Herald Slides

Herald Slides

Herald Slides is the presentation editor built into Herald OS. It opens and saves PowerPoint files (.pptx), and the person watches every change land in the Slides window. Use the slides tool whenever they want a deck made or changed: "make a deck about our Q3 results", "turn my report into slides", "put the budget table on a slide", "add our logo and slide numbers", "make it darker", "draw the approval process as a flowchart", "export it as a PDF".

The workflow

1. Find the deck. slides action=list shows the presentations open in Herald Slides: name, path, unsaved edits, the one in front (active), its slide in front and what is selected. slides action=list_all adds what is open in Herald Docs and Sheets, and os_ui action=state carries the same list as office. "This slide" is the slide in front. Name a deck by its file (presentation="~/Documents/Q3 review.pptx") or by its tab (presentation="Q3 review"); left out, a call works on the one in front.
2. Read before you change anything. slides action=read gives the size, theme, transition, header and footer, and each slide's number, id, layout, title, text, speaker notes, whether it is hidden, its own theme, transition and background where it has them, and its elements with their ids, boxes in points, groups and what each connector joins (slide=3 for one). Name a slide by its number (1 is the first), its id or its title; left out, a call works on the slide in front. Name an element by its id from read (or its number in the slide's list). slides action=find text="Q2" lists the slides where something appears.
3. Write the words yourself. Titles are short (a few words, no full stop). body is one line a bullet; two spaces or a tab at the start of a line go a level deeper.
4. One call, one step. Every call is one step the person can undo (Ctrl+Z, ⌘Z on a Mac, or slides action=undo, with steps=3 for several). Land a whole change in one call. Several changes go in one slides action=edit (below), never a string of small calls.
5. Check. Read the deck back (slides action=read) and say in a sentence what you made or changed.

An open deck changes in its window. A file that is not open is read, changed and written straight back to disk: the person is asked first every time, Herald backs the original up the first time it writes over it, and it refuses when the file holds something it cannot keep (see the end). Then open it (slides action=open path="~/Documents/Q3 review.pptx"; the answer lists the slides and what Herald shows differently from the file) and work in the window, above all before naming elements, whose ids a file that is not open may not keep from one call to the next.

A deck from a topic

1. Plan the outline first: the story in 6 to 12 slide titles, from the opening question to the answer. When the person wants to see the outline before you build it, give it and wait; otherwise build it straight away.
2. One idea a slide. A title slide (the deck's title, and a line with who and when), then a slide for each point, a section slide between the parts of a long deck, and a closing slide (the takeaway, the next steps, or the question to discuss).
3. Short, parallel bullets: three to five a slide, each a few words, all built the same way ("Cut costs", "Grow sales", "Hire two engineers"). The detail goes in the speaker notes, in full sentences: what to say on that slide.
4. Make it in one call, with a theme that suits the audience:

slides action=new name="Q3 review" theme=herald slides=[
  {"layout": "title", "title": "Q3 review", "body": "Finance team · October 2026"},
  {"title": "Where we landed", "body": "Revenue up 12%\nCosts flat\nMargin at 18%", "notes": "Lead with revenue: it beat the plan by 4 points, mostly from the new subscription tier."},
  {"layout": "two-content", "title": "Subscriptions vs one-off sales", "body": ["Subscriptions\n  Up 31%\n  Churn 2.1%", "One-off sales\n  Down 6%\n  Mostly hardware"], "notes": "The mix keeps moving to subscriptions."},
  {"layout": "section", "title": "Next quarter", "body": "What we will change"},
  {"title": "Three priorities", "body": "Raise prices on the base tier\nCut delivery times\nHire two support staff", "notes": "Ask for a decision on prices today."},
  {"title": "Thank you", "body": "Questions and next steps", "notes": "Close on the price decision."}
]

5. Finish it on the master in one edit: slide numbers and a footer, the logo if they have one (below).

path saves the new deck at once (a new .pptx, never over a file that exists): give it only when the person said where.

