> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rebellapp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# my.setScreenBrightness

> Set the screen brightness level.

Use this API to set the screen brightness level. This is useful for QR code display screens or reading modes.

## Parameters

| Property   | Type     | Required | Description                                                   |
| ---------- | -------- | -------- | ------------------------------------------------------------- |
| brightness | Number   | Yes      | Brightness value (0-1), where 0 is darkest and 1 is brightest |
| success    | Function | No       | Callback on success                                           |
| fail       | Function | No       | Callback on failure                                           |
| complete   | Function | No       | Callback that always executes                                 |

## Code Example

### Basic Usage

```javascript theme={null}
my.setScreenBrightness({
  brightness: 1.0, // Maximum brightness
  success() {
    console.log('Brightness set');
  }
});
```

### QR Code Display

```javascript theme={null}
Page({
  data: {
    originalBrightness: 0.5
  },

  onLoad() {
    // Save original brightness
    my.getScreenBrightness({
      success: (res) => {
        this.setData({ originalBrightness: res.brightness });
        // Set to max for QR code
        my.setScreenBrightness({ brightness: 1.0 });
      }
    });
  },

  onUnload() {
    // Restore original brightness
    my.setScreenBrightness({
      brightness: this.data.originalBrightness
    });
  }
});
```

### Reading Mode Toggle

```javascript theme={null}
Page({
  data: {
    readingMode: false,
    savedBrightness: 0.5
  },

  toggleReadingMode() {
    if (this.data.readingMode) {
      // Exit reading mode
      my.setScreenBrightness({
        brightness: this.data.savedBrightness,
        success: () => {
          this.setData({ readingMode: false });
        }
      });
    } else {
      // Enter reading mode (dim screen)
      my.getScreenBrightness({
        success: (res) => {
          this.setData({ savedBrightness: res.brightness });
          my.setScreenBrightness({
            brightness: 0.3,
            success: () => {
              this.setData({ readingMode: true });
            }
          });
        }
      });
    }
  }
});
```

### Brightness Slider

```javascript theme={null}
Page({
  onSliderChange(e) {
    const brightness = e.detail.value / 100;
    my.setScreenBrightness({
      brightness: brightness
    });
  }
});
```

<Warning>
  Always restore the original brightness when leaving a page that modified it. Users may find it disruptive if brightness changes persist unexpectedly.
</Warning>

## Related APIs

<CardGroup cols={2}>
  <Card title="my.getScreenBrightness" icon="sun" href="/jsapi/device/screen-brightness/my.getScreenBrightness">
    Get current brightness
  </Card>
</CardGroup>