Add a new layouter 'CollapsingLayouter', which is used by BTwoDimensionalLayout to collapse empty rows or columns. Update BGridLayout so that empty rows/columns are given min/max constraints of B_SIZE_UNSET by default, which allows them to be collapsed. Fixes #6979

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@41252 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/interface/GridLayout.cpp

@@ -90,7 +90,7 @@ public:
 	{
 		if (Info* info = _InfoAt(index))
 			return info->minSize;
-		return -1;
+		return B_SIZE_UNSET;
 	}
 
 	void SetMinSize(int32 index, float size)
@@ -103,7 +103,7 @@ public:
 	{
 		if (Info* info = _InfoAt(index))
 			return info->maxSize;
-		return B_SIZE_UNLIMITED;
+		return B_SIZE_UNSET;
 	}
 
 	void SetMaxSize(int32 index, float size)
@@ -138,8 +138,8 @@ private:
 			for (int32 i = count; i <= index; i++) {
 				Info* info = new Info;
 				info->weight = 1;
-				info->minSize = 0;
+				info->minSize = B_SIZE_UNSET;
-				info->maxSize = B_SIZE_UNLIMITED;
+				info->maxSize = B_SIZE_UNSET;
 				fInfos.AddItem(info);
 			}
 		}

src/kits/interface/Jamfile

@@ -133,6 +133,7 @@ MergeObject <libbe>interface_kit.o :
 	WidthBuffer.cpp
 
 	# layouter
+	CollapsingLayouter.cpp
 	ComplexLayouter.cpp
 	Layouter.cpp
 	LayoutOptimizer.cpp

src/kits/interface/TwoDimensionalLayout.cpp

@@ -18,9 +18,7 @@
 
 #include <Referenceable.h>
 
-#include "ComplexLayouter.h"
+#include "CollapsingLayouter.h"
-#include "OneElementLayouter.h"
-#include "SimpleLayouter.h"
 
 
 
@@ -706,12 +704,7 @@ BTwoDimensionalLayout::CompoundLayouter::ValidateMinMax()
 
 	int elementCount = _CountElements();
 
-	if (elementCount <= 1)
+	fLayouter = new CollapsingLayouter(elementCount, _Spacing());
-		fLayouter = new OneElementLayouter();
-	else if (_HasMultiElementItems())
-		fLayouter = new ComplexLayouter(elementCount, _Spacing());
-	else
-		fLayouter = new SimpleLayouter(elementCount, _Spacing());
 
 	// tell the layouter about our constraints
 	// TODO: We should probably ignore local layouters whose view is hidden.

