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這篇文章主要講解了“android如何實(shí)現(xiàn)自定義圓形取色盤”，文中的講解內(nèi)容簡單清晰，易于學(xué)習(xí)與理解，下面請大家跟著小編的思路慢慢深入，一起來研究和學(xué)習(xí)“android如何實(shí)現(xiàn)自定義圓形取色盤”吧！
這是一個(gè)自定義色盤，根據(jù)點(diǎn)，直線和圓的幾何學(xué)加上hsv顏色模型完成
幾何：
(x-a)²+(y-b)²=r²
已知直線上的兩點(diǎn)P1(X1,Y1) P2(X2,Y2)， P1 P2兩點(diǎn)不重合。
AX+BY+C=0
A = Y2 - Y1
B = X1 - X2
C = X2*Y1 - X1*Y2
點(diǎn)在圓內(nèi)、點(diǎn)在圓上、點(diǎn)在圓外。假設(shè)圓的半徑為r，點(diǎn)到圓心的距離為d，則有：d＜r點(diǎn)在圓內(nèi)，d=r點(diǎn)在圓上，d＞r點(diǎn)在圓外。
點(diǎn)P（x1,y1) 與圓(x-a)²+(y-b)²=r²的位置關(guān)系：
當(dāng)(x-a)²+(y-b)²＞r²時(shí)，則點(diǎn)P在圓外。
當(dāng)(x-a)²+(y-b)²=r²時(shí)，則點(diǎn)P在圓上。
當(dāng)(x-a)²+(y-b)²＜r²時(shí)，則點(diǎn)P在圓內(nèi)。
一條直線與某平面直角坐標(biāo)系橫軸正半軸方向的夾角的正切值即該直線相對于該坐標(biāo)系的斜率
斜率 k=tanα（α傾斜角）
與x軸垂直的直線不存在斜率
直線的斜率公式為：k=y2-y1）/（x2-x1）或（y1-y2）/（x1-x2）
記（x,y) 是象限中的一點(diǎn)
第一象限中的點(diǎn)：x > 0, y > 0
第二象限中的點(diǎn)：x < 0, y > 0
第三象限中的點(diǎn)：x < 0, y < 0
第四象限中的點(diǎn)：x > 0, y < 0
值得注意的是原點(diǎn)和坐標(biāo)軸上的點(diǎn)不屬于任何象限。
自定義View、ComposeShader、SweepGradient、RadialGradient、Paint。
上源碼
代碼都比較簡單這里就不介紹了
class RoundColorPaletteHSV360 constructor(context: Context, attrs: AttributeSet?, defStyleAttr:Int): View(context,attrs,defStyleAttr) {
constructor(context: Context):this(context,null,0)
constructor(context: Context,attrs: AttributeSet?):this(context,attrs,0)
//取色范圍半徑
var radius:Float = 0f
private set(value){
field = value-stroke-gap-colorRadius
}
//取色圓半徑
var colorRadius = 50f
set(value){
if (value >= 0)
field = value
}
//取色圓邊框半徑
var colorStroke = 8f
set(value){
if (value >= 0)
field = value
}
//取色圓邊框顏色
var colorStrokeColor = Color.BLACK
//取色顏色
var color = Color.WHITE
//邊框半徑
var stroke = 24f
set(value){
if (value >= 0)
field = value
}
//邊框顏色
var strokeColor = Color.YELLOW
//間隙半徑
var gap = 4f
set(value){
if (value >= 0)
field = value
}
var isOutOfBounds:Boolean = false
private val paint = Paint()
private val colors1:IntArray
private val positions1 :FloatArray
private val colors2:IntArray
private val positions2 :FloatArray
private var xColor: Float = 0f
private var yColor: Float = 0f
private var colorChangeCallBack: ColorChangeCallBack? = null
init {
// <declare-styleable name="RoundColorPaletteHSV360">
// <attr name="colorRadius" format="dimension"/>
// <attr name="colorStroke" format="dimension"/>
// <attr name="gap" format="dimension"/>
// <attr name="stroke" format="dimension"/>
// <attr name="colorStrokeColor" format="color"/>
// <attr name="strokeColor" format="color"/>
// <attr name="isOutOfBounds" format="boolean"/>
// </declare-styleable>
val typedArray = context.obtainStyledAttributes(attrs, R.styleable.RoundColorPaletteHSV360)
colorRadius = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_colorRadius,50f)
colorStroke = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_colorStroke,8f)
gap = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_gap,4f)
stroke = typedArray.getDimension(R.styleable.RoundColorPaletteHSV360_stroke,24f)
colorStrokeColor = typedArray.getColor(R.styleable.RoundColorPaletteHSV360_colorStrokeColor,Color.BLACK)
strokeColor = typedArray.getColor(R.styleable.RoundColorPaletteHSV360_strokeColor,Color.YELLOW)
isOutOfBounds = typedArray.getBoolean(R.styleable.RoundColorPaletteHSV360_isOutOfBounds,false)
typedArray.recycle()
val colorCount1 = 360
val colorCount2 = 255
val colorAngleStep = 360 / colorCount1
positions1 = FloatArray(colorCount1+1){i-> i/(colorCount1*1f)}
var hsv = floatArrayOf(0f, 1f, 1f)
colors1 = IntArray(colorCount1+1){ i->
hsv[0] = 360 - i * colorAngleStep % 360f
Color.HSVToColor(hsv)
}
hsv = floatArrayOf(0f, 0f, 1f)
positions2 = FloatArray(colorCount2+1){i-> i/(colorCount2*1f)}
colors2 = IntArray(colorCount2+1){ i->
Color.HSVToColor(255 * (colorCount2 -i) / colorCount2 , hsv)
}
}
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
val width = MeasureSpec.getSize(widthMeasureSpec)/2f
val height = MeasureSpec.getSize(heightMeasureSpec)/2f
radius = if(width-height<0) width else height
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
}
@SuppressLint("DrawAllocation")
override fun onDraw(canvas: Canvas?) {
createColorWheel(canvas)
createColorRadius(canvas,xColor,yColor)
super.onDraw(canvas)
}
//色盤
private fun createColorWheel(canvas: Canvas?){
paint.reset()
paint.isAntiAlias = true
paint.shader = ComposeShader(
SweepGradient(
width / 2f,
height / 2f,
colors1,
positions1
), RadialGradient(
width / 2f,
height / 2f,
radius-colorRadius,
colors2,
positions2,
Shader.TileMode.CLAMP
), PorterDuff.Mode.SRC_OVER)
canvas?.drawCircle(width / 2f,height / 2f,radius,paint)
paint.shader = null
paint.style = Paint.Style.STROKE
paint.strokeWidth = stroke.toFloat()
paint.color = strokeColor
canvas?.drawCircle(width / 2f,height / 2f,radius+gap+stroke/2,paint)
}
//取色圓
private fun createColorRadius(canvas: Canvas?, rx: Float, ry: Float){
var x = rx
var y = ry
if(x==0f || y==0f ){
x = width / 2f
y = height / 2f
}
paint.reset()
paint.isAntiAlias = true
paint.color = color
canvas?.drawCircle(x,y,colorRadius,paint)
paint.style = Paint.Style.STROKE
paint.color = colorStrokeColor
paint.strokeWidth = colorStroke
canvas?.drawCircle(x,y,colorRadius+colorStroke/2,paint)
}
fun setColorChangeCallBack(colorChangeCallBack: ColorChangeCallBack){
this.colorChangeCallBack = colorChangeCallBack
}
override fun onTouchEvent(event: MotionEvent?): Boolean {
