@nativescript-community/ui-htmlcanvasapi/lib/html-canvas-view/index.js

An HTML Canvas API implementation on top of android and iOS native APIs

var HTMLCanvasView_1;
import { Canvas, CanvasView, createRectF, Paint } from '@nativescript-community/ui-canvas';
import { booleanConverter, CSSType, Property } from '@nativescript/core';
import { HTMLCanvasElement } from '../elements/HTMLCanvasElement';
import { SCREEN_SCALE } from '../helpers';
function onLayoutChange(args) {
    const view = args.object;
    // During view layout, offscreen buffer is also resized
    if (view.isOffscreenBufferEnabled) {
        const measuredWidth = view.getMeasuredWidth();
        const measuredHeight = view.getMeasuredHeight();
        if (measuredWidth != 0 && measuredHeight != 0) {
            view._resizeOffscreenBuffer(measuredWidth, measuredHeight);
        }
        else {
            view._disposeOffscreenBuffer();
        }
    }
}
const isOffscreenBufferEnabledProperty = new Property({
    name: 'isOffscreenBufferEnabled',
    defaultValue: false,
    valueConverter: booleanConverter,
});
let HTMLCanvasView = HTMLCanvasView_1 = class HTMLCanvasView extends CanvasView {
    constructor() {
        super();
        this._canvasElement = new HTMLCanvasElement(this);
    }
    get canvasElement() {
        return this._canvasElement;
    }
    get nativeContext() {
        return this._offscreenContext != null ? this._offscreenContext : this._currentCanvas;
    }
    disposeNativeView() {
        super.disposeNativeView();
        this._disposeOffscreenBuffer();
    }
    getContext(contextId, contextAttributes) {
        return this._canvasElement.getContext(contextId, contextAttributes);
    }
    transferControlToOffscreen() {
        return this._canvasElement.transferControlToOffscreen();
    }
    toDataURL(type, encoderOptions) {
        return this._canvasElement.toDataURL(type, encoderOptions);
    }
    isDrawing() {
        return this._isDrawing;
    }
    onDraw(canvas) {
        this._isDrawing = true;
        this._currentCanvas = canvas;
        super.onDraw(canvas);
        if (this._offscreenContext != null) {
            // Canvas instance might be view canvas or data export canvas
            const rect = createRectF(0, 0, canvas.getWidth(), canvas.getHeight());
            canvas.drawBitmap(this._offscreenContext.getImage(), null, rect, this._offscreenPaint);
        }
        this._currentCanvas = null;
        this._isDrawing = false;
    }
    _resizeOffscreenBuffer(width, height) {
        if (this._offscreenContext != null) {
            this._offscreenContext.release();
        }
        this._offscreenContext = new Canvas(width, height);
        this._offscreenContext.scale(SCREEN_SCALE, SCREEN_SCALE);
    }
    _disposeOffscreenBuffer() {
        if (this._offscreenContext != null) {
            this._offscreenContext.release();
            this._offscreenContext = null;
        }
        this._offscreenPaint = null;
    }
    [isOffscreenBufferEnabledProperty.setNative](value) {
        if (value) {
            this._offscreenPaint = new Paint();
            this._offscreenPaint.setAntiAlias(true);
            this.on(HTMLCanvasView_1.layoutChangedEvent, onLayoutChange);
        }
        else {
            this.off(HTMLCanvasView_1.layoutChangedEvent, onLayoutChange);
            this._disposeOffscreenBuffer();
        }
    }
};
HTMLCanvasView = HTMLCanvasView_1 = __decorate([
    CSSType('HTMLCanvasView'),
    __metadata("design:paramtypes", [])
], HTMLCanvasView);
isOffscreenBufferEnabledProperty.register(HTMLCanvasView);
export { HTMLCanvasView, isOffscreenBufferEnabledProperty, SCREEN_SCALE };
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