feat: add dpr

DOC.md

@@ -5655,6 +5655,43 @@ function download(
 download('test', 'test.txt');
 ```
 
+## dpr 
+
+Device pixel ratio helper.
+
+<details>
+<summary>Type Definition</summary>
+
+```typescript
+namespace dpr {
+    interface IDpr extends Emitter {
+        get(): number;
+    }
+}
+const dpr: dpr.IDpr;
+```
+
+</details>
+
+### on
+
+Bind change event.
+
+### off
+
+Unbind change event.
+
+### get
+
+Get current device pixel ratio.
+
+```javascript
+dpr.on('change', function(dpr) {
+    console.log(dpr); // -> 2
+});
+dpr.get(); // -> 1
+```
+
 ## durationFormat 
 
 Simple duration format function.

DOC_CN.md

@@ -5647,6 +5647,43 @@ function download(
 download('test', 'test.txt');
 ```
 
+## dpr
+
+设备像素比工具库。
+
+<details>
+<summary>类型定义</summary>
+
+```typescript
+namespace dpr {
+    interface IDpr extends Emitter {
+        get(): number;
+    }
+}
+const dpr: dpr.IDpr;
+```
+
+</details>
+
+### on
+
+绑定 change 事件。
+
+### off
+
+解绑 change 事件。
+
+### get
+
+获取当前设备像素比。
+
+```javascript
+dpr.on('change', function(dpr) {
+    console.log(dpr); // -> 2
+});
+dpr.get(); // -> 1
+```
+
 ## durationFormat
 
 简单时间格式化。

cspell.json

@@ -112,6 +112,7 @@
     "Dispatcher",
     "dotCase",
     "download",
+    "dpr",
     "durationFormat",
     "each",
     "easing",

demo/dpr.demo.html

@@ -0,0 +1,5 @@
+<require>dpr</require>
+<script>
+    console.log(dpr.get());
+    dpr.on('change', dpr => console.log(dpr));
+</script>

i18n/dpr.md

@@ -0,0 +1,15 @@
+## CN
+
+设备像素比工具库。
+
+### on
+
+绑定 change 事件。
+
+### off
+
+解绑 change 事件。
+
+### get
+
+获取当前设备像素比。

index.json

@@ -2250,6 +2250,20 @@
             "browser"
         ]
     },
+    "dpr": {
+        "demo": true,
+        "dependencies": [
+            "Emitter",
+            "MediaQuery"
+        ],
+        "description": "Device pixel ratio helper.",
+        "env": [
+            "browser"
+        ],
+        "test": [
+            "browser"
+        ]
+    },
     "durationFormat": {
         "dependencies": [
             "toInt",

src/dpr.js

@@ -0,0 +1,57 @@
+/* Device pixel ratio helper.
+ *
+ * ### on
+ *
+ * Bind change event.
+ *
+ * ### off
+ *
+ * Unbind change event.
+ *
+ * ### get
+ *
+ * Get current device pixel ratio.
+ */
+
+/* example
+ * dpr.on('change', function(dpr) {
+ *     console.log(dpr); // -> 2
+ * });
+ * dpr.get(); // -> 1
+ */
+
+/* module
+ * env: browser
+ */
+
+/* typescript
+ * export declare namespace dpr {
+ *     interface IDpr extends Emitter {
+ *         get(): number;
+ *     }
+ * }
+ * export declare const dpr: dpr.IDpr;
+ */
+
+_('Emitter MediaQuery');
+
+const m = new MediaQuery(`(resolution: ${get()}dppx)`);
+
+exports = {
+    get
+};
+
+Emitter.mixin(exports);
+
+function get() {
+    return window.devicePixelRatio || 1;
+}
+
+function change() {
+    const dpr = get();
+    m.setQuery(`(resolution: ${dpr}dppx)`);
+    exports.emit('change', dpr);
+}
+
+m.on('match', change);
+m.on('unmatch', change);

test/dpr.js

@@ -0,0 +1 @@
+expect(dpr.get()).to.equal(window.devicePixelRatio);