PowerPoint 97-2003 files (.ppt)

Presentation.Open, Office.Open, Office.ExtractText and Office.Convert read PowerPoint binary presentations. The file is read at record level (RecursiveAI.OneDocument.Ppt.Binary, on the shared OfficeArt reader in officeart.md), converted to PresentationML in memory, and the presentation hub opens that package as typed views. Everything the hub does with a .pptx it does with the converted file: edit, render, template, save as .pptx. Presentation.ImportLoss lists what did not map; Presentation.SourceFormat is OfficeFormat.Ppt. Writing .ppt is not offered.

The result has no file path, so Save() never writes over the binary original; SaveAs writes PresentationML.

Structure that is read

Edit chain and persist directory ([MS-PPT] §2.1.2, §2.3.3 to §2.3.6). PowerPoint appends to the stream on every incremental save: the objects that changed, a PersistDirectoryAtom, and a UserEditAtom that names its predecessor. The reader starts at the edit the Current User stream names and follows offsetLastEdit back while the offset strictly decreases. The persist directory of each edit is read newest first and the first definition of a persist identifier wins, so the last edit wins and older copies stay in the stream untouched. A persist object is parsed when first asked for and cached.

Repairs, each a defect with the stream offset:

• no usable Current User stream, or an offset that is not a UserEditAtom: the edits are found by scanning the top-level records;
• a chain that does not move backwards ends at the loop;
• a user edit whose directory is not there: its objects are ignored, older edits still serve;
• a document persist identifier that is not listed: the first top-level DocumentContainer is used;
• a record that claims more bytes than the stream holds is clamped (art.record-overrun).

Encrypted files (header token or a CryptSession10Container reference) are decrypted with OpenContext.Password, or raise OfficeEncryptedException; see encryption.md. PowerPoint 4.0 and 95 files (a PersistentStorage Directory stream, no user edits) are OfficeUnsupportedException: [MS-PPT] does not describe them.

Text

A text body is a TextHeaderAtom and the records after it: TextCharsAtom (UTF-16) or TextBytesAtom (Latin-1), StyleTextPropAtom, metacharacter atoms (slide number, date, header, footer), TextSpecialInfoAtom (language), TextRulerAtom, interactive records. Paragraphs end at U+000D, forced line breaks are U+000B; every body has an implicit terminating break, so style runs cover the text plus one. Bodies live in the shape's OfficeArtClientTextbox, or in the document's slide list when the shape holds an OutlineTextRefAtom (the older layout).

TextPFException and TextCFException are read with their mask bits; a field exists only when its bit is set, and what is not set inherits from the master text styles, exactly as in PowerPoint. The converter writes only the set fields, so the hub's inheritance resolves them the same way. TextRulerAtom supplies the left margin and indent per level that paragraph runs cannot carry. Paragraph spacing: 0 to 13200 is a percentage of the line, a negative value is master units. Master units are 1/576 inch (1,587.5 EMU).

Conversion

• Masters and layouts. Each main master becomes a slide master with a theme, txStyles from its TextMasterStyleAtom records (title, body, other) and its drawing. PowerPoint 97-2003 has no layouts; one layout is written per distinct slide layout type and placeholder set used with a master, modelled on the first slide that uses it (placeholders only, positions from that slide). A title master becomes the "Title Slide" layout of its main master, with its shapes. Layout type names follow SlideLayoutType.
• Colours. The eight scheme colours become the theme (dk1 text, lt1 background, dk2 shadows, lt2 title text, accents 1 to 4 fill, accent, accent and hyperlink, accent and followed hyperlink). A scheme index becomes a theme colour when the slide's scheme equals its master's, otherwise the slide's RGB value.
• Slides. Shapes keep their z-order, groups become groups with the group's coordinate space as child extents. Rotation and flips come from the OfficeArt properties. Backgrounds (the drawing's background shape) are written unless the slide uses the master's. Slide flags: follow master objects is showMasterSp, hidden comes from the transition record.
• Geometry. Preset shape types (about 130) map to DrawingML presets; freeforms become custom geometry from the vertex and segment arrays; the rounded rectangle's corner is converted; other adjustments are dropped (reported).
• Fill, line, shadow. Solid, picture, texture and gradient fills; dash styles, compound lines, caps, joins, arrowheads; an outer shadow. Pictures come from the BLIP store (Pictures stream), metafiles inflated, DIBs given a BMP header; crops become srcRect.
• Text boxes and placeholders. Insets, anchors, wrap, text flow and fit-shape-to-text come from the text properties. Placeholder types map to ph types with indexes assigned in order (date 10, footer 11, slide number 12). WordArt text (geometry text) is written as plain text.
• Fields. Slide numbers and dates become a:fld; a header or footer metacharacter becomes the text of the page's HeadersFooters record, else the document's.
• Tables as PowerPoint 2003 stores them: a group whose properties mark it a table and whose children are cell rectangles in row-major order; the row count is the length of tableRowProperties. A regular grid becomes a:tbl with each cell's own outline as its borders; anything else stays a group.
• Notes become notes slides with a notes master, the handout master a handout master, each with a theme.
• Comments (PowerPoint 2002 extension data) become legacy comment parts with an author list; positions are master units, as in p:pos.
• Hyperlinks on shapes and text ranges: web and file targets become external relationships, slideId,slideNumber,title targets slide jumps, jump actions (next, previous, first, last, end show) the matching ppaction.
• Transitions map by effect type and direction; advance on click, automatic advance time and speed are carried. Effects PowerPoint 97 had that PresentationML lacks are reported.

Loss report

Presentation.ImportLoss items (code, feature, count, message); each is also a defect with the record offset in the source stream.

Open questions

The specification leaves these open; PowerPoint decides at the final gate. testdata/ppt holds LibreOffice's PowerPoint 97 output for the generated decks and tools/office-oracle cases ask PowerPoint to open each file and save it as .pptx for comparison; the answers are not in yet.

• gradient angle: fillAngle is counter-clockwise from the upward vector; the conversion measures DrawingML's clockwise angle from the x axis as 270 degrees minus fillAngle;
• the ribbon pair (shape types 53 and 54, 107 and 108) maps to ribbon2/ribbon and ellipseRibbon2/ellipseRibbon by position, not by a verified correspondence;
• first-line indent is written relative to the left margin (indent - marL) as DrawingML defines it;
• layout modelling: one layout per layout type and placeholder set, not the layouts PowerPoint itself would generate;
• table borders from the cell outlines, not from the separate line shapes.

Limits

The limits object applies throughout: MaxRecordCount, MaxRecordSize, MaxRecursionDepth (record nesting and group nesting), MaxAllocationBytes (inflated metafiles), MaxPartSize (the streams), MaxDefects. Record lengths are checked against the data before anything is allocated.

Tools

tools/PptProbe opens, dumps, converts and lists streams; tools/ppt/make-fixtures.sh makes the LibreOffice fixtures, tools/ppt/check.sh converts a directory and runs the schema and LibreOffice checks; fuzz target ppt.