Mermaid Editor

Mermaid Editor is VSCode extension inspired by official mermaid live editor which provides mainly the following features:

• Live edit mermaid.js diagram file with mermaid.js diagram
• Generate image file from mermaid.js diagram file with preferred format (png, jpg, webp and svg).
• Copy image to clipboard directly.
• Customize configuration for individual mermaid.js diagram by using atrribute which is available in this extension.

Mermaid Editor does not contain syntax highlighting for Mermaid charting language. But don't warry, a great plugin Mermaid Markdown Syntax Highlighting works with Mermaid Editor.

Mermaid Editor is also available on Open VSX Registry for developers who love FLOSS binaries of VSCode.

Mermaid Editor is implemented as 100% local solution mainly using mermaid.js and VSCode SDK. It means Mermaid Editor does NOT require online environment and NOT send your code to any remote server in order to work.

Enjoy!

Usage

This VSCode extension is activated when opening .mmd or .mermaid file. The supported file extensions follows the official guide.

Open live preview

• Select Mermaid:Preview mermaid from context menu or command palette
• Click Mermaid:Preview diagram icon at right corner
• ctrl+alt+[ on .mmd or .mermaid file

Generate image

Generate command is only available when mermaid.js diagram file is opened and live preview is activated.

• Select Mermaid:Generate image from context menu or command palette
• Click Mermaid:Generate image icon
• ctrl+alt+] on .mmd or .mermaid file

Copy image to clipboard

Copy command is only availab e when "Mermaid Editor Preview" is focused.

• Click Mermaid:Copy image icon
• ctrl+alt+; on Mermaid Editor Preview

Change scale of live preview

Zoom in/out is supported for live preview.

• Select Mermaid:Zoom in, Mermaid:Zoom out, Mermaid:Reset zoom, Mermaid:Zoom to specific scale from command palette
• Click Mermaid:Zoom in, Mermaid:Zoom out icon focusing live preview panel
• Zoom out: ctrl+alt+-
• Zoom in: ctrl+alt+=
• Reset zoom: ctrl+alt+0

Change mermaid.js version without the extension update

Changing mermaid.js integrated in the extension with an another version is supported. The following commands are available on the command palette. This is availabe only online because this feature depends on CDN services as described below.

ATTENTION: This extension does not fully assure to work fine with the other version of mermaid library. Please change it as your own risk.

Command	Description
Mermaid:Update mermaid library to the latest	Update mermaid.js through cdnjs. This extension can refer to the latest version delivered by cdnjs instead of the integrated one after.
Mermaid:Set an URL to hosted mermaid library on CDN	Set an arbitrary URL for mermaid.js hosted on CDNs. Note that https://www.jsdelivr.com and https://cdnjs.com are only supported. The other schemes or domains are not supported.
Mermaid:Reset mermaid library to the default	Reset mermaid.js library referred by this extension to the integrated one.
Mermaid:Show current mermaid library setting	Show the current mermaid.js library referred by this extension. The output is appeard in mermaid-editor channel of the "OUTPUT" tab. Note that mermaid.js version is also displayed in the status bar if the version is determined.

Attributes

This extension supports attribute to specify preferred configuration for each mermaid.js diagram file. The attribute have to be described in comment of mermaid syntax.

NOTE: The attribute syntax with curly brackets (@config{}, @backgroundColor{}, @outputScale{}) was obsoleted. Use parenthesis (@config(), @backgroundColor(), @outputScale()) instead, please.

@config(path_to_config)

Each mermaid diagram file can be associated with mermaid configuration. With this attribute, .mmd or .mermaid file can read specified configuration. path_to_config have to be described as relative path to the config json file from associated mermaid.js diagram file. If this attribute is not provided, default config file setting up in mermaid-editor.preview.defaultMermaidConfig is applied.

sequenceDiagram
%% @config(./path/to/config.json)
    Alice->>John: Hello John, how are you?

@backgroundColor(color)

Each mermaid diagram file can be associated with preferred background color. With this attribute, .mmd or .mermaid can read specifed background color with CSS style property format.If this attribute is not provided, default background color setting up in mermaid-editor.preview.backgroundColor is applied. The followings are example.

sequenceDiagram
%% @backgroundColor(red)
    Alice->>John: Hello John, how are you?

sequenceDiagram
%% @backgroundColor(#ff0000)
    Alice->>John: Hello John, how are you?

sequenceDiagram
%% @backgroundColor(rgb(255, 0, 0))
    Alice->>John: Hello John, how are you?

@outputScale(scale_factor)

Each mermaid.js diagram file can be associated with preferred output scale. With this attribute, the diagram can be generated with preferred scale factor.If this attribute is not provided, default scale setting up in mermaid-editor.generate.scale is applied. Positive number is only permitted for this attribute. If invalid value is set, default value is used as above. The followings are example.

sequenceDiagram
%% @outputScale(2.5)
    Alice->>John: Hello John, how are you?

Configuration

Settings for look & feel in preview or image generator.

Setting	Default	Description
mermaid-editor.preview.defaultMermaidConfig		Relative path to the default configuration json file for mermaidjs.
mermaid-editor.preview.backgroundColor	white	Default background color for live preview and generated image.
mermaid-editor.preview.errorOutputOnSave	true	Show error output console whe saving file if there's error message. Note: Error output in the console itself is always available regardless of this configuration.
mermaid-editor.generate.type	svg	Output image file type [svg, png, jpg, webp].
mermaid-editor.generate.outputPath		Relative path to the output target directory from project root.
mermaid-editor.generate.useCurrentPath	true	Use relative output path as same as target mermaid diagram file instead of 'outputPath'.
mermaid-editor.generate.scale	1.0	Scale of the output image. Only positive number (>0) is permitted. Otherwise, 1.0 is used.
mermaid-editor.generate.quality	1.0	Quality of the output image. A number between 0 and 1 to be used when creating images using file formats that support lossy compression like jpeg or webp. Otherwise, ignored.

Credits

This extension uses Feather icon set under CC BY 3.0