[11748] | 1 | // License: GPL. For details, see LICENSE file.
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| 2 | package org.openstreetmap.josm.gui.mappaint.styleelement.placement;
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| 3 |
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| 4 | import java.awt.font.GlyphVector;
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| 5 | import java.awt.geom.AffineTransform;
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| 6 | import java.awt.geom.Rectangle2D;
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| 7 | import java.util.ArrayList;
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| 8 | import java.util.Collections;
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| 9 | import java.util.Comparator;
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| 10 | import java.util.Iterator;
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| 11 | import java.util.List;
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| 12 | import java.util.Optional;
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| 13 | import java.util.stream.IntStream;
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| 14 |
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| 15 | import org.openstreetmap.josm.gui.MapViewState.MapViewPoint;
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| 16 | import org.openstreetmap.josm.gui.draw.MapViewPath;
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| 17 | import org.openstreetmap.josm.gui.draw.MapViewPath.PathSegmentConsumer;
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| 18 | import org.openstreetmap.josm.gui.draw.MapViewPositionAndRotation;
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| 19 |
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| 20 | /**
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| 21 | * Places the label onto the line.
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| 22 | *
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| 23 | * @author Michael Zangl
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| 24 | * @since 11722
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| 25 | * @since 11748 moved to own file
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| 26 | */
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| 27 | public class OnLineStrategy implements PositionForAreaStrategy {
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| 28 | /**
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| 29 | * An instance of this class.
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| 30 | */
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| 31 | public static final OnLineStrategy INSTANCE = new OnLineStrategy(0);
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| 32 |
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| 33 | private final double yOffset;
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| 34 |
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| 35 | /**
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| 36 | * Create a new strategy that places the text on the line.
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| 37 | * @param yOffset The offset sidewards to the line.
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| 38 | */
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| 39 | public OnLineStrategy(double yOffset) {
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| 40 | this.yOffset = yOffset;
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| 41 | }
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| 42 |
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| 43 | @Override
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| 44 | public MapViewPositionAndRotation findLabelPlacement(MapViewPath path, Rectangle2D nb) {
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| 45 | return findOptimalWayPosition(nb, path).map(best -> {
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| 46 | MapViewPoint center = best.start.interpolate(best.end, .5);
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| 47 | return new MapViewPositionAndRotation(center, upsideTheta(best));
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| 48 | }).orElse(null);
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| 49 | }
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| 50 |
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[11752] | 51 | private static double upsideTheta(HalfSegment best) {
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[11748] | 52 | double theta = theta(best.start, best.end);
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| 53 | if (theta < -Math.PI / 2) {
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| 54 | return theta + Math.PI;
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| 55 | } else if (theta > Math.PI / 2) {
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| 56 | return theta - Math.PI;
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| 57 | } else {
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| 58 | return theta;
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| 59 | }
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| 60 | }
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| 61 |
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| 62 | @Override
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| 63 | public boolean supportsGlyphVector() {
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| 64 | return true;
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| 65 | }
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| 66 |
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| 67 | @Override
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| 68 | public List<GlyphVector> generateGlyphVectors(MapViewPath path, Rectangle2D nb, List<GlyphVector> gvs,
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| 69 | boolean isDoubleTranslationBug) {
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[11752] | 70 | // Find the position on the way the font should be placed.
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| 71 | // If none is found, use the middle of the way.
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[11748] | 72 | double middleOffset = findOptimalWayPosition(nb, path).map(segment -> segment.offset)
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| 73 | .orElse(path.getLength() / 2);
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| 74 |
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[11752] | 75 | // Check that segment of the way. Compute in which direction the text should be rendered.
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| 76 | // It is rendered in a way that ensures that at least 50% of the text are rotated with the right side up.
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[11748] | 77 | UpsideComputingVisitor upside = new UpsideComputingVisitor(middleOffset - nb.getWidth() / 2,
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| 78 | middleOffset + nb.getWidth() / 2);
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| 79 | path.visitLine(upside);
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[11752] | 80 | boolean doRotateText = upside.shouldRotateText();
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[11748] | 81 |
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[11752] | 82 | // Compute the list of glyphs to draw, along with their offset on the current line.
