cvat/cvat-canvas

Module CVAT-CANVAS

Description

The CVAT module written in TypeScript language. It presents a canvas to viewing, drawing and editing of annotations.

Commands

• Building of the module from sources in the dist directory:

yarn run build
yarn run build --mode=development     # without a minification

API Methods

For API methods, their arguments and return types, please look at canvas.ts.

API CSS

• All drawn objects (shapes, tracks) have an id cvat_canvas_shape_{objectState.clientID}
• Drawn shapes and tracks have classes cvat_canvas_shape, cvat_canvas_shape_activated, cvat_canvas_shape_selection, cvat_canvas_shape_merging, cvat_canvas_shape_drawing, cvat_canvas_shape_occluded
• Drawn review ROIs have an id cvat_canvas_issue_region_{issue.id}
• Drawn review roi has the class cvat_canvas_issue_region
• Drawn texts have the class cvat_canvas_text
• Tags have the class cvat_canvas_tag
• Canvas image has ID cvat_canvas_image
• Grid on the canvas has ID cvat_canvas_grid and cvat_canvas_grid_pattern
• Crosshair during a draw has class cvat_canvas_crosshair
• To stick something to a specific position you can use an element with id cvat_canvas_attachment_board

Events

Standard JS events are used.

    - canvas.setup
    - canvas.activated => {state: ObjectState}
    - canvas.clicked => {state: ObjectState}
    - canvas.moved => {states: ObjectState[], x: number, y: number}
    - canvas.find => {states: ObjectState[], x: number, y: number}
    - canvas.drawn => {state: DrawnData}
    - canvas.interacted => {shapes: InteractionResult[]}
    - canvas.editstart
    - canvas.edited => {state: ObjectState, points: number[], rotation?: number}
    - canvas.splitted => {state: ObjectState, frame: number, duration: number}
    - canvas.grouped => {states: ObjectState[], duration: number}
    - canvas.joined => {states: ObjectState[], points: number[], duration: number}
    - canvas.sliced => {state: ObjectState, results: number[][], duration: number}
    - canvas.merged => {states: ObjectState[], duration: number}
    - canvas.canceled
    - canvas.dragstart
    - canvas.dragstop
    - canvas.zoomstart
    - canvas.zoomstop
    - canvas.zoom
    - canvas.reshape
    - canvas.fit
    - canvas.regionselected => {points: number[]}
    - canvas.dragshape => {duration: number, state: ObjectState}
    - canvas.roiselected => {points: number[]}
    - canvas.resizeshape => {duration: number, state: ObjectState}
    - canvas.contextmenu => { mouseEvent: MouseEvent, objectState: ObjectState,  pointID: number }
    - canvas.message => { messages: { type: 'text' | 'list'; content: string | string[]; className?: string; icon?: 'info' | 'loading' }[] | null, topic: string }
    - canvas.error => { exception: Error, domain?: string }
    - canvas.destroy

WEB

// Create an instance of a canvas
const canvas = new window.canvas.Canvas();

console.log('Version ', window.canvas.CanvasVersion);
console.log('Current mode is ', window.canvas.mode());

// Put canvas to a html container
htmlContainer.appendChild(canvas.html());
canvas.fitCanvas();

// Next you can use its API methods. For example:
canvas.rotate(270);
canvas.draw({
  enabled: true,
  shapeType: 'rectangle',
  crosshair: true,
  rectDrawingMethod: window.Canvas.RectDrawingMethod.CLASSIC,
});

API Reaction

	IDLE	GROUP	SPLIT	DRAW	MERGE	EDIT	DRAG	RESIZE	ZOOM_CANVAS	DRAG_CANVAS	INTERACT	JOIN	SLICE	SELECT_REGION
setup()	+	+	+	+/-	+	+/-	+/-	+/-	+	+	+	+	+	+
activate()	+	-	-	-	-	-	-	-	-	-	-	-	-	-
rotate()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
focus()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
fit()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
grid()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
draw()	+	-	-	+	-	-	-	-	-	-	-	-	-	-
interact()	+	-	-	-	-	-	-	-	-	-	+	-	-	-
split()	+	-	+	-	-	-	-	-	-	-	-	-	-	-
group()	+	+	-	-	-	-	-	-	-	-	-	-	-	-
merge()	+	-	-	-	+	-	-	-	-	-	-	-	-	-
edit()	+	-	-	-	-	+	-	-	-	-	-	-	-	-
join()	+	-	-	-	-	-	-	-	-	-	-	+	-	-
slice()	+	-	-	-	-	-	-	-	-	-	-	-	+	-
selectRegion()	+	-	-	-	-	-	-	-	-	-	-	-	-	+
fitCanvas()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
dragCanvas()	+	-	-	-	-	-	+	-	-	+	-	-	-	-
zoomCanvas()	+	-	-	-	-	-	-	+	+	-	-	-	-	-
cancel()	-	+	+	+	+	+	+	+	+	+	+	+	+	+
configure()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
bitmap()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
setZLayer()	+	+	+	+	+	+	+	+	+	+	+	+	+	+
destroy()	+	+	+	+	+	+	+	+	+	+	+	+	+	+

You can call setup() during editing, dragging, and resizing only to update objects, not to change a frame. You can change frame during draw only when you do not redraw an existing object

Other methods do not change state and can be used at any time.