Editing text in a PDF

Editing text is the core of blupdf. Every page is analysed into blocks - paragraphs, headings, table cells, labels, footers - and each block can be clicked and retyped in place. This page explains what happens at each step so you know what to expect from the result.

Selecting a block

Move the pointer over a page and blocks light up with a thin outline. Click one to select it; the outline turns solid and the text toolbar appears above the page with the block's font, size and color. Blocks are detected when the document is parsed (50 credits per digital page, 80 per scanned page), so there is nothing to set up.

A table is one block per column, a paragraph is one block, and a line that mixes styles (a bold label followed by regular text) is split where the style changes. If two pieces of text that belong together were split, edit them one at a time; each block keeps its own position, so the rest of the page never moves.

Retyping in place

Click inside the selected block to place the cursor, or start typing to replace it. You edit the text where it sits on the page, in its own font, and it re-wraps inside the block's original box: the left and right edges, the line height and the alignment stay as they were. Press Enter for a deliberate line break.

Two things keep rows tidy while you type. On a line shared with other blocks (a form row, an order line), the cells beside yours slide along when your text gets longer or shorter, so the row stays aligned. A right-aligned block that outgrows its box, such as an amount column, grows to the left and keeps its right edge.

Click outside the block or press Escape to finish. Edits save automatically; the Save button in the top bar reads Saved when nothing is pending. New text costs 1 credit per character when it is saved, not while you type.

The text toolbar

Control	What it does
Font	Opens the font picker with the document's own fonts and blupdf's library. Type to search.
Size	Minus and plus step the size. The box is kept, so a smaller size fits more text on the same lines.
Bold, Italic	Toggle the weight and the slant.
Text color	Any color. The original color is read from the page.
Alignment	Left, centered, right or justified.
Spacing	Line spacing and letter spacing in points, for matching a tight heading or spreading characters across boxes.
Delete block	Removes the block from the page.

Fonts: embedded first, then the closest match

blupdf reads four properties from the block you clicked and applies them to what you type:

Property	Digital PDF	Scanned PDF
Font	The font embedded in the file, reused as-is when it contains the characters you type	The closest library family to the recognised style
Size	Exact point size	The size measured by the recognition engine
Color	Exact fill color	The color measured from the text
Alignment	As detected from the block's lines	As detected from the line edges

Most PDFs embed their fonts as a subset that contains only the characters used in the file. When you type a character the subset does not have, or when a font is referenced but not embedded, blupdf switches the block to the closest family from its library of 35 open-licence families (sans, serif, monospace and handwriting), each in every weight from thin to black where the family has them. The match keeps the category, weight, width and x-height, so the substitution is designed to be invisible at reading size. Common names map directly: Arial and Helvetica to Arimo, Calibri to Carlito, Cambria to Caladea, Times New Roman to Tinos, Georgia to Gelasio, Courier to Cousine, Segoe UI to Open Sans, Futura to Jost, and the macOS system font (used by PDFs printed from Chrome or Safari) to Inter. You can pick any other family from the toolbar's font picker.

See Editing scanned PDFs with OCR for how fonts are chosen when there is no embedded font at all.

Adding text

Choose Text in the toolbar, then click where the text goes. A new block is created at that spot with the font and size of the nearest text on the page. Type, then click away. New blocks are ordinary blocks: drag them to move them, restyle them from the toolbar, delete them if needed.

Deleting text

Select a block and press Delete or Backspace, or use the toolbar's Delete block button. On a digital page the original text is removed from the page content, not covered up, so nothing is left behind in the file. On a scanned page the ink under the block is erased and the paper tone is kept. Deleted blocks are listed under Deleted blocks in the top bar and can be restored from there at any time.

Undo, redo and coming back later

Undo (⌘Z or Ctrl+Z) and Redo (⌘⇧Z or Ctrl+Shift+Z) step through every change in the session, including changes made by blupdf AI. Because edits save automatically, you can close the tab and open the document again later from Studio's Recent list or the Documents page; everything is where you left it. The original file is kept, and Download always gives you the edited copy.

Zoom

Documents open fitted to the window. ⌘ with plus or minus zooms in and out, ⌘0 returns to 100%, and the top bar has zoom buttons. On a phone, pinch to zoom and tap a block to zoom in on it.

Credits used

• Parsing: 50 credits per digital page, charged once when the document opens; 80 per scanned page when it is recognised.
• New text: 1 credit per character, charged when the edit is saved.
• Deleting, restyling, moving, undo and downloading are free.

The mechanics are in Credits & billing.