Documentation

Overview

    Package draw provides image composition functions.

    See "The Go image/draw package" for an introduction to this package: https://golang.org/doc/articles/image_draw.html

    Index

    Examples

    Constants

    This section is empty.

    Variables

    This section is empty.

    Functions

    func Draw

    func Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point, op Op)

      Draw calls DrawMask with a nil mask.

      func DrawMask

      func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mask image.Image, mp image.Point, op Op)

        DrawMask aligns r.Min in dst with sp in src and mp in mask and then replaces the rectangle r in dst with the result of a Porter-Duff composition. A nil mask is treated as opaque.

        Types

        type Drawer

        type Drawer interface {
        	// Draw aligns r.Min in dst with sp in src and then replaces the
        	// rectangle r in dst with the result of drawing src on dst.
        	Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point)
        }

          Drawer contains the Draw method.

          Example (FloydSteinberg)
          Output:
          
          
          var FloydSteinberg Drawer = floydSteinberg{}

            FloydSteinberg is a Drawer that is the Src Op with Floyd-Steinberg error diffusion.

            type Image

            type Image interface {
            	image.Image
            	Set(x, y int, c color.Color)
            }

              Image is an image.Image with a Set method to change a single pixel.

              type Op

              type Op int

                Op is a Porter-Duff compositing operator.

                const (
                	// Over specifies “(src in mask) over dst”.
                	Over Op = iota
                	// Src specifies “src in mask”.
                	Src
                )

                func (Op) Draw

                func (op Op) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point)

                  Draw implements the Drawer interface by calling the Draw function with this Op.

                  type Quantizer

                  type Quantizer interface {
                  	// Quantize appends up to cap(p) - len(p) colors to p and returns the
                  	// updated palette suitable for converting m to a paletted image.
                  	Quantize(p color.Palette, m image.Image) color.Palette
                  }

                    Quantizer produces a palette for an image.

                    Source Files