src/kits/interface/layouter/CollapsingLayouter.cpp

@@ -0,0 +1,334 @@
+/*
+ * Copyright 2011, Haiku, Inc.
+ * All rights reserved. Distributed under the terms of the MIT License.
+ */
+
+#include "CollapsingLayouter.h"
+
+#include "ComplexLayouter.h"
+#include "OneElementLayouter.h"
+#include "SimpleLayouter.h"
+
+#include <ObjectList.h>
+#include <Size.h>
+
+
+class CollapsingLayouter::ProxyLayoutInfo : public LayoutInfo {
+public:
+	ProxyLayoutInfo(LayoutInfo* target, int32 elementCount)
+		:
+		fTarget(target),
+		fElementCount(elementCount)
+	{
+		fElements = new int32[elementCount];
+	}
+
+	~ProxyLayoutInfo()
+	{
+		delete[] fElements;
+		delete fTarget;
+	}
+
+	void
+	LayoutTarget(Layouter* layouter, float size)
+	{
+		if (layouter)
+			layouter->Layout(fTarget, size);
+	}
+
+	void
+	SetElementPosition(int32 element, int32 position)
+	{
+		fElements[element] = position;
+	}
+
+	float
+	ElementLocation(int32 element)
+	{
+		if (element < 0 || element >= fElementCount || fElements[element] < 0)
+			return 0;
+		return fTarget->ElementLocation(fElements[element]);
+	}
+
+	float
+	ElementSize(int32 element)
+	{
+		if (element < 0 || element >= fElementCount || fElements[element] < 0)
+			return 0;
+		return fTarget->ElementSize(fElements[element]);
+	}
+
+	float
+	ElementRangeSize(int32 element, int32 length)
+	{
+		if (element < 0 || element >= fElementCount || fElements[element] < 0)
+			return 0;
+		return fTarget->ElementRangeSize(fElements[element], length);
+	}
+
+private:
+	int32*					fElements;
+	LayoutInfo*				fTarget;
+	int32					fElementCount;
+};
+
+
+struct CollapsingLayouter::Constraint {
+	int32 length;
+	float min;
+	float max;
+	float preferred;
+};
+
+
+struct CollapsingLayouter::ElementInfo {
+	float weight;
+	int32 position;
+	bool valid;
+	BObjectList<Constraint> constraints;
+
+	ElementInfo()
+		:
+		weight(0),
+		position(-1),
+		valid(false),
+		constraints(5, true)
+	{
+	}
+
+	~ElementInfo()
+	{
+	}
+
+	void SetTo(const ElementInfo& other)
+	{
+		weight = other.weight;
+		position = other.position;
+		valid = other.valid;
+		for (int32 i = other.constraints.CountItems() - 1; i >= 0; i--)
+			constraints.AddItem(new Constraint(*other.constraints.ItemAt(i)));
+	}
+
+	int32 LengthOfLongestConstraint()
+	{
+		int32 length = 0;
+		for (int32 i = constraints.CountItems() - 1; i >= 0; i--)
+			length = max_c(length, constraints.ItemAt(i)->length);
+		return length;
+	}
+};
+
+
+CollapsingLayouter::CollapsingLayouter(int32 elementCount, float spacing)
+	:
+	fElementCount(elementCount),
+	fElements(new ElementInfo[elementCount]),
+	fValidElementCount(0),
+	fHaveMultiElementConstraints(false),
+	fSpacing(spacing),
+	fLayouter(NULL)
+{
+}
+
+
+CollapsingLayouter::~CollapsingLayouter()
+{
+	delete[] fElements;
+	delete fLayouter;
+}
+
+
+void
+CollapsingLayouter::AddConstraints(int32 element, int32 length, float min,
+	float max, float preferred)
+{
+	if (min == B_SIZE_UNSET && max == B_SIZE_UNSET)
+		return;
+	if (element < 0 || length <= 0 || element + length > fElementCount)
+		return;
+
+	Constraint* constraint = new Constraint();
+	constraint->length = length;
+	constraint->min = min;
+	constraint->max = max;
+	constraint->preferred = preferred;
+
+	if (length > 1)
+		fHaveMultiElementConstraints = true;
+	
+	int32 validElements = fValidElementCount;
+
+	for (int32 i = element; i < element + length; i++) {
+		if (fElements[i].valid == false) {
+			fElements[i].valid = true;
+			fValidElementCount++;
+		}
+	}
+
+	fElements[element].constraints.AddItem(constraint);
+	if (fValidElementCount > validElements) {
+		delete fLayouter;
+		fLayouter = NULL;
+	}
+
+	if (fLayouter)
+		_AddConstraints(element, constraint);
+	
+}
+
+
+void
+CollapsingLayouter::SetWeight(int32 element, float weight)
+{
+	if (element < 0 || element >= fElementCount)
+		return;
+
+	ElementInfo& elementInfo = fElements[element];
+	elementInfo.weight = weight;
+
+	if (fLayouter && elementInfo.position >= 0)
+		fLayouter->SetWeight(elementInfo.position, weight);
+}
+
+
+float
+CollapsingLayouter::MinSize()
+{
+	_ValidateLayouter();
+	return fLayouter->MinSize();
+}
+
+
+float
+CollapsingLayouter::MaxSize()
+{
+	_ValidateLayouter();
+	return fLayouter->MaxSize();
+}
+
+
+float
+CollapsingLayouter::PreferredSize()
+{
+	_ValidateLayouter();
+	return fLayouter->PreferredSize();
+}
+
+
+LayoutInfo*
+CollapsingLayouter::CreateLayoutInfo()
+{
+	_ValidateLayouter();
+
+	return new ProxyLayoutInfo(fLayouter->CreateLayoutInfo(), fElementCount);
+}
+
+
+void
+CollapsingLayouter::Layout(LayoutInfo* layoutInfo, float size)
+{
+	_ValidateLayouter();
+	ProxyLayoutInfo* info = static_cast<ProxyLayoutInfo*>(layoutInfo);
+	for (int32 i = 0; i < fElementCount; i++) {
+		info->SetElementPosition(i, fElements[i].position);
+	}
+
+	info->LayoutTarget(fLayouter, size);
+}
+
+
+Layouter*
+CollapsingLayouter::CloneLayouter()
+{
+	CollapsingLayouter* clone = new CollapsingLayouter(fElementCount, fSpacing);
+	for (int32 i = 0; i < fElementCount; i++)
+		clone->fElements[i].SetTo(fElements[i]);
+
+	clone->fValidElementCount = fValidElementCount;
+	clone->fHaveMultiElementConstraints = fHaveMultiElementConstraints;
+
+	if (fLayouter)
+		clone->fLayouter = fLayouter->CloneLayouter();
+	return clone;
+}
+
+
+void
+CollapsingLayouter::_ValidateLayouter()
+{
+	if (fLayouter)
+		return;
+
+	_CreateLayouter();
+	_DoCollapse();
+	_AddConstraints();
+	_SetWeights();
+}
+
+
+Layouter*
+CollapsingLayouter::_CreateLayouter()
+{
+	if (fLayouter)
+		return fLayouter;
+
+	if (fValidElementCount == 0) {
+		fLayouter =  NULL;
+	} else if (fValidElementCount == 1) {
+		fLayouter =  new OneElementLayouter();
+	} else if (fHaveMultiElementConstraints) {
+		fLayouter =  new ComplexLayouter(fValidElementCount, fSpacing);
+	} else {
+		fLayouter = new SimpleLayouter(fValidElementCount, fSpacing);
+	}
+
+	return fLayouter;
+}
+
+
+void
+CollapsingLayouter::_DoCollapse()
+{
+	int32 shift = 0;
+	for (int32 i = 0; i < fElementCount; i++) {
+		ElementInfo& element = fElements[i];
+		if (!element.valid) {
+			shift++;
+			element.position = -1;
+			continue;
+		} else {
+			element.position = i - shift;
+		}
+	}
+}
+
+
+void
+CollapsingLayouter::_AddConstraints()
+{
+	if (fLayouter == NULL)
+		return;
+
+	for (int32 i = 0; i < fElementCount; i++) {
+		ElementInfo& element = fElements[i];
+		for (int32 i = element.constraints.CountItems() - 1; i >= 0; i--)
+			_AddConstraints(element.position, element.constraints.ItemAt(i));
+	}
+}
+
+
+void
+CollapsingLayouter::_AddConstraints(int32 position, const Constraint* c)
+{
+	fLayouter->AddConstraints(position, c->length, c->min, c->max,
+		c->preferred);
+}
+
+
+void
+CollapsingLayouter::_SetWeights()
+{
+	for (int32 i = 0; i < fElementCount; i++) {
+		fLayouter->SetWeight(fElements[i].position, fElements[i].weight);
+	}
+}

