画布旋转和绘制位图 [英] Canvas rotate and drawbitmap

问题描述

我有路径rect和位图，想在路径内添加位图，在开始绘制时按预期显示，但是在旋转和绘制位图超出范围时.这是我的代码.

I have path rect and bitmap, want to add bitmap inside path, While draw on start it appears as expected, but while rotate and draw bitmap goes outside bounds. Here is my code.

canvas!!.rotate(rotateAngle.toFloat(), rectF2.centerX(), rectF2.centerY())
canvas!!.drawPath(path, mPaint)
bitmap?.let {
    canvas!!.drawBitmap(it, rectF2.left, rectF2.top, mPaint)
}
canvas!!.restore()

RotateAngle为0

旋转角度为50

推荐答案

以下是使用矩阵的有效解决方案.

Here is the working solution with matrix.

bitmap?.let {
    val rotate = Matrix()
    rotate.setRotate(rotateAngle.toFloat(), it.width / 2.0f, it.height / 2.0f)
    rotate.postTranslate((rectF2.centerX() - it.width / 2.0f), (rectF2.centerY() - it.height / 2.0f))
    canvas!!.drawBitmap(it, rotate, mPaint)
}

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