-value pair is 'publish with default settings'
  }
  window.location.search = '?' + settings;
});
    </script>
  </body>
</html>

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