Desktop: move the magnifier and use ← ↑ ↓ → for 1-pixel precision. Mobile: tap to place, or use the guide-line mode below to drag and drop vector lines.
X: ---- Y: ----
Use ← ↑ ↓ → arrow keys to move exactly 1 pixel at a time before locking in.
Tap/click once to start a line, again to place it.
Tip: tap the image to aim, then use arrows for 1-pixel adjustments.
