HTML to Image in Golang

Overview

This page serves as a guide for using the PDFCrowd API to capture web pages and HTML content to image screenshots in Golang applications.

Installation

You can install the client library from Github

go get github.com/pdfcrowd/pdfcrowd-go

Clone pdfcrowd-go from Github into your project source folder:

git clone https://github.com/pdfcrowd/pdfcrowd-go src/github.com/pdfcrowd/pdfcrowd-go

Download pdfcrowd-6.5.0-go.zip.
Import pdfcrowd.go in your code using its package path.

Quick Start

Below are Golang examples to help you quickly get started with the API. Explore our additional examples for more insights.

package main

import (
    "os"
    "fmt"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    // Create an API client instance.
    client := pdfcrowd.NewHtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d")

    // Configure the conversion.
    client.SetOutputFormat("png")

    // Run the conversion and save the result to a file.
    err := client.ConvertUrlToFile("http://www.example.com", "example.png")

    // Check for the conversion error.
    handleError(err)
}

func handleError(err error) {
    if err != nil {
        why, ok := err.(pdfcrowd.Error)
        if ok {
            os.Stderr.WriteString(fmt.Sprintf("PDFCrowd Error: %s\n", why))
        } else {
            os.Stderr.WriteString(fmt.Sprintf("Generic Error: %s\n", err))
        }

        panic(err.Error())
    }
}

package main

import (
    "os"
    "fmt"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    // Create an API client instance.
    client := pdfcrowd.NewHtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d")

    // Configure the conversion.
    client.SetOutputFormat("png")

    // Run the conversion and save the result to a file.
    err := client.ConvertFileToFile("/path/to/MyLayout.html", "MyLayout.png")

    // Check for the conversion error.
    handleError(err)
}

func handleError(err error) {
    if err != nil {
        why, ok := err.(pdfcrowd.Error)
        if ok {
            os.Stderr.WriteString(fmt.Sprintf("PDFCrowd Error: %s\n", why))
        } else {
            os.Stderr.WriteString(fmt.Sprintf("Generic Error: %s\n", err))
        }

        panic(err.Error())
    }
}

package main

import (
    "os"
    "fmt"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    // Create an API client instance.
    client := pdfcrowd.NewHtmlToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d")

    // Configure the conversion.
    client.SetOutputFormat("png")

    // Run the conversion and save the result to a file.
    err := client.ConvertStringToFile("<html><body><h1>Hello World!</h1></body></html>", "HelloWorld.png")

    // Check for the conversion error.
    handleError(err)
}

func handleError(err error) {
    if err != nil {
        why, ok := err.(pdfcrowd.Error)
        if ok {
            os.Stderr.WriteString(fmt.Sprintf("PDFCrowd Error: %s\n", why))
        } else {
            os.Stderr.WriteString(fmt.Sprintf("Generic Error: %s\n", err))
        }

        panic(err.Error())
    }
}

Authentication

To access the API, you will need to use your PDFCrowd username and API key. For initial testing, you may use the following demo credentials without registering:

Username: demo
API key: ce544b6ea52a5621fb9d55f8b542d14d

To obtain your personal API credentials, start a free trial or purchase the API license.

Customization

The table below highlights the most common customizations you might find useful. Refer to the Option Reference for a detailed description of all available options. For an interactive experience, explore these options in the API Playground.

For additional customization options and Troubleshooting, please visit the FAQ section of our website where you can find answers and help related to frequent queries and common issues.

Image size	Customize the dimensions of the captured images using the setScreenshotWidth() and setScreenshotHeight().
Image format	Change the ouput image format using setOutputFormat().
Hide or Remove Contents	Use the following classes in your HTML code to hide or remove elements from the output: `pdfcrowd-remove`: This class applies `display:none!important` to the element, effectively removing it from the layout. `pdfcrowd-hide`: This class applies `visibility:hidden!important` to the element, making it invisible but still occupying space in the layout. For additional methods and detailed explanation, refer to this FAQ article.
Custom CSS Styling	To customize CSS styling specifically for the conversion, use setCustomCss() to inject additional styles. Alternatively, you can directly incorporate conversion-specific styling into your main stylesheet. Just prefix your CSS selectors with `.pdfcrowd-body` to ensure the styles apply only during the conversion process. For example: `.pdfcrowd-body h1 { font-size: 48px; }` `.pdfcrowd-body footer { display: none; }`
Use `@media print`	Activate the print version of a webpage (if available) using setUsePrintMedia(). This function instructs the API to apply the CSS rules defined within the `@media print` stylesheet, ensuring the output mirrors the print-optimized version of the webpage.
Inject Custom JavaScript	Use setCustomJavascript() or setOnLoadJavascript() to modify HTML content using custom JavaScript scripts. These scripts run when the page loads, allowing you to dynamically alter elements, styles, or behavior. In addition to the standard browser JavaScript APIs, your scripts can leverage helper functions provided by our JavaScript library.
HTML Templates	Add data to your HTML templates for dynamic generation tailored to specific content needs. For details, refer to HTML Template to Image.

Error Handling

It is recommended that you implement error handling to catch errors the API may return. Effective error handling is vital as it ensures application stability and provides clearer diagnostics. See the example code below for guidance on implementing error handling, and refer to this list of status codes for more information.

// Call the API 

    // Log the complete error
    os.Stderr.WriteString(fmt.Sprintf("PDFCrowd Error: %s\n", why))

    // Log the HTTP status code
    os.Stderr.WriteString(fmt.Sprintf("Status Code: %v\n", why.getStatusCode()))

    // Log the reason code
    os.Stderr.WriteString(fmt.Sprintf("Reason Code: %v\n", why.getReasonCode()))

    // Log the error message
    os.Stderr.WriteString(fmt.Sprintf("Error Message: %v\n", why.getMessage()))

    // Log the documentation link
    os.Stderr.WriteString(fmt.Sprintf("Documentation Link: %v\n", why.getDocumentationLink()))

Troubleshooting

If you are receiving an error, refer to the API Status Codes for more information.
Use setDebugLog() and getDebugLogUrl() to obtain detailed information about the conversion process, including load errors, load times, browser console output, etc.
Consult the FAQ for answers to common questions.
The maximum size for any created image is 65 megapixels. Images exceeding this size are cropped vertically to meet this limit.
Contact us if you need assistance or if there is a feature you are missing.

API Method Reference

Refer to the HTML to Image Golang Reference for a description of all API methods.

HTML to Image / Golang Guide