/*
* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).
* All rights reserved.
* This component and the accompanying materials are made available
* under the terms of "Eclipse Public License v1.0"
* which accompanies this distribution, and is available
* at the URL "http://www.eclipse.org/legal/epl-v10.html".
*
* Initial Contributors:
* Nokia Corporation - initial contribution.
*
* Contributors:
*
* Description: interface for layout policy
*
*/
#ifndef I_ALFGRIDLAYOUTMANAGER
#define I_ALFGRIDLAYOUTMANAGER
#include <alf/ialfinterfacebase.h>
#include <alf/alftypes.h>
class CAlfLayout;
class CAlfControl;
namespace Alf
{
class CAlfWidgetControl;
namespace ialfgridlayoutpolicy
{
static const IfId Ident =
{
0, "gridlayoutpolicy"
};
}
using Alf::CAlfWidgetControl;
/**
* The interface for grid layout policy
*
* Provides grid specific layout APIs
*
* @code
* // Create layout manager interface.
* IAlfLayoutManager* layoutManager = IAlfInterfaceBase::makeInterface<IAlfLayoutManager>(control);
*
* // See if layout policy is supported in the given layout manager.
* IAlfGridLayoutPolicy* layoutPolicy = IAlfInterfaceBase::makeInterface<IAlfGridLayoutPolicy>(layoutManager);
*
* if(layoutPreferences != 0)
* {
* int rows = layoutPolicy->dimensionCount(EAlfGridDimensionRow);
* }
* @endcode
*
* @lib alfwidgetmodel.lib
* @since S60 ?S60_version
* @status Draft
*/
class IAlfGridLayoutPolicy : public IAlfInterfaceBase
{
public:
static inline const IfId& type()
{
return ialfgridlayoutpolicy::Ident;
}
virtual inline ~IAlfGridLayoutPolicy() {}
public:
/* Each dimension corresponds to a different axis for the grid blocks */
enum gridLayoutDimension
{
EGridDimensionColumn = 0,
EGridDimensionRow
};
public:
/**
* Sets the number and weights of blocks in this grid layout in the direction of the specified
* dimension. Each block's weight will be set to equal the supplied value, the result
* of which is that all blocks will be equally spaced, whatever the units.
*
* @see appendWeight; for more information on how weights are used to calculate layout positions.
*
* @note This API could be useful if then subsequent calls to @c replaceWeight are made to
* change specific values, depending on how many of the values are different.
* @note Calling this with aCount set to 0 will clear all of the existing weights in the direction
* of the specified dimension.
* @note this is the same as using metrics with unit type EAlfUnitWeight.
*
* @param aDim the dimension along which to fill
* @param aCount The number of lines of blocks to fill
* @param aWeight the weights to be used for all blocks
* @throw AlfVisualException
*/
virtual void fillWeights(gridLayoutDimension aDim, int aCount, const TAlfMetric& aWeight) = 0;
/**
* Add a new line of blocks to this grid layout at the last position in the direction of the
* specified dimension. It will have the supplied weight. Weights can be any metric value,
* hence different units can be used for each block. In particular, EAlfUnitWeight can be used
* to represent weight values in aribtrary proportional units.
*
* In the case of proportional weights, the effect of this will be to cause the other blocks to
* resize according to the new total weight.
*
* @note If non-relative coordinates are specified (e.g., real pixels), the combined blocks might not
* fill the entire layout area. However, weights will always stretch to fill all available space
* after the fixed units have been determined. Therefore, depending on circumstances it may
* be better to use EAlfUnitWeight
* @note For example [2 weights, 1 weight, 2 weights] in a layout of 100 pixels would result
* in [40 pixels, 20 pixels, 40 pixels].
* @note For example [10 pixels, 1 weight, 15 pixels] in a layout of 100 pixels would result
* in [10 pixels, 75 pixels, 15 pixels].
*
* @param aDim the dimension to which the weight corresponds
* @param aWeight the weight to be used for the block in the specified dimension,
* replacing any previously existing weight for that block
* @throw AlfVisualException
*/
virtual void appendWeight(gridLayoutDimension aDim, const TAlfMetric& aWeight) = 0;
/**
* Add a new line of blocks to this grid layout at the specified position in the direciton of
* the specified dimension. It will have the supplied weight. In the case of proportional
* weights, the effect of this will be to cause the other blocks to resize according to the new
* total weight. It will also mean that many child visuals will now occupy different blocks within
* the grid according to how the blocks wrap.
*
* @note will leave if the specified position is greater than the number of objects currently in the array,
* so check first by calling @c preferredDimensionCount
* @see appendWeight for more information on how weights are used to calculate layout positions.
*
* @param aDim the dimension to which the weight corresponds
* @param aWeight the weight to be used for the block in the specified dimension,
* replacing any previously existing weight for that block
* @param aPos the index of the block
* @throw AlfVisualException
*/
virtual void insertWeight(gridLayoutDimension aDim, const TAlfMetric& aWeight, int aPos) = 0;
/**
* Sets the weight of a specific line of blocks in this grid layout, in the direction of the supplied dimension.
* In the case of proportional weights, the effect of this will be to cause the
* other blocks to resize according to the new total weight.
*
* @see appendWeight for more information on how weights are used to calculate layout positions.
*
* @param aDim the dimension to which the weight corresponds
* @param aWeight the weight to be used for the block in the specified dimension,
* replacing any previously existing weight for that cell
* @param aPos the index of the cell
* @throw AlfVisualException
*/
virtual void replaceWeight(gridLayoutDimension aDim, const TAlfMetric& aWeight, int aPos) = 0;
/**
* Remove a line of blocks from this grid layout at the specified position in the
* specified dimension. In the case of proportional weights, the effect of this will
* be to cause the other blocks to resize according to the new total weight. It will also mean
* that many child visuals will now occupy different blocks within the grid according to how
* the blocks wrap.
*
* @see appendWeight for more information on how weights are used to calculate layout positions.
*
* @param aDim the dimension to which the weight corresponds
* @param aPos the index of the cell
* @throw AlfVisualException
*/
virtual void removeWeight(gridLayoutDimension aDim, int aPos) = 0;
/**
* Returns the weight of a specific line of blocks in this grid layout, in the
* specified dimension.
*
* @see appendWeight for more information on how weights are used to calculate layout positions.
*
* @param aDim the dimension to which the weight corresponds
* @param aPos the index of the cell
* @return the weight being used for the cell in the specified dimension, will be 0 magnitude if not set
* @throw AlfVisualException
*/
virtual TAlfMetric weight(gridLayoutDimension aDim, int aPos) const = 0;
/**
* Return the number of lines of blocks in this grid, along the specified dimension
*
* @param aDim the dimension along which to count
* @return The number of lines of blocks in this grid.
*/
virtual int count(gridLayoutDimension aDim) const = 0;
public:
// from base class IAlfInterfaceBase
/**
* Interface getter.
* @see IAlfInterfaceBase::MakeInterface
*
* @param aType The type id of the queried interface.
* @return The queried interface, or NULL if the interface is not
* supported or available.
*/
virtual IAlfInterfaceBase* makeInterface( const IfId& aType ) = 0;
};
} // namespace Alf
#endif // I_ALFGRIDLAYOUTMANAGER