* A mouse shake detecting BMessageFilter that's easily integrated in any app.

* A test app for it. I added a src/test/kits/shared folder as i found it was the
 most logical place for it. Shake it up.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32602 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/shared/ShakeTrackingFilter.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2009, Alexandre Deckner, alex@zappotek.com
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef SHAKE_TRACKING_FILTER_H
+#define SHAKE_TRACKING_FILTER_H
+
+
+#include <MessageFilter.h>
+#include <Point.h>
+
+class BView;
+class BHandler;
+class BMessageRunner;
+
+namespace BPrivate {
+
+class LowPassFilter {
+public:
+						LowPassFilter(uint32 size);
+						~LowPassFilter();
+
+			void	    Input(const BPoint& p);
+			BPoint		Output() const;
+private:
+	BPoint* fPoints;
+	uint32	fSize;
+	BPoint	fSum;
+};
+
+
+class ShakeTrackingFilter : public BMessageFilter {
+public:
+								ShakeTrackingFilter(
+									BView* targetView,
+									uint32 messageWhat,
+									uint32 countThreshold = 2,
+									bigtime_t timeTreshold = 400000);
+
+								~ShakeTrackingFilter();
+
+			filter_result		Filter(BMessage* message, BHandler** _target);
+
+private:
+			BView*				fTargetView;
+			uint32				fMessageWhat;
+
+			BMessageRunner*		fCancelRunner;
+			LowPassFilter		fLowPass;
+			BPoint				fLastDelta;
+			BPoint				fLastPosition;
+			uint32				fCounter;
+			uint32				fCountThreshold;
+			bigtime_t			fTimeThreshold;
+};
+
+}	// namespace BPrivate
+
+using BPrivate::ShakeTrackingFilter;
+using BPrivate::LowPassFilter;
+
+#endif	// SHAKE_TRACKING_FILTER_H

src/kits/shared/Jamfile

@@ -20,6 +20,7 @@ StaticLibrary libshared.a :
 	DragTrackingFilter.cpp
 	HashString.cpp
 	RWLockManager.cpp
+	ShakeTrackingFilter.cpp
 	Variant.cpp
 ;
 

src/kits/shared/ShakeTrackingFilter.cpp

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2009, Alexandre Deckner, alex@zappotek.com
+ * Distributed under the terms of the MIT License.
+ */
+
+/*!
+	\class ShakeTrackingFilter
+	\brief A simple mouse shake detection filter
+	*
+	* A simple mouse filter that detects quick mouse shakes.
+	*
+	* It's detecting rough edges (u-turns) in the mouse movement
+	* and counts them within a time window.
+	* You can configure the message sent, the u-turn count threshold
+	* and the time threshold.
+	* It sends the count along with the message.
+	* For now, detection is limited within the view bounds, but
+	* it might be modified to accept a BRegion mask.
+	*
+*/
+
+#include <ShakeTrackingFilter.h>
+
+#include <Message.h>
+#include <Messenger.h>
+#include <MessageRunner.h>
+#include <View.h>
+
+
+ShakeTrackingFilter::ShakeTrackingFilter(BView* targetView, uint32 messageWhat,
+	uint32 countThreshold, bigtime_t timeThreshold)
+	:
+	BMessageFilter(B_ANY_DELIVERY, B_ANY_SOURCE),
+	fTargetView(targetView),
+	fMessageWhat(messageWhat),
+	fCancelRunner(NULL),
+	fLowPass(8),
+	fLastDelta(0, 0),
+	fCounter(0),
+	fCountThreshold(countThreshold),
+	fTimeThreshold(timeThreshold)
+{
+}
+
+
+ShakeTrackingFilter::~ShakeTrackingFilter()
+{
+	delete fCancelRunner;
+}
+
+
+filter_result
+ShakeTrackingFilter::Filter(BMessage* message, BHandler** /*_target*/)
+{
+	if (fTargetView == NULL)
+		return B_DISPATCH_MESSAGE;
+
+	switch (message->what) {
+		case B_MOUSE_MOVED:
+		{
+			BPoint position;
+			message->FindPoint("be:view_where", &position);
+
+			// TODO: allow using BRegion masks
+			if (!fTargetView->Bounds().Contains(position))
+				return B_DISPATCH_MESSAGE;
+
+			fLowPass.Input(position - fLastPosition);
+
+			BPoint delta = fLowPass.Output();
+
+			// normalized dot product
+			float norm = delta.x * delta.x + delta.y * delta.y;
+			if (norm > 0.01) {
+				delta.x /= norm;
+				delta.y /= norm;
+			}
+
+			norm = fLastDelta.x * fLastDelta.x + fLastDelta.y * fLastDelta.y;
+			if (norm > 0.01) {
+				fLastDelta.x /= norm;
+				fLastDelta.y /= norm;
+			}
+
+			float dot = delta.x * fLastDelta.x + delta.y * fLastDelta.y;
+
+			if (dot < 0.0) {
+				if (fCounter == 0) {
+					BMessage * cancelMessage = new BMessage(kMsgCancel);
+		 			fCancelRunner = new BMessageRunner(BMessenger(fTargetView),
+		 				cancelMessage, fTimeThreshold, 1);
+				}
+
+				fCounter++;
+
+				if (fCounter >= fCountThreshold) {
+					BMessage shakeMessage(fMessageWhat);
+					shakeMessage.AddUInt32("count", fCounter);
+					BMessenger messenger(fTargetView);
+					messenger.SendMessage(&shakeMessage);
+				}
+			}
+
+			fLastDelta = fLowPass.Output();
+			fLastPosition = position;
+
+			return B_DISPATCH_MESSAGE;
+		}
+
+		case kMsgCancel:
+			delete fCancelRunner;
+			fCancelRunner = NULL;
+			fCounter = 0;
+			return B_SKIP_MESSAGE;
+
+		default:
+			break;
+	}
+
+	return B_DISPATCH_MESSAGE;
+}
+
+
+//	#pragma mark -
+
+
+LowPassFilter::LowPassFilter(uint32 size)
+	:
+	fSize(size)
+{
+	fPoints = new BPoint[fSize];
+}
+
+
+LowPassFilter::~LowPassFilter()
+{
+	delete [] fPoints;
+}
+
+
+void
+LowPassFilter::Input(const BPoint& p)
+{
+	// A fifo buffer that maintains a sum of its elements
+	fSum -= fPoints[0];
+	for (uint32 i = 0; i < fSize - 1; i++)
+		fPoints[i] = fPoints[i + 1];
+	fPoints[fSize - 1] = p;
+	fSum += p;
+}
+
+
+BPoint
+LowPassFilter::Output() const
+{
+	return BPoint(fSum.x / (float) fSize, fSum.y / (float) fSize);
+}

