Placeholders¶

From a user perspective, a placeholder is a container into which content can be inserted. The position, size, and formatting of content inserted into the placeholder is determined by the placeholder, allowing those key presentation design characteristics to be determined at design time and kept consistent across presentations created from a particular template.

The placeholder appearing on a slide is only part of the overall placeholder mechanism however. Placeholder behavior requires three different categories of placeholder shape; those that exist on a slide master, those on a slide layout, and those that ultimately appear on a slide in a presentation.

These three categories of placeholder participate in a property inheritance hierarchy, either as an inheritor, an inheritee, or both. Placeholder shapes on masters are inheritees only. Conversely placeholder shapes on slides are inheritors only. Placeholders on slide layouts are both, a possible inheritor from a slide master placeholder and an inheritee to placeholders on slides linked to that layout.

A layout inherits from its master differently than a slide inherits from its layout. A layout placeholder inherits from the master placeholder sharing the same type. A slide placeholder inherits from the layout placeholder having the same idx value.

Glossary¶

placeholder shape: A shape on a slide that inherits from a layout placeholder.
layout placeholder: a shorthand name for the placeholder shape on the slide layout from which a particular placeholder on a slide inherits shape properties
master placeholder: the placeholder shape on the slide master which a layout placeholder inherits from, if any.

Schema excerpt¶

<xsd:complexType name="CT_ApplicationNonVisualDrawingProps">
  <xsd:sequence>
    <xsd:element   name="ph"            type="CT_Placeholder"      minOccurs="0"/>
    <xsd:choice minOccurs="0">  <!-- a:EG_Media -->
      <xsd:element name="audioCd"       type="CT_AudioCD"/>
      <xsd:element name="wavAudioFile"  type="CT_EmbeddedWAVAudioFile"/>
      <xsd:element name="audioFile"     type="CT_AudioFile"/>
      <xsd:element name="videoFile"     type="CT_VideoFile"/>
      <xsd:element name="quickTimeFile" type="CT_QuickTimeFile"/>
    </xsd:choice>
    <xsd:element   name="custDataLst"   type="CT_CustomerDataList" minOccurs="0"/>
    <xsd:element   name="extLst"        type="CT_ExtensionList"    minOccurs="0"/>
  </xsd:sequence>
  <xsd:attribute name="isPhoto"   type="xsd:boolean" default="false"/>
  <xsd:attribute name="userDrawn" type="xsd:boolean" default="false"/>
</xsd:complexType>

<xsd:complexType name="CT_Placeholder">
  <xsd:sequence>
    <xsd:element name="extLst" type="CT_ExtensionListModify" minOccurs="0"/>
  </xsd:sequence>
  <xsd:attribute name="type"            type="ST_PlaceholderType" default="obj"/>
  <xsd:attribute name="orient"          type="ST_Direction"       default="horz"/>
  <xsd:attribute name="sz"              type="ST_PlaceholderSize" default="full"/>
  <xsd:attribute name="idx"             type="xsd:unsignedInt"    default="0"/>
  <xsd:attribute name="hasCustomPrompt" type="xsd:boolean"        default="false"/>
</xsd:complexType>

<xsd:simpleType name="ST_PlaceholderType">
  <xsd:restriction base="xsd:token">
    <xsd:enumeration value="title"/>
    <xsd:enumeration value="body"/>
    <xsd:enumeration value="ctrTitle"/>
    <xsd:enumeration value="subTitle"/>
    <xsd:enumeration value="dt"/>
    <xsd:enumeration value="sldNum"/>
    <xsd:enumeration value="ftr"/>
    <xsd:enumeration value="hdr"/>
    <xsd:enumeration value="obj"/>
    <xsd:enumeration value="chart"/>
    <xsd:enumeration value="tbl"/>
    <xsd:enumeration value="clipArt"/>
    <xsd:enumeration value="dgm"/>
    <xsd:enumeration value="media"/>
    <xsd:enumeration value="sldImg"/>
    <xsd:enumeration value="pic"/>
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="ST_PlaceholderSize">
  <xsd:restriction base="xsd:token">
    <xsd:enumeration value="full"/>
    <xsd:enumeration value="half"/>
    <xsd:enumeration value="quarter"/>
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="ST_Direction">
  <xsd:restriction base="xsd:token">
    <xsd:enumeration value="horz"/>
    <xsd:enumeration value="vert"/>
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="ST_PlaceholderSize">
  <xsd:restriction base="xsd:token">
    <xsd:enumeration value="full"/>
    <xsd:enumeration value="half"/>
    <xsd:enumeration value="quarter"/>
  </xsd:restriction>
</xsd:simpleType>

Notes on footer item placeholders¶

Recommendation and Argumentation¶

Place page number (and perhaps copyright, date) on master in plain text boxes. Use “Hide Background Graphics” option on title slide to prevent them showing there if desired.

