Changeset 26489 in osm for applications/editors/josm/plugins/piclayer

Timestamp:

2011-08-08T17:37:37+02:00 (13 years ago)

Author:

bastik

Message:

fix: Get map scale from the center of the image and not from the center of the screen. Otherwise, the displayed image will grow and shrink when panning the map up and down. (yes, this is somewhat pedantic)

Location:

applications/editors/josm/plugins/piclayer/src/org/openstreetmap/josm/plugins/piclayer

Files:

• PicLayerAbstract.java (modified) (6 diffs)
• PicLayerPlugin.java (modified) (1 diff)

applications/editors/josm/plugins/piclayer/src/org/openstreetmap/josm/plugins/piclayer/PicLayerAbstract.java

@@ -25 +25 @@
 import java.awt.Color;
 import java.awt.Component;
-import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Image;
 import java.awt.Toolkit;
 import java.awt.event.ActionEvent;
-import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.FileInputStream;
-import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.List;
@@ -49 +45 @@
 import org.openstreetmap.josm.data.Bounds;
 import org.openstreetmap.josm.data.coor.EastNorth;
+import org.openstreetmap.josm.data.coor.LatLon;
 import org.openstreetmap.josm.data.osm.visitor.BoundingXYVisitor;
 import org.openstreetmap.josm.gui.MapView;
@@ -202 +199 @@
             EastNorth center = Main.map.mapView.getCenter();
             EastNorth leftop = Main.map.mapView.getEastNorth( 0, 0 );
+            // Number of pixels for one unit in east north space.
+            // This is the same in x- and y- direction.
             double pixel_per_en = ( Main.map.mapView.getWidth() / 2.0 ) / ( center.east() - leftop.east() );
 
@@ -208 +207 @@
             double pic_offset_y = (( leftop.north() - m_position.north() ) * pixel_per_en);
 
-            // Let's use Graphics 2D
             Graphics2D g = (Graphics2D)g2.create();
             // Move
@@ -215 +213 @@
             g.rotate( m_angle * Math.PI / 180.0 );
             // Scale
-            double scalex = m_scalex * m_initial_scale / Main.map.mapView.getDist100Pixel();
-            double scaley = m_scaley * m_initial_scale / Main.map.mapView.getDist100Pixel();
+            double scalex = m_scalex * m_initial_scale * pixel_per_en / getMetersPerEasting(m_position) / 100;
+            double scaley = m_scaley * m_initial_scale * pixel_per_en / getMetersPerNorthing(m_position) / 100;
             g.scale( scalex, scaley );
             // Shear
@@ -239 +237 @@
         }
     }
-
+    
+    /**
+     * Returns the distance in meter, that corresponds to one unit in east north
+     * space. For normal projections, it is about 1 (but usually changing with 
+     * latitude).
+     * For EPSG:4326, it is the distance from one meridian of full degree to the 
+     * next (a couple of kilometers).
+     */
+    private double getMetersPerEasting(EastNorth en) {
+        /* Natural scale in east/north units per pixel.
+         * This means, the projection should be able to handle
+         * a shift of that size in east north space without
+         * going out of bounds.
+         * 
+         * Also, this should get us somewhere in the range of meters,
+         * so we get the result at the point 'en' and not some average.
+         */
+        double naturalScale = Main.getProjection().getDefaultZoomInPPD();
+        naturalScale *= 0.01; // make a little smaller
+        
+        LatLon ll1 = Main.getProjection().eastNorth2latlon(
+                new EastNorth(en.east() - naturalScale, en.north()));
+        LatLon ll2 = Main.getProjection().eastNorth2latlon(
+                new EastNorth(en.east() + naturalScale, en.north()));
+        
+        double dist = ll1.greatCircleDistance(ll2) / naturalScale / 2;
+        return dist;
+    }
+
+    /* see getMetersPerEasting */
+    private double getMetersPerNorthing(EastNorth en) {
+        double naturalScale = Main.getProjection().getDefaultZoomInPPD();
+        naturalScale *= 0.01;
+        
+        LatLon ll1 = Main.getProjection().eastNorth2latlon(
+                new EastNorth(en.east(), en.north()- naturalScale));
+        LatLon ll2 = Main.getProjection().eastNorth2latlon(
+                new EastNorth(en.east(), en.north() + naturalScale));
+        
+        double dist = ll1.greatCircleDistance(ll2) / naturalScale / 2;
+        return dist;
+    }
+    
     /**
      * Moves the picture. Scaled in EastNorth...

applications/editors/josm/plugins/piclayer/src/org/openstreetmap/josm/plugins/piclayer/PicLayerPlugin.java

@@ -62 +62 @@
         super(info);
 
-        System.err.println("hi there!");
         // Create menu entry
         if ( Main.main.menu != null ) {