# Read from a Specific Area

## Set a Scan Region on Camera

<div class="sample-code-prefix"></div>
>- Objective-C
>- Swift
>
>1. 
```objc
DSRect *region = [[DSRect alloc] init];
region.left = 0.15;
region.top = 0.25;
region.right = 0.85;
region.bottom = 0.65;
[self.dce setScanRegion:region error:nil];
```
2. 
```swift
let region = Rect()
region.left = 0.15
region.top = 0.25
region.right = 0.85
region.bottom = 0.65
try? dce.setScanRegion(region)
```

**Related APIs**

- [`CameraEnhancer`](/barcode-reader/docs/mobile/programming/objectivec-swift/api-reference/camera-enhancer/camera-enhancer.html)
   - [`setScanRegion`](/barcode-reader/docs/mobile/programming/objectivec-swift/api-reference/camera-enhancer/camera-enhancer.html#setscanregion)

## Set an ROI via Simplified Settings

> [!Important]
> Simplified Settings are only available for the **Foundational APIs**.

<div class="sample-code-prefix"></div>
>- Objective-C
>- Swift
>
>1. 
```objc
NSError *error = nil;
DSSimplifiedCaptureVisionSettings *captureVisionSettings = [self.cvr getSimplifiedSettings:DSPresetTemplateReadBarcodes error:&error];
NSArray<NSValue *> *points = @[
   [NSValue valueWithCGPoint:CGPointMake(15, 30)],
   [NSValue valueWithCGPoint:CGPointMake(85, 30)],
   [NSValue valueWithCGPoint:CGPointMake(85, 70)],
   [NSValue valueWithCGPoint:CGPointMake(15, 70)]
];
DSQuadrilateral *roiQuad = [[DSQuadrilateral alloc] initWithPointArray:points];
captureVisionSettings.roi = roiQuad;
captureVisionSettings.roiMeasuredInPercentage = YES;
[self.cvr updateSettings:DSPresetTemplateReadBarcodes settings:captureVisionSettings error:&error];
```
2. 
```swift
let captureVisionSettings = try cvr.getSimplifiedSettings(PresetTemplate.readBarcodes.rawValue)
let point0 = CGPoint(x: 15, y: 30) as NSValue
let point1 = CGPoint(x: 85, y: 30) as NSValue
let point2 = CGPoint(x: 85, y: 55) as NSValue
let point3 = CGPoint(x: 15, y: 55) as NSValue
let roiQuad = Quadrilateral.init(pointArray: [point0,point1,point2,point3])
captureVisionSettings.roi = roiQuad
captureVisionSettings.roiMeasuredInPercentage = true
do {
   try cvr.updateSettings(PresetTemplate.readBarcodes.rawValue, settings: captureVisionSettings)
} catch {
}
```

## Set ROIs in Customized Template

Define a single ROI:

```json
{
   "CaptureVisionTemplates": [
      {
            "Name" : "CV_0",
            "ImageROIProcessingNameArray": ["barcode-decoding-roi-1" ]
      }       
   ],
   "TargetROIDefOptions" : [
      {
         "Name" : "barcode-decoding-roi-1",
         "TaskSettingNameArray": ["barcode-decoding-task-1"],
         "Location": 
         {
            "Offset": {
               "MeasuredByPercentage" : 1,
               "FirstPoint" : [ 15, 30 ],
               "SecondPoint" : [ 85, 30 ],
               "ThirdPoint" : [ 85, 70 ],
               "FourthPoint" : [ 15, 70 ],
            }
         }
      }
   ]
}
```

You can define multiple ROIs in `TargetROIDefOptions`. For each ROI, you can assign a different task or reuse the same task.

```json
{
   "CaptureVisionTemplates": [
      {
            "Name" : "CV_0",
            "ImageROIProcessingNameArray": ["barcode-decoding-roi-1","barcode-decoding-roi-2" ]
      }       
   ],
   "TargetROIDefOptions" : [
      {
         "Name" : "barcode-decoding-roi-1",
         "TaskSettingNameArray": ["barcode-decoding-task-1"],
         "Location": 
         {
            "Offset": {
               "MeasuredByPercentage" : 1,
               "FirstPoint" : [ 15, 20 ],
               "SecondPoint" : [ 85, 40 ],
               "ThirdPoint" : [ 85, 40 ],
               "FourthPoint" : [ 15, 20 ]
            }
         }
      },{
         "Name" : "barcode-decoding-roi-2",
         "TaskSettingNameArray": ["barcode-decoding-task-1"],
         "Location": 
         {
            "Offset": {
               "MeasuredByPercentage" : 1,
               "FirstPoint" : [ 15, 60 ],
               "SecondPoint" : [ 85, 80 ],
               "ThirdPoint" : [ 85, 80 ],
               "FourthPoint" : [ 15, 60 ]
            }
         }
      }
   ]
}
```