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Drawing on canvas with custom font face does not work

See original GitHub issue

Using a custom font face to draw to a canvas does not work. Test case (based on pdf.js test):

var jsdom = require('jsdom');

var HTML = "<html><head><style id='test'>@font-face { font-family: 'plus'; src: url(data:font/opentype;base64,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); }</style></head><body><div id='canvasHolder'></div></body></html>";

var document = jsdom.jsdom(HTML).createWindow().document;

console.log(checkCanvas('plus') ? "font-face supported" : "font-face NOT supported");

function checkCanvas(font) {
  var canvas = document.createElement('canvas');
  var canvasHolder = document.getElementById('canvasHolder');
  canvasHolder.appendChild(canvas);
  var ctx = canvas.getContext('2d');
  ctx.font = '40px \'' + font + '\'';
  ctx.fillText('\u0060', 0, 40);
  var data = ctx.getImageData(0, 0, 40, 40).data;
  canvasHolder.removeChild(canvas);

  // detects plus figure
  var minx = 40, maxx = 0, miny = 40, maxy = 0;
  for (var y = 0; y < 40; y++) {
    for (var x = 0; x < 40; x++) {
      if (data[x * 4 + y * 160 + 3] == 0) continue; // no color
      minx = Math.min(minx, x); miny = Math.min(miny, y);
      maxx = Math.max(maxx, x); maxy = Math.max(maxy, y);
    }
  }

  var colors = [[0, 0, 0], [0, 0, 0], [0, 0, 0]];
  var counts = [[0, 0, 0], [0, 0, 0], [0, 0, 0]];
  for (var y = miny; y <= maxy; y++) {
    for (var x = minx; x <= maxx; x++) {
      var i = Math.floor((x - minx) * 3 / (maxx - minx + 1));
      var j = Math.floor((y - miny) * 3 / (maxy - miny + 1));
      counts[i][j]++;
      if (data[x * 4 + y * 160 + 3] != 0)
        colors[i][j]++;
    }
  }
  var isPlus =
    colors[0][0] * 3 < counts[0][0] &&
    colors[0][1] * 3 > counts[0][1] &&
    colors[0][2] * 3 < counts[0][2] &&
    colors[1][0] * 3 > counts[1][0] &&
    colors[1][1] * 3 > counts[1][1] &&
    colors[1][2] * 3 > counts[1][2] &&
    colors[2][0] * 3 < counts[2][0] &&
    colors[2][1] * 3 > counts[2][1] &&
    colors[2][2] * 3 < counts[2][2];
  return isPlus;
}

It seems there is no connection for passing custom font face to canvas?

Issue Analytics

State:
Created 10 years ago
Comments:6 (6 by maintainers)

Top GitHub Comments

6reactions

astururcommented, Mar 21, 2019

Is this still an issue? i would like to do something to get it fixed.

4reactions

challakoushikcommented, Mar 29, 2018

Any updates on this?? I’m really stuck at the same issue, I’m using pdfkit and frontend canvas code (by jsdom) to generate a pdf of a book with images and text. I just cant get the fonts working because of this