fix(ui-canvas): ios support for iosAccessibilityAdjustsFontSize

Author: farfromrefug

src/ui-canvas/canvas.ios.ts

@@ -2,6 +2,7 @@
 import { CSSType, Color, Font, ImageSource, Utils, View } from '@nativescript/core';
 import { FontStyleType, FontWeightType } from '@nativescript/core/ui/styling/font';
 import { Canvas as ICanvas, FontMetrics as IFontMetrics, Matrix as IMatrix, Paint as IPaint, Path as IPath, PorterDuffXfermode as IPorterDuffXfermode, Rect as IRect, RectF as IRectF } from './canvas';
+import type { CanvasView } from './index.ios';
 export * from './canvas.common';
 
 const identity = CGAffineTransformIdentity;
@@ -1288,6 +1289,7 @@ export class Canvas implements ICanvas {
     mWidth: number;
     mHeight: number;
     mScale = 1;
+    view: WeakRef<CanvasView>;
 
     setBitmap(image) {
         // if (image instanceof ImageSource) {
@@ -2263,10 +2265,11 @@ export class StaticLayout {
             this.nsAttributedString = NSAttributedString.alloc().initWithString(text + '');
         }
     }
-    createAttributedStringToDraw() {
+    createAttributedStringToDraw(canvas?) {
         if (this.mToDraw) {
             return;
         }
+
         const nsAttributedString: NSMutableAttributedString = NSMutableAttributedString.alloc().initWithStringAttributes(this.nsAttributedString.string, this.paint.getDrawTextAttribs());
 
         const paragraphStyle = NSMutableParagraphStyle.alloc().init();
@@ -2298,7 +2301,7 @@ export class StaticLayout {
     draw(canvas: Canvas, maxHeight = Number.MAX_VALUE) {
         canvas.startApplyPaint(this.paint);
         const ctx = canvas.ctx;
-        this.createAttributedStringToDraw();
+        this.createAttributedStringToDraw(canvas);
         // const attributes = this.paint.getDrawTextAttribs();
         // if (this.align || this.ellipsize) {
         //     let paragraphStyle = attributes.objectForKey(NSParagraphStyleAttributeName) as NSMutableParagraphStyle;

src/ui-canvas/index.ios.ts

@@ -1,10 +1,29 @@
 /* eslint-disable no-redeclare */
-import { CSSType, Utils } from '@nativescript/core';
+import { CSSType, Font, Utils } from '@nativescript/core';
 import { Canvas, Paint } from './canvas.ios';
 import { CanvasBase } from './index.common';
+import { iosAccessibilityAdjustsFontSizeProperty, iosAccessibilityMaxFontScaleProperty, iosAccessibilityMinFontScaleProperty } from '@nativescript/core/accessibility/accessibility-properties';
+import { fontScaleInternalProperty } from '@nativescript/core/ui/styling/style-properties';
 
 export * from './canvas';
 
+export function adjustMinMaxFontScale(value, view) {
+    let finalValue;
+    if (view.iosAccessibilityAdjustsFontSize) {
+        finalValue = value;
+
+        if (view.iosAccessibilityMinFontScale && view.iosAccessibilityMinFontScale > value) {
+            finalValue = view.iosAccessibilityMinFontScale;
+        }
+        if (view.iosAccessibilityMaxFontScale && view.iosAccessibilityMaxFontScale < value) {
+            finalValue = view.iosAccessibilityMaxFontScale;
+        }
+    } else {
+        finalValue = 1.0;
+    }
+    return finalValue;
+}
+
 @NativeClass
 export class UICustomCanvasView extends UIView {
     mCanvas: Canvas; // CGContextRef;
@@ -31,6 +50,7 @@ export class UICustomCanvasView extends UIView {
         }
         if (!this.mCanvas) {
             this.mCanvas = new Canvas(0, 0);
+            this.mCanvas.view = this.mOwner;
         }
         this.mCanvas.setContext(context, size.width, size.height);
         if (owner.callDrawBeforeShapes) {
@@ -96,4 +116,30 @@ export class CanvasView extends CanvasBase {
             this.nativeViewProtected.setNeedsDisplay();
         }
     }
+
+    [fontScaleInternalProperty.setNative](value) {
+        const font = this.style.fontInternal || Font.default.withFontSize(16);
+        const finalValue = adjustMinMaxFontScale(value, this);
+
+        // Request layout on font scale as it's not done automatically
+        if (font.fontScale !== finalValue) {
+            this.style.fontInternal = font.withFontScale(finalValue);
+            this.requestLayout();
+        } else {
+            if (!this.style.fontInternal) {
+                this.style.fontInternal = font;
+            }
+        }
+    }
+    [iosAccessibilityAdjustsFontSizeProperty.setNative](value: boolean) {
+        this[fontScaleInternalProperty.setNative](this.style.fontScaleInternal);
+    }
+
+    [iosAccessibilityMinFontScaleProperty.setNative](value: number) {
+        this[fontScaleInternalProperty.setNative](this.style.fontScaleInternal);
+    }
+
+    [iosAccessibilityMaxFontScaleProperty.setNative](value: number) {
+        this[fontScaleInternalProperty.setNative](this.style.fontScaleInternal);
+    }
 }