gowebstockchart

README

gowebstockchart

HTML5 stock chart module in go

Generate interactive, responsive, and perfomant chart with HTML5 canvas and web assembly, and embed it into any HTML pages.

features

• draw candlestick with OHLC series
• X time axis navigator
• X time axis with auto scale and autolabelling
• zoom-in and zoom-out with the mouse wheel inside the navbar
• shift left and right with Shift-Key and the mouse wheel inside the navbar
• Y value axis, with auto scale and auto labelling
• responsive: handle resize event, and browser zoom
• embedding chart with a single HTML elemnt

characteristics

• fast drawing on any browser accepting HTML5 canvas & Webassembly
• only GO, no JS

Runing the example

The example folder provides a webserver example embedding an interactive gowebstockchart.

The file structure is the followwing one

example/
+- wasm/            
 - dataset.go      a simgle function to build the dataset for the example
 - main.go         source code of the wasm code to be built to be loaded by the browser
+- webapp/          
 - index.html      static html file of this example
 - main.wasm       compiled version of the code to be loaded by the browser
 - myapp.js        a minimal and required js code to be loaded by your web pages, to be customized
 - wasm_exec.js    provided by go, see here after
+- webserver
 - main.go         an optional simple webserver serving static files located in webapp, see here after

Technicals

Written in go 1.19

The Web Assembly code generated is based on the webapi package.

Use Web Assembly with go

Some documentation available here https://tinygo.org/docs/guides/webassembly/ and here https://github.com/golang/go/wiki/WebAssembly

Go provides a specific js file called wasm_exec.js that need to be served by your webpapp. This file is located in the /misc/wasm/ subdirectory of your go root path. Usually we copy it to the folder containing all static files of your webapp, like cp "$(go env GOROOT)/misc/wasm/wasm_exec.js" /example/webapp for the above example. It's important to get the version corresponding to your go environment, it's why we recomend to copy it from your GOROOT.

Change log

• v0.1.0 alpha: contains lines commented with // DEBUG: for debug purpose only
• v0.2.0 alpha:
  • X time axis cursor position in the graph area