README.md

Module CVAT-CANVAS

Description

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

Versioning

If you make changes in this package, please do following:

• After not important changes (typos, backward compatible bug fixes, refactoring) do: npm version patch
• After changing API (backward compatible new features) do: npm version minor
• After changing API (changes that break backward compatibility) do: npm version major

Commands

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

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

Using

Canvas itself handles:

• Shape context menu (PKM)
• Image moving (mousedrag)
• Image resizing (mousewheel)
• Image fit (dblclick)
• Remove point (PKM)
• Polyshape editing (Shift + LKM)

API Methods

    enum RectDrawingMethod {
        CLASSIC = 'By 2 points',
        EXTREME_POINTS = 'By 4 points'
    }

    enum CuboidDrawingMethod {
        CLASSIC = 'From rectangle',
        CORNER_POINTS = 'By 4 points',
    }

    enum Mode {
        IDLE = 'idle',
        DRAG = 'drag',
        RESIZE = 'resize',
        DRAW = 'draw',
        EDIT = 'edit',
        MERGE = 'merge',
        SPLIT = 'split',
        GROUP = 'group',
        DRAG_CANVAS = 'drag_canvas',
        ZOOM_CANVAS = 'zoom_canvas',
    }

    interface Configuration {
        displayAllText?: boolean;
        undefinedAttrValue?: string;
    }

    interface DrawData {
        enabled: boolean;
        shapeType?: string;
        rectDrawingMethod?: RectDrawingMethod;
        cuboidDrawingMethod?: CuboidDrawingMethod;
        numberOfPoints?: number;
        initialState?: any;
        crosshair?: boolean;
    }

    interface GroupData {
        enabled: boolean;
        resetGroup?: boolean;
    }

    interface MergeData {
        enabled: boolean;
    }

    interface SplitData {
        enabled: boolean;
    }

    interface DrawnData {
        shapeType: string;
        points: number[];
        objectType?: string;
        occluded?: boolean;
        attributes?: [index: number]: string;
        label?: Label;
        color?: string;
    }

    interface Canvas {
        html(): HTMLDivElement;
        setZLayer(zLayer: number | null): void;
        setup(frameData: any, objectStates: any[]): void;
        activate(clientID: number, attributeID?: number): void;
        rotate(frameAngle: number): void;
        focus(clientID: number, padding?: number): void;
        fit(): void;
        grid(stepX: number, stepY: number): void;

        draw(drawData: DrawData): void;
        group(groupData: GroupData): void;
        split(splitData: SplitData): void;
        merge(mergeData: MergeData): void;
        select(objectState: any): void;

        fitCanvas(): void;
        bitmap(enabled: boolean): void;
        dragCanvas(enable: boolean): void;
        zoomCanvas(enable: boolean): void;

        mode(): Mode;
        cancel(): void;
        configure(configuration: Configuration): void;
        isAbleToChangeFrame(): boolean;
    }

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_grouping, cvat_canvas_shape_merging, cvat_canvas_shape_drawing, cvat_canvas_shape_occluded
• 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

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.editstart
    - canvas.edited => {state: ObjectState, points: number[]}
    - canvas.splitted => {state: ObjectState}
    - canvas.groupped => {states: ObjectState[]}
    - canvas.merged => {states: ObjectState[]}
    - canvas.canceled
    - canvas.dragstart
    - canvas.dragstop
    - canvas.zoomstart
    - canvas.zoomstop
    - canvas.zoom
    - canvas.fit
    - canvas.dragshape => {id: number}
    - canvas.resizeshape => {id: number}
    - canvas.contextmenu => { mouseEvent: MouseEvent, objectState: ObjectState,  pointID: number }

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
setup()	+	+	+	+/-	+	+/-	+/-	+/-	+	+
activate()	+	-	-	-	-	-	-	-	-	-
rotate()	+	+	+	+	+	+	+	+	+	+
focus()	+	+	+	+	+	+	+	+	+	+
fit()	+	+	+	+	+	+	+	+	+	+
grid()	+	+	+	+	+	+	+	+	+	+
draw()	+	-	-	-	-	-	-	-	-	-
split()	+	-	+	-	-	-	-	-	-	-
group()	+	+	-	-	-	-	-	-	-	-
merge()	+	-	-	-	+	-	-	-	-	-
fitCanvas()	+	+	+	+	+	+	+	+	+	+
dragCanvas()	+	-	-	-	-	-	+	-	-	+
zoomCanvas()	+	-	-	-	-	-	-	+	+	-
cancel()	-	+	+	+	+	+	+	+	+	+
configure()	+	+	+	+	+	+	+	+	+	+
bitmap()	+	+	+	+	+	+	+	+	+	+
setZLayer()	+	+	+	+	+	+	+	+	+	+

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 everytime.