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[11748] | 83 | List<OffsetGlyph> offsetGlyphs = computeOffsetGlyphs(gvs,
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| 84 | middleOffset + (doRotateText ? 1 : -1) * nb.getWidth() / 2, doRotateText);
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| 85 |
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[11752] | 86 | // Order the glyphs along the line to ensure that they are drawn corretly.
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[11753] | 87 | Collections.sort(offsetGlyphs, Comparator.comparing(OffsetGlyph::getOffset));
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[11752] | 88 |
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| 89 | // Now translate all glyphs. This will modify the glyphs stored in gvs.
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[11748] | 90 | path.visitLine(new GlyphRotatingVisitor(offsetGlyphs, isDoubleTranslationBug));
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| 91 | return gvs;
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| 92 | }
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| 93 |
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| 94 | /**
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| 95 | * Create a list of glyphs with an offset along the way
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| 96 | * @param gvs The list of glyphs
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| 97 | * @param startOffset The offset in the line
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| 98 | * @param rotateText Rotate the text by 180°
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| 99 | * @return The list of glyphs.
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| 100 | */
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[11749] | 101 | private static List<OffsetGlyph> computeOffsetGlyphs(List<GlyphVector> gvs, double startOffset, boolean rotateText) {
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[11748] | 102 | double offset = startOffset;
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| 103 | ArrayList<OffsetGlyph> offsetGlyphs = new ArrayList<>();
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| 104 | for (GlyphVector gv : gvs) {
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| 105 | double gvOffset = offset;
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| 106 | IntStream.range(0, gv.getNumGlyphs())
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| 107 | .mapToObj(i -> new OffsetGlyph(gvOffset, rotateText, gv, i))
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| 108 | .forEach(offsetGlyphs::add);
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| 109 | offset += (rotateText ? -1 : 1) + gv.getLogicalBounds().getBounds2D().getWidth();
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| 110 | }
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| 111 | return offsetGlyphs;
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| 112 | }
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| 113 |
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[11752] | 114 | private static Optional<HalfSegment> findOptimalWayPosition(Rectangle2D rect, MapViewPath path) {
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[11748] | 115 | // find half segments that are long enough to draw text on (don't draw text over the cross hair in the center of each segment)
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| 116 | List<HalfSegment> longHalfSegment = new ArrayList<>();
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| 117 | double minSegmentLength = 2 * (rect.getWidth() + 4);
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| 118 | double length = path.visitLine((inLineOffset, start, end, startIsOldEnd) -> {
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| 119 | double segmentLength = start.distanceToInView(end);
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| 120 | if (segmentLength > minSegmentLength) {
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| 121 | MapViewPoint center = start.interpolate(end, .5);
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| 122 | double q = computeQuality(start, center);
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| 123 | // prefer the first one for quality equality.
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| 124 | longHalfSegment.add(new HalfSegment(start, center, q + .1, inLineOffset + .25 * segmentLength));
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| 125 |
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| 126 | q = computeQuality(center, end);
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| 127 | longHalfSegment.add(new HalfSegment(center, end, q, inLineOffset + .75 * segmentLength));
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| 128 | }
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| 129 | });
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| 130 |
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| 131 | // find the segment with the best quality. If there are several with best quality, the one close to the center is prefered.
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| 132 | return longHalfSegment.stream().max(
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| 133 | Comparator.comparingDouble(segment -> segment.quality - 1e-5 * Math.abs(segment.offset - length / 2)));
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| 134 | }
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| 135 |
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| 136 | private static double computeQuality(MapViewPoint p1, MapViewPoint p2) {
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| 137 | double q = 0;
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| 138 | if (p1.isInView()) {
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| 139 | q += 1;
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| 140 | }
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| 141 | if (p2.isInView()) {
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| 142 | q += 1;
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| 143 | }
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| 144 | return q;
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| 145 | }
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| 146 |
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| 147 | /**
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| 148 | * A half segment that can be used to place text on it. Used in the drawTextOnPath algorithm.
