The RasterInfo Font

RasterInfo.ttf is a means to show various properties of the TrueType bytecode interpreter used to hint the TrueType fonts on the current HTML page. If you only see one or more letters ‘E’ instead of digits, the TrueType bytecode interpreter is not active.

At the same time, it is a showcase to demonstrate how to change glyph shapes with TrueType instructions.

Now the characters contained in the font. The value in parentheses gives the character to be used in the RasterInfo font. For more details on the various parameters, please consult the source code file for the font, to be found on github. The special zebra glyphs (‘#$’) are designed to test gamma correction and LCD filtering; they should not, ideally, have any moiré or color fringes.

#$
#$

The current PPEM value used in this paragraph (‘0’): 0

The version of the TrueType bytecode interpreter (‘1’): 1

If rotation is on, digit 1 is shown (‘2’): 2

If stretching is on, digit 1 is shown (‘3’): 3

If grayscale rendering is on, digit 1 is shown (‘4’): 4

If ClearType is enabled, digit 1 is shown (‘5’): 5

If ClearType's compatible width mode is on, digit 1 is shown (‘6’): 6

If ClearType uses vertical LCD subpixels (this is, a subpixel's longer side is horizontally positioned), digit 1 is shown (‘7’): 7

If ClearType uses BGR (blue-green-red) rendering instead of RGB (red-green-blue), digit 1 is shown (‘8’): 8

If ClearType uses subpixel positioning, digit 1 is shown (‘9’): 9

If ClearType symmetrical smoothing is active, digit 1 is shown (‘:’): :

If Gray ClearType is active, digit 1 is shown (‘;’): ;

As an example, the image below shows the values as displayed by the Edge browser (version 40) on Windows 10.

RasterInfo display on Windows 10 using Edge 40

On this page, the font is set up with an @font-face CSS instruction, to be used within a span.

<head>
  ...
  <style type="text/css">
    @font-face {
      font-family: "RasterInfo";
      src: url("RasterInfo.ttf");
      font-weight: normal;
      font-style: normal;
      text-rendering: optimizeLegibility; }
    ...
    span.RasterInfo { font-family: "RasterInfo"; }
  </style>
</head>

<body>
  ...
  <span class="RasterInfo">1</span>
  ...
</body>

RasterInfo.ttf was written by Werner Lemberg; the font is licensed under the SIL Open Font License. The current version is 1.02.

Last update: 13-Feb-2018