Cloudinary Blog

Create Markdown Diagrams and Charts for Developers and Architects

Create Markdown Diagrams and Charts

Oftentimes, developers and architects must supplement their project documents with diagrams, charts, sequence drawings, and the like. Instead of creating them with traditional software like Microsoft Visio, I searched for a more developer-friendly alternative and found a project with just the right tool, which I was able to integrate with Cloudinary with gratifying results. This post describes the tool and the integration steps.

Note
We created a live environment for users to test the markdown diagram tool at mermaid.cloudinary.us

Visio’s Limitations

Although Visio is a viable tool, I found it difficult to use because of these limitations:

  • All team members must procure the software or establish an account with the service.
  • Artifacts are stored outside the source hierarchy.
  • Running diff to compare changes is onerous.

Additionally, I had to pinpoint the right color combinations and laboriously arrange the objects in diagrams to make them look pretty. Those chores were time-consuming and distracting from the core task of documenting a complex workflow. I wanted a tool with which I could simply “write” a markdown diagram, after which the tool would do the heavy lifting of prettying up the image with the right colors, spacing, and fonts. Guess what, I found just such a tool—in mermaid!

Webinar
How to Optimize for Page Load Speed

Mermaid’s Capabilities

Highlighted on mermaid’s repo’s page is the goal of the project:

Generate diagrams, charts, graphs, or flows from Markdown-like text via JavaScript.

You can create many types of diagrams on mermaid: flow charts, Gantt charts, sequence diagrams, class diagrams, state diagrams. Since the actual diagram is rendered in plain Markdown, you can add the source to version control so that updates are readily accessible by your team for collaboration. Also, mermaid offers a live editor, which you can download and then host the code for your team. Alternatively, you can use the publicly-hosted editor.

A Cloudinary-Mermaid Integration

I was hooked on mermaid from the start and used it heavily. However, the Scalable Vector Graphics (SVG) images it produces don’t work well for presentations. To resolve that issue, I exported the SVG format to a raster format like PNG. Below are the steps. Disclaimer: I’m not a React developer. This is my first attempt at hacking so please ignore my lack of syntactic elegance.

Step 1: Add an option to the Actions tab.

The mermaid live editor offers two options in the Actions tab: Link to View and Download SVG, which produces a .svg file.

Action to download image

I added an option called Download Image

default actions

—by adding the following code to the render method in the src/components/Preview.js file:

Copy to clipboard
<Divider type='vertical' />
          <a href='' download='' target='_blank' onClick={this.handleOnDownloadImage}>Download Image</a>

Since all my code was in a file called uploader.js, which exported a method called upload, I imported that method, like this:

Copy to clipboard
import { upload } from './uploader'

Next, I registered the handle in the constructor:

Copy to clipboard
this.handleOnDownloadImage = this.handleOnDownloadImage.bind(this)

I then added the function for the onClick handler, as follows:

Copy to clipboard
handleOnDownloadImage (event) {
    const svgObject = `data:image/svg+xml;base64,${Base64.encode(this.container.innerHTML)}`   
    event.target.href = upload(svgObject)
    // useful if you right-click and download
    event.target.download = 'mermaid.png'
  }

See the full Preview.js file for reference.

Step 2: Add the upload capability.

To add the function that handles uploads to Cloudinary, I made use of the unsigned upload method, which requires no authentication, enabling everyone to access the image. To simplify the process, I uploaded with a raw API POST request instead of working through an SDK. Here are the details of the upload request:

  • API endpoint: https://api.cloudinary.com/v1_1/mermaid/upload, where mermaid is the cloud name. If you have a Cloudinary account, replace mermaid in the code with your cloud name.

