devexpress-richedit/lib/common/commands/selection/go-to-next-page-command.js

DevExpress Rich Text Editor is an advanced word-processing tool designed for working with rich text documents.

import { MixedSize } from '../../../common/utils/mixed-size';
import { GoToPageCommandBase } from './go-to-page-command-base';
export class GoToNextPageCommandBase extends GoToPageCommandBase {
    goToPage(layoutPosition, x, y) {
        const visibleAreaHeight = MixedSize.fromUI(this.control.viewManager.sizes.getVisibleAreaHeight(false)).useScale(this.scale);
        const viewportHeight = MixedSize.fromLayout(Math.max(layoutPosition.row.height, visibleAreaHeight.LayoutSize)).useScale(this.scale);
        const viewportBottom = MixedSize.fromUI(this.control.viewManager.canvas.scrollTop).useScale(this.scale).addSize(viewportHeight);
        let page = layoutPosition.page;
        const pageIndex = this.findPageIndexByOffsetY(viewportBottom.LayoutSize);
        this.scrollToPosition(pageIndex, viewportBottom.LayoutSize);
        const newY = MixedSize.add(MixedSize.fromLayout(y).useScale(this.scale), viewportHeight);
        const position = this.getPosition(page, MixedSize.fromLayout(x).useScale(this.scale), newY, viewportBottom, viewportHeight);
        this.changeSelection(position);
    }
    getPosition(currentPage, x, y, viewportTop, viewportHeight) {
        const currentPageY = this.control.viewManager.sizes.getPageOffsetY(currentPage);
        const newAbsoluteY = MixedSize.max(y.addLayoutSize(currentPageY), viewportTop);
        let pageIndex = this.findPageIndexByOffsetY(newAbsoluteY.LayoutSize);
        const pageY = this.getPageOffsetY(pageIndex);
        const htr = this.calculateHitTestResult(pageIndex, x.LayoutSize, newAbsoluteY.LayoutSize - pageY);
        const rowY = htr.getLayoutY() + pageY + htr.row.height / 2;
        if (rowY > viewportTop.LayoutSize)
            return htr.getPosition();
        const viewportBottom = MixedSize.add(viewportTop, viewportHeight);
        const position = this.tryFindVisiblePosition(x.LayoutSize, newAbsoluteY.LayoutSize, viewportBottom.LayoutSize);
        if (position !== null)
            return position;
        return htr.getPosition();
    }
}
export class GoToNextPageCommand extends GoToNextPageCommandBase {
    extendSelection() {
        return false;
    }
}
export class ExtendGoToNextPageCommand extends GoToNextPageCommandBase {
    extendSelection() {
        return true;
    }
}