static/widgets/fontscale.ts

// Copyright (c) 2021, Compiler Explorer Authors
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
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//     * Redistributions of source code must retain the above copyright notice,
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//     * Redistributions in binary form must reproduce the above copyright
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//       documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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import EventEmitter from 'events';
import $ from 'jquery';
import {options} from '../options';
import {editor} from 'monaco-editor';
import IEditor = editor.IEditor;

import {FontScaleState} from './fontscale.interfaces';

function makeFontSizeDropdown(elem: JQuery, obj: FontScale, buttonDropdown: JQuery) {
    function onClickEvent(this: JQuery) {
        // Toggle off the selection of the others
        $(this)
            .addClass('active')
            .siblings().removeClass('active');
        // Send the data
        obj.scale = $(this).data('value');
        obj.apply();
        obj.emit('change');
    }

    for (let i = 8; i <= 30; i++) {
        const item = $('<button></button>');

        item.attr('data-value', i)
            .addClass('dropdown-item btn btn-sm btn-light')
            .text(i)
            .appendTo(elem)
            .on('click', onClickEvent);

        if (obj.scale === i) {
            item.addClass('active');
        }
    }

    if (buttonDropdown) {
        buttonDropdown.on('wheel', (e: any) => {
            e.preventDefault();
            let selectedId = elem.find('.active').index();
            if (e.originalEvent.deltaY >= 0 && selectedId < elem.children().length - 1) {
                selectedId++;
            } else if (e.originalEvent.deltaY < 0 && selectedId > 0) {
                selectedId--;
            }
            elem.children().eq(selectedId).trigger('click');
        });
    }
}

function convertOldScale(oldScale: number): number {
    // New low + ((new max - new low) * (oldScale - old low) / (old max - old low))
    return Math.floor(8 + (22 * (oldScale - 0.3) / 2.7));
}

export class FontScale extends EventEmitter.EventEmitter {
    private domRoot: JQuery;
    public scale: number;
    private readonly usePxUnits: boolean;
    private fontSelectorOrEditor: JQuery | IEditor;
    private isFontOfStr: boolean;

    constructor(domRoot: JQuery, state: FontScaleState & any, fontSelectorOrEditor: JQuery | IEditor) {
        super();
        this.domRoot = domRoot;
        // Old scale went from 0.3 to 3. New one uses 8 up to 30, so we can convert the old ones to the new format
        this.scale = state.fontScale || options.defaultFontScale;
        // The check seems pointless, but it ensures a false in case it's undefined
        // FontScale assumes it's an old state if it does not see a fontUsePx in the state, so at first it will use pt.
        // So the second condition is there to make new objects actually use px
        this.usePxUnits = state.fontUsePx === true || !state.fontScale;
        if (this.scale < 8) {
            this.scale = convertOldScale(this.scale);
        }
        this.setTarget(fontSelectorOrEditor);
        this.apply();
        makeFontSizeDropdown(
            this.domRoot.find('.font-size-list'),
            this,
            this.domRoot.find('.fs-button')
        );
    }

    apply() {
        if (this.isFontOfStr) {
            this.domRoot
                .find(this.fontSelectorOrEditor as JQuery)
                .css('font-size', this.scale + (this.usePxUnits ? 'px' : 'pt'));
        } else {
            (this.fontSelectorOrEditor as IEditor).updateOptions({
                fontSize: this.scale,
            });
        }
    }

    addState(state: any) {
        state.fontScale = this.scale;
        state.fontUsePx = true;
    }

    setScale(scale: number) {
        this.scale = scale;
        this.apply();
    }

    setTarget(target: JQuery | IEditor) {
        this.fontSelectorOrEditor = target;
        this.isFontOfStr = typeof (this.fontSelectorOrEditor) === 'string';
    }
}