pariola / sketch

ASCII Canvas

This service implements an ASCII art drawing canvas as a web service.

The Canvas has a default size of 28x12, it can automatically expand when trying to draw a Rectangle that goes beyond its original size.

This service persists state across launches by encoding all the canvas' state with encoding/gob in a file (configured as sketch.gob) at the current directory.

Run

Run the command below to start the Sketch Service on port 5000.

go run main.go

To run tests on the project:

go test ./...

Client View (read-only)

uses a websocket to provide near realtime changes to the Canvas. Should be viewed with a browser.

Create Canvas

http://localhost:5000/ - creates a new canvas and redirects to the canvas view.

View Canvas

http://localhost:5000/[CANVAS ID] - displays the canvas.

API Endpoints

NOTE: URL parameter id refers to the ID of the canvas.

Create Canvas

GET /api/canvas Creates a new canvas then returns the ID.

Request:

curl -XGET 'http://localhost:5000/api/canvas'

Response:

78587113-74e0-4997-852c-2b0d469e5194

Draw Rectangle

POST /api/canvas/:id/draw Draws a Rectangle on the canvas then prints it.

Parameters:

• pos_x: coordinates for the upper-left corner (X-axis)
• pos_y: coordinates for the upper-left corner (Y-axis)
• width: width of the rectangle
• height: height of the rectangle
• fill: (Optional) a character to fill the rectangle with
• outline: (Optional) a character to outline the rectangle with

NOTE: One of either fill or outline should always be present.

Request:

curl -XPOST -H "Content-type: application/json" -d '{
  "pos_x": 3,
  "pos_y": 2,
  "width": 5,
  "height": 3,
  "fill": "X",
  "outline": "@"
}' 'http://localhost:5000/api/canvas/78587113-74e0-4997-852c-2b0d469e5194/draw'

Response:

@@@@@ @XXX@ @@@@@

Flood Fill

POST /api/canvas/:id/floodfill Performs the flood fill operation on the canvas and then prints it.

Parameters:

• pos_x: start coordinates (X-axis)
• pos_y: start coordinates (Y-axis)
• fill: a character to use in the operation

Request:

curl -XPOST -H "Content-type: application/json" -d '{
  "pos_x": 4,
  "pos_y": 3,
  "fill": "-"
}' 'http://localhost:5000/api/canvas/78587113-74e0-4997-852c-2b0d469e5194/floodfill'

Response:

@@@@@ @---@ @@@@@

Print Canvas

GET /api/canvas/:id Returns the content of the canvas with the referenced id.

Request:

curl -XGET 'http://localhost:5000/api/canvas/78587113-74e0-4997-852c-2b0d469e5194'

Response:

@@@@@ @---@ @@@@@