Version 15, March 2013

[GpsPrune.git] / tim / prune / gui / map / MapUtils.java

diff --git a/tim/prune/gui/map/MapUtils.java b/tim/prune/gui/map/MapUtils.java
index 78206a3956959f6126ed1568a29893a61ce76e36..49d94676f77c70cc137fa1d204a11dffcd4eea27 100644 (file)
--- a/tim/prune/gui/map/MapUtils.java
+++ b/tim/prune/gui/map/MapUtils.java
@@ -1,7 +1,10 @@
 package tim.prune.gui.map;
 
+import java.awt.Color;
+import java.awt.image.BufferedImage;
+
 /**
- * Class to manage coordinate conversions for maps
+ * Class to manage coordinate conversions and other stuff for maps
  */
 public abstract class MapUtils
 {
@@ -49,4 +52,50 @@ public abstract class MapUtils
                double n = Math.PI * (1 - 2 * inY);
                return 180 / Math.PI * Math.atan(0.5 * (Math.exp(n) - Math.exp(-n)));
        }
+
+       /**
+        * Tests whether there are any dark pixels in the image within the specified x,y rectangle
+        * @param inImage image to test
+        * @param inX left X coordinate
+        * @param inY bottom Y coordinate
+        * @param inWidth width of rectangle
+        * @param inHeight height of rectangle
+        * @param inTextColour colour of text
+        * @return true if the rectangle overlaps stuff too close to the given colour
+        */
+       public static boolean overlapsPoints(BufferedImage inImage, int inX, int inY,
+               int inWidth, int inHeight, Color inTextColour)
+       {
+               // each of the colour channels must be further away than this to count as empty
+               final int BRIGHTNESS_LIMIT = 80;
+               final int textRGB = inTextColour.getRGB();
+               final int textLow = textRGB & 255;
+               final int textMid = (textRGB >> 8) & 255;
+               final int textHigh = (textRGB >> 16) & 255;
+               try
+               {
+                       // loop over x coordinate of rectangle
+                       for (int x=0; x<inWidth; x++)
+                       {
+                               // loop over y coordinate of rectangle
+                               for (int y=0; y<inHeight; y++)
+                               {
+                                       int pixelColor = inImage.getRGB(inX + x, inY - y);
+                                       // split into four components rgba
+                                       int pixLow = pixelColor & 255;
+                                       int pixMid = (pixelColor >> 8) & 255;
+                                       int pixHigh = (pixelColor >> 16) & 255;
+                                       //int fourthBit = (pixelColor >> 24) & 255; // alpha ignored
+                                       // If colours are too close in any channel then it's an overlap
+                                       if (Math.abs(pixLow-textLow) < BRIGHTNESS_LIMIT ||
+                                               Math.abs(pixMid-textMid) < BRIGHTNESS_LIMIT ||
+                                               Math.abs(pixHigh-textHigh) < BRIGHTNESS_LIMIT) {return true;}
+                               }
+                       }
+               }
+               catch (NullPointerException e) {
+                       // ignore null pointers, just return false
+               }
+               return false;
+       }
 }