1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.gui.layer.imagery;
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3 |
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4 | import java.awt.Transparency;
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5 | import java.awt.image.BufferedImage;
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6 | import java.awt.image.LookupOp;
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7 | import java.awt.image.ShortLookupTable;
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8 |
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9 | import org.openstreetmap.josm.Main;
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10 | import org.openstreetmap.josm.gui.layer.ImageProcessor;
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11 |
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12 | /**
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13 | * An image processor which adjusts the gamma value of an image.
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14 | * @since 10547
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15 | */
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16 | public class GammaImageProcessor implements ImageProcessor {
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17 | private double gamma = 1;
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18 | final short[] gammaChange = new short[256];
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19 | private final LookupOp op3 = new LookupOp(
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20 | new ShortLookupTable(0, new short[][]{gammaChange, gammaChange, gammaChange}), null);
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21 | private final LookupOp op4 = new LookupOp(
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22 | new ShortLookupTable(0, new short[][]{gammaChange, gammaChange, gammaChange, gammaChange}), null);
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23 |
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24 | /**
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25 | * Returns the currently set gamma value.
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26 | * @return the currently set gamma value
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27 | */
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28 | public double getGamma() {
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29 | return gamma;
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30 | }
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31 |
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32 | /**
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33 | * Sets a new gamma value, {@code 1} stands for no correction.
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34 | * @param gamma new gamma value
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35 | */
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36 | public void setGamma(double gamma) {
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37 | this.gamma = gamma;
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38 | for (int i = 0; i < 256; i++) {
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39 | gammaChange[i] = (short) (255 * Math.pow(i / 255., gamma));
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40 | }
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41 | }
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42 |
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43 | @Override
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44 | public BufferedImage process(BufferedImage image) {
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45 | if (gamma == 1) {
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46 | return image;
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47 | }
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48 | try {
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49 | final int bands = image.getRaster().getNumBands();
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50 | if (image.getType() != BufferedImage.TYPE_CUSTOM && bands == 3) {
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51 | return op3.filter(image, null);
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52 | } else if (image.getType() != BufferedImage.TYPE_CUSTOM && bands == 4) {
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53 | return op4.filter(image, null);
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54 | }
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55 | } catch (IllegalArgumentException ignore) {
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56 | Main.trace(ignore);
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57 | }
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58 | final int type = image.getTransparency() == Transparency.OPAQUE ? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
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59 | final BufferedImage to = new BufferedImage(image.getWidth(), image.getHeight(), type);
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60 | to.getGraphics().drawImage(image, 0, 0, null);
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61 | return process(to);
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62 | }
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63 |
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64 | @Override
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65 | public String toString() {
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66 | return "GammaImageProcessor [gamma=" + gamma + ']';
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67 | }
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68 | }
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