go lang image scale and add watermark

image-scale-and-addwatermark/go.mod

@@ -0,0 +1,10 @@
+module hatter.ink/tool/image-scale-and-addwatermark
+
+go 1.25.5
+
+require (
+	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646
+	golang.org/x/image v0.36.0
+)
+
+require golang.org/x/text v0.34.0 // indirect

image-scale-and-addwatermark/go.sum

@@ -0,0 +1,6 @@
+github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 h1:zYyBkD/k9seD2A7fsi6Oo2LfFZAehjjQMERAvZLEDnQ=
+github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646/go.mod h1:jpp1/29i3P1S/RLdc7JQKbRpFeM1dOBd8T9ki5s+AY8=
+golang.org/x/image v0.36.0 h1:Iknbfm1afbgtwPTmHnS2gTM/6PPZfH+z2EFuOkSbqwc=
+golang.org/x/image v0.36.0/go.mod h1:YsWD2TyyGKiIX1kZlu9QfKIsQ4nAAK9bdgdrIsE7xy4=
+golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
+golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=

image-scale-and-addwatermark/main.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/jpeg"
+	"os"
+	"path/filepath"
+
+	"github.com/nfnt/resize"
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/opentype"
+	"golang.org/x/image/math/fixed"
+)
+
+func addWatermark(img *image.RGBA, text string, textColor color.Color, bgColor color.Color) {
+	fontData, err := os.ReadFile("/System/Library/Fonts/Courier.ttc")
+	if err != nil {
+		fmt.Println("Error loading font:", err)
+		return
+	}
+	ttCollection, err := opentype.ParseCollection(fontData)
+	if err != nil {
+		fmt.Println("Error parsing font collection:", err)
+		return
+	}
+	ttFont, err := ttCollection.Font(0)
+	if err != nil {
+		fmt.Println("Error getting font from collection:", err)
+		return
+	}
+	fontSize := 20.0
+	face, err := opentype.NewFace(ttFont, &opentype.FaceOptions{
+		Size:    fontSize,
+		DPI:     72,
+		Hinting: font.HintingFull,
+	})
+	if err != nil {
+		fmt.Println("Error creating face:", err)
+		return
+	}
+
+	// 计算文字尺寸
+	d := &font.Drawer{
+		Dst:  img,
+		Src:  image.NewUniform(textColor),
+		Face: face,
+		Dot:  fixed.Point26_6{},
+	}
+	textBounds := d.MeasureString(text)
+	textWidth := int(textBounds.Ceil())
+	textHeight := int(face.Metrics().Height.Ceil())
+
+	// 设置水印文字的位置为右下角，添加内边距
+	padding := 8
+	x := img.Bounds().Max.X - textWidth - padding
+	y := img.Bounds().Max.Y - padding - textHeight/2 + 4
+
+	// 绘制背景矩形（上下左右居中于文字）
+	bgRect := image.Rect(x-padding/2, y-textHeight/2-padding/2+4, x+textWidth+padding/2, y+textHeight/2+padding/2)
+	draw.Draw(img, bgRect, image.NewUniform(bgColor), image.Point{}, draw.Src)
+
+	// 绘制文字
+	d.Dot = fixed.Point26_6{X: fixed.I(x), Y: fixed.I(y + 8)}
+	d.DrawString(text)
+}
+
+func main() {
+	inputImagePath := "input.jpg"   // 输入图片路径
+	outputImagePath := "output.jpg" // 输出图片路径
+
+	maxSize := 1200 // 默认最大尺寸
+
+	file, err := os.Open(inputImagePath)
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+		return
+	}
+	defer file.Close()
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		fmt.Println("Error decoding image:", err)
+		return
+	}
+
+	bounds := img.Bounds()
+	width := bounds.Max.X
+	height := bounds.Max.Y
+	fmt.Printf("Image %s, width: %d, height: %d\n", inputImagePath, width, height)
+
+	var resizedImg image.Image
+	if width > maxSize && height > maxSize {
+		if width < height {
+			resizedImg = resize.Resize(uint(maxSize), 0, img, resize.Lanczos3)
+		} else {
+			resizedImg = resize.Resize(0, uint(maxSize), img, resize.Lanczos3)
+		}
+	} else {
+		resizedImg = img
+	}
+
+	// 将图片转换为 RGBA 格式以便添加水印
+	rgbaImg := image.NewRGBA(resizedImg.Bounds())
+	if rgbaImg.Stride != rgbaImg.Rect.Size().X*4 {
+		fmt.Println("Unsupported image format")
+		return
+	}
+	for y := rgbaImg.Rect.Min.Y; y < rgbaImg.Rect.Max.Y; y++ {
+		for x := rgbaImg.Rect.Min.X; x < rgbaImg.Rect.Max.X; x++ {
+			rgbaImg.Set(x, y, resizedImg.At(x, y))
+		}
+	}
+
+	// 添加水印（使用柔和的深灰色文字和米白色背景）
+	softTextColor := color.RGBA{R: 60, G: 60, B: 60, A: 255}
+	softBgColor := color.RGBA{R: 250, G: 250, B: 245, A: 255}
+	addWatermark(rgbaImg, "email@example.com", softTextColor, softBgColor)
+
+	outFile, err := os.Create(outputImagePath)
+	if err != nil {
+		fmt.Println("Error creating file:", err)
+		return
+	}
+	defer outFile.Close()
+
+	err = jpeg.Encode(outFile, rgbaImg, nil)
+	if err != nil {
+		fmt.Println("Error encoding image:", err)
+		return
+	}
+
+	fmt.Println("Image processed and saved as", filepath.Base(outputImagePath))
+}