Word · Pictures

There's a whole PDF hidden inside this Word for Mac picture

Pasted charts and logos in Office files are often EMF, a Windows format no browser can draw. The ones from Word for Mac carry a surprise.

· 2 min read

Real documents are full of pictures that aren't really pictures. A chart pasted from Excel, a logo copied from another program, a table pasted as an image. Office often stores these as EMF, the Windows metafile format.

EMF is a list of drawing instructions for Windows' old graphics system: move here, draw a line, fill this polygon, write this text in this font. No browser can display it. PowerPoint doesn't care, it runs on Windows. A browser just shows an empty box.

Until this week, those boxes stayed empty. The very first deck I worked on had two embedded spreadsheets whose previews were EMF, and back then I just noted that they "cannot be drawn".

Drawing EMF

The fix is to play the instructions back yourself: read each record, keep track of the pens, brushes, fonts and transforms Windows would be tracking, and draw the result. Tedious, but well documented.

Text is the interesting part. EMF stores text as text, with a font and a position for every character. Draw it as text and you get real, selectable words. Turn it into pixels and a pasted table becomes a blurry picture of a table.

The surprise in the Mac files

Then I opened some documents made in Word for Mac. Their EMF pictures were nearly empty: a few placeholder records and not much else. Yet Word draws them perfectly.

It turns out Word for Mac tucks a complete PDF of the picture inside the EMF, in a comment record. Windows ignores it and draws the poorer EMF version. Office on the Mac reads the PDF.

So now I do what the Mac does: if there's a PDF inside, draw that. You get the real colours, including Pantone spot colours a designer picked on purpose, and embedded photos at full quality.

The text inside that hidden PDF is drawn from the outlines of the font embedded in it, so it comes out exactly right whatever fonts the reader has.

Why this matters more than it sounds

These pictures are often the most important thing on the page: the chart in the annual report, the logo on the cover. An empty box there is worse than a slightly wrong font everywhere else. It's the first thing people notice.