Better layout for checkboxes.

frontend/app/framework/angular/forms/editors/checkbox-group.component.html

@@ -1,4 +1,5 @@
-<div class="form-check" *ngFor="let value of values">
+<div #container (sqxResized)="updateContainerWidth($event.width)">
+    <div class="form-check" [class.form-check-block]="!isSingleLine" [class.form-check-inline]="isSingleLine" *ngFor="let value of values">
         <input type="checkbox" class="form-check-input" id="{{controlId}}{{value}}"
             (blur)="callTouched()"
             (change)="check($event.target.checked, value)" 
@@ -6,4 +7,5 @@
             [disabled]="snapshot.isDisabled">
     
         <label class="form-check-label" for="{{controlId}}{{value}}">{{value}}</label>
+    </div>
 </div>

frontend/app/framework/angular/forms/editors/checkbox-group.component.scss

@@ -1,13 +1,10 @@
-.form-check {
-    display: block;
+.form-check-block {
+    & {
         margin-bottom: .5rem;
         margin-left: 0;
-}
+    }
 
-.form-check-input {
+    .form-check-input {
         margin-top: .4rem;
-}
-
-label {
-    min-width: 5rem;
+    }
 }

frontend/app/framework/angular/forms/editors/checkbox-group.component.ts

@@ -7,7 +7,7 @@
 
 // tslint:disable: readonly-array
 
-import { ChangeDetectionStrategy, ChangeDetectorRef, Component, forwardRef, Input } from '@angular/core';
+import { AfterViewChecked, AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, ElementRef, forwardRef, Input, OnChanges, ViewChild } from '@angular/core';
 import { NG_VALUE_ACCESSOR } from '@angular/forms';
 
 import {
@@ -20,6 +20,8 @@ export const SQX_CHECKBOX_GROUP_CONTROL_VALUE_ACCESSOR: any = {
     provide: NG_VALUE_ACCESSOR, useExisting: forwardRef(() => CheckboxGroupComponent), multi: true
 };
 
+let CACHED_FONT: string;
+
 interface State {
     // The checked values.
     checkedValues: ReadonlyArray<string>;
@@ -34,9 +36,18 @@ interface State {
     ],
     changeDetection: ChangeDetectionStrategy.OnPush
 })
-export class CheckboxGroupComponent extends StatefulControlComponent<State, string[]> {
+export class CheckboxGroupComponent extends StatefulControlComponent<State, string[]> implements AfterViewInit, AfterViewChecked, OnChanges {
+    private childrenWidth = 0;
+    private containerWidth = 0;
+    private labelsMeasured = false;
+
     public readonly controlId = MathHelper.guid();
 
+    public isSingleLine = false;
+
+    @ViewChild('container', { static: false })
+    public containerElement: ElementRef<HTMLDivElement>;
+
     @Input()
     public values: ReadonlyArray<string> = [];
 
@@ -46,6 +57,88 @@ export class CheckboxGroupComponent extends StatefulControlComponent<State, stri
         });
     }
 
+    public ngAfterViewInit() {
+        this.calculateWidth();
+    }
+
+    public ngAfterViewChecked() {
+        this.calculateWidth();
+    }
+
+    public ngOnChanges() {
+        this.labelsMeasured = false;
+
+        this.calculateWidth();
+    }
+
+    public updateContainerWidth(width: number) {
+        this.containerWidth = width;
+
+        this.calculateSingleLine();
+    }
+
+    private calculateWidth() {
+        this.calculateStyle();
+
+        if (this.labelsMeasured) {
+            return;
+        }
+
+        if (!CACHED_FONT ||
+            !this.containerElement ||
+            !this.containerElement.nativeElement) {
+            return;
+        }
+
+        if (!canvas) {
+            canvas = document.createElement('canvas');
+        }
+
+        if (canvas) {
+            const ctx = canvas.getContext('2d');
+
+            if (ctx) {
+                ctx.font = CACHED_FONT;
+
+                let width = 0;
+
+                for (let text of this.values) {
+                    width += 30;
+                    width += ctx.measureText(text).width;
+                }
+
+                this.childrenWidth = width;
+
+                this.calculateSingleLine();
+
+                this.labelsMeasured = true;
+            }
+        }
+    }
+
+    private calculateSingleLine() {
+        this.isSingleLine = this.childrenWidth < this.containerWidth;
+    }
+
+    private calculateStyle() {
+        if (CACHED_FONT ||
+            !this.containerElement ||
+            !this.containerElement.nativeElement) {
+            return;
+        }
+
+        const style = window.getComputedStyle(this.containerElement.nativeElement);
+
+        const fontSize = style.getPropertyValue('font-size');
+        const fontFamily = style.getPropertyValue('font-family');
+
+        if (!fontSize || !fontFamily) {
+            return;
+        }
+
+        CACHED_FONT = `${fontSize} ${fontFamily}`;
+    }
+
     public writeValue(obj: any) {
         const checkedValues = Types.isArrayOfString(obj) ? obj.filter(x => this.values.indexOf(x) >= 0) : [];
 
@@ -70,3 +163,5 @@ export class CheckboxGroupComponent extends StatefulControlComponent<State, stri
         return this.snapshot.checkedValues.indexOf(value) >= 0;
     }
 }
+
+let canvas: HTMLCanvasElement | null = null;