Drop screenshots here
Each file is matched to a platform by its pixel dimensions.
x-height ÷ em
em is the nominal font size — “14 pt Arial” means a 14 pt em. Nothing in the word is actually 14 pt tall; the em is the design grid the glyphs are drawn on.
x-height is how tall a lowercase x actually is: the
body of the letter, with no ascender or descender. It is what your eye reads,
and it is what the tool can measure from a screenshot.
The ratio between them varies by typeface. Futura sets x-height at 0.46 of the em; Inter at 0.55. So two fonts at the same “14 pt” can differ by nearly 20% in the size that actually matters. The tool measures x-height in pixels and divides by this ratio to recover the point size — which is why picking the right font in Font metrics matters more than anything else in the pipeline.
pt and px are not interchangeable here. On the Deck's 216 ppi panel, 11 pt of em is 33 px — but 11 px of lowercase is only 7.08 pt of em. Valve's spec is in pixels of lowercase height, which is why the standard defaults to that form.
OCR boxes
The Boxes toggle draws a rectangle around every run of text the OCR found — one per line of text, not per letter. Green means the run clears the platform minimum, amber that it is within the measurement band of it, red that it falls short. Click any row in Measurements to highlight its box.
The boxes are the OCR's own idea of where the text is, and they are loose — they include antialias haze and a little padding. They are for locating text on screen, not what gets measured. The actual measurement re-finds each glyph's true edges in the source pixels.
If boxes are missing over stylised or outlined text, that is OCR failing to recognise it. Lower Min confidence, try a different page segmentation mode, or use Manual measure to drag over it yourself.
Where the minimum comes from
A point is a physical unit — 1/72 inch — so the same pt is comfortable on a handheld and unreadable across a room. What stays constant is visual angle: how much of your retina the letter covers.
Valve writes the Steam Deck rule in pixels, not points: “Interface text must be easily readable at a distance of 12 inches/30 cm from the screen. In other words, the smallest on-screen font character should never fall below 9 pixels in height at 1280×800.” 9 px is the Deck Verified floor; Valve recommends 12 px. “Smallest character” is the lowercase body — the x-height.
You pick one such rule; the tool turns it into an angular threshold and derives each platform's minimum from that platform's own viewing distance. A handheld is held at 12 in, a TV sits 8 ft away — so the TV needs roughly eight times the physical size for the same legibility.
Reading a verdict
✓ meets Steam Deck — this run clears that platform's minimum, allowing for measurement uncertainty.
borderline on Switch 2 — the reading and the minimum
are within the ± band of each other. The glyph was rasterised to
whole pixels, so the true size can't be pinned down more tightly. Treat as a
fail if it matters.
3.1 pt under Steam Deck — how far short it is. Hover the verdict to see the pixel size it would need instead.
The Cross-platform check panel answers the wider question: how many of this image's runs clear every platform, so you can see at a glance whether a Steam Deck-tuned UI survives on Switch 2 handheld.