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Added dwt-addons in original directory structure of eclipse.org
author Frank Benoit <benoit@tionex.de>
date Sat, 14 Mar 2009 18:23:29 +0100
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11:43904fec5dca 12:bc29606a740c
1 /*******************************************************************************
2 * Copyright (c) 2006, 2007 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
12 *******************************************************************************/
13 module org.eclipse.jface.internal.text.revisions.Colors;
14
15 import org.eclipse.jface.internal.text.revisions.HunkComputer; // packageimport
16 import org.eclipse.jface.internal.text.revisions.LineIndexOutOfBoundsException; // packageimport
17 import org.eclipse.jface.internal.text.revisions.Hunk; // packageimport
18 import org.eclipse.jface.internal.text.revisions.ChangeRegion; // packageimport
19 import org.eclipse.jface.internal.text.revisions.Range; // packageimport
20 import org.eclipse.jface.internal.text.revisions.RevisionPainter; // packageimport
21 import org.eclipse.jface.internal.text.revisions.RevisionSelectionProvider; // packageimport
22
23
24 import java.lang.all;
25 import java.util.Set;
26
27
28 import org.eclipse.swt.SWT;
29 import org.eclipse.swt.graphics.RGB;
30 import org.eclipse.core.runtime.Assert;
31
32 /**
33 * Utility for color operations.
34 *
35 * @since 3.3
36 */
37 public final class Colors {
38 /*
39 * Implementation note: Color computation assumes sRGB, which is probably not true, and does not
40 * always give good results. CIE based algorithms would be better, see
41 * http://www.w3.org/TR/PNG-ColorAppendix.html and http://en.wikipedia.org/wiki/Lab_color_space
42 */
43
44 /**
45 * Returns the human-perceived brightness of a color as float in [0.0, 1.0]. The used RGB
46 * weights come from http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9.
47 *
48 * @param rgb the color
49 * @return the gray-scale value
50 */
51 public static float brightness(RGB rgb) {
52 return Math.min(1f, (0.2126f * rgb.red + 0.7152f * rgb.green + 0.0722f * rgb.blue + 0.5f) / 255f);
53 }
54
55 /**
56 * Normalizes a color in its perceived brightness. Yellows are darkened, while blues and reds
57 * are lightened. Depending on the hue, the brightness range within the RGB gamut may be
58 * different, outside values are clipped. Note that this is an approximation; the returned RGB
59 * is not guaranteed to have the requested {@link #brightness(RGB) brightness}.
60 *
61 * @param color the color to normalize
62 * @param brightness the requested brightness, in [0,&nbsp;1]
63 * @return a normalized version of <code>color</code>
64 * @see #brightness(RGB)
65 */
66 public static RGB adjustBrightness(RGB color, float brightness_) {
67 float[] hsi= toHSI(color);
68 float psychoFactor= brightness_ - brightness(color);
69 float weight= 0.5f; // found by trial and error
70 hsi[2]= Math.max(0, Math.min(1.0f, hsi[2] + psychoFactor * weight));
71 color= fromHSI(hsi);
72 return color;
73 }
74
75 /**
76 * Converts an {@link RGB} to an <a href="http://en.wikipedia.org/wiki/HSL_color_space">HSI</a>
77 * triplet.
78 *
79 * @param color the color to convert
80 * @return the HSI float array of length 3
81 */
82 private static float[] toHSI(RGB color) {
83 float r = color.red / 255f;
84 float g = color.green / 255f;
85 float b = color.blue / 255f;
86 float max = Math.max(Math.max(r, g), b);
87 float min = Math.min(Math.min(r, g), b);
88 float delta = max - min;
89 float maxPlusMin= max + min;
90 float intensity = maxPlusMin / 2;
91 float saturation= intensity < 0.5 ? delta / maxPlusMin : delta / (2 - maxPlusMin);
92
93 float hue = 0;
94 if (delta !is 0) {
95 if (r is max) {
96 hue = (g - b) / delta;
97 } else {
98 if (g is max) {
99 hue = 2 + (b - r) / delta;
100 } else {
101 hue = 4 + (r - g) / delta;
102 }
103 }
104 hue *= 60;
105 if (hue < 0) hue += 360;
106 }
107 return [hue, saturation, intensity];
108 }
109
110 /**
111 * Converts a <a href="http://en.wikipedia.org/wiki/HSL_color_space">HSI</a> triplet to an RGB.
112 *
113 * @param hsi the HSI values
114 * @return the RGB corresponding to the HSI spec
115 */
116 private static RGB fromHSI(float[] hsi) {
117 float r, g, b;
118 float hue= hsi[0];
119 float saturation= hsi[1];
120 float intensity= hsi[2];
121 if (saturation is 0) {
122 r = g = b = intensity;
123 } else {
124 float temp2= intensity < 0.5f ? intensity * (1.0f + saturation) : (intensity + saturation) - (intensity * saturation);
125 float temp1= 2f * intensity - temp2;
126 if (hue is 360) hue = 0;
127 hue /= 360;
128
129 r= hue2RGB(temp1, temp2, hue + 1f/3f);
130 g= hue2RGB(temp1, temp2, hue);
131 b= hue2RGB(temp1, temp2, hue - 1f/3f);
132 }
133
134 int red = cast(int)(r * 255 + 0.5);
135 int green = cast(int)(g * 255 + 0.5);
136 int blue = cast(int)(b * 255 + 0.5);
137 return new RGB(red, green, blue);
138 }
139
140 private static float hue2RGB(float t1, float t2, float hue) {
141 if (hue < 0)
142 hue += 1;
143 else if (hue > 1)
144 hue -= 1;
145 if (6f * hue < 1)
146 return t1 +(t2 - t1) * 6f * hue;
147 if (2f * hue < 1)
148 return t2;
149 if (3f * hue < 2)
150 return t1 + (t2 - t1) * (2f/3f - hue) * 6f;
151 return t1;
152 }
153
154 /**
155 * Returns an RGB that lies between the given foreground and background
156 * colors using the given mixing factor. A <code>factor</code> of 1.0 will produce a
157 * color equal to <code>fg</code>, while a <code>factor</code> of 0.0 will produce one
158 * equal to <code>bg</code>.
