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 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) ¶
package main import ( "fmt" "image" "image/color" "image/draw" "math" ) func main() { const width = 130 const height = 50 im := image.NewGray(image.Rectangle{Max: image.Point{X: width, Y: height}}) for x := 0; x < width; x++ { for y := 0; y < height; y++ { dist := math.Sqrt(math.Pow(float64(x-width/2), 2)/3+math.Pow(float64(y-height/2), 2)) / (height / 1.5) * 255 var gray uint8 if dist > 255 { gray = 255 } else { gray = uint8(dist) } im.SetGray(x, y, color.Gray{Y: 255 - gray}) } } pi := image.NewPaletted(im.Bounds(), []color.Color{ color.Gray{Y: 255}, color.Gray{Y: 160}, color.Gray{Y: 70}, color.Gray{Y: 35}, color.Gray{Y: 0}, }) draw.FloydSteinberg.Draw(pi, im.Bounds(), im, image.ZP) shade := []string{" ", "░", "▒", "▓", "█"} for i, p := range pi.Pix { fmt.Print(shade[p]) if (i+1)%width == 0 { fmt.Print("\n") } } }
Output:
var FloydSteinberg Drawer = floydSteinberg{}
FloydSteinberg is a Drawer that is the Src Op with Floyd-Steinberg error diffusion.
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