从 Gallery Kotlin Android 旋转图像方向

Question

当我将图库中的图像上传到我的 kotlin 应用程序时，图像方向始终向一侧旋转。我怎样才能旋转它们，使它们变直。

Answer 1

正如 Commensware 建议的那样，您可以使用ExifInterface来旋转图像文件

。这是我用于图像旋转的类，

import android.content.Context
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.graphics.Matrix
import android.media.ExifInterface
import java.io.BufferedOutputStream
import java.io.File
import java.io.FileOutputStream
object GetProperImageRotation {
fun getRotatedImageFile(photoFile: File, context: Context?): File? {
val option = BitmapFactory.Options()
option.inSampleSize = 4
val convertedBitmap: Bitmap =
modifyOrientation(
BitmapFactory.decodeFile(photoFile.absolutePath, option),
photoFile.absolutePath
)
return saveImage(convertedBitmap, context)
}
private fun saveImage(image: Bitmap, context: Context?): File? {
val filename = getImageFilePath(context)
val imageFile = File(filename)
val os = BufferedOutputStream(FileOutputStream(imageFile))
image.compress(Bitmap.CompressFormat.JPEG, 100, os)
os.close()
return imageFile
}
private fun getImageFilePath(context: Context?): String {
val filename = "${System.currentTimeMillis()}.jpg"
val dir = context?.getExternalFilesDir(null)
return if (dir == null) {
filename
} else {
"${dir.absolutePath}/$filename"
}
}

private fun modifyOrientation(bitmap: Bitmap, image_absolute_path: String): Bitmap {
val ei: ExifInterface = ExifInterface(image_absolute_path);
val orientation: Int =
ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
when (orientation) {
ExifInterface.ORIENTATION_ROTATE_90 -> {
return rotate(bitmap, 90f)
}
ExifInterface.ORIENTATION_ROTATE_180 -> {
return rotate(bitmap, 180f)
}
ExifInterface.ORIENTATION_TRANSVERSE -> {
return rotate(bitmap, 270f)
}
ExifInterface.ORIENTATION_ROTATE_270 -> {
return rotate(bitmap, 270f)
}
ExifInterface.ORIENTATION_FLIP_HORIZONTAL -> {
return flip(bitmap, true, vertical = false)
}
ExifInterface.ORIENTATION_FLIP_VERTICAL -> {
return flip(bitmap, false, vertical = true)
}
else -> {
return bitmap
}
}
}
private fun rotate(bitmap: Bitmap, degrees: Float): Bitmap {
val matrix = Matrix()
matrix.postRotate(degrees)
return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
}
private fun flip(bitmap: Bitmap, horizontal: Boolean, vertical: Boolean): Bitmap {
val matrix = Matrix()
matrix.preScale(if (horizontal) (-1f) else 1f, if (vertical) (-1f) else 1f)
return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true);
}
}

你可以这样使用

var rotatedImageFile = GetProperImageRotation.getRotatedImageFile(File("imagefilepath"),context)