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# lineScreen()

Creates a monochrome image with a series of small lines to add detail.

```
class func lineScreen() -> any CIFilter & CILineScreen
```

## Return Value

The modified image.

## Discussion

This method applies a line screen filter to an image. The effect generates a monochrome image containing a series of lines creating detail. The halftone effect is a set of lines, dots, or circles that contain detail. When viewing the image from a distance, the markings blend together, creating the illusion of continuous lines and shapes. Print media commonly uses this effect.

The line screen filter uses the following properties:

- `inputImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).
- `center`: A set of coordinates marking the center of the image as a <doc://com.apple.documentation/documentation/CoreFoundation/CGPoint>.
- `angle`: A `float` representing the angle of the pattern as an <doc://com.apple.documentation/documentation/Foundation/NSNumber>.
- `width`: A `float` representing the distance between lines in the pattern as an <doc://com.apple.documentation/documentation/Foundation/NSNumber>.
- `sharpness`: A `float` representing the sharpness of the pattern as an <doc://com.apple.documentation/documentation/Foundation/NSNumber>.

The following code creates a filter that creates a monochrome image containing small lines of detail on a black background:

```swift
func line(inputImage: CIImage) -> CIImage {
    let lineScreen = CIFilter.lineScreen()
    lineScreen.inputImage = inputImage
    lineScreen.center = CGPoint(x: 2016, y: 1512)
    lineScreen.angle = 1
    lineScreen.width = 35
    lineScreen.sharpness = 0.7
    return lineScreen.outputImage!
}
```

![Two photographs of a wooden barrel of green artichokes. The artichokes are crisp with good lighting. The photo one the left has no modifications to color or detail. In the photo on the right, a line screen filter is applied, resulting in a lighter, monochrome image with an overlay of lines, creating the detail of the image.](images/com.apple.coreimage/media-3595915@2x.png)

---

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