There is no way to explicitly specify the navigation order among elements on a presentation slide.
Provide a specific mechanism for defining the ordering of objects on a slide - for example, considers amending the "id" attribute on the cNvPr element (page 3022) to specifically state that it shall be used for this purpose.
Page 3044 Part 4, Section 4.4.1.35
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Proposed Disposition of DIS 29500 Comment CA-0072 (Modified: 2008-01-03) Agreed; we should provide a mechanism to associate a navigation index to content controls and form controls in order to meet accessibility guidelines. We should also modify the specification to include specific details regarding the navigation order among elements in a presentation slide. The following changes will be made: In Part 4, §2.5.2, add a new subclause, which becomes the new §2.5.2.40: tabIndex (Structured Document Navigation Order Index) This element specifies the position of the current structured document tag in the navigation (tab) order used in the document. The index shall be stored on this element’s val attribute and is analogous to the tabIndex attribute in HTML. Objects that support tab index shall be navigated by consumers in the following order: 1. Objects for which the XML specifies a non-zero tabIndex value are navigated first. Navigation proceeds with the element with the lowest resolved value of tabIndex to the element with the highest resolved value of tabIndex. a. Objects that specify identical resolved values of tabIndex will be navigated in the lexical order in which the elements appear in the underlying WordprocessingML. 2. Objects for which the XML does not specify an index or objects for which the XML specifies a resolved tabIndex value of 0 are navigated last. These objects are navigated in the lexical order in which they appear in the underlying WordprocessingML. [Example: Consider the following two structured document tags where each structured document tag specifies a tab index: <w:sdt> <w:sdtPr> <w:id w:val="5" /> <w:tabIndex w:val="1" /> </w:sdtPr> <w:sdtContent> <w:p> <w:r> <w:t>First Name</w:t> </w:r> </w:p> </w:sdtContent> </w:sdt> … <w:sdt> <w:sdtPr> <w:id w:val="6" /> <w:tabIndex w:val="2" /> </w:sdtPr> <w:sdtContent> <w:p> <w:r> <w:t>Last Name</w:t> </w:r> </w:p> </w:sdtContent> </w:sdt> The tabIndex element specifies that the structured document tag with an identifier value of 5 shall be the first content to be reached via tabbing, whereas the structured document tag with an identifier value of 6 shall be the second content to be reached via tabbing. end example] Attributes Description val (Positive Decimal Number Value) Specifies that the contents of this attribute will contain a positive decimal number. The contents of this positive decimal number are interpreted based on the context of the parent XML element. [Example: Consider the following numeric WordprocessingML property of type ST_UnsignedDecimalNumber : <w:… w:val="15" /> The value of the val attribute is a decimal number whose value must be interpreted in the context of the parent element. end example] The possible values for this attribute are defined by the ST_UnsignedDecimalNumber simple type (§2.18.108). In Part 4, §2.5.2.37, page 585, line 22, one more child element will be included in the Child Elements table Child Elements Subclause tabIndex (Structured Document Navigation Order Index) §2.5.2.40 Child Elements Subclause tag (Programmatic Tag) §2.5.2.4 1 0 temporary (Remove Structured Document Tag When Contents Are Edited) §2.5.2.4 2 1 text (Plain Text Structured Document Tag) §2.5.2.4 3 2 In Part 4, §2.16.17, page 1,586, line 16, one more child element will be included in the Child Elements table Child Elements Subclause tabIndex (Form Field Navigation Order Index) §2.16.33 textInput (Text Box Form Field Properties) §2.16.3 3 4 In Part 4, §2.16, add a new subclause, which becomes the new §2.16.33: tabIndex (Form Field Navigation Order Index) This element specifies the position of the current form field in the navigation (tab) order used in the document. The tabbing index shall be stored on this element’s val attribute and is analogous to the tabIndex attribute in HTML. Objects that support tab index shall be navigated by consumers in the following order: 1. Objects for which the XML specifies a non-zero tabIndex value are navigated first. Navigation proceeds with the element with the lowest resolved value of tabIndex to the element with the highest resolved value of tabIndex. a. Objects that specify identical resolved values of tabIndex will be navigated in the lexical order in which the elements appear in the underlying WordprocessingML. 2. Objects for which the XML does not specify an index or objects for which the XML specifies a resolved tabIndex value of 0 are navigated last. These objects are navigated in the lexical order in which they appear in the underlying WordprocessingML. [Example: Consider the following two text box form fields where form field specifies a tab index: <w:ffData> <w:name w:val="FirstName" /> <w:enabled /> <w:textInput /> <w:tabIndex w:val="1" /> </w:ffData> … <w:ffData> <w:name w:val="LastName" /> <w:enabled /> <w:textInput /> <w:tabIndex w:val="2" /> </w:ffData> The tabIndex element specifies that the FirstName form field shall be the first content to be reached via tabbing, whereas the LastName form field shall be the second content to be reached via tabbing. end example] Attributes Description val (Positive Decimal Number Value) Specifies that the contents of this attribute will contain a positive decimal number. The contents of this positive decimal number are interpreted based on the context of the parent XML element. [Example: Consider the following numeric WordprocessingML property of type ST_UnsignedDecimalNumber : <w:… w:val="15" /> The value of the val attribute is a decimal number whose value must be interpreted in the context of the parent element. end example] The possible values for this attribute are defined by the ST_UnsignedDecimalNumber simple type (§2.18.108). In wml.xsd: The tabIndex element will be added to the CT_SdtPr and CT_FFData content models. In Part 4, §4.4.1.42, page 3,051, line 16 This element specifies all shape-based objects shapes within a slide. Contained within here are all the shapes , either grouped or not, that can be referenced on a given slide. In Part 4, §4.4.1.42, page 3,052, after line 5 Each shape-based object within the shape tree, whether grouped or not, shall represent one unique level of z-ordering on the slide. The z-order for each shape-based object shall be determined by the lexical ordering of each shape-based object within the shape tree: the first shape-based object shall have the lowest z-order, while the last shape-based object shall have the highest z-order. The z-ordering of shape-based objects within the shape tree shall also determine the navigation (tab) order of the shape-based objects: the shape-based object with the lowest z-order (the first shape in lexical order) shall be first in navigation order, with objects being navigated in ascending z-order. [Example: Consider the following PresentationML slide with two shapes <p:sld> <p:cSld> <p:spTree> … <p:sp> <p:nvSpPr> <p:cNvPr id="5" name="Oval 4" /> … </p:nvSpPr> … </p:sp> <p:sp> <p:nvSpPr> <p:cNvPr id="4" name="Isosceles Triangle 3" /> … </p:nvSpPr> … </p:sp> </p:spTree> </p:cSld> … </p:sld> In the above example the shape with name Oval 4 has the lowest z-order value since that shape is the first shape in the shape tree. Oval 4 is also the first shape in navigation order. The shape with name Isosceles Triangle 3 has the highest z positioning value since that shape is the last shape in the shape tree. Isosceles Triangle 3 is also the last shape in navigation order. end example] Similar Comments: ECMA-0040 , US-0023
Overloading the meaning “id” attribute doesn’t sound like a wise idea. Rather, there should be an additional attributes, say “predecessor” or “successor” that allows the specification of order.
“successor” would be the bare minimum, both would be ideal. “predecessor” alone would only allow reverse traversal, which is of little benefit on its own.