概述
这是一个自定义色盘，根据点，直线和圆的几何学加上hsv颜色模型完成
技术点
几何：
圆的标准方程式：
(x-a)²+(y-b)²=r²
直线一般方程式：
已知直线上的两点P1(X1,Y1) P2(X2,Y2)， P1 P2两点不重合。 AX+BY+C=0 A = Y2 - Y1 B = X1 - X2 C = X2*Y1 - X1*Y2点与圆的位置关系：
点在圆内、点在圆上、点在圆外。假设圆的半径为r，点到圆心的距离为d，则有：d＜r点在圆内，d=r点在圆上，d＞r点在圆外。
点P（x1,y1) 与圆(x-a)²+(y-b)²=r²的位置关系：
当(x-a)²+(y-b)²＞r²时，则点P在圆外。
当(x-a)²+(y-b)²=r²时，则点P在圆上。
当(x-a)²+(y-b)²＜r²时，则点P在圆内。
直线的斜率：
一条直线与某平面直角坐标系横轴正半轴方向的夹角的正切值即该直线相对于该坐标系的斜率
斜率 k=tanα（α倾斜角）
与x轴垂直的直线不存在斜率
直线的斜率公式为：k=y2-y1）/（x2-x1）或（y1-y2）/（x1-x2）
象限：
记
（x,y) 是象限中的一点
第一象限中的点：x > 0, y > 0
第二象限中的点：x < 0, y > 0
第三象限中的点：x < 0, y < 0
第四象限中的点：x > 0, y < 0
值得注意的是原点和坐标轴上的点不属于任何象限。
解方程:
Android：
自定义View、ComposeShader、SweepGradient、RadialGradient、Paint。
上源码
代码都比较简单这里就不介绍了
1 class RoundColorPaletteHSV360 constructor(context: Context, attrs: AttributeSet?, defStyleAttr:Int): View(context,attrs,defStyleAttr) {
2
3 constructor(context: Context):this(context,null,0)
4
5 constructor(context: Context,attrs: AttributeSet?):this(context,attrs,0)
6
7 //取色范围半径
8 var radius:Float = 0f
9 private set(value){
10 field = value-stroke-gap-colorRadius
11 }
12
13 //取色圆半径
14 var colorRadius = 50f
15 set(value){
16 if (value >= 0)
17 field = value
18 }
19
20 //取色圆边框半径
21 var colorStroke = 8f
22 set(value){
23 if (value >= 0)
24 field = value
25 }
26
27 //取色圆边框颜色
28 var colorStrokeColor = Color.BLACK
29
30 //取色颜色
31 var color = Color.WHITE
32
33 //边框半径
34 var stroke = 24f
35 set(value){
36 if (value >= 0)
37 field = value
38 }
39
40 //边框颜色
41 var strokeColor = Color.YELLOW
42
43 //间隙半径
44 var gap = 4f
45 set(value){
46 if (value >= 0)
47 field = value
48 }
49
50 var isOutOfBounds:Boolean = false
51
52 private val paint = Paint()
53 private val colors1:IntArray
54 private val positions1 :FloatArray
55 private val colors2:IntArray
56 private val positions2 :FloatArray
57 private var xColor: Float = 0f
58 private var yColor: Float = 0f
59 private var colorChangeCallBack: ColorChangeCallBack? = null
60
61 init {
62 // <declare-styleable name="RoundColorPaletteHSV360">
63 // <attr name="colorRadius" format="dimension"/>
64 // <attr name="colorStroke" format="dimension"/>
65 // <attr name="gap" format="dimension"/>
66 // <attr name="stroke" format="dimension"/>
67 // <attr name="colorStrokeColor" format="color"/>
68 // <attr name="strokeColor" format="color"/>
69 // <attr name="isOutOfBounds" format="boolean"/>
70 // </declare-styleable>
71 val typedArray = context.obtainStyledAttributes(attrs, R.styleable.RoundColorPaletteHSV360)
72 colorRadius = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_colorRadius,50f)
73 colorStroke = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_colorStroke,8f)
74 gap = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_gap,4f)
75 stroke = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_stroke,24f)
76 colorStrokeColor = typedArray.getColor(R.styleable.RoundColorPaletteHSV360_colorStrokeColor,Color.BLACK)
77 strokeColor = typedArray.getColor(R.styleable.RoundColorPaletteHSV360_strokeColor,Color.YELLOW)
