* Make the magnetic border code more accessible by moving the code into a separate class and use it in a new protected WindowBehaviour method.

* Simplify the algorithm a bit, no functional changes are intended.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42377 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/DefaultWindowBehaviour.cpp

@@ -210,8 +210,7 @@ struct DefaultWindowBehaviour::DragState : MouseTrackingState {
 		bool activateOnMouseUp, bool minimizeCheckOnMouseUp)
 		:
 		MouseTrackingState(behavior, where, activateOnMouseUp,
-			minimizeCheckOnMouseUp),
-		fLastSnapTime(0)
+			minimizeCheckOnMouseUp)
 	{
 	}
 
@@ -235,7 +234,7 @@ struct DefaultWindowBehaviour::DragState : MouseTrackingState {
 		if (!(fWindow->Flags() & B_NOT_MOVABLE)) {
 			BPoint oldLeftTop = fWindow->Frame().LeftTop();
 
-			_AlterDeltaForSnap(delta, now);
+			fBehavior.AlterDeltaForSnap(fWindow, delta, now);
 			fDesktop->MoveWindowBy(fWindow, delta.x, delta.y);
 
 			// constrain delta to true change in position
@@ -243,78 +242,6 @@ struct DefaultWindowBehaviour::DragState : MouseTrackingState {
 		} else
 			delta = BPoint(0, 0);
 	}
-
-private:
-	void _AlterDeltaForSnap(BPoint& delta, bigtime_t now)
-	{
-		// Alter the delta (which is a proposed offset used while dragging a
-		// window) so that the frame of the window 'snaps' to the edges of the
-		// screen.
-
-		const bigtime_t kSnappingDuration = 1500000LL;
-		const bigtime_t kSnappingPause = 3000000LL;
-		const float kSnapDistance = 8.0f;
-
-		if (now - fLastSnapTime > kSnappingDuration
-			&& now - fLastSnapTime < kSnappingPause) {
-			// Maintain a pause between snapping.
-			return;
-		}
-
-		BRect frame = fWindow->Frame();
-		BPoint offsetWithinFrame;
-		// TODO: Perhaps obtain the usable area (not covered by the Deskbar)?
-		BRect screenFrame = fWindow->Screen()->Frame();
-
-		Decorator* decorator = fWindow->Decorator();
-		if (decorator) {
-			frame = decorator->GetFootprint().Frame();
-			offsetWithinFrame.x = fWindow->Frame().left - frame.left;
-			offsetWithinFrame.y = fWindow->Frame().top - frame.top;
-		}
-
-		frame.OffsetBy(delta);
-
-		float leftDist = fabs(frame.left - screenFrame.left);
-		float topDist = fabs(frame.top - screenFrame.top);
-		float rightDist = fabs(frame.right - screenFrame.right);
-		float bottomDist = fabs(frame.bottom - screenFrame.bottom);
-
-		bool snapped = false;
-		if (leftDist < kSnapDistance || rightDist < kSnapDistance) {
-			snapped = true;
-			if (leftDist < rightDist) {
-				frame.right -= frame.left;
-				frame.left = 0.0f;
-			} else {
-				frame.left -= frame.right - screenFrame.right;
-				frame.right = screenFrame.right;
-			}
-		}
-
-		if (topDist < kSnapDistance || bottomDist < kSnapDistance) {
-			snapped = true;
-			if (topDist < bottomDist) {
-				frame.bottom -= frame.top;
-				frame.top = 0.0f;
-			} else {
-				frame.top -= frame.bottom - screenFrame.bottom;
-				frame.bottom = screenFrame.bottom;
-			}
-		}
-		if (snapped && now - fLastSnapTime > kSnappingPause)
-			fLastSnapTime = now;
-
-
-		frame.top += offsetWithinFrame.y;
-		frame.left += offsetWithinFrame.x;
-
-		delta.y = frame.top - fWindow->Frame().top;
-		delta.x = frame.left - fWindow->Frame().left;
-	}
-
-private:
-	bigtime_t			fLastSnapTime;
 };
 
 
@@ -965,6 +892,14 @@ DefaultWindowBehaviour::ModifiersChanged(int32 modifiers)
 }
 
 
+bool
+DefaultWindowBehaviour::AlterDeltaForSnap(Window* window, BPoint& delta,
+	bigtime_t now)
+{
+	return fMagneticBorder.AlterDeltaForSnap(window, delta, now);
+}
+
+
 bool
 DefaultWindowBehaviour::_IsWindowModifier(int32 modifiers) const
 {

src/servers/app/DefaultWindowBehaviour.h

@@ -17,8 +17,9 @@
 
 #include "WindowBehaviour.h"
 
-#include "ServerCursor.h"
 #include "Decorator.h"
+#include "MagneticBorder.h"
+#include "ServerCursor.h"
 
 
 class Desktop;
@@ -39,6 +40,9 @@ public:
 
 	virtual	void				ModifiersChanged(int32 modifiers);
 
+protected:
+	virtual bool				AlterDeltaForSnap(Window* window, BPoint& delta,
+									bigtime_t now);
 private:
 			enum Action {
 				ACTION_NONE,
@@ -104,6 +108,8 @@ protected:
 			Desktop*			fDesktop;
 			State*				fState;
 			int32				fLastModifiers;
+
+			MagneticBorder		fMagneticBorder;
 };
 
