1 package tim.prune.gui.map;
4 * Class to hold the current position of the map
6 public class MapPosition
8 /** Width and height of each tile of map */
9 private static final int MAP_TILE_SIZE = 256;
11 /** x position (scale depends on zoom) */
12 private int _xPosition = 0;
13 /** y position (scale depends on zoom) */
14 private int _yPosition = 0;
16 /** Zoom level, from 2 to max */
17 private int _zoom = 12;
18 /** Factor to zoom by, 2 to the power of zoom */
19 private int _zoomFactor = 1 << _zoom;
20 /** Flag to mark if this position has ever been set */
21 private boolean _empty = true;
22 /** Maximum zoom level */
23 private static final int MAX_ZOOM = 21;
27 * Zoom and pan to show the selected area
28 * @param inMinX minimum transformed X
29 * @param inMaxX maximum transformed X
30 * @param inMinY minimum transformed Y
31 * @param inMaxY maximum transformed Y
32 * @param inWidth width of display
33 * @param inHeight height of display
35 public void zoomToXY(double inMinX, double inMaxX, double inMinY, double inMaxY, int inWidth, int inHeight)
37 // System.out.println("Zooming to " + inMinX + ", " + inMaxX + ", " + inMinY + ", " + inMaxY + "; width=" + inWidth + ", height=" + inHeight);
38 double diffX = Math.abs(inMaxX - inMinX);
39 double diffY = Math.abs(inMaxY - inMinY);
40 // Find out what zoom level to go to
41 int requiredZoom = -1;
42 for (int currZoom = MAX_ZOOM; currZoom >= 2; currZoom--)
44 if (transformToPixels(diffX, currZoom) < inWidth
45 && transformToPixels(diffY, currZoom) < inHeight)
47 requiredZoom = currZoom;
51 if (requiredZoom < 2) requiredZoom = 2;
53 setZoom(requiredZoom);
54 _xPosition = transformToPixels((inMinX + inMaxX) / 2.0);
55 _yPosition = transformToPixels((inMinY + inMaxY) / 2.0);
60 * Ensure that zoom and zoomFactor remain in sync
61 * @param inZoom zoom level to set
63 private void setZoom(int inZoom)
66 _zoomFactor = 1 << _zoom;
71 * Zoom and pan to show the selected area
72 * @param inMinX minimum pixels X
73 * @param inMaxX maximum pixels X
74 * @param inMinY minimum pixels Y
75 * @param inMaxY maximum pixels Y
76 * @param inWidth width of display
77 * @param inHeight height of display
79 public void zoomToPixels(int inMinX, int inMaxX, int inMinY, int inMaxY, int inWidth, int inHeight)
81 // System.out.println("Current position is " + _xPosition + ", " + _yPosition);
82 int diffX = Math.abs(inMaxX - inMinX);
83 int diffY = Math.abs(inMaxY - inMinY);
84 // Find out what zoom level to go to
85 int requiredZoom = -1;
87 for (int currZoom = MAX_ZOOM; currZoom >= _zoom; currZoom--)
89 multFactor = 1 << (currZoom - _zoom);
90 if ((diffX * multFactor) < inWidth && (diffY * multFactor) < inHeight)
92 requiredZoom = currZoom;
96 setZoom(requiredZoom);
98 _xPosition = (_xPosition - inWidth/2 + (inMinX + inMaxX) / 2) * multFactor;
99 _yPosition = (_yPosition - inHeight/2 + (inMinY + inMaxY) / 2) * multFactor;
104 * Transform a given coordinate into pixels using the current zoom value
105 * @param inValue value to transform
108 private int transformToPixels(double inValue)
110 return transformToPixels(inValue, _zoom);
114 * Transform a given coordinate into pixels using the specified zoom value
115 * @param inValue value to transform
116 * @param inZoom zoom value to use
119 private static int transformToPixels(double inValue, int inZoom)
121 return (int) (inValue * MAP_TILE_SIZE * (1 << inZoom));
125 * Convert pixels back into x coordinates
126 * @param inPixelX x coordinate on screen
127 * @param inWidth current width of window
128 * @return x coordinate
130 public double getXFromPixels(int inPixelX, int inWidth)
132 return ((inPixelX - inWidth/2) + _xPosition) * 1.0 / MAP_TILE_SIZE / _zoomFactor;
136 * Convert pixels back into y coordinates
137 * @param inPixelY y coordinate on screen
138 * @param inHeight current height of window
139 * @return y coordinate
141 public double getYFromPixels(int inPixelY, int inHeight)
143 return ((inPixelY - inHeight/2) + _yPosition) * 1.0 / MAP_TILE_SIZE / _zoomFactor;
147 * Get the horizontal offset from the centre
148 * @param inValue value to transform
149 * @return number of pixels right (+ve) or left (-ve) from the centre
151 public int getXFromCentre(double inValue)
153 return transformToPixels(inValue) - _xPosition;
157 * Get the vertical offset from the centre
158 * @param inValue value to transform
159 * @return number of pixels up (+ve) or down (-ve) from the centre
161 public int getYFromCentre(double inValue)
163 return transformToPixels(inValue) - _yPosition;
167 * Convert a pixel value into a bounds value for sensitivity
168 * @param inPixels number of pixels
169 * @return bounds value to use for x,y checking
171 public double getBoundsFromPixels(int inPixels) {
172 return (inPixels * 1.0 / MAP_TILE_SIZE / _zoomFactor);
176 * Get the leftmost, rightmost, upper and lower index boundaries for the tiles to display
177 * @param inWidth width of window
178 * @param inHeight height of window
179 * @return tile indices as array left, right, up, down
181 public int[] getTileIndices(int inWidth, int inHeight)
183 int[] result = new int[4];
184 result[0] = getTileIndex(_xPosition - inWidth/2);
185 result[1] = getTileIndex(_xPosition + inWidth/2);
186 result[2] = getTileIndex(_yPosition - inHeight/2);
187 result[3] = getTileIndex(_yPosition + inHeight/2);
192 * Get the pixel offsets for the display
193 * @param inWidth width of window
194 * @param inHeight height of window
195 * @return offsets as x, y
197 public int[] getDisplayOffsets(int inWidth, int inHeight)
199 int[] result = new int[2];
200 result[0] = getDisplayOffset(_xPosition - inWidth/2);
201 result[1] = getDisplayOffset(_yPosition - inHeight/2);
206 * @return x index of the centre tile
208 public int getCentreTileX()
210 return getTileIndex(_xPosition);
214 * @return y index of the centre tile
216 public int getCentreTileY()
218 return getTileIndex(_yPosition);
222 * @param inPosition position of point
223 * @return tile index for that point
225 private int getTileIndex(int inPosition)
227 return inPosition / MAP_TILE_SIZE;
231 * @param inPosition position of point
232 * @return pixel offset for that point
234 private int getDisplayOffset(int inPosition)
236 return inPosition % MAP_TILE_SIZE;
237 // I thought that &255 would be slightly faster, but it gives the wrong result
245 if (_zoom < MAX_ZOOM)
256 public void zoomOut()
267 * @return current zoom level
275 * Pan map by the specified amount
276 * @param inDeltaX amount to pan right
277 * @param inDeltaY amount to pan down
279 public void pan(int inDeltaX, int inDeltaY)
281 // TODO: Check bounds?
282 _xPosition += inDeltaX;
283 _yPosition += inDeltaY;
287 * @return true if this position has never been set
289 public boolean isEmpty()