78 isOutOfBounds = typedArray.getBoolean(R.styleable.RoundColorPaletteHSV360_isOutOfBounds,false)
79 typedArray.recycle()
80
81 val colorCount1 = 360
82 val colorCount2 = 255
83 val colorAngleStep = 360 / colorCount1
84 positions1 = FloatArray(colorCount1+1){i-> i/(colorCount1*1f)}
85 var hsv = floatArrayOf(0f, 1f, 1f)
86 colors1 = IntArray(colorCount1+1){ i->
87 hsv[0] = 360 - i * colorAngleStep % 360f
88 Color.HSVToColor(hsv)
89 }
90 hsv = floatArrayOf(0f, 0f, 1f)
91 positions2 = FloatArray(colorCount2+1){i-> i/(colorCount2*1f)}
92 colors2 = IntArray(colorCount2+1){ i->
93 Color.HSVToColor(255 * (colorCount2 -i) / colorCount2 , hsv)
94 }
95
96 }
97
98 override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
99 val width = MeasureSpec.getSize(widthMeasureSpec)/2f
100 val height = MeasureSpec.getSize(heightMeasureSpec)/2f
101 radius = if(width-height<0) width else height
102 super.onMeasure(widthMeasureSpec, heightMeasureSpec)
103 }
104
105 @SuppressLint("DrawAllocation")
106 override fun onDraw(canvas: Canvas?) {
107 createColorWheel(canvas)
108 createColorRadius(canvas,xColor,yColor)
109 super.onDraw(canvas)
110 }
111
112 //色盘
113 private fun createColorWheel(canvas: Canvas?){
114 paint.reset()
115 paint.isAntiAlias = true
116 paint.shader = ComposeShader(
117 SweepGradient(
118 width / 2f,
119 height / 2f,
120 colors1,
121 positions1
122 ), RadialGradient(
123 width / 2f,
124 height / 2f,
125 radius-colorRadius,
126 colors2,
127 positions2,
128 Shader.TileMode.CLAMP
129 ), PorterDuff.Mode.SRC_OVER)
130 canvas?.drawCircle(width / 2f,height / 2f,radius,paint)
131 paint.shader = null
132 paint.style = Paint.Style.STROKE
133 paint.strokeWidth = stroke.toFloat()
134 paint.color = strokeColor
135 canvas?.drawCircle(width / 2f,height / 2f,radius+gap+stroke/2,paint)
136 }
137
138 //取色圆
139 private fun createColorRadius(canvas: Canvas?, rx: Float, ry: Float){
140 var x = rx
141 var y = ry
142 if(x==0f || y==0f ){
143 x = width / 2f
144 y = height / 2f
145 }
146 paint.reset()
147 paint.isAntiAlias = true
148 paint.color = color
149 canvas?.drawCircle(x,y,colorRadius,paint)
150 paint.style = Paint.Style.STROKE
151 paint.color = colorStrokeColor
152 paint.strokeWidth = colorStroke
153 canvas?.drawCircle(x,y,colorRadius+colorStroke/2,paint)
154 }
155
156 fun setColorChangeCallBack(colorChangeCallBack: ColorChangeCallBack){
157 this.colorChangeCallBack = colorChangeCallBack
158 }
159
160 override fun onTouchEvent(event: MotionEvent?): Boolean {
161 event?.let {
162 val pointToCircle = pointToCircle(it.x, it.y)
163 if( pointToCircle <= radius - if(isOutOfBounds) 0f else (colorRadius-colorStroke)){
164 xColor = it.x
165 yColor = it.y
166 color = Color.HSVToColor(floatArrayOf((angdeg(it.x,it.y)),pointToCircle/radius,1f))
167 colorChangeCallBack?.onChange(color)
168 }else{
169 findPoint( it.x, it.y)
170 }
171 invalidate()
172 }
173 return true
174 }
175
176 //点到圆心距离
177 private fun pointToCircle(x: Float = width / 2f, y: Float = height / 2f ) =
