EPUB Accessibility Metadata Examples

Pre Processing

Before working directly with the metadata we must read the metadata in the Package document (OPF file) inside the EPUB. This is a common starting point for all techniques that allows us to query the metadata directly.

This algorithm takes the package_document_as_text argument: a UTF-8 string representing the Package document.

To generate the internal representation, run the following steps:

1. LET package_document_content be textual representation of the Package document for the publication given package_document_as_text.
2. LET package_document be the DOM tree that results from parsing package_document_content using an XML DOM parser.
3. Return package_document.

Check for Node

Many of the techniques rely on checking for the presence or absence of metadata in the metadata section of the Package document.

This algorithm takes:

• the package_document argument: the internal representation of the Package document (output of pre processing);
• the path argument: the XPATH of the node to check the presence of.

To check for node, run the following steps:

1. IF package_document contains path: THEN return True.
2. ELSE return False.

Visual adjustments

This technique relates to Visual adjustments key information.

This algorithm takes the package_document_as_text argument: a UTF-8 string representing the Package document.

Understanding the variables

all_textual_content_can_be_modified

If true it indicates that the accessibilityFeature="displayTransformability" (All textual content can be modified) is present in the OPF file, otherwise if false it means that the metadata is not present.

All textual content can be modified means that the digital publication does not restrict the ability of users to modify and reflow the display of any textual content to the full extent allowed by the reading system (i.e. to change the text size or typeface, line height and word spacing, colors).

is_fixed_layout

If true it indicates that the layout="pre-paginated" (Fixed format) is present in the OPF file, otherwise if false it means that the metadata is not present.

Fixed format means that digital publication is in fixed format (e.g. EPUB Fixed Layout).

Variables setup

1. LET package_document be the result of calling pre processing given package_document_as_text.
2. LET all_textual_content_can_be_modified be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityFeature" and text()="displayTransformability"].
3. LET is_fixed_layout be the result of calling check for node on package_document, /package/metadata/meta[@property="rendition:layout" and text()="pre-paginated"].

Instructions

1. IF all_textual_content_can_be_modified: THEN display "Appearance can be modified".
2. ELSE IF is_fixed_layout: THEN display "Appearance cannot be modified".
3. ELSE display "Appearance modifiability not known".

Supports nonvisual reading

This technique relates to Supports nonvisual reading key information.

This algorithm takes the package_document_as_text argument: a UTF-8 string representing the Package document.

Understanding the variables

all_necessary_content_textual

If true it indicates that the accessModeSufficient="textual" (all main content is provided in textual form) is present in the OPF file, otherwise if false it means that the metadata is not present.

All non-decorative content supports reading without sight means that all contents of the digital publication necessary to use and understanding, including text, images (via their alternative descriptions), audio and video material (via their transcripts, descriptions, captions or subtitles) are fully accessible via suitable reading devices, for example text-to-speech screen readers or tactile reading devices (‘Braille displays’), and nothing in the digital publication prevents or blocks the use of alternative reading modes. The entire publication can be navigated and ‘read’ using only text rendered via sound or touch, and does not require visual perception.

non_textual_content_images

If true it indicates that at least one of the following is present in the OPF file:

• accessMode="chartOnVisual" (Charts and Graphs);
• accessMode="chemOnVisual" (Chemistry);
• accessMode="diagramOnVisual" (Diagrams);
• accessMode="mathOnVisual" (Math);
• accessMode="musicOnVisual" (Music);
• accessMode="textOnVisual" (Images of text);
• otherwise if false it means that this metadata is not present.

This means that the content contains images of any type.

textual_alternative_images

If true it indicates that at least one of the following is present in the OPF file:

• accessibilityFeature="alternativeText" (Short alternative textual descriptions);
• accessibilityFeature="longDescription" (Full alternative textual descriptions);
• accessibilityFeature="describedMath" (Visual of math fully described));
• otherwise if false it means that this metadata is not present.

This means that there are textual alternatives for images.

Variables setup

1. LET package_document be the result of calling pre processing given package_document_as_text.
2. LET all_necessary_content_textual be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessModeSufficient" and text()="textual"].
3. LET non_textual_content_images be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityFeature" and
(text()="chartOnVisual" or text()="chemOnVisual" or
text()="diagramOnVisual" or text()="mathOnVisual" or
text()="musicOnVisual" or text()="textOnVisual")].
4. LET textual_alternative_images be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityFeature" and
(text()="longDescription" or text()="alternativeText" or text()="describedMath")].

