fix(material/progress-spinner): animation not working on some zoom levels in Safari

Fixes that the progress spinner animation was broken on Safari on non-default zoom levels. The problem seems to be that the `transform-origin` was being offset by the amount of zoom. These changes work around it by setting the origin based on the zoom level.

Fixes #23668.

Author: crisbeto

src/material/progress-spinner/progress-spinner.html

@@ -14,7 +14,8 @@
   preserveAspectRatio="xMidYMid meet"
   focusable="false"
   [ngSwitch]="mode === 'indeterminate'"
-  aria-hidden="true">
+  aria-hidden="true"
+  #svg>
 
   <!--
     Technically we can reuse the same `circle` element, however Safari has an issue that breaks
@@ -31,7 +32,8 @@
     [style.animation-name]="'mat-progress-spinner-stroke-rotate-' + _spinnerAnimationLabel"
     [style.stroke-dashoffset.px]="_getStrokeDashOffset()"
     [style.stroke-dasharray.px]="_getStrokeCircumference()"
-    [style.stroke-width.%]="_getCircleStrokeWidth()"></circle>
+    [style.stroke-width.%]="_getCircleStrokeWidth()"
+    [style.transform-origin]="_getCircleTransformOrigin(svg)"></circle>
 
   <circle
     *ngSwitchCase="false"
@@ -40,5 +42,6 @@
     [attr.r]="_getCircleRadius()"
     [style.stroke-dashoffset.px]="_getStrokeDashOffset()"
     [style.stroke-dasharray.px]="_getStrokeCircumference()"
-    [style.stroke-width.%]="_getCircleStrokeWidth()"></circle>
+    [style.stroke-width.%]="_getCircleStrokeWidth()"
+    [style.transform-origin]="_getCircleTransformOrigin(svg)"></circle>
 </svg>

src/material/progress-spinner/progress-spinner.scss

@@ -26,7 +26,6 @@ $_default-circumference: variables.$pi * $_default-radius * 2;
   circle {
     @include private.private-animation-noop();
     fill: transparent;
-    transform-origin: center;
     transition: stroke-dashoffset 225ms linear;
 
     @include a11y.high-contrast(active, off) {

src/material/progress-spinner/progress-spinner.ts

@@ -19,6 +19,8 @@ import {
   Optional,
   ViewEncapsulation,
   OnInit,
+  ChangeDetectorRef,
+  OnDestroy,
 } from '@angular/core';
 import {CanColor, mixinColor} from '@angular/material/core';
 import {ANIMATION_MODULE_TYPE} from '@angular/platform-browser/animations';
@@ -124,7 +126,8 @@ const INDETERMINATE_ANIMATION_TEMPLATE = `
   changeDetection: ChangeDetectionStrategy.OnPush,
   encapsulation: ViewEncapsulation.None,
 })
-export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnInit, CanColor {
+export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnInit, OnDestroy,
+  CanColor {
   private _diameter = BASE_SIZE;
   private _value = 0;
   private _strokeWidth: number;
@@ -185,15 +188,16 @@ export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnIni
   }
 
   constructor(elementRef: ElementRef<HTMLElement>,
-              /**
-               * @deprecated `_platform` parameter no longer being used.
-               * @breaking-change 14.0.0
-               */
-              _platform: Platform,
+              private _platform: Platform,
               @Optional() @Inject(DOCUMENT) private _document: any,
               @Optional() @Inject(ANIMATION_MODULE_TYPE) animationMode: string,
               @Inject(MAT_PROGRESS_SPINNER_DEFAULT_OPTIONS)
-                  defaults?: MatProgressSpinnerDefaultOptions) {
+                  defaults?: MatProgressSpinnerDefaultOptions,
+              /**
+               * @deprecated `changeDetectorRef` parameter to become required.
+               * @breaking-change 14.0.0
+               */
+              private _changeDetectorRef?: ChangeDetectorRef) {
 
     super(elementRef);
 
@@ -218,6 +222,14 @@ export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnIni
         this.strokeWidth = defaults.strokeWidth;
       }
     }
+
+    // Safari has an issue where the circle isn't positioned correctly when the page has a
+    // different zoom level from the default. This handler triggers a recalculation of the
+    // `transform-origin` when the page zoom level changes.
+    // See `_getCircleTransformOrigin` for more info.
+    if (_platform.isBrowser && _platform.SAFARI) {
+      window.addEventListener('resize', this._resizeHandler);
+    }
   }
 
   ngOnInit() {
@@ -231,6 +243,12 @@ export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnIni
     element.classList.add('mat-progress-spinner-indeterminate-animation');
   }
 
+  ngOnDestroy() {
+    if (this._platform.isBrowser) {
+      window.removeEventListener('resize', this._resizeHandler);
+    }
+  }
+
   /** The radius of the spinner, adjusted for stroke width. */
   _getCircleRadius() {
     return (this.diameter - BASE_STROKE_WIDTH) / 2;
@@ -261,6 +279,16 @@ export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnIni
     return this.strokeWidth / this.diameter * 100;
   }
 
+  /** Gets the `transform-origin` for the inner circle element. */
+  _getCircleTransformOrigin(svg: HTMLElement): string {
+    // Safari has an issue where the `transform-origin` doesn't work as expected when the page
+    // has a different zoom level from the default. The problem appears to be that a zoom
+    // is applied on the `svg` node itself. We can work around it by calculating the origin
+    // based on the zoom level. On all other browsers the `currentScale` appears to always be 1.
+    const scale = ((svg as unknown as SVGSVGElement).currentScale ?? 1) * 50;
+    return `${scale}% ${scale}%`;
+  }
+
   /** Dynamically generates a style tag containing the correct animation for this diameter. */
   private _attachStyleNode(): void {
     const styleRoot = this._styleRoot;
@@ -300,6 +328,16 @@ export class MatProgressSpinner extends _MatProgressSpinnerBase implements OnIni
     return this.diameter.toString().replace('.', '_');
   }
 
+  /** Handles window `resize` events. */
+  private _resizeHandler = () => {
+    // When the window is resize while the spinner is in `indeterminate` mode, we
+    // have to mark for check so the transform origin of the circle can be recomputed.
+    if (this.mode === 'indeterminate') {
+      // @breaking-change 14.0.0 Remove null check for `_changeDetectorRef`.
+      this._changeDetectorRef?.markForCheck();
+    }
+  }
+
   static ngAcceptInputType_diameter: NumberInput;
   static ngAcceptInputType_strokeWidth: NumberInput;
   static ngAcceptInputType_value: NumberInput;
@@ -333,8 +371,9 @@ export class MatSpinner extends MatProgressSpinner {
               @Optional() @Inject(DOCUMENT) document: any,
               @Optional() @Inject(ANIMATION_MODULE_TYPE) animationMode: string,
               @Inject(MAT_PROGRESS_SPINNER_DEFAULT_OPTIONS)
-                  defaults?: MatProgressSpinnerDefaultOptions) {
-    super(elementRef, platform, document, animationMode, defaults);
+                  defaults?: MatProgressSpinnerDefaultOptions,
+              changeDetectorRef?: ChangeDetectorRef) {
+    super(elementRef, platform, document, animationMode, defaults, changeDetectorRef);
     this.mode = 'indeterminate';
   }
 }