  • JSON request body:

    • file: This is a Base64-encoded string of the SVG object. *tag: This is a tag with the value mermaid. You can add more meaningful data to it, e.g., the diagram type, the diagram context, the associated project, etc.
    • upload_preset: This is the preset that is defined in your account. Below are my settings:

Upload transformation

Here’s the code for the upload function:

Copy to clipboard
var url = 'https://api.cloudinary.com/v1_1/mermaid/upload'
  var xhr = new XMLHttpRequest() 
  var fd = new FormData() 
  xhr.open('POST', url, false)
  xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest')
  // fd.append('public_id', publicId)
  fd.append('upload_preset', 'mermaid')
  fd.append('tags', 'Mermaid') 
  fd.append('file', svgImage)

This function obtains the SVG image data from Preview.js, invokes the upload function, and picks up the URL for the uploaded SVG image. I added the following Cloudinary transformations to enhance the image:

  1. Convert the image format from SVG to PNG.
  2. Apply three transformations:

Cloudinary then returns the final URL and the browser opens the image in a new tab. Here’s the complete code of the uploader. The diagram below image explains the workflow.

Diagram

Here’s the markup for the sequence diagram:

Copy to clipboard
sequenceDiagram
User-->>Mermaid: Create a diagram
Mermaid-->>Mermaid: Generate SVG
Note over User, Mermaid: Update diagram as it is being edited
User-->>Mermaid: Click Download Image
Mermaid-->>Uploader: Pass SVG data
Uploader-->>Uploader: Build unsigned upload POST request
Uploader-->>Cloudinary: Upload SVG
Cloudinary-->>Uploader: Generate Cloudinary URL
Uploader-->>Uploader: Build transformed PNG URL
Note over Uploader,Mermaid: Change format, transparency, overlay
Uploader-->>Mermaid: Respond with Cloudinary PNG URL
Mermaid-->>User: Display image

Image Security

Recall that the integration makes use of the simple unsigned upload method. For tighter security, switch to the signed upload method instead. Also, to prevent unauthorized users from uploading images to your account, do not turn on unsigned upload. You could also lock down access to your images. For details on the various ways of securing digital assets, read this Cloudinary Support article. Would this Cloudinary-mermaid integration be of use to you? If so, do give it a try.

About Cloudinary

Cloudinary provides easy-to-use, cloud-based media management solutions for the world’s top brands. With offices in the US, UK and Israel, Cloudinary has quickly become the de facto solution used by developers and marketers at major companies around the world to streamline rich media management and deliver optimal end-user experiences.

For more information, visit www.cloudinary.com or follow us on Twitter

Recent Blog Posts

Transitioning JPEG-Based to JPEG XL-Based Images for Web Platforms

When the JPEG codec was being developed in the late 1980s, no standardized, lossy image-compression formats existed. JPEG became ready at exactly the right time in 1992, when the World Wide Web and digital cameras were about to become a thing. The introduction of HTML’s <img> tag in 1995 ensured the recognition of JPEG as the web format—at least for photographs. During the 1990s, digital cameras replaced analog ones and, given the limited memory capacities of that era, JPEG became the standard format for photography, especially for consumer-grade cameras.

Read more

Amplify Your Jamstack With Video

By Alex Patterson
Amplify Your Jamstack With Cloudinary Video

As defined by Amazon Web Services (AWS), Amplify is a set of products and tools with which mobile and front-end web developers can build and deploy AWS-powered, secure, and scalable full-stack apps. Also, you can efficiently configure their back ends, connect them to your app with just a few lines of code, and deploy static web apps in only three steps. Historically, because of their performance issues, managing images and videos is a daunting challenge for developers. Even though you can easily load media to an S3 bucket with AWS Amplify, transforming, compressing, and responsively delivering them is labor intensive and time consuming.

Read more
Cloudinary Helps Move James Hardie’s Experience Online

While COVID has affected most businesses, it has been particularly hard on those that sell products for the physical ‘brick and mortar’ world. One company that literally fits that bill is our Australian customer James Hardie, the largest global manufacturer of fibre cement products used in both domestic and commercial construction. These are materials that its buyers ideally want to see up close, in detail. When customers have questions, they expect personal service.

Read more
How to Build an Enhanced Gravatar Service, Part 2

Part 1 of this post defines the capabilities of an enhanced Gravatar service, which I named Clavatar, and describes the following initial steps for building it:

This post, part 2 of the series, explains how to make Clavatar work like Gravatar and to develop Clavatar’s capabilities of enabling requests for various versions of the images related to user accounts.

Read more