In the slide placeholder method, an individually selectable footer item placeholder is present on the slide:
- It can be moved accidentally, losing the placement consistency originally imposed by the master. Recovering exact placement requires reapplying the layout which may make other, unwanted changes.
- It can be deleted, which could be a plus or minus depending.
- It can be formatted inconsistently.
- In can be accidentally selected and generally pollutes the shape space of the slide.
I’m not sure python-pptx does the right thing when adding slides from layouts containing footer items, at least not the same thing as PowerPoint does in automatically working out which footer items to copy over.

Also, there’s no method to copy over footer items from the layout.
Alternatives:
1. A page number can be placed on the master as a text box. This causes it to appear on every layout and every slide. No refreshing is necessary as this item is inherited, not copied at slide or layout create time.
  
  It can be excluded from an individual layout (such as a title slide layout) by setting the Hide Background Graphics flag on a layout-by-layout basis. Unfortunately, this also hides other items such as a logo, copyright text, and slide background, but these can be reapplied individually directly to that slide layout. Since the title slide layout is generally the only one folks want to hide a slide number from, this is perhaps not a great burden. Others, like perhaps closing slides, might have their own background anyway.

Hypothesis:¶

There is a class of placeholders known as “footer elements”, comprising date and time, footer text, and slide number.
These placeholders can only be directly added to a master. They are not available as options to add directly to a layout or to a slide.
In every case, these placeholders are copied, although some attributes may be inherited at run time (not sure). Footer items are copied from the master to a new layout. Likewise, items are copied from a layout to a slide, but only when explicitly asked for using Insert > Header and Footer. PowerPoint sometimes adds these automatically when they’re already present on other slides (don’t know the rules it uses).

Intended procedure¶

This is how slide footer items are designed to be used:

Add footer placeholders to master with intended standard position and formatting.
Available by default on each layout. Can be disabled for individual layouts, for example, the title slide layout using the Slide Master Ribbon > Edit Layout > Allow Footers checkbox. Also can be deleted and formatting changed individually on a layout-by-layout basis.
Hidden by default on new slides. Use Insert > Header and Footer dialog to add which items to show. Can be applied to all slides. Under certain circumstances, PowerPoint adds selected footer items to new slides automatically, based on them being present on other slides already in the presentation.

PowerPoint Behaviors¶

Layout: Slide Master (ribbon) > Edit Layout > Allow Footers (checkbox)
- Adding or removing a footer item from a layout, does not automatically reflect that change on existing slides based on that layout. The change is also not reflected when you reapply the layout, at least for deleting case.
  - It does not appear when you reapply the layout (‘Reset Layout to Default Settings’ on Mac)
Position appears to be inherited as long as you haven’t moved the placeholder on the slide. This applies at master -> layout as well as layout -> slide level.
- Refreshing the layout after the page number item has been deleted leaves the page number item, but repositions it to a default (right justified to right slide edge) position. Apparently it attempts to inherit the position from the layout but not presence (or not).
The Allow Footers checkbox is inactive (not greyed out but can’t be set on) when there are no footer placeholder items on the master.
Allow footers seems to be something of a one-way street. You can’t clear the checkbox once it’s set. However, if you delete the footer placeholder(s), the checkbox clears all by itself.
The placeholder copied from master to layout can be repositioned and formatted (font etc.).
Menu > Insert > Header and Footer … Is available on individual slides and can be applied to all slides. It also works for removing footer items. This applies to slides, not to slide layouts.

This dialog is also available from the Page Setup dialog.
Hide background graphics flag does not control footer items. It does however control visibility of all non-placeholder items on the layout (or slide). It’s available at both the layout and slide level. Not sure how that’s reflected in the XML.
When creating a new slide layout, the footer placeholders from the master are all automatically shown. This is to say that the “Allow Footers” ribbon option defaults to True when adding a new slide layout.

Clicking Allow Footers off hides all the footer items. They can also be deleted or formatted individually.
In order to appear (at create time anyway), footer items need to be:
1. Present on the master
2. Present on the layout (‘Allow Footers’ turned on, ph not deleted)
3. Insert Header and Footer turned on for each ph element to be shown. This is applied on a slide-by-slide basis.

Notes¶

Header is a misnomer as far as slides are concerned. There are no header items for a slide. A notes page can have a header though, which I expect is why it appears, since the same dialog is used for slides and notes pages (and handouts).
A master is intended only to contain certain items:
- Title
- Body
- Footer placeholders (date/time, footer text, slide number)
- Background and theme items, perhaps logos and static text
http://www.powerpointninja.com/templates/powerpoint-templates-beware-of-the-footers/
https://github.com/scanny/python-pptx/issues/64