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| 149 | * @author Michael Zangl
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| 150 | */
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| 151 | private static class HalfSegment {
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| 152 | /**
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| 153 | * start point of half segment
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| 154 | */
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| 155 | private final MapViewPoint start;
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| 156 |
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| 157 | /**
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| 158 | * end point of half segment
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| 159 | */
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| 160 | private final MapViewPoint end;
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| 161 |
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| 162 | /**
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| 163 | * quality factor (off screen / partly on screen / fully on screen)
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| 164 | */
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| 165 | private final double quality;
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| 166 |
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| 167 | /**
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| 168 | * The offset in the path.
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| 169 | */
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| 170 | private final double offset;
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| 171 |
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| 172 | /**
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| 173 | * Create a new half segment
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| 174 | * @param start The start along the way
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| 175 | * @param end The end of the segment
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| 176 | * @param quality A quality factor.
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| 177 | * @param offset The offset in the path.
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| 178 | */
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| 179 | HalfSegment(MapViewPoint start, MapViewPoint end, double quality, double offset) {
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| 180 | super();
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| 181 | this.start = start;
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| 182 | this.end = end;
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| 183 | this.quality = quality;
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| 184 | this.offset = offset;
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| 185 | }
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| 186 |
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| 187 | @Override
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| 188 | public String toString() {
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[11814] | 189 | return "HalfSegment [start=" + start + ", end=" + end + ", quality=" + quality + ']';
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[11748] | 190 | }
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| 191 | }
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| 192 |
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| 193 | /**
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| 194 | * A visitor that computes the side of the way that is the upper one for each segment and computes the dominant upper side of the way.
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| 195 | * This is used to always place at least 50% of the text correctly.
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| 196 | */
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[11749] | 197 | private static class UpsideComputingVisitor implements PathSegmentConsumer {
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[11748] | 198 |
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| 199 | private final double startOffset;
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| 200 | private final double endOffset;
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| 201 |
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[11752] | 202 | private double upsideUpLines;
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| 203 | private double upsideDownLines;
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[11748] | 204 |
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| 205 | UpsideComputingVisitor(double startOffset, double endOffset) {
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| 206 | super();
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| 207 | this.startOffset = startOffset;
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| 208 | this.endOffset = endOffset;
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| 209 | }
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| 210 |
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| 211 | @Override
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| 212 | public void addLineBetween(double inLineOffset, MapViewPoint start, MapViewPoint end, boolean startIsOldEnd) {
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| 213 | if (inLineOffset > endOffset) {
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| 214 | return;
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| 215 | }
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| 216 | double length = start.distanceToInView(end);
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| 217 | if (inLineOffset + length < startOffset) {
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| 218 | return;
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| 219 | }
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| 220 |
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| 221 | double segmentStart = Math.max(inLineOffset, startOffset);
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| 222 | double segmentEnd = Math.min(inLineOffset + length, endOffset);
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| 223 |
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| 224 | double segmentLength = segmentEnd - segmentStart;
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| 225 |
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| 226 | if (start.getInViewX() < end.getInViewX()) {
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| 227 | upsideUpLines += segmentLength;
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| 228 | } else {
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| 229 | upsideDownLines += segmentLength;
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| 230 | }
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| 231 | }
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| 232 |
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[11752] | 233 | /**
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| 234 | * Check if the text should be rotated by 180°
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| 235 | * @return if the text should be rotated.
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| 236 | */
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| 237 | boolean shouldRotateText() {
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[11748] | 238 | return upsideUpLines < upsideDownLines;
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| 239 | }
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| 240 | }
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| 241 |
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| 242 | /**
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| 243 | * Rotate the glyphs along a path.
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| 244 | */
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| 245 | private class GlyphRotatingVisitor implements PathSegmentConsumer {
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| 246 | private final Iterator<OffsetGlyph> gvs;
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| 247 | private final boolean isDoubleTranslationBug;
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| 248 | private OffsetGlyph next;
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| 249 |
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[11752] | 250 | /**
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| 251 | * Create a new {@link GlyphRotatingVisitor}
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| 252 | * @param gvs The glyphs to draw. Sorted along the line
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| 253 | * @param isDoubleTranslationBug true to fix a double translation bug.
