go-client

Handwriting.io Client

Installation

go get github.com/handwritingio/go-client/handwritingio

Basic Example

Set up the client, render an image, and write it to a file:

package main

import (
	"fmt"
	"io"
	"net/url"
	"os"

	"github.com/handwritingio/go-client/handwritingio"
)

func main() {
	u, err := url.Parse(os.Getenv("HANDWRITINGIO_API_URL"))
	if err != nil {
		fmt.Println("Make sure you have your environment variable HANDWRITINGIO_API_URL set correctly")
		fmt.Println(err)
		return
	}

	c, err := handwritingio.NewClient(u)
	if err != nil {
		fmt.Println(err)
		return
	}

	var params = handwritingio.DefaultRenderParamsPNG
	params.HandwritingID = "31SB3NWR00E0" // found in our catalog or by listing handwritings
	params.Text = "Handwriting with Go!"
	params.Height = "auto"
	r, err := c.RenderPNG(params)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer r.Close()

	f, err := os.Create("handwriting.png")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer f.Close()

	_, err = io.Copy(f, r)
	if err != nil {
		fmt.Println(err)
	}

	return
}

If all goes well, this should create an image similar to the following:

Advanced Examples

Overlaying handwriting on a background image:

package main

import (
	"fmt"
	"image"
	"image/draw"
	_ "image/jpeg"
	"image/png"
	"log"
	"net/url"
	"os"

	"github.com/handwritingio/go-client/handwritingio"
)

func main() {

	// Original https://golang.org/doc/gopher/fiveyears.jpg
	// By Renee French, used under Creative Commons license
	// More gophers at https://blog.golang.org/gopher
	f, err := os.Open("fiveyears.jpg")
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	src, _, err := image.Decode(f)
	if err != nil {
		log.Fatal(err)
	}

	// draw.Draw doesn't work with JPEG image as destination
	// So we're creating a new RGBA to hold the result
	b := src.Bounds()
	m := image.NewRGBA(image.Rect(0, 0, b.Dx(), b.Dy()))
	draw.Draw(m, m.Bounds(), src, b.Min, draw.Src)

	u, err := url.Parse(os.Getenv("HANDWRITINGIO_API_URL"))
	if err != nil {
		fmt.Println("Make sure you have your environment variable HANDWRITINGIO_API_URL set correctly")
		log.Fatal(err)
		return
	}

	c, err := handwritingio.NewClient(u)
	if err != nil {
		fmt.Println(err)
		return
	}

	var params = handwritingio.DefaultRenderParamsPNG
	params.HandwritingID = "31SB3NWR00E0" // found in our catalog or by listing handwritings
	params.Text = "Handwriting with Go!"
	params.Height = "auto"
	r, err := c.RenderPNG(params)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer r.Close()

	src, _, err = image.Decode(r)
	if err != nil {
		log.Fatal(err)
	}

	sr := src.Bounds().Add(image.Pt(476, 10))
	draw.Draw(m, sr, src, image.ZP, draw.Over)

	f, err = os.Create("handwriting_overlay.png")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer f.Close()

	err = png.Encode(f, m)
	if err != nil {
		fmt.Println(err)
	}

	return
}

It should create an image like this : handwriting_overlay.png

Reference

See the API Documentation for details on all endpoints and parameters. For the most part, the Client passes parameters through to the API directly.

The endpoints map to client methods as follows:

• GET /handwritings -> client.ListHandwritings(params)
• GET /handwritings/{id} -> client.GetHandwriting(handwriting_id)
• GET /render/png -> client.RenderPNG(params)
• GET /render/pdf -> client.RenderPDF(params)

Version Numbers

Version numbers for this package work slightly differently than standard semantic versioning. For this package, the major version number will match the Handwriting.io API version number, and the minor version will be incremented for any breaking changes to this package. The patch version will be incremented for bug fixes and changes that add functionality only.

Issues

Please open an issue on Github or contact us directly for help with any problems you find.