用 “github.com/fogleman/gg” 可以画线, 框
用 “github.com/disintegration/imaging” 可以变换颜色

一、渲染

1.1 框和字

import "github.com/fogleman/gg"func DrawRectangles(inPath string, cRects []ColorTextRect, fnImgNameChange FnImgNameChange) (string, error) {img, err := gg.LoadImage(inPath)if err != nil {return "", err}dc := gg.NewContextForImage(img)dc.SetLineWidth(10)for _, cRect := range cRects {dc.SetColor(cRect.Color)dc.DrawRectangle(float64(cRect.Rect.X), float64(cRect.Rect.Y), float64(cRect.Rect.Width), float64(cRect.Rect.Height))err := dc.LoadFontFace("ch.ttf", 60) // 青鸟华光简美黑.ttfif err != nil {log.Errorf("load font face error: %v", err)}textX, textY := float64(cRect.Rect.X+15), float64(cRect.Rect.Y+15)dc.DrawString(cRect.Text, textX, textY)dc.Stroke()}outPath := fnImgNameChange(inPath)if err := dc.SavePNG(outPath); err != nil {return "", err}return outPath, nil
}

二、裁剪

import "github.com/disintegration/imaging"func Clip(inPath string, rect entity.Rect, fnImgNameChange FnImgNameChange) (string, error) {img, err := imaging.Open(inPath)if err != nil {return "", err}croppedImg := imaging.Crop(img, image.Rect(int(rect.X), int(rect.Y), int(rect.X+rect.Width), int(rect.Y+rect.Height)))outPath := fnImgNameChange(inPath)if err := imaging.Save(croppedImg, outPath); err != nil {return "", err}return outPath, nil
}