Merge pull request #111 from RobertSasak/features/zoom-ios

Implement pinch to zoom
RobertSasak · May 4, 2021 · ae8a12d · ae8a12d
2 parents 405e0b4 + bb41122
commit ae8a12d
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Showing 5 changed files with 46 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -284,3 +284,7 @@ Note: If you are getting errors, double check that you have completed all of the
 
 - OpenALPR built from [OpenALPR-iOS](https://github.com/twelve17/openalpr-ios)
 - Project scaffold based on [react-native-camera](https://github.com/lwansbrough/react-native-camera)
+
+## Sponsors
+
+- [repocoin.io](https://repocoin.io)
diff --git a/example/App.js b/example/App.js
@@ -317,7 +317,7 @@ export default class App extends Component {
         </TouchableOpacity>
         <Text style={styles.plateText}>{plate}</Text>
         <Text style={styles.confidenceText}>
-          {confidence ? confidence + '%' : ''}
+          {confidence ? (+confidence).toFixed(1) + '%' : ''}
         </Text>
         <TouchableOpacity
           style={styles.takePicture}

diff --git a/ios/ALPRCamera.m b/ios/ALPRCamera.m
@@ -163,6 +163,14 @@ - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
         {
             [self.camFocus removeFromSuperview];
         }
+        NSDictionary *event = @{
+          @"target": self.reactTag,
+          @"touchPoint": @{
+            @"x": [NSNumber numberWithDouble:touchPoint.x],
+            @"y": [NSNumber numberWithDouble:touchPoint.y]
+          }
+        };
+        [self.bridge.eventDispatcher sendAppEventWithName:@"focusChanged" body:event];
 
         // Show animated rectangle on the touched area
         if (_touchToFocus) {
@@ -181,13 +189,12 @@ - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
     if (allTouchesEnded) {
         _multipleTouches = NO;
     }
-    
+
 }
 
 -(void) handlePinchToZoomRecognizer:(UIPinchGestureRecognizer*)pinchRecognizer {
-
     if (pinchRecognizer.state == UIGestureRecognizerStateChanged) {
-        return;
+        [self.manager zoom:pinchRecognizer.velocity reactTag:self.reactTag];
     }
 }
 

diff --git a/ios/ALPRCameraManager.h b/ios/ALPRCameraManager.h
@@ -54,5 +54,6 @@ typedef NS_ENUM(NSInteger, ALPRCameraTorchMode) {
 - (void)startSession;
 - (void)stopSession;
 - (void)focusAtThePoint:(CGPoint) atPoint;
+- (void)zoom:(CGFloat)velocity reactTag:(NSNumber *)reactTag;
 
 @end
diff --git a/ios/ALPRCameraManager.mm b/ios/ALPRCameraManager.mm
@@ -563,6 +563,36 @@ - (void)focusAtThePoint:(CGPoint) atPoint;
     }
 }
 
+- (void)zoom:(CGFloat)velocity reactTag:(NSNumber *)reactTag{
+    if (isnan(velocity)) {
+        return;
+    }
+    const CGFloat pinchVelocityDividerFactor = 20.0f; // TODO: calibrate or make this component's property
+    NSError *error = nil;
+    AVCaptureDevice *device = [[self videoCaptureDeviceInput] device];
+    if ([device lockForConfiguration:&error]) {
+        CGFloat zoomFactor = device.videoZoomFactor + atan(velocity / pinchVelocityDividerFactor);
+        if (zoomFactor > device.activeFormat.videoMaxZoomFactor) {
+            zoomFactor = device.activeFormat.videoMaxZoomFactor;
+        } else if (zoomFactor < 1) {
+            zoomFactor = 1.0f;
+        }
+
+        NSDictionary *event = @{
+          @"target": reactTag,
+          @"zoomFactor": [NSNumber numberWithDouble:zoomFactor],
+          @"velocity": [NSNumber numberWithDouble:velocity]
+        };
+
+        [self.bridge.eventDispatcher sendAppEventWithName:@"zoomChanged" body:event];
+
+        device.videoZoomFactor = zoomFactor;
+        [device unlockForConfiguration];
+    } else {
+        NSLog(@"error: %@", error);
+    }
+}
+
 - (void)setCaptureQuality:(NSString *)quality
 {
 #if !(TARGET_IPHONE_SIMULATOR)