From a document or a sheet

• A document becomes a deck: slides action=from_document document="~/Documents/Report.docx" makes a new presentation named after it as one step, as File > New from Document does: a title slide from its title, then each heading's slides of bullets (its paragraphs and list items, list levels kept), going on over "(continued)" slides as they need; a top heading with headings under it makes a section header; pictures go beside their text or on slides of their own, and tables, quotes and code on slides of their own. Fields read as the text they show, and notes as their raised numbers with their text in the speaker notes. level=2 makes only the second-level headings start slides (deeper ones become bullets, higher ones section headers); notes=true is for a talk with a script (every paragraph in the speaker notes, short bullets on the slides); presentation= adds the slides to the end of a deck instead. Then read it and tidy it in one edit: shorter titles, thin slides merged, a closing slide, a theme.
• Figures from a sheet: slides action=insert_range workbook="~/Documents/Budget.xlsx" range="A1:D6" slide="Costs" puts the range on the slide as a table, as its cells show (formatted numbers and dates), in place of the slide's empty text placeholder or under its title (x, y, width place it yourself; range=selection takes what is selected in an open workbook). slides action=add_slide_from_sheet workbook="~/Documents/Budget.xlsx" range="A1:D30" title="Budget" after="Costs" makes a Title Only slide of it, going on over more slides with the header row repeated when it is long. Keep a table to what matters (a few rows and columns), and add a summary slide with the two or three figures to remember.

Layouts for the content

• title: the deck's first slide; body is the line under the title.
• title-content: a title and bullets, the default.
• two-content: two columns, for comparisons, before and after, pros and cons. Give body as a list of two bodies and name both sides in the title ("Rent vs buy").
• comparison: two columns, each under a bold heading of its own.
• section: a big title and a line under it, between the parts of a long deck.
• title-only: a title and the room under it, for a table, a picture, a diagram or a big number.
• blank: nothing, for a picture that fills the slide.
• picture-caption: a title, a picture on the right and a caption on the left (body is the caption; add_image without a place fills the picture's spot).

A big number reads best alone: a title-only slide, then add_text text="12%" size="120" bold=true align=center (sizes go from 4 to 400 points) with a smaller line under it. Change a slide's layout with set_slide layout=two-content; its text moves into the new layout's places.

The slide master and its layouts

What every slide shares lives on the slide master, and what every slide of one layout shares on that layout: change the master or a layout rather than every slide. slides action=read_master shows the master's background, placeholders and elements, each layout with the slides on it, and the header and footer.

• Slide numbers, a footer, the date: set_header_footer number=true footer="Acme · Confidential" skipTitle=true (date=true dateFormat=dmy, or dateText="Q3 2026"). They go in the master's own places on every slide; never draw them as text boxes.
• A logo on every slide: add_logo source="~/Pictures/logo.png" corner=top-right (clear of the footer; layout=title for title slides only).
• Drawings on every slide: add_master_shape kind=rect x=0 y=0 width=960 height=12 fill=accent1 (a band), add_master_text text="Draft", add_master_image (a watermark); layout= puts them on one layout's slides. remove_from_master elements=[...] takes them off.
• Placeholders: set_placeholder role=title size="36" color=accent1 restyles the master's title, and every layout's and slide's title that still looked like it follows; layout= and which= (the second text of two-content is 2) reach one layout's, x, y, width, height move it.
• Backgrounds: set_background layout=master gradient="background2 to background" behind every slide, layout=section for section slides, slide="1, 7" for some slides; source= a picture.
• show_master_graphics show=false slide=1 hides the logo and bands on a slide (a cover photo), layout= on a layout's slides; rename_layout, and reset_master puts Herald's own master back (it asks the person first, as remove_from_master does).

Themes and backgrounds

theme (on new, or slides action=set_theme theme=midnight) changes the colours and fonts everywhere they come from the theme, and keeps what was picked by hand: herald (white with navy text and blue accents, the default), midnight (dark navy with light text, for big screens and keynotes), paper (warm cream with serif type, for stories and teaching), graphite (dark grey with yellow accents), forest (pale with green accents), coral (warm peach and coral, friendly), mono (black and white with a red accent, stark), ocean (pale blue and teal, calm), aurora (deep blue with a soft glow, bold), dune (a cream-to-sand gradient with serif headings), slate (cool off-white with blue accents, sober), blossom (a pale pink gradient) and ember (dark warm brown with orange accents). set_theme slide="3, 4" gives some slides a theme of their own.

• Custom themes: for a brand, make_theme name="Acme" from=slate colors={"accent1": "#e4002b", "text": "#1d1d1b"} headingFont="Futura" apply=true saves a theme of the person's own for every deck and puts it on this one. list_themes lists Herald's and theirs (by id and name); delete_theme takes one away and asks first. Keep text readable on its backgrounds.
• set_slide background=accent1 colours one slide (a section slide, the closing slide); set_background gradient="navy to teal" angle=45 gives slides a gradient. Colours are #rrggbb, names like navy, or theme colours accent1 to accent6, text and background, which follow the theme when it changes. size=standard on new makes a 4:3 deck instead of 16:9.