STTouchDisplay

STTouchDisplay draws touch markers over an iOS app. It is an Objective-C static library for iOS 15 and later.

Integrate

Add STTouchDisplay.xcodeproj to your app project as a project reference. Make STTouchDisplay a target dependency of your app, link libSTTouchDisplay.a, and add $(BUILT_PRODUCTS_DIR)/include to the app target's Header Search Paths. The library exports STTouchDisplay.h and STTouchDisplayView.h under STTouchDisplay/.

Demo

Open STTouchDisplay.xcworkspace and run the STTouchDisplayDemo scheme on an iOS simulator. The demo links the root project's libSTTouchDisplay.a product through an Xcode project reference. Tap the button or drag on the screen to see markers without blocking the app's controls.

Display touches

Install one display view in each window you want to observe. For an iOS scene, create your window with initWithWindowScene:, assign its root view controller, and install the overlay before making the window key and visible. A window subclass can forward touch events:

#import <STTouchDisplay/STTouchDisplay.h>

@interface TouchDisplayWindow : UIWindow
@property(nonatomic, strong) STTouchDisplayView *touchDisplay;
- (void)installTouchDisplay;
@end

@implementation TouchDisplayWindow
- (void)installTouchDisplay {
    self.touchDisplay = [[STTouchDisplayView alloc] initWithFrame:self.bounds];
    self.touchDisplay.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    [self addSubview:self.touchDisplay];
}

- (void)sendEvent:(UIEvent *)event {
    [super sendEvent:event];
    [self.touchDisplay updateWithEvent:event];
}
@end

In your scene delegate's scene:willConnectToSession:options:, after creating rootViewController:

UIWindowScene *windowScene = (UIWindowScene *)scene;
TouchDisplayWindow *window = [[TouchDisplayWindow alloc] initWithWindowScene:windowScene];
window.rootViewController = rootViewController;
[window installTouchDisplay];
self.window = window;
[window makeKeyAndVisible];

The overlay does not intercept touches and only tracks events from its own window. Markers are a visual aid, not a measurement of finger contact area.

Marker size scales uniformly with UIKit's UITouch.majorRadius; a nonpositive radius uses the default size. The display does not represent contact rotation or an exact ellipse.

Development

The STTouchDisplay scheme in the root project runs the library's unit tests. The demo scheme runs a UI test for button interaction and touch marker lifecycle. CI checks formatting, builds and analyzes both projects, and runs both test targets. STTouchDisplayImage.m contains embedded image data and is excluded from the formatting check.

Run the same checks locally with ./scripts/check-formatting.sh, ./scripts/build-library.sh, ./scripts/test-library.sh, and ./scripts/analyze-library.sh. For the demo, run ./scripts/build-demo.sh, ./scripts/test-demo-ui.sh, and ./scripts/analyze-demo.sh. Both test scripts use an iPhone 17 simulator by default; pass an Xcode destination string as the argument to use another device.

License

The project is licensed under the MIT License.