private fun updateBaseMatrix(): Matrix? {
val drawable = drawable ?: return null
val viewWidth = (width - paddingLeft - paddingRight).toFloat() //view的宽度
val viewHeight = (height - paddingTop - paddingBottom).toFloat()
val drawableWidth = drawable.intrinsicWidth //图片的宽度
val drawableHeight = drawable.intrinsicHeight
mBaseMatrix.reset()
val widthScale = viewWidth / drawableWidth //缩放比例
val heightScale = viewHeight / drawableHeight //缩放比例
if (mScaleType == ImageView.ScaleType.CENTER) {
mBaseMatrix.postTranslate((viewWidth - drawableWidth) / 2f,
(viewHeight - drawableHeight) / 2f)
} else if (mScaleType == ImageView.ScaleType.CENTER_CROP) {
val scale = Math.max(widthScale, heightScale)
mBaseMatrix.postScale(scale, scale)
mBaseMatrix.postTranslate((viewWidth - drawableWidth * scale) / 2f,
(viewHeight - drawableHeight * scale) / 2f)
} else if (mScaleType == ImageView.ScaleType.CENTER_INSIDE) {
val scale = Math.min(1.0f, Math.min(widthScale, heightScale))
mBaseMatrix.postScale(scale, scale)
mBaseMatrix.postTranslate((viewWidth - drawableWidth * scale) / 2f,
(viewHeight - drawableHeight * scale) / 2f)
} else {
val mTempSrc = RectF(0f, 0f, drawableWidth.toFloat(), drawableHeight.toFloat())
val mTempDst = RectF(0f, 0f, viewWidth, viewHeight)
when (mScaleType) {
ImageView.ScaleType.FIT_CENTER -> mBaseMatrix.setRectToRect(mTempSrc, mTempDst, Matrix.ScaleToFit.CENTER)
ImageView.ScaleType.FIT_START -> mBaseMatrix.setRectToRect(mTempSrc, mTempDst, Matrix.ScaleToFit.START)
ImageView.ScaleType.FIT_END -> mBaseMatrix.setRectToRect(mTempSrc, mTempDst, Matrix.ScaleToFit.END)
ImageView.ScaleType.FIT_XY -> mBaseMatrix.setRectToRect(mTempSrc, mTempDst, Matrix.ScaleToFit.FILL)
else -> {
}
}
}
return mBaseMatrix
}
使用：
val matrix = updateBaseMatrix()
imageMatrix = matrix （相当于java的setImageMatrix）
