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1# Graphics Development
2
3## How do I obtain the DPI of a device?
4
5Applicable to: OpenHarmony 3.2 Beta5 (API version 9, stage model)
6
7**Solution**
8
9Import the **@ohos.display** module and call the **getDefaultDisplaySync\(\)** API.
10
11**Example**
12
13```
14import display from '@ohos.display';
15let displayClass = null;
16try {
17  displayClass = display.getDefaultDisplaySync();
18  console.info('Test densityDPI:' + JSON.stringify(displayClass.densityDPI));
19} catch (exception) {
20  console.error('Failed to obtain the default display object. Code: ' + JSON.stringify(exception));
21}
22```
23
24## How do I obtain the window width and height?
25
26Applicable to: OpenHarmony 3.2 Beta5 (API version 9, stage model)
27
28**Solution**
29
30Import the **@ohos.window** module, obtain a **Window** object, and use **getWindowProperties\(\)** of the object to obtain the window properties. The **windowRect** field in the properties specifies the window width and height.
31
32**Example**
33
34```
35import window from '@ohos.window';
36let windowClass = null;
37try {
38    let promise = window.getLastWindow(this.context);
39    promise.then((data)=> {
40        // Obtain a Window object.
41        windowClass = data;
42        try {
43            // Obtain the window properties.
44            let properties = windowClass.getWindowProperties();
45            let rect = properties.windowRect;
46            // rect.width: window width; rect.height: window height.
47        } catch (exception) {
48             console.error('Failed to obtain the window properties. Cause: ' + JSON.stringify(exception));
49        }
50        console.info('Succeeded in obtaining the top window. Data: ' + JSON.stringify(data));
51    }).catch((err)=>{
52        console.error('Failed to obtain the top window. Cause: ' + JSON.stringify(err));
53    });} catch (exception) {
54    console.error('Failed to obtain the top window. Cause: ' + JSON.stringify(exception));
55}
56```
57
58## How do I perform Gaussian blurring on images?
59
60Applicable to: OpenHarmony 3.2 Beta5 (API version 9)
61
62**Solution**
63
64Import the **@ohos.multimedia.image** and **@ohos.effectKit** modules to process the image and add the blur effect.
65
66**Example**
67
68```
69import image from "@ohos.multimedia.image";
70import effectKit from "@ohos.effectKit";
71
72  const color = new ArrayBuffer(96);
73  let opts = { editable: true, pixelFormat: 3, size: { height: 4, width: 6 } };
74  image.createPixelMap(color, opts).then((pixelMap) => {
75    let radius = 5;
76    let headFilter = effectKit.createEffect(pixelMap);
77    if (headFilter != null) {
78      headFilter.blur(radius);
79    }
80  })
81```
82
83**Reference**
84
85[blur](../reference/apis/js-apis-effectKit.md#blur)
86