159 * @param bg the background color
160 * @param fg the foreground color
161 * @param factor the mixing factor, must be in [0,&nbsp;1]
162 *
163 * @return the interpolated color
164 */
165 public static RGB blend(RGB bg, RGB fg, float factor) {
166 Assert.isLegal(bg !is null);
167 Assert.isLegal(fg !is null);
168 Assert.isLegal(factor >= 0f && factor <= 1f);
169
170 float complement= 1f - factor;
171 return new RGB(
172 cast(int) (complement * bg.red + factor * fg.red),
173 cast(int) (complement * bg.green + factor * fg.green),
174 cast(int) (complement * bg.blue + factor * fg.blue)
175 );
176 }
177
178 /**
179 * Returns an array of colors in a smooth palette from <code>start</code> to <code>end</code>.
180 * <p>
181 * The returned array has size <code>steps</code>, and the color at index 0 is <code>start</code>, the color
182 * at index <code>steps&nbsp;-&nbsp;1</code> is <code>end</code>.
183 *
184 * @param start the start color of the palette
185 * @param end the end color of the palette
186 * @param steps the requested size, must be &gt; 0
187 * @return an array of <code>steps</code> colors in the palette from <code>start</code> to <code>end</code>
188 */
189 public static RGB[] palette(RGB start, RGB end, int steps) {
190 Assert.isLegal(start !is null);
191 Assert.isLegal(end !is null);
192 Assert.isLegal(steps > 0);
193
194 if (steps is 1)
195 return [ start ];
196
197 float step= 1.0f / (steps - 1);
198 RGB[] gradient= new RGB[steps];
199 for (int i= 0; i < steps; i++)
200 gradient[i]= blend(start, end, step * i);
201
202 return gradient;
203 }
204
205 /**
206 * Returns an array of colors with hues evenly distributed on the hue wheel defined by the <a
207 * href="http://en.wikipedia.org/wiki/HSV_color_space">HSB color space</a>. The returned array
208 * has size <code>steps</code>. The distance <var>d</var> between two successive colors is
209 * in [120&#176;,&nbsp;180&#176;].
210 * <p>
211 * The color at a given <code>index</code> has the hue returned by
212 * {@linkplain #computeHue(int) computeHue(index)}; i.e. the computed hues are not equidistant,
213 * but adaptively distributed on the color wheel.
214 * </p>
215 * <p>
216 * The first six colors returned correspond to the following {@link SWT} color constants:
217 * {@link SWT#COLOR_RED red}, {@link SWT#COLOR_GREEN green}, {@link SWT#COLOR_BLUE blue},
218 * {@link SWT#COLOR_YELLOW yellow}, {@link SWT#COLOR_CYAN cyan},
219 * {@link SWT#COLOR_MAGENTA magenta}.
220 * </p>
221 *
222 * @param steps the requested size, must be &gt;= 2
223 * @return an array of <code>steps</code> colors evenly distributed on the color wheel
224 */
225 public static RGB[] rainbow(int steps) {
226 Assert.isLegal(steps >= 2);
227
228 RGB[] rainbow= new RGB[steps];
229 for (int i= 0; i < steps; i++)
230 rainbow[i]= new RGB(computeHue(i), 1f, 1f);
231
232 return rainbow;
233 }
234
235 /**
236 * Returns an indexed hue in [0&#176;,&nbsp;360&#176;), distributing the hues evenly on the hue wheel
237 * defined by the <a href="http://en.wikipedia.org/wiki/HSV_color_space">HSB (or HSV) color
238 * space</a>. The distance <var>d</var> between two successive colors is in [120&#176;,&nbsp;180&#176;].
239 * <p>
240 * The first six colors returned correspond to the following {@link SWT} color constants:
241 * {@link SWT#COLOR_RED red}, {@link SWT#COLOR_GREEN green}, {@link SWT#COLOR_BLUE blue},
242 * {@link SWT#COLOR_YELLOW yellow}, {@link SWT#COLOR_CYAN cyan},
243 * {@link SWT#COLOR_MAGENTA magenta}.
244 * </p>
245 *
246 * @param index the index of the color, must be &gt;= 0
247 * @return a color hue in [0&#176;,&nbsp;360&#176;)
248 * @see RGB#RGB(float, float, float)
249 */
250 public static float computeHue(int index) {
251 Assert.isLegal(index >= 0);
252 /*
253 * Base 3 gives a nice partitioning for RGB colors with red, green, blue being the colors
254 * 0,1,2, and yellow, cyan, magenta colors 3,4,5.
255 */
256 final int base= 3;
257 final float range= 360f;
258
259 // partition the baseRange by using the least significant bit to select one half of the
260 // partitioning
261 int baseIndex= index / base;
262 float baseRange= range / base;
263 float baseOffset= 0f;
264 while (baseIndex > 0) {
265 baseRange /= 2;
266 int lsb= baseIndex % 2;
267 baseOffset += lsb * baseRange;
268 baseIndex >>= 1;
269 }
270
271 final int baseMod= index % base;
272 final float hue= baseOffset + baseMod * range / base;
273 Assert.isTrue(hue >= 0 && hue < 360);
274 return hue;
275 }
276
277 private this() {
278 // not instantiatable
279 }
280
281 }