pico - convert PDF to images with progress

A Go implementation for @Belval's Python pdf2image but with progress support.

Install package and dependency

$ go install github.com/DeathKing/pico/...@latest

NOTICE
this will also install the binary pdf2image in $GOPATH/bin folder.

Windows

Windows users will have to build or download poppler for Windows. I recommend @oschwartz10612 version which is the most up-to-date. You will then have to add the bin/ folder to PATH or use WithPopperPath("C:/path/to/poppler-xx/bin").

Mac

Mac users will have to install poppler.

Installing using Brew:

brew install poppler

Linux

Most distros ship with pdftoppm and pdftocairo. If they are not installed, refer to your package manager to install poppler-utils

Platform-independant (Using conda)

Install poppler: conda install -c conda-forge poppler

Usage

Programmatically use it as a library

import "github.com/DeathKing/pico"

func main() {

    // Case 1. Silently convert file with single worker, you must use `Wait()`
    //         for synchronization
    // see _example/single/main.go
    task, _ := pico.Convert("path/to/pdf")
    task.Wait()

    // Case 2. Convert single file with multiple worker, instead of `Wait()`
    //         for final result, we take the per-page conversion result through
    //         `Entries` channel. In this situation, `task.Wait()` is not a
    //         neccessary
    // see _example/woker/main.go
    task, _ = pico.Convert("path/to/pdf",
        pico.WithJob(4),
    )

    // entry is like ["current_page" "total_page" "output_filename" "worker_index"]
    for entry := range task.Entries {
		fmt.Printf("page %s is converted as file %s \n",
			entry[0], // current page
			entry[2], // output filename
		)
	}

    // Case 3. A more fancy usage
    task, _ = pico.Convert("path/to/pdf",
        pico.WithPopperPath("path/to/poppler"),
        pico.WithFormat("jpg"),
        pico.WithDPI(72),
        pico.WithPageRange(22, 42),             // Convert from Page 22 to Page 42 (included)
        pico.WithJob(3)                         // Using 3 worker/process to convert
        pico.WithTimeout(10 * time.Second)      // Must finished within 10 seconds
    )

    // `WaitAndCollect()` will blocked the excution and collect the conversion
    // result into a slice.
    for _, item := task.WaitAndCollect() {
        fmt.Printf("[worker#%d] file: %s %s/%s", entry[3], entry[2], entry[0], entry[1])
    }
}

Use it as a command line tool

df2image [-d dpi] [-f firstPage] [-l lastPage] [-j n] [-o outputFolder] path/to/file pattern/to/folder

For more detail , see cmd/pdf2image/main.go.

TODO

• outputFileFn() to specify output filename by function.
• Converts() function which support concurrently convert multiple files.
• implement WithScale()/WithSize()/WithScaleToX()/WithScaleToY option
  • WithScale(400) or WithSize(400) will fit the image to a 400x400 box, preserving aspect ratio.
  • WithScaleToX(400) will make the image 400 pixels wide, preserving aspect ratio.
  • WithScaleToY(400) will make the image 400 pixels height, preserving aspect ratio.
• explaining each parameters in detail.
• more robust command line parsing.
• more test cases.

Limitations / known issues

1. Not working well with filename or path that contains CJK characters (this may caused by poppler).

Credit

Much thanks go to Edouard Belval for not only his original Python library pdf2image which inspires this Golang variation, but also the poppler installation instructions.