iPhone: reduce controller present and dismiss latency

- add simple shutter to mask video start
anisibor · Aug 22, 2011 · 93560e8 · 93560e8
1 parent 98fe10d
commit 93560e8
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Showing 7 changed files with 90 additions and 8 deletions.
diff --git a/iphone/ChangeLog b/iphone/ChangeLog
@@ -1,3 +1,7 @@
+version 1.2.2:
+  * reduce controller present and dismiss latency
+    - add simple shutter to mask video start
+
 version 1.2.1:
   * fix overlay resizing bug
 

diff --git a/iphone/ZBarReaderViewController.m b/iphone/ZBarReaderViewController.m
@@ -217,6 +217,8 @@ - (void) cleanup
     readerView = nil;
     [controls release];
     controls = nil;
+    [shutter release];
+    shutter = nil;
 }
 
 - (void) dealloc
@@ -355,6 +357,15 @@ - (void) viewDidLoad
     readerView.enableCache = enableCache;
     [view addSubview: readerView];
 
+    shutter = [[UIView alloc]
+                  initWithFrame: r];
+    shutter.backgroundColor = [UIColor blackColor];
+    shutter.opaque = NO;
+    shutter.autoresizingMask =
+        UIViewAutoresizingFlexibleWidth |
+        UIViewAutoresizingFlexibleHeight;
+    [view addSubview: shutter];
+
     if(cameraOverlayView) {
         assert(!cameraOverlayView.superview);
         [cameraOverlayView removeFromSuperview];
@@ -386,7 +397,11 @@ - (void) viewWillAppear: (BOOL) animated
 
     [readerView willRotateToInterfaceOrientation: self.interfaceOrientation
                 duration: 0];
-    [readerView start];
+    [readerView performSelector: @selector(start)
+                withObject: nil
+                afterDelay: .001];
+    shutter.alpha = 1;
+    shutter.hidden = NO;
 
     UIApplication *app = [UIApplication sharedApplication];
     BOOL willHideStatusBar =
@@ -410,7 +425,7 @@ - (void) dismissModalViewControllerAnimated: (BOOL) animated
 
 - (void) viewWillDisappear: (BOOL) animated
 {
-    [readerView stop];
+    readerView.captureReader.enableReader = NO;
 
     if(didHideStatusBar) {
         [[UIApplication sharedApplication]
@@ -422,6 +437,13 @@ - (void) viewWillDisappear: (BOOL) animated
     [super viewWillDisappear: animated];
 }
 
+- (void) viewDidDisappear: (BOOL) animated
+{
+    // stopRunning can take a really long time (>1s observed),
+    // so defer until the view transitions are complete
+    [readerView stop];
+}
+
 - (BOOL) shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation) orient
 {
     return((supportedOrientationsMask >> orient) & 1);
@@ -620,7 +642,7 @@ - (void) removeHelp: (NSString*) tag
 
 // ZBarReaderViewDelegate
 
-- (void) readerView: (ZBarReaderView*) view
+- (void) readerView: (ZBarReaderView*) readerView
      didReadSymbols: (ZBarSymbolSet*) syms
           fromImage: (UIImage*) image
 {
@@ -633,6 +655,19 @@ - (void) readerView: (ZBarReaderView*) view
                 nil]];
 }
 
+- (void) readerViewDidStart: (ZBarReaderView*) readerView
+{
+    if(!shutter.hidden)
+        [UIView animateWithDuration: .25
+                animations: ^{
+                    shutter.alpha = 0;
+                }
+                completion: ^(BOOL finished) {
+                    shutter.hidden = YES;
+                }];
+}
+
+
 // "deprecated" properties
 
 #define DEPRECATED_PROPERTY(getter, setter, type, val, ignore) \

diff --git a/iphone/ZBarReaderViewImpl_Capture.m b/iphone/ZBarReaderViewImpl_Capture.m
@@ -267,6 +267,9 @@ - (void) onVideoStart: (NSNotification*) note
     }
     else
         zlog(@"failed to lock device: %@", error);
+
+    if([readerDelegate respondsToSelector: @selector(readerViewDidStart:)])
+        [readerDelegate readerViewDidStart: self];
 }
 
