OpenType 1.8.3 errata

  • Article

This page documents errors in the OpenType specification that have technical significance and could lead to incorrect implementations. The scope is limited to issues in which the OpenType 1.8.3 specification as originally published implies technical details that are contrary to the intended design. Corrections may include corrections to incorrect values related to certain table fields, incorrect formulas for computing certain values, or similar issues. Corrections will not include any changes to data structures. If the textual change required for the correction is minor, the correction will be made in the specification and also listed here. If larger textual changes are required, the issue may be described here, but actual changes may be left to a future version. In either case, the status will be indicated in the table below.

Certain minor, editorial errors such as mis-spelling of words with no technical impact may on occasion be corrected silently, without notice or version update.

Date Page Description Status
19 August 2020 The TrueType Instruction Set In the description for the Jump Relative on False (JROF) instruction, the figures that show changes occuring on the stack have operands in the wrong order: they show the jump offset popped off the stack first, and the binary-test element popped off the stack element. The preceding prose description gives operands in the correct order: the binary-test element is popped first, and the jump offset is popped second. Will be corrected in the next version.
17 August 2020 The TrueType Instruction Set When content was ported from Microsoft Word, some incorrect text was inadvertently added to the description of Round to Half Grid (RTHG). Corrected in 1.8.3 (2020-08-17)
17 August 2020 The TrueType Instruction Set When content was ported from Microsoft Word, an error was inadvertently introduced to the description of logical OR. Corrected in 1.8.3 (2020-08-17)
8 July 2020 Registerd features (p – t) The entry for 'ssty' was incorrectly listed as 'psts'. Corrected in 1.8.3 (2020-07-08)
22 April 2020 The TrueType Instruction Set When content was ported from Microsoft Word, the MIRP Code range was incorrectly described as 0xC0 - 0xDF. The correct range is 0xE0 - 0xFF. Corrected in 1.8.3 (2020-04-22)
21 Feb 2020 Registerd features (p – t) The example for 'ssty' had errors and was incomplete. Corrected in 1.8.3 (2020-02-21)
22 Jan 2020 Embedded Bitmap Location Table Corrected text from "16-bit alignment" to "32-bit alignment". Corrected in 1.8.3 (2020-01-22)
22 Nov 2019 Embedded Bitmap Scaling Table Corrected text in "EBSC Header" from "EBLC" to "EBSC". Corrected in 1.8.3 (2019-11-22)
28 Aug 2019 The TrueType Instruction Set Corrected text for the normalized coordinates in GETVARIATION[] from "padded with zeroes in the upper 16 bits" to "sign-extended in the upper 16 bits." Corrected in 1.8.3 (2019-8-28)
11 July 2019 cmap — Character to Glyph Index Mapping Table Typo was present in the glyphId index value equation. Corrected text in equation from "startCount" to "startCode". Corrected in 1.8.3 (2019-7-11)
21 May 2019 The TrueType Instruction Set The description for FLIPRGOFF was incorrectly the same as that for FLIPRGON. The description for FLIPRGOFF has been corrected to reflect that it has the opposite effect to FLIPRGON. Corrected in 1.8.3 (2019-5-21)
21 May 2019 The TrueType Instruction Set Corrected IUP uses by removing freedom_vector and projection_vector. Corrected in 1.8.3 (2019-5-21)
9 May 2019 OpenType Font Variations Overview Corrected the arithmetic details in the last part of the example in the Interpolation Example section. Corrected in 1.8.3 (2019-5-09)
26 April 2019 CFF2 — Compact Font Format (CFF) Version 2 CFF2 table specification has been corrected to reflect the correct number of glyphs (65535) supported by FDSelect Format 3. Corrected in 1.8.3 (2019-4-26)
26 August 2018 glyf — Glyph Data The Simple Glyph Description section incorrectly stated that simple glyph descriptions apply for numberOfContours “greater than zero”. (The description for the numberOfContours field correctly states “greater than or equal to zero”.) Corrected in 1.8.3 (2018-8-26)
26 August 2018 The TrueType Instruction Set When content was ported from Microsoft Word, changes made in OpenType 1.8.1 were not retained, and some text was inadvertently removed. Corrected in 1.8.3 (2018-8-26)
26 August 2018 The TrueType Instruction Set In the description of GET VARIATIONS, two examples are provided of using an IDEF for the GET VARIATIONS op code. In OpenType 1.8, the examples incorrectly used NPUSHB instead of NPUSHW. In OpenType 1.8.1, this was corrected in one example, but the error in the other example was missed. Corrected in 1.8.3 (2018-8-26)
26 August 2018 OpenType Specification Change Log Change made to ttinst1.doc in OpenType 1.5 was not listed. Corrected in 1.8.3 (2018-8-26)