178 sqrt((x - width / 2f)*(x - width / 2f) + (y-height / 2f)*(y-height / 2f))
179
180 //离目标最近的点 待开发
181 private fun findPoint(x1: Float = width / 2f, y1: Float = height / 2f ){
182 // 直线一般方程
183 // 以圆心为坐标0，0 重新计算点（a，b）坐标
184 val a = y1 - height / 2f
185 val b = x1 - width / 2f
186 val r = radius - if(isOutOfBounds) 0f else (colorRadius-colorStroke)
187 //r^2/((b/a)^2+1)的开平方
188 yColor = sqrt( (r * r) / ((b / a) * (b / a) + 1))
189 //判断开平方的正负值
190 if(a<0) yColor = -yColor
191 xColor = (b*yColor)/a + width / 2f
192 yColor += height / 2f
193 color = Color.HSVToColor(floatArrayOf((angdeg(xColor,yColor)),1f,1f))
194 colorChangeCallBack?.onChange(color)
195
196 }
197
198
199 //角度
200 private fun angdeg(x: Float = width / 2f, y: Float = height / 2f ):Float{
201 var angdeg = 0
202
203 //特殊角度, 与x轴垂直不存在斜率
204 if(x - width / 2f == 0f && y - height / 2f < 0){
205 angdeg = 90
206 }else{
207 //到圆心的斜率
208 val k = ((y-height / 2f)*(y-height / 2f))/((x - width / 2f)*(x - width / 2f))
209 //二分法
210 var min = 0.00
211 var max = 90.00
212 while(max-min>1){
213 val deg = min + (max - min) / 2
214 if(k>tan(toRadians(deg))) min = deg else max = deg
215 }
216 angdeg = (max-1).toInt()
217 }
218
219 if((x - width / 2f <= 0f && y - height / 2f <= 0f)) {//第二象限 90~180
220 angdeg = 180 - angdeg
221 }else if((x - width / 2f <= 0f && y - height / 2f >= 0f)) {//第三象限 180~270
222 angdeg += 180
223 }else if((x - width / 2f >= 0f && y - height / 2f >= 0f)) {//第四象限 270~360
224 angdeg = 360 - angdeg
225 }
226
227 return angdeg.toFloat()
228 }
229
230 interface ColorChangeCallBack{
231 fun onChange(@ColorInt color: Int)
232 }
233 }
View Code
# 圆形取色盘
#### 仓库地址
https://gitee.com/yangguizhong/circular-color-plate
#### 安装教程
gradle 7.0以上的在 settings.gradle 添加：
```
dependencyResolutionManagement {
repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
repositories {
google()
mavenCentral()
maven {url "https://gitee.com/yangguizhong/circular-color-plate/raw/master"}
jcenter() // Warning: this repository is going to shut down soon
}
}
```
gradle 7.0以下的在根 build.gradle 添加：
```
allprojects {
repositories {
google()
mavenCentral()
maven {url "https://gitee.com/yangguizhong/circular-color-plate/raw/master"}
}
}
```
build.gradle 添加：
```
implementation 'com.xiaotie.colorPicker:colorPicker:1.0.0'
```
#### 使用说明
```
<com.wifiled.ipixels.view.RoundColorPaletteHSV360
android:id="@+id/color_picker"
android:layout_width="300dp"
android:layout_height="300dp"
app:gap="1dp"//取色背景和背景边框的间隙
app:colorRadius="20dp"//取色圆的半径
app:colorStroke="3dp"//取色圆的边框宽度
app:stroke="8dp"//背景边框的宽度
app:strokeColor="#FFF7A6"//背景边框的颜色
app:isOutOfBounds="true"//是否超出边框
app:colorStrokeColor="#2E3C3C"//取色圆的边框宽度
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
```
```
colorPickerView.setColorChangeCallBack(object:RoundColorPaletteHSV360.ColorChangeCallBack{
override fun onChange(color: Int) {
//返回的颜色
}
})
```
标签：自定义,val,RoundColorPaletteHSV360,app,value,取色,var,Android From： https://www.cnblogs.com/xiao-tie/p/16587737.html