 - (void) onVideoStop: (NSNotification*) note
@@ -277,6 +280,11 @@ - (void) onVideoStop: (NSNotification*) note
 
     [device unlockForConfiguration];
     running = NO;
+
+    if([readerDelegate respondsToSelector:
+                           @selector(readerView:didStopWithError:)])
+        [readerDelegate readerView: self
+                        didStopWithError: nil];
 }
 
 - (void) onVideoError: (NSNotification*) note
@@ -289,9 +297,15 @@ - (void) onVideoError: (NSNotification*) note
     }
     NSError *err =
         [note.userInfo objectForKey: AVCaptureSessionErrorKey];
-    NSLog(@"ZBarReaderView: ERROR during capture: %@: %@",
-          [err localizedDescription],
-          [err localizedFailureReason]);
+
+    if([readerDelegate respondsToSelector:
+                           @selector(readerView:didStopWithError:)])
+        [readerDelegate readerView: self
+                        didStopWithError: err];
+    else
+        NSLog(@"ZBarReaderView: ERROR during capture: %@: %@",
+              [err localizedDescription],
+              [err localizedFailureReason]);
 }
 
 // NSKeyValueObserving

diff --git a/iphone/ZBarReaderViewImpl_Simulator.m b/iphone/ZBarReaderViewImpl_Simulator.m
@@ -125,6 +125,10 @@ - (void) start
         return;
     [super start];
     running = YES;
+
+    [self performSelector: @selector(onVideoStart)
+          withObject: nil
+          afterDelay: 0.5];
 }
 
 - (void) stop
@@ -133,6 +137,10 @@ - (void) stop
         return;
     [super stop];
     running = NO;
+
+    [self performSelector: @selector(onVideoStop)
+          withObject: nil
+          afterDelay: 0.5];
 }
 
 - (void) scanImage: (UIImage*) image
@@ -192,4 +200,20 @@ - (void) didReadSymbols: (ZBarSymbolSet*) syms
     scanImage = nil;
 }
 
+- (void) onVideoStart
+{
+    if(running &&
+       [readerDelegate respondsToSelector: @selector(readerViewDidStart:)])
+        [readerDelegate readerViewDidStart: self];
+}
+
+- (void) onVideoStop
+{
+    if(!running &&
+       [readerDelegate respondsToSelector:
+                           @selector(readerView:didStopWithError:)])
+        [readerDelegate readerView: self
+                        didStopWithError: nil];
+}
+
 @end
diff --git a/iphone/include/ZBarSDK/ZBarReaderView.h b/iphone/include/ZBarSDK/ZBarReaderView.h
@@ -36,6 +36,11 @@
      didReadSymbols: (ZBarSymbolSet*) symbols
           fromImage: (UIImage*) image;
 
+@optional
+- (void) readerViewDidStart: (ZBarReaderView*) readerView;
+- (void) readerView: (ZBarReaderView*) readerView
+   didStopWithError: (NSError*) error;
+
 @end
 
 // read barcodes from the displayed video preview.  the view maintains

diff --git a/iphone/include/ZBarSDK/ZBarReaderViewController.h b/iphone/include/ZBarSDK/ZBarReaderViewController.h
@@ -56,7 +56,7 @@
     BOOL showsZBarControls, tracksSymbols, enableCache;
 
     ZBarHelpController *helpController;
-    UIView *controls;
+    UIView *controls, *shutter;
     BOOL didHideStatusBar, rotating;
     ZBarCameraSimulator *cameraSim;
 }

diff --git a/iphone/res/ZBarSDK-Info.plist b/iphone/res/ZBarSDK-Info.plist
@@ -7,7 +7,7 @@
 	<key>CFBundleName</key>
 	<string>ZBarSDK</string>
 	<key>CFBundleVersion</key>
-	<string>1.2.1</string>
+	<string>1.2.2</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>NSHumanReadableCopyright</key>