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Short note: 2D translation

Short answer

Translation moves points by adding offsets: x'=x+tx, y'=y+ty. In homogeneous 3×3 matrix form. It preserves shape and size. Inverse is translation by (-tx,-ty). Two successive translations add: T(tx1,ty1)·T(tx2,ty2)=T(tx1+tx2,ty1+ty2).

Write a short note on 2D translation.

Translation moves an object from one position to another along a straight path without changing its shape or size. Every point P(x, y) is shifted by translation distances tx (along x) and ty (along y):

x' = x + tx, y' = y + ty

Matrix form (homogeneous coordinates):

| x' |   | 1 0 tx | | x |
| y' | = | 0 1 ty | | y |
| 1  |   | 0 0 1  | | 1 |

Points:

  • It is a rigid-body transformation: distances and angles are preserved.
  • Inverse translation is T(−tx, −ty).
  • Two translations add: T(tx1, ty1)·T(tx2, ty2) = T(tx1+tx2, ty1+ty2).

Example: P(2, 3) translated by (4, −1) gives P'(6, 2).

✓ Answer checked by Claude Opus 5.5 (high effort)

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