start converting stuffs!

.gitignore

@@ -0,0 +1,2 @@
+2023.*/
+*.pdf

.tool-versions

@@ -0,0 +1 @@
+golang 1.17

README.md

@@ -0,0 +1,24 @@
+# PDFTOJPG
+
+No frils CLI command to convert pdf to jpg image(s).
+
+## Prerequisite
+- GO 1.17
+- imagemagick
+
+## Build
+```shell
+# install imagemagick
+brew install ghostscript imagemagick
+# allow CFLAG to compile main.go
+export CGO_CFLAGS_ALLOW='-Xpreprocessor'
+
+go build # will output `pdftojpg` binary
+```
+
+## Usage
+
+```shell
+# pass in pdf source, jpg output, number of page
+./pdftojpg 2023.3.10.pdf 2023.3.10 440
+```

go.mod

@@ -0,0 +1,5 @@
+module github.com/vtno/pdftojpg
+
+go 1.17
+
+require gopkg.in/gographics/imagick.v3 v3.4.0

go.sum

@@ -0,0 +1,2 @@
+gopkg.in/gographics/imagick.v3 v3.4.0 h1:kSnbsXOWofo81VJEn/Hw8w3qqoOrfTyWwjAQzSdtPlg=
+gopkg.in/gographics/imagick.v3 v3.4.0/go.mod h1:+Q9nyA2xRZXrDyTtJ/eko+8V/5E7bWYs08ndkZp8UmA=

main.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+
+	"gopkg.in/gographics/imagick.v3/imagick"
+)
+
+func main() {
+	if len(os.Args) == 1 {
+		fmt.Println("Usage: pdftojpg <pdf file> <output> <number of page>")
+		os.Exit(1)
+	}
+
+	pdfName := os.Args[1]
+	imageName := os.Args[2]
+	pagesStr := os.Args[3]
+
+	fmt.Printf("Converting %s to %s\n", pdfName, imageName)
+
+	if pdfName == "" || imageName == "" || pagesStr == "" {
+		log.Fatal("No pdf file or output file or number of pages specified")
+		os.Exit(1)
+	}
+
+	pages, err := strconv.ParseInt(pagesStr, 10, 32)
+	if err != nil {
+		log.Fatal(err)
+		os.Exit(1)
+	}
+
+	if err := ConvertPdfToJpg(pdfName, imageName, pages); err != nil {
+		log.Fatal(err)
+		os.Exit(1)
+	}
+}
+
+// ConvertPdfToJpg will take a filename of a pdf file and convert the file into an
+// image which will be saved back to the same location. It will save the image as a
+// high resolution jpg file with minimal compression.
+func ConvertPdfToJpg(pdfName string, imageName string, pages int64) error {
+
+	// Setup
+	imagick.Initialize()
+	defer imagick.Terminate()
+
+	mw := imagick.NewMagickWand()
+	defer mw.Destroy()
+
+	// Must be *before* ReadImageFile
+	// Make sure our image is high quality
+	if err := mw.SetResolution(100, 100); err != nil {
+		return err
+	}
+
+	// Load the image file into imagick
+	if err := mw.ReadImage(pdfName); err != nil {
+		return err
+	}
+
+	// Must be *after* ReadImageFile
+	// Flatten image and remove alpha channel, to prevent alpha turning black in jpg
+	if err := mw.SetImageAlphaChannel(imagick.ALPHA_CHANNEL_REMOVE); err != nil {
+		return err
+	}
+
+	// Set any compression (100 = max quality)
+	if err := mw.SetCompressionQuality(50); err != nil {
+		return err
+	}
+
+	for i := int64(0); i < pages; i++ {
+		// Select only first page of pdf
+		mw.SetIteratorIndex(int(i))
+
+		// Convert into JPG
+		if err := mw.SetFormat("jpg"); err != nil {
+			return err
+		}
+
+		// Save File
+		err := mw.WriteImage(fmt.Sprintf("%03d.jpg", i + 1))
+		if err != nil {
+			log.Fatal(fmt.Sprintf("error at page: %d", i+1))
+			fmt.Printf("error: %v", err)
+			os.Exit(1)
+		}
+	}
+
+	return nil
+}