Java tutorial
/* This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.opentripplanner.api.resource; import java.io.ByteArrayOutputStream; import java.util.Date; import java.util.Locale; import javax.ws.rs.DefaultValue; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.QueryParam; import javax.ws.rs.core.CacheControl; import javax.ws.rs.core.Context; import javax.ws.rs.core.Response; import org.apache.commons.codec.binary.Base64; import org.opentripplanner.analyst.request.SampleGridRenderer; import org.opentripplanner.analyst.request.SampleGridRenderer.WTWD; import org.opentripplanner.analyst.request.SampleGridRequest; import org.opentripplanner.api.common.RoutingResource; import org.opentripplanner.common.geometry.ZSampleGrid; import org.opentripplanner.common.geometry.ZSampleGrid.ZSamplePoint; import org.opentripplanner.common.model.GenericLocation; import org.opentripplanner.routing.core.RoutingRequest; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import ar.com.hjg.pngj.ImageInfo; import ar.com.hjg.pngj.ImageLineHelper; import ar.com.hjg.pngj.ImageLineInt; import ar.com.hjg.pngj.PngWriter; import ar.com.hjg.pngj.chunks.PngChunkTEXT; import ar.com.hjg.pngj.chunks.PngChunkTextVar; /** * Return a grid with time for a set of points. * * Example of request: * * <code> * http://localhost:8080/otp-rest-servlet/ws/timegrid?routerId=bordeaux&fromPlace=47.059,-0.880&date=2013/10/01&time=12:00:00&maxWalkDistance=1000&mode=WALK,TRANSIT * </code> * * @author laurent */ @Path("/timegrid") public class TimeGridWs extends RoutingResource { public enum DataChannel { TIME, /* Clock time */ BOARDINGS, /* Number of boardings */ WALK_DISTANCE, /* Total walk distance */ } @SuppressWarnings("unused") private static final Logger LOG = LoggerFactory.getLogger(TimeGridWs.class); @Context // FIXME use Application injection private SampleGridRenderer sampleGridRenderer; @QueryParam("maxTimeSec") private Integer maxTimeSec; @QueryParam("precisionMeters") @DefaultValue("200") private Integer precisionMeters; @QueryParam("coordinateOrigin") private String coordinateOrigin; @QueryParam("zDataType") @DefaultValue("TIME") private DataChannel zDataType; private static final String OTPA_GRID_CORNER = "OTPA-Grid-Corner"; private static final String OTPA_GRID_CELL_SIZE = "OTPA-Grid-Cell-Size"; private static final String OTPA_OFFROAD_DIST = "OTPA-OffRoad-Dist"; @GET @Produces({ "image/png" }) public Response getTimeGridPng(@QueryParam("base64") @DefaultValue("false") boolean base64) throws Exception { if (precisionMeters < 10) throw new IllegalArgumentException("Too small precisionMeters: " + precisionMeters); // Build the request RoutingRequest sptRequest = buildRequest(0); SampleGridRequest tgRequest = new SampleGridRequest(); tgRequest.maxTimeSec = maxTimeSec; tgRequest.precisionMeters = precisionMeters; if (coordinateOrigin != null) tgRequest.coordinateOrigin = new GenericLocation(null, coordinateOrigin).getCoordinate(); // Get a sample grid ZSampleGrid<WTWD> sampleGrid = sampleGridRenderer.getSampleGrid(tgRequest, sptRequest); int cols = sampleGrid.getXMax() - sampleGrid.getXMin() + 1; int rows = sampleGrid.getYMax() - sampleGrid.getYMin() + 1; int channels = 4; // Hard-coded to RGBA // We force to 8 bits channel depth, some clients won't support more than 8 // (namely, HTML5 canvas...) ImageInfo imgInfo = new ImageInfo(cols, rows, 8, true, false, false); /** * TODO: PNGJ allow for progressive (ie line-by-line) writing. Thus we could theorically * prevent