@geogirafe/lib-geoportal
Version:
GeoGirafe is a flexible application to build online geoportals.
67 lines (66 loc) • 2.9 kB
JavaScript
import { toRadians } from 'ol/math';
import GeoConsts from '../../../tools/geoconsts';
import SimpleMaskLayer from '../../../tools/layers/simplemasklayer';
/**
* A layer to display a mask with a scale- and page size dependent cut-out box for printing.
*/
class PrintMaskLayer extends SimpleMaskLayer {
constructor(options = {}) {
super({ className: 'printMask', ...options });
Object.defineProperty(this, "scaleFn", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
}
/**
* Sets the provided scale function to retrieve the current scale.
*/
setGetScaleFn(scaleFn) {
this.scaleFn = scaleFn;
}
getRotation() {
// Not implemented yet
return 0;
}
/**
* Draw the print canvas mask.
*/
render(frameState) {
if (this.size === null) {
throw Error('Cannot render Mask : size has not been set.');
}
if (!this.scaleFn) {
throw Error('Cannot render Mask : scaleDn has not been set.');
}
const cwidth = frameState.size[0];
const cheight = frameState.size[1];
const center = [cwidth / 2, cheight / 2];
const height = this.size[1];
const width = this.size[0];
const resolution = frameState.viewState.resolution;
const scale = this.scaleFn(frameState);
const extentHalfWidth = ((width / GeoConsts.PRINT_DOTS_PER_INCH / GeoConsts.INCHES_PER_METER) * scale) / resolution / 2;
const extentHalfHeight = ((height / GeoConsts.PRINT_DOTS_PER_INCH / GeoConsts.INCHES_PER_METER) * scale) / resolution / 2;
const rotation = this.getRotation !== undefined ? toRadians(this.getRotation()) : 0;
// diagonal = distance p1 to center.
const diagonal = Math.sqrt(Math.pow(extentHalfWidth, 2) + Math.pow(extentHalfHeight, 2));
// gamma = angle between horizontal and diagonal (with rotation).
const gamma = Math.atan(extentHalfHeight / extentHalfWidth) - rotation;
// omega = angle between diagonal and vertical (with rotation).
const omega = Math.atan(extentHalfWidth / extentHalfHeight) - rotation;
// Calculation of each corner.
const x1 = center[0] - Math.cos(gamma) * diagonal;
const y1 = center[1] + Math.sin(gamma) * diagonal;
const x2 = center[0] + Math.sin(omega) * diagonal;
const y2 = center[1] + Math.cos(omega) * diagonal;
const x3 = center[0] + Math.cos(gamma) * diagonal;
const y3 = center[1] - Math.sin(gamma) * diagonal;
const x4 = center[0] - Math.sin(omega) * diagonal;
const y4 = center[1] - Math.cos(omega) * diagonal;
this.drawBoxMask(cwidth, cheight, [x1, y1], [x2, y2], [x3, y3], [x4, y4]);
return this.context.canvas;
}
}
export default PrintMaskLayer;