golang pdf 转图片

go get github.com/signintech/gopdf/...

package main

import (
    "bufio"
    "flag"
    "fmt"
    "github.com/signintech/gopdf"
    "image"
    "image/jpeg"
    "image/png"
    "os"
    "path/filepath"
    "strings"
)

var (
    inputFile        string // 输入的 PDF 文件名
    outputFilePrefix string // 输出的图片文件名前缀
    outputFormat     string // 输出的图片格式
    dpi              int    // 输出图片分辨率（DPI）
)

func main() {
    flag.StringVar(&inputFile, "input", "", "Input PDF filename")
    flag.StringVar(&outputFilePrefix, "prefix", "", "Output image filename prefix")
    flag.StringVar(&outputFormat, "format", "png", "Output image format: png or jpeg")
    flag.IntVar(&dpi, "dpi", 72, "Output image resolution (DPI)")
    flag.Parse()

    if inputFile == "" {
        fmt.Println("Please specify input PDF filename using -input")
        return
    }

    if outputFilePrefix == "" {
        outputFilePrefix = strings.TrimSuffix(inputFile, filepath.Ext(inputFile))
    }

    pdf, err := gopdf.Open(inputFile)
    if err != nil {
        fmt.Println("Failed to open PDF file:", err)
        return
    }
    defer pdf.Close()

    numPages := pdf.GetPageCount()
    if numPages == 0 {
        fmt.Println("PDF file contains no page")
        return
    }

    for i := 1; i <= numPages; i++ {
        page := pdf.GetPage(i)
        if page == nil {
            continue
        }
        defer page.Close()

        img := page.Render(dpi, dpi, nil)
        if img == nil {
            fmt.Println("Failed to render page", i)
            return
        }

        outputFile := fmt.Sprintf("%s_%d.%s", outputFilePrefix, i, outputFormat)
        file, err := os.Create(outputFile)
        if err != nil {
            fmt.Println("Failed to create output file:", err)
            return
        }
        defer file.Close()

        writer := bufio.NewWriter(file)
        if outputFormat == "png" {
            if err := png.Encode(writer, img); err != nil {
                fmt.Println("Failed to encode image:", err)
                return
            }
        } else {
            if err := jpeg.Encode(writer, img, &jpeg.Options{Quality: 95}); err != nil {
                fmt.Println("Failed to encode image:", err)
                return
            }
        }

        fmt.Println("Page", i, "saved to", outputFile)
    }

    fmt.Println("Done")
}

go run pdf2img.go -input input.pdf

go run pdf2img.go -input input.pdf -prefix output -format jpeg -dpi 300