[pyramation]

Summary

Interactive pictures (\userline, uservariable plots) read the pointer with event.offsetX (mouse) or clientX - target.getBoundingClientRect().left (touch). Both are in screen pixels, while the drawing works in the picture's natural pixel space. When a page draws the svg smaller than its natural size (latex2js.com / mathapedia.com now zoom wide pictures down to fit a phone), the dragged vector no longer follows the finger: it lands at the scaled distance from the origin. The touch path also measured event.target, so a touch on a child path used that path's box.

New psgraph.pointerCoords(svg, clientX, clientY) measures the svg itself and divides out the drawn scale (rect.width / width attr). Used by both the psgraph.pspicture listeners and the React Pspicture mouse/touch handlers:

// before
var coords = [event.offsetX || 0, event.offsetY || 0];
// after
drawLayer(psgraph.pointerCoords(svg.node(), event.clientX, event.clientY), { pointer: true });

Unscaled pictures are unchanged (scale = 1).

Evidence

• New test in packages/html5/test/pspicture.test.ts draws a 200px picture at 100px and moves the pointer. Fails before the fix (Expected: 100, Received: 0), passes after.
• pstricks 202/202, html5 74/74 tests pass; react tsc clean.
• Browser check on latex2js.com /examples/unit-circle with this build overlaid: pointer at 75%/25% of the drawn picture puts the userline end at (0.749, 0.25) of natural size at 1024px (no zoom) and (0.749, 0.248) at 390px (zoom: 0.606). Before the fix the mobile endpoint was off.

Needed for the mobile fixes in latex2js.com / mathapedia.com to keep draggable diagrams accurate. Those sites need a new @latex2js/pstricks + latex2react publish to pick this up.

Link to Devin session: https://app.devin.ai/sessions/7fcd2deb6fb144849a9dd3f8dc116d42
Open in Devin Desktop: https://app.devin.ai/desktop/session/7fcd2deb6fb144849a9dd3f8dc116d42?variant=devin
Requested by: @pyramation

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring