Merge pull request #11403 from osmandapp/track_line_fixes

Track line fixes

OsmAnd-java/src/main/java/net/osmand/GPXUtilities.java

@@ -328,6 +328,16 @@ public class GPXUtilities {
 			}
 		}
 
+		public void setColor(ColorizationType type, int color) {
+			if (type == ColorizationType.SPEED) {
+				speedColor = color;
+			} else if (type == ColorizationType.ELEVATION) {
+				altitudeColor = color;
+			} else if (type == ColorizationType.SLOPE) {
+				slopeColor = color;
+			}
+		}
+
 		public String getBackgroundType() {
 			return getExtensionsToRead().get(BACKGROUND_TYPE_EXTENSION);
 		}
@@ -1103,6 +1113,15 @@ public class GPXUtilities {
 		return trackBounds;
 	}
 
+	public static QuadRect calculateTrackBounds(List<TrkSegment> segments) {
+		QuadRect trackBounds = new QuadRect(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY,
+				Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
+		for (TrkSegment segment : segments) {
+			updateBounds(trackBounds, segment.points, 0);
+		}
+		return trackBounds;
+	}
+
 	public static void updateBounds(QuadRect trackBounds, List<WptPt> pts, int startIndex) {
 		for (int i = startIndex; i < pts.size(); i++) {
 			WptPt pt = pts.get(i);

OsmAnd-java/src/main/java/net/osmand/osm/edit/OsmMapUtils.java

@@ -340,6 +340,30 @@ public class OsmMapUtils {
 		}
 	}
 
+	public static void simplifyDouglasPeucker(List<Node> nodes, int start, int end, List<Node> survivedNodes, double epsilon) {
+		double dmax = Double.NEGATIVE_INFINITY;
+		int index = -1;
+
+		Node startPt = nodes.get(start);
+		Node endPt = nodes.get(end);
+
+		for (int i = start + 1; i < end; i++) {
+			Node pt = nodes.get(i);
+			double d = MapUtils.getOrthogonalDistance(pt.getLatitude(), pt.getLongitude(),
+					startPt.getLatitude(), startPt.getLongitude(), endPt.getLatitude(), endPt.getLongitude());
+			if (d > dmax) {
+				dmax = d;
+				index = i;
+			}
+		}
+		if (dmax > epsilon) {
+			simplifyDouglasPeucker(nodes, start, index, survivedNodes, epsilon);
+			simplifyDouglasPeucker(nodes, index, end, survivedNodes, epsilon);
+		} else {
+			survivedNodes.add(nodes.get(end));
+		}
+	}
+
 	private static double orthogonalDistance(int zoom, Node nodeLineStart, Node nodeLineEnd, Node node) {
 		LatLon p = MapUtils.getProjection(node.getLatitude(), node.getLongitude(), nodeLineStart.getLatitude(),
 				nodeLineStart.getLongitude(), nodeLineEnd.getLatitude(), nodeLineEnd.getLongitude());

OsmAnd-java/src/main/java/net/osmand/router/RouteColorize.java

@@ -35,6 +35,7 @@ public class RouteColorize {
     public static final int RED = rgbaToDecimal(243, 55, 77, 255);
     public static final int[] colors = new int[] {GREEN, YELLOW, RED};
 
+    private static final float DEFAULT_BASE = 17.2f;
     private static final int MAX_SLOPE_VALUE = 25;
 
     public enum ColorizationType {
@@ -241,7 +242,6 @@ public class RouteColorize {
         if (dataList == null) {
             dataList = new ArrayList<>();
             for (int i = 0; i < latitudes.length; i++) {
-                //System.out.println(latitudes[i] + " " + longitudes[i] + " " + values[i]);
                 dataList.add(new RouteColorizationPoint(i, latitudes[i], longitudes[i], values[i]));
             }
         }
@@ -250,11 +250,13 @@ public class RouteColorize {
         for (RouteColorizationPoint data : dataList) {
             nodes.add(new net.osmand.osm.edit.Node(data.lat, data.lon, data.id));
         }
-        OsmMapUtils.simplifyDouglasPeucker(nodes, zoom + 5, 1, result, true);
+
+        double epsilon = Math.pow(2.0, DEFAULT_BASE - zoom);
+        result.add(nodes.get(0));
+        OsmMapUtils.simplifyDouglasPeucker(nodes, 0, nodes.size() - 1, result, epsilon);
 
         List<RouteColorizationPoint> simplified = new ArrayList<>();
-
+        for (int i = 1; i < result.size(); i++) {
-        for (int i = 1; i < result.size() - 1; i++) {
             int prevId = (int) result.get(i - 1).getId();
             int currentId = (int) result.get(i).getId();
             List<RouteColorizationPoint> sublist = dataList.subList(prevId, currentId);
@@ -477,7 +479,7 @@ public class RouteColorize {
     }
 
     public static class RouteColorizationPoint {
-        int id;
+        public int id;
         public double lat;
         public double lon;
         public double val;

OsmAnd-java/src/main/java/net/osmand/util/MapUtils.java

@@ -747,7 +747,9 @@ public class MapUtils {
 		return Math.sqrt((endX - startX) * (endX - startX) + (endY - startY) * (endY - startY));
 	}
 
-
+	public static double getSqrtDistance(float startX, float startY, float endX, float endY) {
+		return Math.sqrt((endX - startX) * (endX - startX) + (endY - startY) * (endY - startY));
+	}
 }
 
 

OsmAnd/src/net/osmand/plus/track/TrackColoringCard.java

@@ -11,6 +11,7 @@ import android.widget.TextView;
 import com.google.android.material.snackbar.Snackbar;
 
 import net.osmand.AndroidUtils;
+import net.osmand.GPXUtilities.Elevation;
 import net.osmand.GPXUtilities.GPXTrackAnalysis;
 import net.osmand.PlatformUtil;
 import net.osmand.plus.R;
@@ -92,7 +93,15 @@ public class TrackColoringCard extends BaseCard {
 		if (scaleType == GradientScaleType.SPEED) {
 			return gpxTrackAnalysis.isSpeedSpecified();
 		} else {
-			return gpxTrackAnalysis.isElevationSpecified();
+			if (!gpxTrackAnalysis.isElevationSpecified()) {
+				return false;
+			}
+			for (Elevation elevation : gpxTrackAnalysis.elevationData) {
+				if (Float.isNaN(elevation.elevation)) {
+					return false;
+				}
+			}
+			return true;
 		}
 	}
 

OsmAnd/src/net/osmand/plus/views/Renderable.java

@@ -14,6 +14,7 @@ import net.osmand.data.RotatedTileBox;
 import net.osmand.plus.track.GradientScaleType;
 import net.osmand.plus.views.layers.geometry.GpxGeometryWay;
 import net.osmand.util.Algorithms;
+import net.osmand.util.MapUtils;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -28,7 +29,6 @@ import java.util.concurrent.atomic.AtomicInteger;
 
 import androidx.annotation.NonNull;
 
-
 public class Renderable {
 
     private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
@@ -61,7 +61,6 @@ public class Renderable {
 
         public List<WptPt> points = null;                           // Original list of points
         protected List<WptPt> culled = new ArrayList<>();           // Reduced/resampled list of points
-        protected List<WptPt> oldCulled = new ArrayList<>();
         protected int pointSize;
         protected double segmentSize;
 
@@ -89,6 +88,9 @@ public class Renderable {
             }
             paint.setColor(p.getColor());
             paint.setStrokeWidth(p.getStrokeWidth());
+            if (scaleType != null) {
+                paint.setAlpha(0xFF);
+            }
         }
 
         public void setBorderPaint(@NonNull Paint paint) {
@@ -117,20 +119,19 @@ public class Renderable {
             updateLocalPaint(p);
             canvas.rotate(-tileBox.getRotate(), tileBox.getCenterPixelX(), tileBox.getCenterPixelY());
             if (scaleType != null) {
-                drawGradient(getPointsForDrawingWithBorder(), p, canvas, tileBox);
+                drawSolid(points, borderPaint, canvas, tileBox);
+                drawGradient(points, paint, canvas, tileBox);
             } else {
-                drawSolid(getPointsForDrawing(), p, canvas, tileBox);
+                drawSolid(getPointsForDrawing(), paint, canvas, tileBox);
             }
             canvas.rotate(tileBox.getRotate(), tileBox.getCenterPixelX(), tileBox.getCenterPixelY());
         }
 
-
         public void drawSegment(double zoom, Paint p, Canvas canvas, RotatedTileBox tileBox) {
             if (QuadRect.trivialOverlap(tileBox.getLatLonBounds(), trackBounds)) { // is visible?
-                if (tileBox.getZoomAnimation() > 0 && !Algorithms.isEmpty(culled) && scaleType != null) {
+                if (scaleType == null) {
-                    oldCulled = new ArrayList<>(culled);
+                    startCuller(zoom);
                 }
-                startCuller(zoom);
                 drawSingleSegment(zoom, p, canvas, tileBox);
             }
         }
@@ -143,16 +144,6 @@ public class Renderable {
             return culled.isEmpty() ? points : culled;
         }
 
-        public List<WptPt> getPointsForDrawingWithBorder() {
-            if (!culled.isEmpty()) {
-                return culled;
-            } else if (!oldCulled.isEmpty()) {
-                return oldCulled;
-            } else {
-                return points;
-            }
-        }
-
         public void drawGeometry(Canvas canvas, RotatedTileBox tileBox, QuadRect quadRect, int arrowColor, int trackColor, float trackWidth) {
             if (geometryWay != null) {
                 List<WptPt> points = getPointsForDrawing();
@@ -177,7 +168,7 @@ public class Renderable {
                         float lastX = tileBox.getPixXFromLatLon(lastPt.lat, lastPt.lon);
                         float lastY = tileBox.getPixYFromLatLon(lastPt.lat, lastPt.lon);
                         if (!path.isEmpty()) {
-                            canvas.drawPath(path, paint);
+                            canvas.drawPath(path, p);
                         }
                         path.reset();
                         path.moveTo(lastX, lastY);
@@ -191,58 +182,99 @@ public class Renderable {
                 lastPt = pt;
             }
             if (!path.isEmpty()) {
-                canvas.drawPath(path, paint);
+                canvas.drawPath(path, p);
             }
         }
 
         protected void drawGradient(List<WptPt> pts, Paint p, Canvas canvas, RotatedTileBox tileBox) {
             QuadRect tileBounds = tileBox.getLatLonBounds();
-            Path currentPath = new Path();
+            Path path = new Path();
-            Path nextPath = new Path();
+            boolean recalculateLastXY = true;
-            Paint paint = new Paint(this.paint);
+            WptPt lastPt = pts.get(0);
 
-            WptPt prevWpt = pts.get(0);
+            List<PointF> gradientPoints = new ArrayList<>();
-            WptPt currWpt = pts.get(1);
+            List<Integer> gradientColors = new ArrayList<>();
-
+            float gradientAngle = 0;
-            PointF prevXY = new PointF();
-            PointF currXY = new PointF();
-            PointF nextXY = new PointF();
-
-            boolean currLineVisible = arePointsInsideTile(prevWpt, currWpt, tileBounds);
-            boolean nextLineVisible;
-
-            if (currLineVisible) {
-                pixXYFromWptPt(tileBox, prevXY, prevWpt);
-                pixXYFromWptPt(tileBox, currXY, currWpt);
-                canvas.drawPath(pathFromStartEnd(currentPath, prevXY, currXY), borderPaint);
-            }
 
             for (int i = 1; i < pts.size(); i++) {
-                currWpt = pts.get(i);
+                WptPt pt = pts.get(i);
-                WptPt nextWpt = i + 1 == pts.size() ? null : pts.get(i + 1);
+                WptPt nextPt = i + 1 < pts.size() ? pts.get(i + 1) : null;
+                float nextX = nextPt == null ? 0 : tileBox.getPixXFromLatLon(nextPt.lat, nextPt.lon);
+                float nextY = nextPt == null ? 0 : tileBox.getPixYFromLatLon(nextPt.lat, nextPt.lon);
+                float lastX = 0;
+                float lastY = 0;
+                if (arePointsInsideTile(pt, lastPt, tileBounds)) {
+                    if (recalculateLastXY) {
+                        recalculateLastXY = false;
+                        lastX = tileBox.getPixXFromLatLon(lastPt.lat, lastPt.lon);
+                        lastY = tileBox.getPixYFromLatLon(lastPt.lat, lastPt.lon);
+                        if (!path.isEmpty()) {
+                            p.setShader(createGradient(gradientPoints, gradientColors));
+                            canvas.drawPath(path, p);
+                        }
+                        path.reset();
+                        path.moveTo(lastX, lastY);
 
-                nextLineVisible = arePointsInsideTile(currWpt, nextWpt, tileBounds);
+                        gradientPoints.clear();
-                if (nextWpt != null && nextLineVisible) {
+                        gradientColors.clear();
-                    pixXYFromWptPt(tileBox, currXY, currWpt);
+                        gradientPoints.add(new PointF(lastX, lastY));
-                    pixXYFromWptPt(tileBox, nextXY, nextWpt);
+                        gradientColors.add(lastPt.getColor(scaleType.toColorizationType()));
-                    canvas.drawPath(pathFromStartEnd(nextPath, currXY, nextXY), borderPaint);
+                    }
+                    float x = tileBox.getPixXFromLatLon(pt.lat, pt.lon);
+                    float y = tileBox.getPixYFromLatLon(pt.lat, pt.lon);
+                    path.lineTo(x, y);
+                    gradientPoints.add(new PointF(x, y));
+                    gradientColors.add(pt.getColor(scaleType.toColorizationType()));
+
+                    if (gradientColors.size() == 2) {
+                        gradientAngle = calculateAngle(lastX, lastY, x, y);
+                    }
+                    if (nextPt != null) {
+                        float nextAngle = calculateAngle(x, y, nextX, nextY);
+                        if (Math.abs(nextAngle - gradientAngle) > 20) {
+                            recalculateLastXY = true;
+                        }
+                    }
+                } else {
+                    recalculateLastXY = true;
                 }
-
+                lastPt = pt;
-                if (currLineVisible) {
-                    int prevColor = prevWpt.getColor(scaleType.toColorizationType());
-                    int currentColor = currWpt.getColor(scaleType.toColorizationType());
-                    LinearGradient gradient = new LinearGradient(prevXY.x, prevXY.y, currXY.x, currXY.y,
-                            prevColor, currentColor, Shader.TileMode.CLAMP);
-                    paint.setShader(gradient);
-                    canvas.drawPath(currentPath, paint);
-                }
-
-                prevWpt = currWpt;
-                currentPath.set(nextPath);
-                prevXY.set(currXY);
-                currXY.set(nextXY);
-                currLineVisible = nextLineVisible;
             }
+            if (!path.isEmpty()) {
+                p.setShader(createGradient(gradientPoints, gradientColors));
+                canvas.drawPath(path, p);
+            }
+        }
+
+        private LinearGradient createGradient(List<PointF> gradientPoints, List<Integer> gradientColors) {
+            float gradientLength = 0;
+            List<Float> pointsLength = new ArrayList<>(gradientPoints.size() - 1);
+            for (int i = 1; i < gradientPoints.size(); i++) {
+                PointF start = gradientPoints.get(i - 1);
+                PointF end = gradientPoints.get(i);
+                pointsLength.add((float) MapUtils.getSqrtDistance(start.x, start.y, end.x, end.y));
+                gradientLength += pointsLength.get(i - 1);
+            }
+
+            float[] positions = new float[gradientPoints.size()];
+            positions[0] = 0;
+            for (int i = 1; i < gradientPoints.size(); i++) {
+                positions[i] = positions[i - 1] + pointsLength.get(i - 1) / gradientLength;
+            }
+
+            int[] colors = new int[gradientColors.size()];
+            for (int i = 0; i < gradientColors.size(); i++) {
+                colors[i] = gradientColors.get(i);
+            }
+
+            PointF gradientStart = gradientPoints.get(0);
+            PointF gradientEnd = gradientPoints.get(gradientPoints.size() - 1);
+            return new LinearGradient(gradientStart.x, gradientStart.y, gradientEnd.x, gradientEnd.y,
+                    colors, positions, Shader.TileMode.CLAMP);
+        }
+
+        private float calculateAngle(float startX, float startY, float endX, float endY) {
+            return (float) Math.abs(Math.toDegrees(Math.atan2(endY - startY, endX - startX)));
         }
 
         protected boolean arePointsInsideTile(WptPt first, WptPt second, QuadRect tileBounds) {
@@ -252,19 +284,6 @@ public class Renderable {
             return Math.min(first.lon, second.lon) < tileBounds.right && Math.max(first.lon, second.lon) > tileBounds.left
                     && Math.min(first.lat, second.lat) < tileBounds.top && Math.max(first.lat, second.lat) > tileBounds.bottom;
         }
-
-        protected PointF pixXYFromWptPt(RotatedTileBox tileBox, PointF pointF, WptPt wptPt) {
-            pointF.x = tileBox.getPixXFromLatLon(wptPt.lat, wptPt.lon);
-            pointF.y = tileBox.getPixYFromLatLon(wptPt.lat, wptPt.lon);
-            return pointF;
-        }
-
-        protected Path pathFromStartEnd(Path path, PointF start, PointF end) {
-            path.reset();
-            path.moveTo(start.x, start.y);
-            path.lineTo(end.x, end.y);
-            return path;
-        }
     }
 
     public static class StandardTrack extends RenderableSegment {
@@ -316,4 +335,4 @@ public class Renderable {
 
         @Override protected void startCuller(double newZoom) {}
     }
-}
+}

OsmAnd/src/net/osmand/plus/views/layers/GPXLayer.java

@@ -69,6 +69,8 @@ import net.osmand.render.RenderingRuleProperty;
 import net.osmand.render.RenderingRuleSearchRequest;
 import net.osmand.render.RenderingRulesStorage;
 import net.osmand.router.RouteColorize;
+import net.osmand.router.RouteColorize.ColorizationType;
+import net.osmand.router.RouteColorize.RouteColorizationPoint;
 import net.osmand.util.Algorithms;
 import net.osmand.util.MapUtils;
 
@@ -117,6 +119,8 @@ public class GPXLayer extends OsmandMapLayer implements IContextMenuProvider, IM
 	private MapMarkersHelper mapMarkersHelper;
 	private GpxSelectionHelper selectedGpxHelper;
 
+	private final Map<String, CachedTrack> segmentsCache = new HashMap<>();
+
 	private List<WptPt> cache = new ArrayList<>();
 	private Map<WptPt, SelectedGpxFile> pointFileMap = new HashMap<>();
 	private MapTextLayer textLayer;
@@ -459,7 +463,10 @@ public class GPXLayer extends OsmandMapLayer implements IContextMenuProvider, IM
 					float trackWidth = getTrackWidth(width, defaultTrackWidth);
 					int trackColor = getTrackColor(selectedGpxFile.getGpxFile(), cachedColor);
 					int arrowColor = UiUtilities.getContrastColor(view.getApplication(), trackColor, false);
-					for (TrkSegment segment : selectedGpxFile.getPointsToDisplay()) {
+					GradientScaleType scaleType = getGradientScaleType(selectedGpxFile.getGpxFile());
+					List<TrkSegment> segments = scaleType != null ?
+							getCachedSegments(selectedGpxFile, scaleType) : selectedGpxFile.getPointsToDisplay();
+					for (TrkSegment segment : segments) {
 						if (segment.renderer instanceof Renderable.RenderableSegment) {
 							((Renderable.RenderableSegment) segment.renderer)
 									.drawGeometry(canvas, tileBox, correctedQuadRect, arrowColor, trackColor, trackWidth);
@@ -681,26 +688,24 @@ public class GPXLayer extends OsmandMapLayer implements IContextMenuProvider, IM
 
 	private void drawSelectedFileSegments(SelectedGpxFile selectedGpxFile, boolean currentTrack, Canvas canvas,
 										  RotatedTileBox tileBox, DrawSettings settings) {
-		OsmandApplication app = view.getApplication();
+		boolean visible = QuadRect.trivialOverlap(tileBox.getLatLonBounds(), GPXUtilities.calculateTrackBounds(selectedGpxFile.getPointsToDisplay()));
-		GPXFile gpxFile = selectedGpxFile.getGpxFile();
+		if (!selectedGpxFile.getGpxFile().hasTrkPt() || !visible) {
-		List<TrkSegment> segments = selectedGpxFile.getPointsToDisplay();
+			return;
-		GradientScaleType scaleType = getGradientScaleType(gpxFile);
+		}
-		List<RouteColorize.RouteColorizationPoint> colorsOfPoints = null;
+
-
+		GPXFile gpxFile = selectedGpxFile.getGpxFile();
-		if (needCalculatePointsColors(segments, scaleType)) {
+		GradientScaleType scaleType = getGradientScaleType(gpxFile);
-			RouteColorize colorize = new RouteColorize(view.getZoom(), gpxFile, selectedGpxFile.getTrackAnalysis(app),
+		List<TrkSegment> segments = new ArrayList<>();
-					scaleType.toColorizationType(), app.getSettings().getApplicationMode().getMaxSpeed());
+
-			colorize.setPalette(getColorizationPalette(gpxFile, scaleType));
+		if (scaleType == null) {
-			colorsOfPoints = colorize.getResult(false);
+			segments.addAll(selectedGpxFile.getPointsToDisplay());
+		} else {
+			segments.addAll(getCachedSegments(selectedGpxFile, scaleType));
 		}
 
-		int startIdx = 0;
 		for (TrkSegment ts : segments) {
 			String width = getTrackWidthName(gpxFile, defaultTrackWidthPref.get());
 			int color = getTrackColor(gpxFile, ts.getColor(cachedColor));
-			if (colorsOfPoints != null) {
-				startIdx = setColorsToPoints(ts, colorsOfPoints, scaleType, startIdx);
-			}
 			if (ts.renderer == null && !ts.points.isEmpty()) {
 				Renderable.RenderableSegment renderer;
 				if (currentTrack) {
@@ -721,53 +726,16 @@ public class GPXLayer extends OsmandMapLayer implements IContextMenuProvider, IM
 		}
 	}
 
-	private boolean needCalculatePointsColors(List<TrkSegment> segments, GradientScaleType scaleType) {
+	private List<TrkSegment> getCachedSegments(SelectedGpxFile selectedGpxFile, GradientScaleType scaleType) {
-		if (scaleType == null) {
+		GPXFile gpxFile = selectedGpxFile.getGpxFile();
-			return false;
+		String path = gpxFile.path;
+		long modifiedTime = gpxFile.modifiedTime;
+		CachedTrack cachedTrack = segmentsCache.get(path);
+		if (cachedTrack == null) {
+			cachedTrack = new CachedTrack(view.getApplication(), modifiedTime);
+			segmentsCache.put(path, cachedTrack);
 		}
-		RouteColorize.ColorizationType colorizationType = scaleType.toColorizationType();
+		return cachedTrack.getCachedSegments(selectedGpxFile, view.getZoom(), scaleType, getColorizationPalette(gpxFile, scaleType));
-		for (int segIdx = segments.size() - 1; segIdx >= 0; segIdx--) {
-			List<WptPt> pts = segments.get(segIdx).points;
-			if (!Algorithms.isEmpty(pts)) {
-				for (int wptIdx = pts.size() - 1; wptIdx >= 0; wptIdx--) {
-					WptPt pt = pts.get(wptIdx);
-					if (pt.getColor(colorizationType) == 0) {
-						return true;
-					}
-				}
-			}
-		}
-		return false;
-	}
-
-	private int setColorsToPoints(TrkSegment segment, List<RouteColorize.RouteColorizationPoint> colors, GradientScaleType scaleType, int startIdx) {
-		int pointsSize = segment.points.size();
-		RouteColorize.RouteColorizationPoint startColor = colors.get(startIdx);
-		RouteColorize.RouteColorizationPoint endColor = colors.get(startIdx + pointsSize - 1);
-		WptPt firstPoint = segment.points.get(0);
-		WptPt lastPoint = segment.points.get(pointsSize - 1);
-		while (!compareCoordinates(firstPoint, startColor) && compareCoordinates(lastPoint, endColor)) {
-			startIdx++;
-			startColor = colors.get(startIdx);
-			endColor = colors.get(startIdx + pointsSize - 1);
-		}
-
-		for (int i = startIdx; i < startIdx + pointsSize; i++) {
-			WptPt currentPoint = segment.points.get(i - startIdx);
-			int currentColor = colors.get(i).color;
-			if (scaleType == GradientScaleType.SPEED) {
-				currentPoint.speedColor = currentColor;
-			} else if (scaleType == GradientScaleType.ALTITUDE) {
-				currentPoint.altitudeColor = currentColor;
-			} else {
-				currentPoint.slopeColor = currentColor;
-			}
-		}
-		return startIdx;
-	}
-
-	private boolean compareCoordinates(WptPt left, RouteColorize.RouteColorizationPoint right) {
-		return left.lat == right.lat && left.lon == right.lon;
 	}
 
 	private float getTrackWidth(String width, float defaultTrackWidth) {
@@ -1247,4 +1215,76 @@ public class GPXLayer extends OsmandMapLayer implements IContextMenuProvider, IM
 			view.getApplication().getItineraryHelper().runSynchronization(group);
 		}
 	}
+
+	private static class CachedTrack {
+
+		private OsmandApplication app;
+
+		private long modifiedTime;
+		private final Map<String, List<TrkSegment>> cache = new HashMap<>();
+
+		public CachedTrack(@NonNull OsmandApplication app, long modifiedTime) {
+			this.app = app;
+			this.modifiedTime = modifiedTime;
+		}
+
+		public List<TrkSegment> getCachedSegments(@NonNull SelectedGpxFile selectedGpxFile, int zoom,
+												  @NonNull GradientScaleType scaleType,
+												  int[] gradientPalette) {
+			GPXFile gpxFile = selectedGpxFile.getGpxFile();
+			String trackId = zoom + "_" + scaleType.toString();
+			if (modifiedTime == gpxFile.modifiedTime) {
+				List<TrkSegment> segments = cache.get(trackId);
+				if (segments == null) {
+					segments = calculateGradientTrack(selectedGpxFile, zoom, scaleType, gradientPalette);
+					cache.put(trackId, segments);
+				}
+				return segments;
+			} else {
+				cache.clear();
+				modifiedTime = gpxFile.modifiedTime;
+				List<TrkSegment> segments = calculateGradientTrack(selectedGpxFile, zoom, scaleType, gradientPalette);
+				cache.put(trackId, segments);
+				return segments;
+			}
+		}
+
+		private List<TrkSegment> calculateGradientTrack(SelectedGpxFile selectedGpxFile, int zoom,
+														GradientScaleType scaleType, int[] gradientPalette) {
+			GPXFile gpxFile = selectedGpxFile.getGpxFile();
+			RouteColorize colorize = new RouteColorize(zoom, gpxFile, selectedGpxFile.getTrackAnalysis(app),
+					scaleType.toColorizationType(), app.getSettings().getApplicationMode().getMaxSpeed());
+			colorize.setPalette(gradientPalette);
+			List<RouteColorizationPoint> colorsOfPoints =  colorize.getResult(true);
+			return createSimplifiedSegments(selectedGpxFile.getGpxFile(), colorsOfPoints, scaleType);
+		}
+
+		private List<TrkSegment> createSimplifiedSegments(GPXFile gpxFile,
+														  List<RouteColorizationPoint> colorizationPoints,
+														  GradientScaleType scaleType) {
+			List<TrkSegment> simplifiedSegments = new ArrayList<>();
+			ColorizationType colorizationType = scaleType.toColorizationType();
+			int id = 0;
+			int colorPointIdx = 0;
+
+			for (TrkSegment segment : gpxFile.getNonEmptyTrkSegments(false)) {
+				TrkSegment simplifiedSegment = new TrkSegment();
+				simplifiedSegments.add(simplifiedSegment);
+				for (WptPt pt : segment.points) {
+					if (colorPointIdx >= colorizationPoints.size()) {
+						return simplifiedSegments;
+					}
+					RouteColorizationPoint colorPoint = colorizationPoints.get(colorPointIdx);
+					if (colorPoint.id == id) {
+						simplifiedSegment.points.add(pt);
+						pt.setColor(colorizationType, colorPoint.color);
+						colorPointIdx++;
+					}
+					id++;
+				}
+			}
+
+			return simplifiedSegments;
+		}
+	}
 }