Instructions

1. IF all_necessary_content_textual: THEN display "Readable in read aloud and braille".
2. ELSE IF non_textual_content_images AND NOT textual_alternative_images: THEN display "Not fully readable in read aloud and braille".
3. ELSE display "May not be fully readable in read aloud and braille".

Conformance

This technique relates to Conformance key information.

Pre-recorded audio

This technique relates to Pre-recorded audio key information.

Conformance

This technique relates to Conformance key information.

Pre-recorded audio

This technique relates to Pre-recorded audio key information.

Navigation

This technique relates to Navigation key information.

Charts, diagrams, and formulas

This technique relates to Charts, diagrams, and formulas key information.

Hazards

This technique relates to Hazards key information.

This algorithm takes the package_document_as_text argument: a UTF-8 string representing the Package document.

Understanding the variables

no_hazards_or_warnings_confirmed

If true it indicates that the accessibilityHazard="none" (no accessibility hazards) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means there is a positive indication in the accessiblity metadata within the EPUB confirming there are no associated hazard warnings with this product.

flashing_hazard

If true it indicates that the accessibilityHazard="flashing" (WARNING - Flashing hazards) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means that there is a positive indication in the accessiblity metadata within the EPUB confirming that the product has a flashing hazard which must be displayed.

no_flashing_hazards

If true it indicates that the accessibilityHazard="noFlashingHazard" (No flashing hazard warning necessary) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means there is a positive indication in the accessiblity metadata within the EPUB confirming there are no flashing hazards associated with this product.

motion_simulation_hazard

If true it indicates that the accessibilityHazard="motionSimulation" (WARNING - Motion simulation hazard) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means that there is a positive indication in the accessiblity metadata within the EPUB confirming that the product has a motion simulation hazard which must be displayed.

no_motion_hazards

If true it indicates that the accessibilityHazard="noMotionSimulationHazard" (No motion simulation hazard warning necessary) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means there is a positive indication in the accessiblity metadata within the EPUB confirming there are no motion simulation hazards associated with this product.

sound_hazard

If true it indicates that the accessibilityHazard="Sound" (WARNING - Sound hazard) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means that there is a positive indication in the accessiblity metadata within the EPUB confirming that the product has a sound hazard which must be displayed.

no_sound_hazards

If true it indicates that the accessibilityHazard="noSoundHazard" (No sound hazard warning necessary) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means there is a positive indication in the accessiblity metadata within the EPUB confirming there are no sound hazards associated with this product.

unknown_if_contains_hazards

If true it indicates that the accessibilityHazard="unknown" (unknown hazards) is present in the OPF file, otherwise if false it means that the metadata is not present.

This means that the product has not been assessed for hazards and there is no information about potential hazards.

Variables setup

1. LET package_document be the result of calling pre processing given package_document_as_text.
2. LET no_hazards_or_warnings_confirmed be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="none"].
3. LET flashing_hazard be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="flashing"].
4. LET no_flashing_hazards be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="noFlashingHazard"].
5. LET motion_simulation_hazard be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="motionSimulation"].
6. LET no_motion_hazards be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="noMotionSimulation"].
7. LET sound_hazard be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="sound"].
8. LET no_sound_hazards be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="noSoundHazard"].
9. LET unknown_if_contains_hazards be the result of calling check for node on package_document, /package/metadata/meta[@property="schema:accessibilityHazard" and text()="unknown"].

Instructions

1. IF no_hazards_or_warnings_confirmed OR (no_flashing_hazards AND no_motion_hazards AND no_sound_hazards): THEN display "No hazards".
2. ELSE IF flashing_hazard OR motion_simulation_hazard OR sound_hazard: THEN LET hazards be an empty array.
   1. IF flashing_hazard: THEN APPEND "flashing" to hazards.
   2. IF motion_simulation_hazard: THEN APPEND "motion" to hazards.
   3. IF sound_hazard: THEN APPEND "sound" to hazards.
   4. LET hazards_string be the result of:
      • calling join on hazards with the separator ", "
      • making uppercase the first character
      • replacing the last occurence of ", " with " and "
      • concatenating " hazards" to the end of the string IF (length of hazards) > 1 ELSE concatenating " hazard" to the end of the string.
   5. display hazards_string.
3. ELSE IF unknown_if_contains_hazards THEN display "The presence of hazards is unknown".
4. ELSE display "No information about possible hazards".

   This key information can be hidden if metadata is missing.

Accessibility summary

This technique relates to Accessibility summary key information.

Additional accessibility information

This technique relates to Additional accessibility information key information.