Application: gvSIG desktop

package org.gvsig.labeling.symbol;

import org.gvsig.fmap.mapcontext.MapContext;

import org.gvsig.fmap.mapcontext.ViewPort;

import org.gvsig.fmap.mapcontext.rendering.symbols.CartographicSupport;

public class SymbolUtils {

        /**

         * Calculates the distance in pixels corresponding to the provided length,

         * according to the current rendering context (output dpi, map scale, map units) and the

         * symbol cartographic settings (unit, size, and unit reference system).

         *

         * @param cartographicElement CartographicSupport object which contains the reference system

         * and the measuring units for the provided length

         * @param length The length to be computed in pixels. The length is supposed to be

         * provided in the units defined in the cartographicElement

         * @param viewPort The viewport, which defines the relationship between pixels and maps units

         * @param dpi The resolution (dots per inch) of the target display device

         * (printer, screen, etc)

         * @return The distance in pixels corresponding to the provided length

         */

        public static double getCartographicLength(

                        CartographicSupport cartographicElement,

                        double length, ViewPort viewPort, double dpi) {

                int unit = cartographicElement.getUnit();

                double lengthInPixel = length;

                if (unit != -1) {

                        double[] trans2Meter=MapContext.getDistanceTrans2Meter();

                        if (cartographicElement.getReferenceSystem() == CartographicSupport.WORLD) {

                                double dist1PixelInMeters = viewPort.getDist1pixel()*trans2Meter[viewPort.getMapUnits()];

                                double realWidthMeter = length*trans2Meter[unit];

                                lengthInPixel = realWidthMeter/dist1PixelInMeters;

                        } else if (cartographicElement.getReferenceSystem() == CartographicSupport.PAPER) {

                                double lengthInInches = 1/trans2Meter[7]*trans2Meter[unit]*length;

                                lengthInPixel = lengthInInches*dpi;

                        }

                } else{

                        double scale=dpi/72;

                        lengthInPixel=lengthInPixel*scale;

                }

                return  (lengthInPixel);

        }

}