Package draw

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.

type Drawer ¶ 1.2

Drawer contains the Draw method.

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)
}

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

var FloydSteinberg Drawer = floydSteinberg{}

type Image ¶

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

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

type Op ¶

Op is a Porter-Duff compositing operator.

type Op int

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

func (Op) Draw ¶ 1.2

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 ¶ 1.2

Quantizer produces a palette for an image.

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
}

type RGBA64Image ¶ 1.17

RGBA64Image extends both the Image and image.RGBA64Image interfaces with a SetRGBA64 method to change a single pixel. SetRGBA64 is equivalent to calling Set, but it can avoid allocations from converting concrete color types to the color.Color interface type.

type RGBA64Image interface {
    image.RGBA64Image
    Set(x, y int, c color.Color)
    SetRGBA64(x, y int, c color.RGBA64)
}