Changeset 568 for trunk

Timestamp:

Jul 24, 2007, 9:51:16 PM (12 years ago)

Author:

Nick Burch

Message:

Support for negative northings

File:

• trunk/gpx.npemap.org.uk/js/mapTiles.js (modified) (4 diffs)

trunk/gpx.npemap.org.uk/js/mapTiles.js

@@ -7 +7 @@
 var sizeGridX = 6;   // Size of visible grid (table) in each dimension
 var sizeGridY = 4;   // Size of visible grid (table) in each dimension
+
+var minY = -86; // Minimum Y at scale 1
 
 var tileWidth = 125;
@@ -196 +198 @@
 
 
-// Need to use substring for IE, and it doesn't take negative numbers.
+// Need to use substring for IE
+// Pads to 3 digits with zeros, or - and 2 digits
 function trimNumber(string) {
-        // If we have a 4 digit number, no need to do any padding
-        if(parseInt(string) >= 1000) { return string; }
+        // If we have a 3+ digit number, no need to do any padding
+        if(parseInt(string) >= 100) { return string; }
+        // Or a 2+ digit negative number, no need to do any padding
+        if(parseInt(string) <= -10) { return string; }
+
+        // Special case for 1 digit negative numbers
+        if(parseInt(string) <= 0) {
+                var num = parseInt(string);
+                return '-0' + (0-num);
+        }
 
         // Pad it so that it'll always have leading 0s, and be at least 3 long
@@ -208 +219 @@
 
 function trimSixDigits(string) {
-        // If we have a 7 digit number, no need to do any padding
-        if(parseInt(string) >= 1000000) { return string; }
+        // If we have a 6+ digit number, no need to do any padding
+        if(parseInt(string) >= 100000) { return string; }
+        // Or a 5+ digit negative number, no need to do any padding
+        if(parseInt(string) <= -10000) { return string; }
+
+        // Is it negative?
+        var num = parseInt(string)
+        var isNegative = (num < 0);
+        if(isNegative) {
+                num = 0 - num;
+        }
 
         // Pad it so that it'll always have leading 0s, and be at least 6 long
-        str = '000000' + string
+        str = '000000' + num;
         // Grab the right most 6 digits, which will have any required padding
-        return str.substring(str.length -6)
-}
+        str = str.substring(str.length -6)
+        // Add back in - at start if needed
+        if(isNegative) {
+                str = '-' + str.substring(1);
+        }
+        return str;
+}
+
 
 function refreshGrid() {
@@ -281 +307 @@
     }
     else if ( theDirection == 'down' ) {
-        if ( offsetGridY > 0 )
+        if ( offsetGridY > Math.round(minY / zooms[zoomLevel]) )
             offsetGridY --;
     }