void drawBitmap(Bitmap bitmap, Matrix matrix, Paint paint) Draw the bitmap using the specified matrix.
使用指定的矩阵绘制位图。也就是可以通过matrix的属性来控制如何绘制位图。该方法有三个参数，分别是：
Bitmap bitmap：要绘制的位图
Matrix matrix：绘制位图时用于变换位图的矩阵
Paint paint:画笔
如何使用：
需求：在坐标点为（100，100）开始绘制，然后图片顺时针旋转45°
关键代码：
matrix.postTranslate(100f, 100f) matrix.preRotate(45f)完整代码：
package com.lxm.apipro.canvas.d6 import android.content.Context import android.graphics.* import android.util.AttributeSet import android.view.View class CanvasView : View { private var mContext: Context? = null private var mBitmap: Bitmap = BitmapFactory.decodeResource(resources, com.lxm.apipro.R.drawable.pic1) private var mPaint: Paint = Paint() constructor(context: Context?) : this(context, null) constructor(context: Context?, attrs: AttributeSet?) : this(context, attrs, 0) constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super( context, attrs, defStyleAttr ) { mContext = context } init { mPaint.isAntiAlias = true mPaint.color = Color.RED mPaint.style = Paint.Style.STROKE mPaint.strokeWidth = 5f } override fun onDraw(canvas: Canvas?) { super.onDraw(canvas) canvas?.save() var matrix = Matrix() matrix.postTranslate(100f, 100f) matrix.preRotate(45f) canvas?.drawBitmap(mBitmap, matrix, null) canvas?.restore() } }效果：