having to allocate a bit pixel array in the first place, but we would need a * line-by-line iterator on the sample grid, which is currently not the case. */ int[][] rgba = new int[rows][cols * channels]; ByteArrayOutputStream baos = new ByteArrayOutputStream(); PngWriter pw = new PngWriter(baos, imgInfo); pw.getMetadata().setText(PngChunkTextVar.KEY_Software, "OTPA"); pw.getMetadata().setText(PngChunkTextVar.KEY_Creation_Time, new Date().toString()); pw.getMetadata().setText(PngChunkTextVar.KEY_Description, "Sample grid bitmap"); String gridCornerStr = String.format(Locale.US, "%.8f,%.8f", sampleGrid.getCenter().y + sampleGrid.getYMin() * sampleGrid.getCellSize().y, sampleGrid.getCenter().x + sampleGrid.getXMin() * sampleGrid.getCellSize().x); String gridCellSzStr = String.format(Locale.US, "%.12f,%.12f", sampleGrid.getCellSize().y, sampleGrid.getCellSize().x); String offRoadDistStr = String.format(Locale.US, "%f", sampleGridRenderer.getOffRoadDistanceMeters(precisionMeters)); PngChunkTEXT gridCornerChunk = new PngChunkTEXT(imgInfo); gridCornerChunk.setKeyVal(OTPA_GRID_CORNER, gridCornerStr); pw.getChunksList().queue(gridCornerChunk); PngChunkTEXT gridCellSzChunk = new PngChunkTEXT(imgInfo); gridCellSzChunk.setKeyVal(OTPA_GRID_CELL_SIZE, gridCellSzStr); pw.getChunksList().queue(gridCellSzChunk); PngChunkTEXT offRoadDistChunk = new PngChunkTEXT(imgInfo); offRoadDistChunk.setKeyVal(OTPA_OFFROAD_DIST, offRoadDistStr); pw.getChunksList().queue(offRoadDistChunk); double unit; switch (zDataType) { case TIME: unit = 1.0; // 1:1sec, max 18h break; case BOARDINGS: unit = 1000.0; // 1:0.001 boarding, max 65.5 break; case WALK_DISTANCE: unit = 10.0; // 1:0.1m, max 6.55km break; default: throw new IllegalArgumentException("Unsupported Z DataType."); } for (ZSamplePoint<WTWD> p : sampleGrid) { WTWD z = p.getZ(); int row = p.getY() - sampleGrid.getYMin(); int col = p.getX() - sampleGrid.getXMin(); double zz; switch (zDataType) { case TIME: zz = z.wTime / z.w; break; case BOARDINGS: zz = z.wBoardings / z.w; break; case WALK_DISTANCE: zz = z.wWalkDist / z.w; break; default: throw new IllegalArgumentException("Unsupported Z DataType."); } int iz; if (Double.isInfinite(zz)) { iz = 65535; } else { iz = ImageLineHelper.clampTo_0_65535((int) Math.round(zz * unit)); if (iz == 65535) iz = 65534; // Clamp } // d is expressed as a percentage of grid size, max 255%. // Sometimes d will be bigger than 2.55 x grid size, // but this should not be too much important as we are off-bounds. int id = ImageLineHelper.clampTo_0_255((int) Math.round(z.d / precisionMeters * 100)); int offset = col * channels; rgba[row][offset + 0] = (iz & 0xFF); // z low 8 bits rgba[row][offset + 1] = (iz >> 8); // z high 8 bits rgba[row][offset + 2] = id; // d /* * Keep the alpha channel at 255, otherwise the RGB channel will be downsampled on some * rendering clients (namely, JS canvas). */ rgba[row][offset + 3] = 255; } for (int row = 0; row < rgba.length; row++) { ImageLineInt iline = new ImageLineInt(imgInfo, rgba[row]); pw.writeRow(iline, row); } pw.end(); // Disallow caching on client side CacheControl cc = new CacheControl(); cc.setNoCache(true); // Also put the meta-data in the HTML header (easier to read from JS) byte[] data = baos.toByteArray(); if (base64) { data = Base64.encodeBase64(data); } return Response.ok().cacheControl(cc).entity(data).header(OTPA_GRID_CORNER, gridCornerStr) .header(OTPA_GRID_CELL_SIZE, gridCellSzStr).header(OTPA_OFFROAD_DIST, offRoadDistStr).build(); } }