Class: Fontisan::Audit::Checks::OtsCompatibilityCheck

Inherits:
Fontisan::Audit::Check show all
Defined in:
lib/fontisan/audit/checks/ots_compatibility_check.rb

Overview

Predicts whether Chrome/Android OTS (OpenType Sanitizer) would reject the font. OTS has strict requirements beyond the base OpenType spec — fonts that pass the spec can still be rejected by browsers.

Ports the most commonly-hit ots-sanitize rules:

- head magicNumber must be 0x5F0F3CF5
- head unitsPerEm must be 16–16384
- name table must have PostScript + Family names
- post table version must be 1.0, 2.0, 2.5, 3.0, or 4.0
- numGlyphs must be ≤ 65534 (uint16 minus sentinel)
- glyf/CFF (depending on sfnt flavor) must be present
- cmap must have at least one Unicode subtable
- OS/2 usWeightClass must be 1–1000
- OS/2 usWidthClass must be 1–9
- Total file size must be under the OTS limit (~30MB)

See Also:

Constant Summary collapse

MAX_GLYPHS =

65534 — OTS rejects fonts with more

0xFFFD
MAX_FILE_SIZE =

30MB — OTS soft limit

30 * 1024 * 1024
VALID_POST_VERSIONS = 
[1.0, 2.0, 2.5, 3.0, 4.0].freeze
HEAD_MAGIC = 
0x5F0F3CF5
MIN_UPM = 
16
MAX_UPM = 
16_384

Class Method Summary collapse

Methods inherited from Fontisan::Audit::Check

issue

Class Method Details

.call(font) ⇒ Array<Models::ValidationReport::Issue>

Parameters:

Returns:



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# File 'lib/fontisan/audit/checks/ots_compatibility_check.rb', line 35

def self.call(font)
  issues = []
  issues.concat(check_head(font))
  issues.concat(check_post(font))
  issues.concat(check_maxp(font))
  issues.concat(check_name(font))
  issues.concat(check_cmap(font))
  issues.concat(check_os2(font))
  issues.concat(check_outlines(font))
  issues
end

.code ⇒ Object 



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# File 'lib/fontisan/audit/checks/ots_compatibility_check.rb', line 47

def self.code
  :ots_compatibility
end