153 lines
3.4 KiB
Go
153 lines
3.4 KiB
Go
package vision
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import (
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"bytes"
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"fmt"
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"image"
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"image/color"
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"image/draw"
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"image/jpeg"
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_ "image/png"
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"strings"
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"apigo.cc/go/file"
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"github.com/fogleman/gg"
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"golang.org/x/image/font"
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)
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// Canvas 代表一个绘图画布，封装了图像处理与绘制能力
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type Canvas struct {
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dc *gg.Context
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bgColor string
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lastColor string
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lastFont font.Face
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}
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// New 创建一个新的画布
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func New(width, height int, backgroundColor ...string) *Canvas {
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img := image.NewRGBA(image.Rect(0, 0, width, height))
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dc := gg.NewContextForImage(img)
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c := &Canvas{
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dc: dc,
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}
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if len(backgroundColor) > 0 && backgroundColor[0] != "" {
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c.bgColor = backgroundColor[0]
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c.SetColor(c.bgColor)
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c.dc.Clear()
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}
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return c
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}
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// Load 从文件加载图像并创建画布
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func Load(path string) (*Canvas, error) {
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if path == "" {
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return nil, fmt.Errorf("path is empty")
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}
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if !file.Exists(path) {
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return nil, fmt.Errorf("file not found: %s", path)
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}
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data, err := file.ReadBytes(path)
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if err != nil {
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return nil, err
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}
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img, _, err := image.Decode(bytes.NewReader(data))
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if err != nil {
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return nil, fmt.Errorf("decode image failed: %v", err)
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}
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return &Canvas{
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dc: gg.NewContextForImage(img),
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}, nil
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}
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// Save 将画布保存到文件
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func Save(c *Canvas, path string, quality ...int) error {
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var err error
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if strings.HasSuffix(strings.ToLower(path), ".jpg") || strings.HasSuffix(strings.ToLower(path), ".jpeg") {
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q := 85
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if len(quality) > 0 {
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q = quality[0]
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}
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// gg 没有内置 SaveJPG 到 context，我们需要手动编码
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f, createErr := file.Create(path)
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if createErr != nil {
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return createErr
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}
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defer f.Close()
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err = jpeg.Encode(f, c.dc.Image(), &jpeg.Options{Quality: q})
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} else {
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err = c.dc.SavePNG(path)
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}
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if err != nil {
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return fmt.Errorf("save image failed: %w", err)
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}
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return nil
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}
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// Image 返回底层图像
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func (c *Canvas) Image() image.Image {
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return c.dc.Image()
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}
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// Width 返回画布宽度
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func (c *Canvas) Width() int {
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return c.dc.Width()
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}
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// Height 返回画布高度
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func (c *Canvas) Height() int {
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return c.dc.Height()
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}
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// SetColor 设置当前绘图颜色 (支持 hex 格式)
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func (c *Canvas) SetColor(hex string) {
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c.lastColor = hex
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c.dc.SetColor(ParseColor(hex))
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}
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// Clear 清除指定区域，如果设置了背景色则填充背景色，否则填充透明
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func (c *Canvas) Clear(x, y, w, h int) {
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if c.bgColor != "" {
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c.dc.Push()
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c.dc.DrawRectangle(float64(x), float64(y), float64(w), float64(h))
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c.dc.SetColor(ParseColor(c.bgColor))
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c.dc.Fill()
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c.dc.Pop()
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return
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}
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if img, ok := c.dc.Image().(*image.RGBA); ok {
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transparent := image.NewUniform(color.RGBA{0, 0, 0, 0})
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draw.Draw(img, image.Rect(x, y, x+w, y+h), transparent, image.Point{}, draw.Src)
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}
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}
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// Sub 提取子区域并返回新画布
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func (c *Canvas) Sub(x, y, w, h int) *Canvas {
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newImg := image.NewRGBA(image.Rect(0, 0, w, h))
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draw.Draw(newImg, newImg.Bounds(), c.dc.Image(), image.Pt(x, y), draw.Src)
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newDC := gg.NewContextForImage(newImg)
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return &Canvas{
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dc: newDC,
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bgColor: c.bgColor,
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lastColor: c.lastColor,
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lastFont: c.lastFont,
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}
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}
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// Clone 克隆当前画布
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func (c *Canvas) Clone() *Canvas {
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bounds := c.dc.Image().Bounds()
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newImg := image.NewRGBA(bounds)
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draw.Draw(newImg, bounds, c.dc.Image(), bounds.Min, draw.Src)
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return &Canvas{
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dc: gg.NewContextForImage(newImg),
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bgColor: c.bgColor,
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lastColor: c.lastColor,
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lastFont: c.lastFont,
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}
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}
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