Android着色器SweepGradient渐变圆环，Kotlin

 

import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.Path
import android.graphics.SweepGradient
import android.util.AttributeSet
import androidx.appcompat.widget.AppCompatImageView


class MyView : AppCompatImageView {
    private var mPaint: Paint? = null
    private var mPath: Path? = null
    private var mSweepGradient: SweepGradient? = null

    constructor(ctx: Context, attributeSet: AttributeSet) : super(ctx, attributeSet) {
        val W = resources.displayMetrics.widthPixels
        val H = resources.displayMetrics.heightPixels

        mPaint = Paint(Paint.ANTI_ALIAS_FLAG or Paint.FILTER_BITMAP_FLAG)
        mPaint?.style = Paint.Style.STROKE
        mPaint?.strokeWidth = 60f

        mPath = Path()
        mPath?.addCircle(W / 2f, H / 2f, W / 3f, Path.Direction.CW)
        mSweepGradient =
            SweepGradient(W / 2f, H / 2f, intArrayOf(Color.TRANSPARENT, Color.RED, Color.BLUE, Color.YELLOW, Color.TRANSPARENT), null)
        mPaint?.setShader(mSweepGradient)
    }

    override fun onDraw(canvas: Canvas) {
        canvas.drawPath(mPath!!, mPaint!!)
    }
}

 

 

 

 

 

 

Android渲染器Shader：梯度渐变扫描渲染器SweepGradient（二）-CSDN博客文章浏览阅读4.5k次。Android渲染器Shader：梯度渐变扫描渲染器SweepGradient（二）附录文章1介绍了线性渐变渲染器。Android的SweepGradient梯度渐变扫描，重点是在构造SweepGradient的中心点选择。我写一个例子。package zhangphil.demo;import android.content.Context;import android_sweepgradienthttps://blog.csdn.net/zhangphil/article/details/52021677