/** * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved. * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license */ import { keyCodes } from '@ckeditor/ckeditor5-utils/src/keyboard'; import Rect from '@ckeditor/ckeditor5-utils/src/dom/rect'; /** * @module widget/verticalnavigationhandler */ /** * Returns 'keydown' handler for up/down arrow keys that modifies the caret movement if it's in a text line next to an object. * * @param {module:engine/controller/editingcontroller~EditingController} editing The editing controller. * @returns {Function} */ export default function verticalNavigationHandler( editing ) { const model = editing.model; return ( evt, data ) => { const arrowUpPressed = data.keyCode == keyCodes.arrowup; const arrowDownPressed = data.keyCode == keyCodes.arrowdown; const expandSelection = data.shiftKey; const selection = model.document.selection; if ( !arrowUpPressed && !arrowDownPressed ) { return; } const isForward = arrowDownPressed; // Navigation is in the opposite direction than the selection direction so this is shrinking of the selection. // Selection for sure will not approach any object. if ( expandSelection && selectionWillShrink( selection, isForward ) ) { return; } // Find a range between selection and closest limit element. const range = findTextRangeFromSelection( editing, selection, isForward ); if ( !range || range.isCollapsed ) { return; } // If the range is a single line (there is no word wrapping) then move the selection to the position closest to the limit element. // // We can't move the selection directly to the isObject element (eg. table cell) because of dual position at the end/beginning // of wrapped line (it's at the same time at the end of one line and at the start of the next line). if ( isSingleLineRange( editing, range, isForward ) ) { model.change( writer => { const newPosition = isForward ? range.end : range.start; if ( expandSelection ) { const newSelection = model.createSelection( selection.anchor ); newSelection.setFocus( newPosition ); writer.setSelection( newSelection ); } else { writer.setSelection( newPosition ); } } ); evt.stop(); data.preventDefault(); data.stopPropagation(); } }; } // Finds the range between selection and closest limit element (in the direction of navigation). // The position next to limit element is adjusted to the closest allowed `$text` position. // // Returns `null` if, according to the schema, the resulting range cannot contain a `$text` element. // // @param {module:engine/controller/editingcontroller~EditingController} editing The editing controller. // @param {module:engine/model/selection~Selection} selection The current selection. // @param {Boolean} isForward The expected navigation direction. // @returns {module:engine/model/range~Range|null} // function findTextRangeFromSelection( editing, selection, isForward ) { const model = editing.model; if ( isForward ) { const startPosition = selection.isCollapsed ? selection.focus : selection.getLastPosition(); const endPosition = getNearestNonInlineLimit( model, startPosition, 'forward' ); // There is no limit element, browser should handle this. if ( !endPosition ) { return null; } const range = model.createRange( startPosition, endPosition ); const lastRangePosition = getNearestTextPosition( model.schema, range, 'backward' ); if ( lastRangePosition && startPosition.isBefore( lastRangePosition ) ) { return model.createRange( startPosition, lastRangePosition ); } return null; } else { const endPosition = selection.isCollapsed ? selection.focus : selection.getFirstPosition(); const startPosition = getNearestNonInlineLimit( model, endPosition, 'backward' ); // There is no limit element, browser should handle this. if ( !startPosition ) { return null; } const range = model.createRange( startPosition, endPosition ); const firstRangePosition = getNearestTextPosition( model.schema, range, 'forward' ); if ( firstRangePosition && endPosition.isAfter( firstRangePosition ) ) { return model.createRange( firstRangePosition, endPosition ); } return null; } } // Finds the limit element position that is closest to startPosition. // // @param {module:engine/model/model~Model} model // @param {} startPosition // @param {'forward'|'backward'} direction Search direction. // @returns {|null} // function getNearestNonInlineLimit( model, startPosition, direction ) { const schema = model.schema; const range = model.createRangeIn( startPosition.root ); const walkerValueType = direction == 'forward' ? 'elementStart' : 'elementEnd'; for ( const { previousPosition, item, type } of range.getWalker( { startPosition, direction } ) ) { if ( schema.isLimit( item ) && !schema.isInline( item ) ) { return previousPosition; } // Stop looking for isLimit element if the next element is a block element (it is for sure not single line). if ( type == walkerValueType && schema.isBlock( item ) ) { return null; } } return null; } // Basing on the provided range, finds the first or last (depending on `direction`) position inside the range // that can contain `$text` (according to schema). // // @param {module:engine/model/schema~Schema} schema The schema. // @param {module:engine/model/range~Range} range The range to find the position in. // @param {'forward'|'backward'} direction Search direction. // @returns {module:engine/model/position~Position} The nearest selection range. // function getNearestTextPosition( schema, range, direction ) { const position = direction == 'backward' ? range.end : range.start; if ( schema.checkChild( position, '$text' ) ) { return position; } for ( const { nextPosition } of range.getWalker( { direction } ) ) { if ( schema.checkChild( nextPosition, '$text' ) ) { return nextPosition; } } } // Checks if the DOM range corresponding to the provided model range renders as a single line by analyzing DOMRects // (verifying if they visually wrap content to the next line). // // @param {module:engine/controller/editingcontroller~EditingController} editing The editing controller. // @param {module:engine/model/range~Range} modelRange The current table cell content range. // @param {Boolean} isForward The expected navigation direction. // @returns {Boolean} // function isSingleLineRange( editing, modelRange, isForward ) { const model = editing.model; const domConverter = editing.view.domConverter; // Wrapped lines contain exactly the same position at the end of current line // and at the beginning of next line. That position's client rect is at the end // of current line. In case of caret at first position of the last line that 'dual' // position would be detected as it's not the last line. if ( isForward ) { const probe = model.createSelection( modelRange.start ); model.modifySelection( probe ); // If the new position is at the end of the container then we can't use this position // because it would provide incorrect result for eg caption of image and selection // just before end of it. Also in this case there is no "dual" position. if ( !probe.focus.isAtEnd && !modelRange.start.isEqual( probe.focus ) ) { modelRange = model.createRange( probe.focus, modelRange.end ); } } const viewRange = editing.mapper.toViewRange( modelRange ); const domRange = domConverter.viewRangeToDom( viewRange ); const rects = Rect.getDomRangeRects( domRange ); let boundaryVerticalPosition; for ( const rect of rects ) { if ( boundaryVerticalPosition === undefined ) { boundaryVerticalPosition = Math.round( rect.bottom ); continue; } // Let's check if this rect is in new line. if ( Math.round( rect.top ) >= boundaryVerticalPosition ) { return false; } boundaryVerticalPosition = Math.max( boundaryVerticalPosition, Math.round( rect.bottom ) ); } return true; } function selectionWillShrink( selection, isForward ) { return !selection.isCollapsed && selection.isBackward == isForward; }