rectgrid

Boundary box operations on rectilinear grids with arbitrary unit systems.

• A crate for operating on a two-point coordinate boundary box and its collections, defined over the grid of an arbitrary unit system — a rectilinear grid whose axes each have an independent increment function. Such a unit system is defined by an intrinsic origin and per-axis increment functions, both expressed in a base unit (unit: a general-purpose unit). It further provides, for any single boundary box, a conversion function into a local unit system (parameter) in which each axis has unit vector length, making it possible to implement boundary tests against arbitrary geometry.
• The base unit system is defined as the unit system whose origin lies at (0, ..., 0) and whose per-axis increment functions all return the constant 1. This base unit is named Px (pixel: picture element).

To enable the geometry module:

[dependencies]
rectgrid = { version = "0.4", features = ["geometry"] }

English | 日本語

Version

This project adheres to Semantic Versioning.

Coordinate system

• When treating rectgrid's x and y as 2D coordinates, x is the axis that becomes the width in the viewport, y is the height direction, and the origin (0,0) is the top-left corner.
• Px passed into a function from outside this crate is global (an external coordinate not yet corrected for origin, e.g. a viewport coordinate); each function subtracts origin internally to make it local. Px derived from a boundary box (base/offset) — the return value of unit_to_px, and anything built on it such as hit_test/*_as_px results — is always local (origin=0 as the reference). If such a value is passed back across a RectGrid boundary, treat it as local px.

Public ports

The reference for every public item, with its contract and a runnable example, is the crate documentation: https://docs.rs/rectgrid

Ja

• 各軸が独立した階差関数を持つ直交座標系(rectilinear grid)の、固有の原点座標と各軸の階差関数を与単位で定義した任意単位系(unit: 一般単位)の格子上で、2点間座標のboundary boxとその集合を操作するための幾何計算クレート。さらに、単一のboundary boxの、各軸のベクトル長を1とした局所単位系(parameter)への変換関数により、任意の幾何による境界判定を実装可能にする。

• 与単位系とは、原点の座標が(0,...,0), 全ての軸の階差関数が定数1を返す単位系を指す。単位名をPx(pixel: picture element)とする。

geometryモジュールはfeature機能で有効化できる:

[dependencies]
rectgrid = { version = "0.4", features = ["geometry"] }

座標系

• rectgridのx, yを2D座標として扱う場合、xはviewportで幅になる軸、yは高さ方向、原点(0,0)は左上隅とする。
• クレート外部から関数引数として渡されるpxはglobal(origin未補正の外部座標、例えばviewport座標)として受け取り、各関数の内部でoriginを差し引いてlocal化する。一方、boundary box(base/offset)由来のpx(unit_to_pxの戻り値や、それを使うhit_test系・*_as_px系の戻り値)は常にlocal(origin=0を基準とした座標)を返す。呼び出し側がRectGridを跨いで再度渡す場合はlocal pxとして扱う。

公開ポート

各公開アイテムの契約と実行可能な例は、クレートドキュメント(https://docs.rs/rectgrid)を参照。アイテムの一覧は[Public ports](#public-ports)にある。