draw
原文：https://pkg.go.dev/image/draw@go1.23.0
Package draw provides image composition functions.
draw 包提供图像合成函数。
See “The Go image/draw package” for an introduction to this package: https://golang.org/doc/articles/image_draw.html
有关此包的介绍，请参阅“Go image/draw 包”：https://golang.org/doc/articles/image_draw.html
常量
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变量
This section is empty.
函数
func Draw
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| func Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point, op Op)
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Draw calls DrawMask with a nil mask.
Draw 使用 nil 蒙版调用 DrawMask。
func DrawMask
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| func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mask image.Image, mp image.Point, op Op)
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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.
DrawMask 将 r.Min 在 dst 中与 src 中的 sp 和 mask 中的 mp 对齐，然后用 Porter-Duff 合成的结果替换 dst 中的矩形 r。将 nil 蒙版视为不透明。
类型
type Drawer <- go1.2
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| 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)
}
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Drawer contains the Draw method.
Drawer 包含 Draw 方法。
Example (FloydSteinberg)
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| 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:
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FloydSteinberg is a Drawer that is the Src Op with Floyd-Steinberg error diffusion.
FloydSteinberg 是一个 Drawer，它是具有 Floyd-Steinberg 错误扩散的 Src Op。
type Image
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| type Image interface {
image.Image
Set(x, y int, c color.Color)
}
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Image is an image.Image with a Set method to change a single pixel.
Image 是一个 image.Image，它具有一个 Set 方法来更改单个像素。
type Op
Op is a Porter-Duff compositing operator.
Op 是一个 Porter-Duff 合成运算符。
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| const (
// Over specifies "(src in mask) over dst".
Over Op = iota
// Src specifies "src in mask".
Src
)
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(Op) Draw <- go1.2
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| func (op Op) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point)
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Draw implements the Drawer interface by calling the Draw function with this Op.
Draw 通过使用此 Op 调用 Draw 函数来实现 Drawer 接口。
type Quantizer <- go1.2
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| 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
}
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Quantizer produces a palette for an image.
Quantizer 为图像生成一个调色板。
type RGBA64Image <- go1.17
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| type RGBA64Image interface {
image.RGBA64Image
Set(x, y int, c color.Color)
SetRGBA64(x, y int, c color.RGBA64)
}
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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.
RGBA64Image 同时扩展了 Image 和 image.RGBA64Image 接口，并通过 SetRGBA64 方法来更改单个像素。SetRGBA64 等同于调用 Set，但它可以避免从将具体颜色类型转换为 color.Color 接口类型而产生的分配。