/*
* Copyright (C) 2014, Gerd Petermann
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 or
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
package uk.me.parabola.splitter.solver;
import java.awt.Rectangle;
import java.util.BitSet;
import uk.me.parabola.splitter.Area;
import uk.me.parabola.splitter.Utils;
/**
* Contains info that is needed by the {@link Tile} class. For a given
* DensityMap we calculate some extra info to allow faster access to row sums
* and column sums.
*
* @author GerdP
*
*/
public class EnhancedDensityMap
{
private final DensityMap densityMap
;
private int[][] xyMap
;
private int[][] yxMap
;
private BitSet xyInPolygon
;
private double[] aspectRatioFactor
;
private int minAspectRatioFactorPos
;
private int maxNodesInDensityMapGridElement =
Integer.
MIN_VALUE;
private int maxNodesInDensityMapGridElementInPoly =
Integer.
MIN_VALUE;
private java.
awt.
geom.
Area polygonArea
;
public EnhancedDensityMap
(DensityMap densities, java.
awt.
geom.
Area polygonArea
) {
this.
densityMap = densities
;
this.
polygonArea = polygonArea
;
prepare
();
}
/**
* If a polygon is given, filter the density data Compute once complex
* trigonometric results for needed for proper aspect ratio calculations.
*
*/
private void prepare
(){
// performance: calculate only once the needed complex math results
aspectRatioFactor =
new double[densityMap.
getHeight()+
1];
int minLat = densityMap.
getBounds().
getMinLat();
int maxLat = densityMap.
getBounds().
getMaxLat();
int lat =
0;
double maxAspectRatioFactor =
Double.
MIN_VALUE;
int minPos =
Integer.
MAX_VALUE;
for (int i =
0; i
< aspectRatioFactor.
length; i++
){
lat = minLat + i
* (1 << densityMap.
getShift());
assert lat
<= maxLat
;
aspectRatioFactor
[i
] =
Math.
cos(Math.
toRadians(Utils.
toDegrees(lat
))) ;
if (maxAspectRatioFactor
< aspectRatioFactor
[i
]){
maxAspectRatioFactor = aspectRatioFactor
[i
];
minPos = i
;
}
}
minAspectRatioFactorPos = minPos
;
assert lat == maxLat
;
// filter the density map and populate xyMap
int width = densityMap.
getWidth();
int height = densityMap.
getHeight();
xyMap =
new int [width
][height
];
if (polygonArea
!=
null)
xyInPolygon =
new BitSet(width
* height
);
int shift = densityMap.
getShift();
for (int x =
0; x
< width
; x++
){
int polyXPos = densityMap.
getBounds().
getMinLong() +
(x
<< shift
);
int[] xCol = xyMap
[x
];
for(int y =
0; y
< height
; y++
){
int count = densityMap.
getNodeCount(x, y
);
if (polygonArea
!=
null){
int polyYPos = densityMap.
getBounds().
getMinLat() +
(y
<< shift
);
if (polygonArea.
intersects(polyXPos, polyYPos,
1<<shift,
1<<shift
)){
xyInPolygon.
set(x
* height + y
);
if (count
> maxNodesInDensityMapGridElementInPoly
){
maxNodesInDensityMapGridElementInPoly = count
;
}
}
}
if (count
> 0){
if (count
> maxNodesInDensityMapGridElement
)
maxNodesInDensityMapGridElement = count
;
xCol
[y
] = count
;
}
}
}
// create and populate yxMap, this helps to speed up row access
yxMap =
new int [height
][width
];
for(int y =
0; y
< height
; y++
){
int[] yRow = yxMap
[y
];
for (int x =
0; x
< width
; x++
){
yRow
[x
] = xyMap
[x
][y
];
}
}
}
public boolean isGridElemInPolygon
(int x,
int y
){
if (polygonArea ==
null)
return true;
return xyInPolygon.
get(x
* densityMap.
getHeight() + y
);
}
// calculate aspect ratio of a tile which is a view on the densityMap
public double getAspectRatio
(Rectangle r
) {
double ratio
;
double maxWidth
;
if (r.
y < minAspectRatioFactorPos
&& r.
y+r.
height > minAspectRatioFactorPos
){
maxWidth = r.
width; // tile crosses equator
}else {
double width1 = r.
width * aspectRatioFactor
[r.
y];
double width2 = r.
width * aspectRatioFactor
[r.
y + r.
height];
maxWidth =
Math.
max(width1, width2
);
}
ratio = maxWidth/r.
height;
return ratio
;
}
public Area getBounds
() {
return densityMap.
getBounds();
}
public DensityMap getDensityMap
() {
return densityMap
;
}
public long getNodeCount
(){
return densityMap.
getNodeCount();
}
public int[] getMapRow
(int mapRow
) {
return yxMap
[mapRow
];
}
public int[] getMapCol
(int mapCol
) {
return xyMap
[mapCol
];
}
public double[] getAspectRatioFactor
() {
return aspectRatioFactor
;
}
public int getMinAspectRatioFactorPos
() {
return minAspectRatioFactorPos
;
}
public int getMaxNodesInDensityMapGridElement
() {
return maxNodesInDensityMapGridElement
;
}
public int getMaxNodesInDensityMapGridElementInPoly
() {
return maxNodesInDensityMapGridElementInPoly
;
}
public java.
awt.
geom.
Area getPolygonArea
() {
return polygonArea
;
}
}