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=0A = Y2 – Y1B = X1 – X2C = 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
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 // 63 // 64 // 65 // 66 // 67 // 68 // 69 // 70 // 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)/2f100 val height = MeasureSpec.getSize(heightMeasureSpec)/2f101 radius = if(width-height<0) width else height102 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 = true116 paint.shader = ComposeShader(117 SweepGradient(118 width / 2f,119 height / 2f,120 colors1,121 positions1122 ), RadialGradient(123 width / 2f,124 height / 2f,125 radius-colorRadius,126 colors2,127 positions2,128 Shader.TileMode.CLAMP129 ), PorterDuff.Mode.SRC_OVER)130 canvas?.drawCircle(width / 2f,height / 2f,radius,paint)131 paint.shader = null132 paint.style = Paint.Style.STROKE133 paint.strokeWidth = stroke.toFloat()134 paint.color = strokeColor135 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 = rx141 var y = ry142 if(x==0f || y==0f ){143 x = width / 2f144 y = height / 2f145 }146 paint.reset()147 paint.isAntiAlias = true148 paint.color = color149 canvas?.drawCircle(x,y,colorRadius,paint)150 paint.style = Paint.Style.STROKE151 paint.color = colorStrokeColor152 paint.strokeWidth = colorStroke153 canvas?.drawCircle(x,y,colorRadius+colorStroke/2,paint)154 }155 156 fun setColorChangeCallBack(colorChangeCallBack: ColorChangeCallBack){157 this.colorChangeCallBack = colorChangeCallBack158 }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.x165 yColor = it.y166 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 true174 }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 / 2f185 val b = x1 - width / 2f186 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 = -yColor191 xColor = (b*yColor)/a + width / 2f192 yColor += height / 2f193 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 = 0202 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 = 90206 }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 = 0.00211 var max = 90.00212 while(max-min>1){213 val deg = min + (max - min) / 2214 if(k>tan(toRadians(deg))) min = deg else max = deg215 }216 angdeg = (max-1).toInt()217 }218 219 if((x - width / 2f <= 0f && y - height / 2f <= 0f)) {//第二象限 90~180220 angdeg = 180 - angdeg221 }else if((x - width / 2f = 0f)) {//第三象限 180~270222 angdeg += 180223 }else if((x - width / 2f >= 0f && y - height / 2f >= 0f)) {//第四象限 270~360224 angdeg = 360 - angdeg225 }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
}
})
“`