1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.google.android.DemoKit;
18 
19 import android.content.Context;
20 import android.graphics.*;
21 import android.util.AttributeSet;
22 import android.view.MotionEvent;
23 import android.view.View;
24 
25 
26 /* This class was masterfully pilfered, Carmen-Sandiego style, from our awesome sample app
27  * ApiDemos.  To see how it looks as a dialog, check out:
28  * http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/ColorPickerDialog.html
29  *
30  */
31 
32   public class ColorWheel extends View {
33       public interface OnColorChangedListener {
colorChanged(int color)34           void colorChanged(int color);
35       }
36 
37       /*
38       */
39 
40       private OnColorChangedListener mListener;
41 
42       private int mInitialColor;
43 
44       private Paint mPaint;
45       private Paint mCenterPaint;
46       private final int[] mColors;
47 
setOnColorChangedListener(OnColorChangedListener l)48       public void setOnColorChangedListener(OnColorChangedListener l) {
49           mListener = l;
50       }
51 
52 
ColorWheel(Context c, AttributeSet attributes)53       public ColorWheel(Context c, AttributeSet attributes) {
54 
55           super(c, attributes);
56 
57           mColors = new int[] {
58               0xFFFF0000, 0xFFFF00FF, 0xFF0000FF, 0xFF00FFFF, 0xFF00FF00,
59               0xFFFFFF00, 0xFFFF0000
60           };
61           Shader s = new SweepGradient(0, 0, mColors, null);
62 
63           mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
64           mPaint.setShader(s);
65           mPaint.setStyle(Paint.Style.STROKE);
66           mPaint.setStrokeWidth(32);
67 
68           mCenterPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
69           mCenterPaint.setColor(0);
70           mCenterPaint.setStrokeWidth(5);
71       }
72 
73 
74 
75       private boolean mTrackingCenter;
76       private boolean mHighlightCenter;
77 
78       @Override
onDraw(Canvas canvas)79       protected void onDraw(Canvas canvas) {
80           super.onDraw(canvas);
81           float r = CENTER_X - mPaint.getStrokeWidth()*0.5f;
82 
83           canvas.translate(CENTER_X, CENTER_X);
84 
85           canvas.drawOval(new RectF(-r, -r, r, r), mPaint);
86           canvas.drawCircle(0, 0, CENTER_RADIUS, mCenterPaint);
87 
88           if (mTrackingCenter) {
89               int c = mCenterPaint.getColor();
90               mCenterPaint.setStyle(Paint.Style.STROKE);
91 
92               if (mHighlightCenter) {
93                   mCenterPaint.setAlpha(0xFF);
94               } else {
95                   mCenterPaint.setAlpha(0x80);
96               }
97               canvas.drawCircle(0, 0,
98                                 CENTER_RADIUS + mCenterPaint.getStrokeWidth(),
99                                 mCenterPaint);
100 
101               mCenterPaint.setStyle(Paint.Style.FILL);
102               mCenterPaint.setColor(c);
103           }
104       }
105 
106       @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)107       protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
108 
109           setMeasuredDimension(CENTER_X*2, CENTER_Y*2);
110       }
111 
112       private static final int CENTER_X = 200;
113       private static final int CENTER_Y = 200;
114       private static final int CENTER_RADIUS = 64;
115 
floatToByte(float x)116       private int floatToByte(float x) {
117           int n = java.lang.Math.round(x);
118           return n;
119       }
pinToByte(int n)120       private int pinToByte(int n) {
121           if (n < 0) {
122               n = 0;
123           } else if (n > 255) {
124               n = 255;
125           }
126           return n;
127       }
128 
ave(int s, int d, float p)129       private int ave(int s, int d, float p) {
130           return s + java.lang.Math.round(p * (d - s));
131       }
132 
interpColor(int colors[], float unit)133       private int interpColor(int colors[], float unit) {
134           if (unit <= 0) {
135               return colors[0];
136           }
137           if (unit >= 1) {
138               return colors[colors.length - 1];
139           }
140 
141           float p = unit * (colors.length - 1);
142           int i = (int)p;
143           p -= i;
144 
145           // now p is just the fractional part [0...1) and i is the index
146           int c0 = colors[i];
147           int c1 = colors[i+1];
148           int a = ave(Color.alpha(c0), Color.alpha(c1), p);
149           int r = ave(Color.red(c0), Color.red(c1), p);
150           int g = ave(Color.green(c0), Color.green(c1), p);
151           int b = ave(Color.blue(c0), Color.blue(c1), p);
152 
153           return Color.argb(a, r, g, b);
154       }
155 
rotateColor(int color, float rad)156       private int rotateColor(int color, float rad) {
157           float deg = rad * 180 / 3.1415927f;
158           int r = Color.red(color);
159           int g = Color.green(color);
160           int b = Color.blue(color);
161 
162           ColorMatrix cm = new ColorMatrix();
163           ColorMatrix tmp = new ColorMatrix();
164 
165           cm.setRGB2YUV();
166           tmp.setRotate(0, deg);
167           cm.postConcat(tmp);
168           tmp.setYUV2RGB();
169           cm.postConcat(tmp);
170 
171           final float[] a = cm.getArray();
172 
173           int ir = floatToByte(a[0] * r +  a[1] * g +  a[2] * b);
174           int ig = floatToByte(a[5] * r +  a[6] * g +  a[7] * b);
175           int ib = floatToByte(a[10] * r + a[11] * g + a[12] * b);
176 
177           return Color.argb(Color.alpha(color), pinToByte(ir),
178                             pinToByte(ig), pinToByte(ib));
179       }
180 
181       private static final float PI = 3.1415926f;
182 
183       @Override
onTouchEvent(MotionEvent event)184       public boolean onTouchEvent(MotionEvent event) {
185           float x = event.getX() - CENTER_X;
186           float y = event.getY() - CENTER_Y;
187           boolean inCenter = java.lang.Math.sqrt(x*x + y*y) <= CENTER_RADIUS;
188 
189           switch (event.getAction()) {
190               case MotionEvent.ACTION_DOWN:
191                   mTrackingCenter = inCenter;
192                   if (inCenter) {
193                       mHighlightCenter = true;
194                       invalidate();
195                       break;
196                   }
197               case MotionEvent.ACTION_MOVE:
198                   if (mTrackingCenter) {
199                       if (mHighlightCenter != inCenter) {
200                           mHighlightCenter = inCenter;
201                           invalidate();
202                       }
203                   } else {
204                       float angle = (float)java.lang.Math.atan2(y, x);
205                       // need to turn angle [-PI ... PI] into unit [0....1]
206                       float unit = angle/(2*PI);
207                       if (unit < 0) {
208                           unit += 1;
209                       }
210                       mCenterPaint.setColor(interpColor(mColors, unit));
211                       invalidate();
212                       mListener.colorChanged(mCenterPaint.getColor());
213                   }
214                   break;
215               case MotionEvent.ACTION_UP:
216                   if (mTrackingCenter) {
217                       if (inCenter) {
218                           mListener.colorChanged(mCenterPaint.getColor());
219                       }
220                       mListener.colorChanged(0);
221                       // mListener.colorChanged(mCenterPaint.getColor());
222                       mTrackingCenter = false;    // so we draw w/o halo
223                       invalidate();
224                   }
225                   break;
226           }
227           return true;
228       }
229   }
230