 

src/servers/app/Jamfile

@@ -39,6 +39,7 @@ Server app_server :
 	InputManager.cpp
 	IntPoint.cpp
 	IntRect.cpp
+	MagneticBorder.cpp
 	MessageLooper.cpp
 	MultiLocker.cpp
 	OffscreenServerWindow.cpp

src/servers/app/MagneticBorder.cpp

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2010-2011, Haiku, Inc.
+ * Distributed under the terms of the MIT license.
+ *
+ * Authors:
+ *		Stephan Aßmus <[email protected]>
+ *		Ingo Weinhold <[email protected]>
+ *		Clemens Zeidler <[email protected]>
+ */
+
+
+#include "MagneticBorder.h"
+
+#include "Decorator.h"
+#include "Window.h"
+#include "Screen.h"
+
+
+MagneticBorder::MagneticBorder()
+	:
+	fLastSnapTime(0)
+{
+
+}
+
+
+bool
+MagneticBorder::AlterDeltaForSnap(Window* window, BPoint& delta, bigtime_t now)
+{
+	BRect frame = window->Frame();
+	Decorator* decorator = window->Decorator();
+	if (decorator)
+		frame = decorator->GetFootprint().Frame();
+
+	return AlterDeltaForSnap(window->Screen(), frame, delta, now);
+}
+
+
+bool
+MagneticBorder::AlterDeltaForSnap(const Screen* screen, BRect& frame,
+	BPoint& delta, bigtime_t now)
+{
+	// Alter the delta (which is a proposed offset used while dragging a
+	// window) so that the frame of the window 'snaps' to the edges of the
+	// screen.
+
+	const bigtime_t kSnappingDuration = 1500000LL;
+	const bigtime_t kSnappingPause = 3000000LL;
+	const float kSnapDistance = 8.0f;
+
+	if (now - fLastSnapTime > kSnappingDuration
+		&& now - fLastSnapTime < kSnappingPause) {
+		// Maintain a pause between snapping.
+		return false;
+	}
+
+	// TODO: Perhaps obtain the usable area (not covered by the Deskbar)?
+	BRect screenFrame = screen->Frame();
+	BRect originalFrame = frame;
+	frame.OffsetBy(delta);
+
+	float leftDist = fabs(frame.left - screenFrame.left);
+	float topDist = fabs(frame.top - screenFrame.top);
+	float rightDist = fabs(frame.right - screenFrame.right);
+	float bottomDist = fabs(frame.bottom - screenFrame.bottom);
+
+	bool snapped = false;
+	if (leftDist < kSnapDistance || rightDist < kSnapDistance) {
+		snapped = true;
+		if (leftDist < rightDist)
+			delta.x = screenFrame.left - originalFrame.left;
+		else
+			delta.x = screenFrame.right - originalFrame.right;
+	}
+
+	if (topDist < kSnapDistance || bottomDist < kSnapDistance) {
+		snapped = true;
+		if (topDist < bottomDist)
+			delta.y = screenFrame.top - originalFrame.top;
+		else
+			delta.y = screenFrame.bottom - originalFrame.bottom;
+	}
+	if (snapped && now - fLastSnapTime > kSnappingPause)
+		fLastSnapTime = now;
+
+	return snapped;
+}

src/servers/app/MagneticBorder.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2011, Haiku, Inc.
+ * Distributed under the terms of the MIT license.
+ *
+ * Authors:
+ *		Clemens Zeidler <[email protected]>
+ */
+#ifndef MAGNETIC_BORDRER_H
+#define MAGNETIC_BORDRER_H
+
+
+#include <Point.h>
+#include <Screen.h>
+
+
+class Screen;
+class Window;
+
+
+class MagneticBorder {
+public:
+								MagneticBorder();
+
+			bool				AlterDeltaForSnap(Window* window, BPoint& delta,
+									bigtime_t now);
+			bool				AlterDeltaForSnap(const Screen* screen,
+									BRect& frame, BPoint& delta, bigtime_t now);
+
+private:
+			bigtime_t			fLastSnapTime;
+};
+
+
+#endif // MAGNETIC_BORDRER_H

src/servers/app/WindowBehaviour.cpp

@@ -29,6 +29,13 @@ WindowBehaviour::ModifiersChanged(int32 modifiers)
 }
 
 
+bool
+WindowBehaviour::AlterDeltaForSnap(Window* window, BPoint& delta, bigtime_t now)
+{
+	return false;
+}
+
+
 /*!	\fn WindowBehaviour::MouseDown()
 	\brief Handles a mouse-down message for the window.
 

src/servers/app/WindowBehaviour.h

@@ -16,6 +16,7 @@
 
 class BMessage;
 class ClickTarget;
+class Window;
 
 
 class WindowBehaviour {
@@ -35,6 +36,13 @@ public:
 			bool				IsDragging() const { return fIsDragging; }
 			bool				IsResizing() const { return fIsResizing; }
 
+protected:
+	/*! The window is going to be moved by delta. This hook should be used to
+	implement the magnetic screen border, i.e. alter the delta accordantly.
+	\return true if delta has been modified. */
+	virtual bool				AlterDeltaForSnap(Window* window, BPoint& delta,
+									bigtime_t now);
+
 protected:
 			bool				fIsResizing : 1;
 			bool				fIsDragging : 1;