Bits of .NET

🖌️ The Anchor Point That Landed Somewhere You Never Clicked

The Pen tool’s snapping behavior compares your cursor position against nearby anchor points and path edges using a fixed pixel radius, and that radius is defined in physical screen pixels, not in document pixels or in anything that scales with your display’s actual resolution. On a high-DPI display running at anything other than 100 percent Windows/macOS display scaling, that fixed snapping radius ends up covering a much larger area of the actual, zoomed-in document than it would at standard DPI – so a click you intend as a precise placement snaps instead to a nearby anchor point that only looks far away because of how much the canvas is magnified on screen.

🔎 The Problem

Setup: a 4K / Retina-class display running Windows or macOS display
scaling above 100% (125%, 150%, 200% are all common defaults)

Symptom: drawing a path with the Pen tool, a click intended to place
a NEW anchor point a few document-pixels away from an existing one
instead snaps directly onto that existing point - even though, at the
zoom level you're working at, the two points look clearly separated
on screen

Why: Photoshop's pen-tool snap radius is a small, fixed number of
PHYSICAL screen pixels. At 200% OS scaling, each of those physical
pixels covers a larger area of the actual document than it would at
100% scaling, so the effective "snap zone" around every existing
anchor point is much bigger than it visually appears to be.

✅ Fix: Zoom In Further, or Reduce OS Display Scaling, Before Precise Pen Work

• Zoom in significantly further in Photoshop’s own canvas (not the OS display scaling) before placing anchor points close together – a higher Photoshop zoom level spreads existing anchors further apart in physical screen pixels, directly shrinking the effective snap zone around them.
• For especially fussy precision work, consider temporarily setting the OS display scaling to 100% for that session, since this removes the DPI-scaling mismatch from the equation entirely, at the cost of a smaller-looking UI.
• Toggle View, then Snap, off entirely for a specific intricate path where points genuinely need to sit extremely close together, then turn it back on afterward for the rest of your normal path-editing workflow.

⚠️ Why This Is Easy to Miss

• The visual distance between two anchor points on screen looks completely normal and clearly non-overlapping, so a click that snaps unexpectedly reads as a Photoshop bug rather than a consequence of a system-level display setting.
• The exact same document and the exact same Pen tool actions behave differently on a different machine with different display scaling, which makes the issue intermittent and hard to pin down across a team working on shared files.