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| 254 | */
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[11748] | 255 | GlyphRotatingVisitor(List<OffsetGlyph> gvs, boolean isDoubleTranslationBug) {
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| 256 | this.isDoubleTranslationBug = isDoubleTranslationBug;
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| 257 | this.gvs = gvs.iterator();
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| 258 | takeNext();
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| 259 | while (next != null && next.offset < 0) {
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| 260 | // skip them
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| 261 | takeNext();
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| 262 | }
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| 263 | }
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| 264 |
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| 265 | private void takeNext() {
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| 266 | if (gvs.hasNext()) {
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| 267 | next = gvs.next();
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| 268 | } else {
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| 269 | next = null;
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| 270 | }
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| 271 | }
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| 272 |
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| 273 | @Override
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| 274 | public void addLineBetween(double inLineOffset, MapViewPoint start, MapViewPoint end, boolean startIsOldEnd) {
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| 275 | double segLength = start.distanceToInView(end);
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| 276 | double segEnd = inLineOffset + segLength;
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| 277 | double theta = theta(start, end);
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| 278 | while (next != null && next.offset < segEnd) {
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| 279 | Rectangle2D rect = next.getBounds();
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| 280 | double centerY = 0;
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| 281 | MapViewPoint p = start.interpolate(end, (next.offset - inLineOffset) / segLength);
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| 282 |
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| 283 | AffineTransform trfm = new AffineTransform();
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| 284 | trfm.translate(-rect.getCenterX(), -centerY);
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| 285 | trfm.translate(p.getInViewX(), p.getInViewY());
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| 286 | trfm.rotate(theta + next.preRotate, rect.getWidth() / 2, centerY);
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| 287 | trfm.translate(0, next.glyph.getFont().getSize2D() * .25);
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| 288 | trfm.translate(0, yOffset);
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| 289 | if (isDoubleTranslationBug) {
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| 290 | // scale the translation components by one half
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| 291 | AffineTransform tmp = AffineTransform.getTranslateInstance(-0.5 * trfm.getTranslateX(),
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| 292 | -0.5 * trfm.getTranslateY());
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| 293 | tmp.concatenate(trfm);
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| 294 | trfm = tmp;
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| 295 | }
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| 296 | next.glyph.setGlyphTransform(next.glyphIndex, trfm);
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| 297 | takeNext();
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| 298 | }
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| 299 | }
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| 300 | }
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| 301 |
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| 302 | private static class OffsetGlyph {
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| 303 | private final double offset;
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| 304 | private final double preRotate;
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| 305 | private final GlyphVector glyph;
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| 306 | private final int glyphIndex;
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| 307 |
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| 308 | OffsetGlyph(double offset, boolean rotateText, GlyphVector glyph, int glyphIndex) {
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| 309 | super();
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| 310 | this.preRotate = rotateText ? Math.PI : 0;
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| 311 | this.glyph = glyph;
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| 312 | this.glyphIndex = glyphIndex;
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| 313 | Rectangle2D rect = getBounds();
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| 314 | this.offset = offset + (rotateText ? -1 : 1) * (rect.getX() + rect.getWidth() / 2);
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| 315 | }
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| 316 |
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[11814] | 317 | Rectangle2D getBounds() {
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[11748] | 318 | return glyph.getGlyphLogicalBounds(glyphIndex).getBounds2D();
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| 319 | }
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| 320 |
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[11814] | 321 | double getOffset() {
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[11753] | 322 | return offset;
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| 323 | }
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| 324 |
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[11748] | 325 | @Override
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| 326 | public String toString() {
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[11814] | 327 | return "OffsetGlyph [offset=" + offset + ", preRotate=" + preRotate + ", glyphIndex=" + glyphIndex + ']';
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[11748] | 328 | }
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| 329 | }
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| 330 |
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| 331 | private static double theta(MapViewPoint start, MapViewPoint end) {
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| 332 | return Math.atan2(end.getInViewY() - start.getInViewY(), end.getInViewX() - start.getInViewX());
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| 333 | }
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| 334 | }
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