grid-flags.h
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#ifndef DALI_DEMO_GRID_FLAGS_H
#define DALI_DEMO_GRID_FLAGS_H
/*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <algorithm>
#include <cassert>
#include <dali/dali.h>
/** Controls the output of application logging. */
//#define DEBUG_PRINT_GRID_DIAGNOSTICS
namespace Dali
{
namespace Demo
{
/**
* @brief A 2D grid of booleans, settable and gettable via integer (x,y) coordinates.
* */
class GridFlags
{
public:
/**
* Create grid of specified dimensions.
*/
GridFlags( unsigned width, unsigned height ) : mCells( width * height ), mWidth( width ), mHeight( height ), mHighestUsedRow( 0 )
{
#ifdef DEBUG_PRINT_GRID_DIAGNOSTICS
fprintf(stderr, "Grid created with dimensions: (%u, %u).\n", mWidth, mHeight );
#endif
}
void Set( const unsigned x, const unsigned y )
{
const unsigned index = CellIndex( x, y );
mCells[index] += 1u; ///< += To allow a debug check of the number of times a cell is set.
mHighestUsedRow = std::max( mHighestUsedRow, y );
}
bool Get( unsigned x, unsigned y ) const
{
return mCells[ CellIndex( x, y ) ] != 0;
}
unsigned GetHighestUsedRow() const
{
return mHighestUsedRow;
}
/**
* @brief Try to find space in a grid of cells for the region requested.
* @return true if any region (not necessarily an exact match) was found, else false.
* @param[in] region The rectangular region requested
* @param[out] outCellX The X coordinate of the region allocated, if any.
* @param[out] outCellY The Y coordinate of the region allocated, if any.
* @param[out] outRegion The rectangle actually found: the lowest-Y exact match region
* or the largest area rectangular region no greater than the requested
* region in x or y. Undefined if false is returned.
*/
bool AllocateRegion( const Vector2& region, unsigned& outCellX, unsigned& outCellY, Vector2& outRegion )
{
const unsigned regionWidth = (region.x + 0.5f);
const unsigned regionHeight = (region.y + 0.5f);
#ifdef DEBUG_PRINT_GRID_DIAGNOSTICS
fprintf( stderr, "Allocation requested for region (%u, %u). Result: ", regionWidth, regionHeight );
#endif
unsigned bestRegionWidth = 0;
unsigned bestRegionHeight = 0;
unsigned bestCellX = 0;
unsigned bestCellY = 0;
// Look for a non-set cell:
for( unsigned y = 0; y < mHeight; ++y )
{
for( unsigned x = 0; x < mWidth; ++x )
{
if ( !Get( x, y) )
{
// Look for clear grid cells under the desired region:
const unsigned clampedRegionHeight = std::min( regionHeight, mHeight - y);
const unsigned clampedRegionWidth = std::min( regionWidth, mWidth - x);
const unsigned regionLimitY = y + clampedRegionHeight;
const unsigned regionLimitX = x + clampedRegionWidth;
for( unsigned regionY = y; regionY < regionLimitY; ++regionY )
{
for( unsigned regionX = x; regionX < regionLimitX; ++regionX )
{
if( Get( regionX, regionY ) )
{
// The region of clear cells is not big enough but remember it
// anyway in case there is no region that fits:
const unsigned clearRegionWidth = regionX - x;
const unsigned clearRegionHeight = (regionY + 1) - y;
if( clearRegionWidth * clearRegionHeight > bestRegionWidth * bestRegionHeight )
{
bestCellX = x;
bestCellY = y;
bestRegionWidth = clearRegionWidth;
bestRegionHeight = clearRegionHeight;
}
goto whole_region_not_found;
}
}
}
// Every cell in the region is clear so check if it is the best one yet:
if( clampedRegionWidth * clampedRegionHeight > bestRegionWidth * bestRegionHeight )
{
bestCellX = x;
bestCellY = y;
bestRegionWidth = clampedRegionWidth;
bestRegionHeight = clampedRegionHeight;
}
// If a big-enough region was found, end the search early and greedily allocate it:
if( clampedRegionHeight == regionHeight && clampedRegionWidth == regionWidth )
{
x = mWidth;
y = mHeight;
}
whole_region_not_found:
continue;
}
}
}
// Allocate and return the best cell region found:
if( bestRegionWidth == 0 || bestRegionHeight == 0 )
{
#ifdef DEBUG_PRINT_GRID_DIAGNOSTICS
fputs( "false.\n", stderr );
#endif
return false;
}
// Allocate the found region:
#ifdef DEBUG_PRINT_GRID_DIAGNOSTICS
fprintf( stderr, " - bestCellX = %u, bestCellY = %u, bestRegionWidth = %u, bestRegionHeight = %u - ", bestCellX, bestCellY, bestRegionWidth, bestRegionHeight );
#endif
for( unsigned y = bestCellY; y < bestCellY + bestRegionHeight; ++y )
{
for( unsigned x = bestCellX; x < bestCellX + bestRegionWidth; ++x )
{
Set( x, y );
}
}
outCellX = bestCellX;
outCellY = bestCellY;
outRegion = Vector2( bestRegionWidth, bestRegionHeight );
#ifdef DEBUG_PRINT_GRID_DIAGNOSTICS
fputs( "true.\n", stderr );
#endif
return true;
}
/** @return True if every cell was set one or zero times, else false. */
bool DebugCheckGridValid()
{
for( unsigned cell = 0; cell < mWidth * mHeight; ++cell )
{
if( mCells[cell] > 1 )
{
return false;
}
}
return true;
}
private:
unsigned CellIndex( unsigned x, unsigned y ) const
{
const unsigned offset = mWidth * y + x;
assert( offset < mCells.size() && "Out of range access to grid." );
return offset;
}
std::vector<unsigned char> mCells;
const unsigned mWidth;
const unsigned mHeight;
unsigned mHighestUsedRow;
};
} // namespace Demo
} // namespace Dali
#endif // DALI_DEMO_GRID_FLAGS_H