src/kits/interface/layouter/CollapsingLayouter.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2011, Haiku, Inc.
+ * All rights reserved. Distributed under the terms of the MIT License.
+ */
+#ifndef COLLAPSING_LAYOUTER_H	
+#define COLLAPSING_LAYOUTER_H
+
+#include "Layouter.h"
+
+
+namespace BPrivate {
+namespace Layout {
+
+
+/* This layouter wraps either a Compound, Simple or OneElement layouter, and
+ * removes elements which have no constraints, or min/max constraints of
+ * B_SIZE_UNSET. The child layouter is given only the constraints for the
+ * remaining elements. When using the LayoutInfo of this layouter,
+ * collapsed (removed) elements are given no space on screen.
+ */
+class CollapsingLayouter : public Layouter {
+public:
+								CollapsingLayouter(int32 elementCount,
+									float spacing);
+	virtual						~CollapsingLayouter();
+
+	virtual	void				AddConstraints(int32 element, int32 length,
+									float min, float max, float preferred);
+	virtual	void				SetWeight(int32 element, float weight);
+
+	virtual	float				MinSize();
+	virtual	float				MaxSize();
+	virtual	float				PreferredSize();
+
+	virtual	LayoutInfo*			CreateLayoutInfo();
+	
+	virtual	void				Layout(LayoutInfo* layoutInfo, float size);
+
+	virtual	Layouter*			CloneLayouter();
+
+
+private:
+	class	ProxyLayoutInfo;
+	struct	Constraint;
+	struct	ElementInfo;
+
+			void				_ValidateLayouter();
+			Layouter*			_CreateLayouter();
+			void				_DoCollapse();
+			void				_AddConstraints();
+			void				_AddConstraints(int32 position,
+									const Constraint* c);
+			void				_SetWeights();
+
+			int32				fElementCount;
+			ElementInfo*		fElements;
+			int32				fValidElementCount;
+			bool				fHaveMultiElementConstraints;
+			float				fSpacing;
+			Layouter*			fLayouter;
+};
+
+} // namespace Layout
+} // namespace BPrivate
+
+using BPrivate::Layout::CollapsingLayouter;
+
+#endif // COLLAPSING_LAYOUTER_H