event?.let {
val pointToCircle = pointToCircle(it.x, it.y)
if( pointToCircle <= radius - if(isOutOfBounds) 0f else (colorRadius-colorStroke)){
xColor = it.x
yColor = it.y
color = Color.HSVToColor(floatArrayOf((angdeg(it.x,it.y)),pointToCircle/radius,1f))
colorChangeCallBack?.onChange(color)
}else{
findPoint( it.x, it.y)
}
invalidate()
}
return true
}
//點(diǎn)到圓心距離
private fun pointToCircle(x: Float = width / 2f, y: Float = height / 2f ) =
sqrt((x - width / 2f)*(x - width / 2f) + (y-height / 2f)*(y-height / 2f))
//離目標(biāo)最近的點(diǎn) 待開發(fā)
private fun findPoint(x1: Float = width / 2f, y1: Float = height / 2f ){
// 直線一般方程
// 以圓心為坐標(biāo)0，0 重新計(jì)算點(diǎn)（a，b）坐標(biāo)
val a = y1 - height / 2f
val b = x1 - width / 2f
val r = radius - if(isOutOfBounds) 0f else (colorRadius-colorStroke)
//r^2/((b/a)^2+1)的開平方
yColor = sqrt( (r * r) / ((b / a) * (b / a) + 1))
//判斷開平方的正負(fù)值
if(a<0) yColor = -yColor
xColor = (b*yColor)/a + width / 2f
yColor += height / 2f
color = Color.HSVToColor(floatArrayOf((angdeg(xColor,yColor)),1f,1f))
colorChangeCallBack?.onChange(color)
}
//角度
private fun angdeg(x: Float = width / 2f, y: Float = height / 2f ):Float{
var angdeg = 0
//特殊角度, 與x軸垂直不存在斜率
if(x - width / 2f == 0f && y - height / 2f < 0){
angdeg = 90
}else{
//到圓心的斜率
val k = ((y-height / 2f)*(y-height / 2f))/((x - width / 2f)*(x - width / 2f))
//二分法
var min = 0.00
var max = 90.00
while(max-min>1){
val deg = min + (max - min) / 2
if(k>tan(toRadians(deg))) min = deg else max = deg
}
angdeg = (max-1).toInt()
}
if((x - width / 2f <= 0f && y - height / 2f <= 0f)) {//第二象限 90~180
angdeg = 180 - angdeg
}else if((x - width / 2f <= 0f && y - height / 2f >= 0f)) {//第三象限 180~270
angdeg += 180
}else if((x - width / 2f >= 0f && y - height / 2f >= 0f)) {//第四象限 270~360
angdeg = 360 - angdeg
}
return angdeg.toFloat()
}
interface ColorChangeCallBack{
fun onChange(@ColorInt color: Int)
}
}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' ```
#### 使用說明
```
<com.wifiled.ipixels.view.RoundColorPaletteHSV360
android:id="@+id/color_picker"
android:layout_width="300dp"
android:layout_height="300dp"
app:gap="1dp"//取色背景和背景邊框的間隙
app:colorRadius="20dp"//取色圓的半徑
app:colorStroke="3dp"//取色圓的邊框?qū)挾?
app:stroke="8dp"//背景邊框的寬度
app:strokeColor="#FFF7A6"//背景邊框的顏色
app:isOutOfBounds="true"//是否超出邊框
app:colorStrokeColor="#2E3C3C"//取色圓的邊框?qū)挾?
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) {
//返回的顏色
}
})
```感謝各位的閱讀，以上就是“android如何實(shí)現(xiàn)自定義圓形取色盤”的內(nèi)容了，經(jīng)過本文的學(xué)習(xí)后，相信大家對android如何實(shí)現(xiàn)自定義圓形取色盤這一問題有了更深刻的體會，具體使用情況還需要大家實(shí)踐驗(yàn)證。這里是億速云，小編將為大家推送更多相關(guān)知識點(diǎn)的文章，歡迎關(guān)注！
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