src/tests/kits/Jamfile

@@ -7,6 +7,7 @@ SubInclude HAIKU_TOP src tests kits locale ;
 SubInclude HAIKU_TOP src tests kits media ;
 SubInclude HAIKU_TOP src tests kits midi ;
 SubInclude HAIKU_TOP src tests kits net ;
+SubInclude HAIKU_TOP src tests kits shared ;
 SubInclude HAIKU_TOP src tests kits storage ;
 SubInclude HAIKU_TOP src tests kits support ;
 SubInclude HAIKU_TOP src tests kits translation ;

src/tests/kits/shared/Jamfile

@@ -0,0 +1,6 @@
+SubDir HAIKU_TOP src tests kits shared ;
+
+SetSubDirSupportedPlatformsBeOSCompatible ;
+AddSubDirSupportedPlatforms libbe_test ;
+
+SubInclude HAIKU_TOP src tests kits shared shake_filter ;

src/tests/kits/shared/shake_filter/Jamfile

@@ -0,0 +1,8 @@
+SubDir HAIKU_TOP src tests kits shared shake_filter ;
+
+UsePrivateHeaders shared ;
+
+Application ShakeFilterTest :
+	ShakeFilterTest.cpp	
+	: libshared.a be $(TARGET_LIBSUPC++)
+;

src/tests/kits/shared/shake_filter/ShakeFilterTest.cpp

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2009, Alexandre Deckner <alex@zappotek.com>
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include <Application.h>
+#include <ShakeTrackingFilter.h>
+#include <Window.h>
+#include <View.h>
+
+#include <stdio.h>
+
+
+static const uint32 kMsgShake = 'Shke';
+
+
+class View : public BView {
+public:
+						View(BRect rect, const char* name, uint32 followMode);
+		virtual			~View();
+
+		virtual	void	AttachedToWindow();
+		virtual	void	MessageReceived(BMessage* msg);
+};
+
+
+View::View(BRect rect, const char* name, uint32 followMode)
+	:
+	BView(rect, name, followMode, B_WILL_DRAW)
+{
+	SetViewColor(ui_color(B_PANEL_BACKGROUND_COLOR));
+	SetHighColor(255, 0, 0);
+}
+
+
+View::~View()
+{
+}
+
+
+void
+View::AttachedToWindow()
+{
+	AddFilter(new ShakeTrackingFilter(this, kMsgShake, 3, 500000));
+}
+
+
+void
+View::MessageReceived(BMessage* msg)
+{
+	if (msg->what == kMsgShake) {
+		uint32 count = 0;
+		msg->FindUInt32("count", &count);
+		printf("Shake! %lu\n", count);
+	} else {
+		BView::MessageReceived(msg);
+	}
+}
+
+
+//	#pragma mark -
+
+
+int
+main(int argc, char **argv)
+{
+	BApplication app("application/x-vnd.haiku-ShakeFilterTest");
+
+	BWindow* window = new BWindow(BRect(100, 100, 400, 400),
+		"ShakeFilter-Test", B_TITLED_WINDOW,
+		B_ASYNCHRONOUS_CONTROLS | B_QUIT_ON_WINDOW_CLOSE);
+
+	BRect frame = window->Bounds();
+
+	window->AddChild(new View(frame, "L ", B_FOLLOW_ALL));
+	window->Show();
+
+	app.Run();
+	return 0;
+}