feat(dpr): able to update dpr by resize

src/PainterBase.ts

@@ -19,7 +19,7 @@ export interface PainterBase {
 
     // constructor(dom: HTMLElement, storage: Storage, opts: PainterOption, id: number): void
 
-    resize(width?: number | string, height?: number | string): void
+    resize(width?: number | string, height?: number | string, devicePixelRatio?: number): void
     refresh(): void
     clear(): void
 

src/canvas/Layer.ts

@@ -354,8 +354,28 @@ export default class Layer extends Eventful {
         return (this._paintRects || []).slice();
     }
 
-    resize(width: number, height: number) {
-        const dpr = this.dpr;
+    /**
+     * Update dpr and keep context markers in sync.
+     * Returns true if dpr changed.
+     */
+    updateDpr(dpr?: number): boolean {
+        if (dpr != null && dpr !== this.dpr) {
+            this.dpr = dpr;
+            // Keep a custom dpr marker in sync for downstream brush logic.
+            if (this.ctx) {
+                (this.ctx as ZRCanvasRenderingContext).dpr = dpr;
+            }
+            if (this.ctxBack) {
+                (this.ctxBack as ZRCanvasRenderingContext).dpr = dpr;
+            }
+            return true;
+        }
+        return false;
+    }
+
+    resize(width: number, height: number, dpr?: number) {
+        this.updateDpr(dpr);
+        dpr = this.dpr;
 
         const dom = this.dom;
         const domStyle = dom.style;

src/canvas/Painter.ts

@@ -1,4 +1,4 @@
-import {devicePixelRatio} from '../config';
+import { devicePixelRatio, getDevicePixelRatio } from '../config';
 import * as util from '../core/util';
 import Layer, { LayerConfig } from './Layer';
 import requestAnimationFrame from '../animation/requestAnimationFrame';
@@ -835,11 +835,24 @@ export default class CanvasPainter implements PainterBase {
 
     /**
      * 区域大小变化后重绘
+     * @param width 宽度
+     * @param height 高度
+     * @param devicePixelRatio 设备像素比，如果未指定，则自动获取当前设备像素比
      */
     resize(
         width?: number | string,
-        height?: number | string
+        height?: number | string,
+        devicePixelRatio?: number
     ) {
+        const newDpr = devicePixelRatio != null
+            ? devicePixelRatio
+            : getDevicePixelRatio();
+
+        const dprChanged = newDpr !== this.dpr;
+        if (dprChanged) {
+            this.dpr = newDpr;
+        }
+
         if (!this._domRoot.style) { // Maybe in node or worker
             if (width == null || height == null) {
                 return;
@@ -848,7 +861,7 @@ export default class CanvasPainter implements PainterBase {
             this._width = width as number;
             this._height = height as number;
 
-            this.getLayer(CANVAS_ZLEVEL).resize(width as number, height as number);
+            this.getLayer(CANVAS_ZLEVEL).resize(width as number, height as number, this.dpr);
         }
         else {
             const domRoot = this._domRoot;
@@ -867,13 +880,13 @@ export default class CanvasPainter implements PainterBase {
             domRoot.style.display = '';
 
             // 优化没有实际改变的resize
-            if (this._width !== width || height !== this._height) {
+            if (this._width !== width || height !== this._height || dprChanged) {
                 domRoot.style.width = width + 'px';
                 domRoot.style.height = height + 'px';
 
                 for (let id in this._layers) {
                     if (this._layers.hasOwnProperty(id)) {
-                        this._layers[id].resize(width, height);
+                        this._layers[id].resize(width, height, this.dpr);
                     }
                 }
 

src/config.ts

@@ -1,14 +1,16 @@
 import env from './core/env';
 
-let dpr = 1;
-
-// If in browser environment
-if (env.hasGlobalWindow) {
-    dpr = Math.max(
-        window.devicePixelRatio
-        || (window.screen && (window.screen as any).deviceXDPI / (window.screen as any).logicalXDPI)
-        || 1, 1
-    );
+export function getDevicePixelRatio(): number {
+    let dpr = 1;
+
+    // If in browser environment
+    if (env.hasGlobalWindow) {
+        dpr = window.devicePixelRatio
+            || (window.screen && (window.screen as any).deviceXDPI / (window.screen as any).logicalXDPI)
+            || 1;
+    }
+
+    return dpr;
 }
 
 /**
@@ -19,7 +21,7 @@ if (env.hasGlobalWindow) {
 export const debugMode = 0;
 
 // retina 屏幕优化
-export const devicePixelRatio = dpr;
+export const devicePixelRatio = getDevicePixelRatio();
 
 
 /**

src/core/PathProxy.ts

@@ -9,7 +9,6 @@
 
 import * as vec2 from './vector';
 import BoundingRect from './BoundingRect';
-import {devicePixelRatio as dpr} from '../config';
 import { fromLine, fromCubic, fromQuadratic, fromArc } from './bbox';
 import { cubicLength, cubicSubdivide, quadraticLength, quadraticSubdivide } from './curve';
 
@@ -177,6 +176,7 @@ export default class PathProxy {
         // Compat. Previously there is no segmentIgnoreThreshold.
         segmentIgnoreThreshold = segmentIgnoreThreshold || 0;
         if (segmentIgnoreThreshold > 0) {
+            const dpr = this.dpr || 1;
             this._ux = mathAbs(segmentIgnoreThreshold / dpr / sx) || 0;
             this._uy = mathAbs(segmentIgnoreThreshold / dpr / sy) || 0;
         }

src/zrender.ts

@@ -338,12 +338,13 @@ class ZRender {
     resize(opts?: {
         width?: number| string
         height?: number | string
+        devicePixelRatio?: number
     }) {
         if (this._disposed) {
             return;
         }
         opts = opts || {};
-        this.painter.resize(opts.width, opts.height);
+        this.painter.resize(opts.width, opts.height, opts.devicePixelRatio);
         this.handler.resize();
     }