Documentation

Overview

    Package geom defines a two-dimensional coordinate system.

    The coordinate system is based on an left-handed Cartesian plane. That is, X increases to the right and Y increases down. For (x,y),

    (0,0) → (1,0)
      ↓   ↘
    (0,1)   (1,1)
    

    The display window places the origin (0, 0) in the upper-left corner of the screen. Positions on the plane are measured in typographic points, 1/72 of an inch, which is represented by the Pt type.

    Any interface that draws to the screen using types from the geom package scales the number of pixels to maintain a Pt as 1/72 of an inch.

    Index

    Constants

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    Variables

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    Functions

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    Types

    type Point

    type Point struct {
    	X, Y Pt
    }

      Point is a point in a two-dimensional plane.

      func (Point) String

      func (p Point) String() string

        String returns a string representation of p like "(1.2,3.4)".

        type Pt

        type Pt float32

          Pt is a length.

          The unit Pt is a typographical point, 1/72 of an inch (0.3527 mm).

          It can be be converted to a length in current device pixels by multiplying with PixelsPerPt after app initialization is complete.

          func (Pt) Px

          func (p Pt) Px(pixelsPerPt float32) float32

            Px converts the length to current device pixels.

            func (Pt) String

            func (p Pt) String() string

              String returns a string representation of p like "3.2pt".

              type Rectangle

              type Rectangle struct {
              	Min, Max Point
              }

                A Rectangle is region of points. The top-left point is Min, and the bottom-right point is Max.

                func (Rectangle) String

                func (r Rectangle) String() string

                  String returns a string representation of r like "(3,4)-(6,5)".

                  Source Files