I have an imageview as background. It is bigger than screen. I want to center it horizontally. It should align to the top. So, top of the original image should seen in the screen. I can resize the original images if necessary.
For example, in the giraffe image, I should be able to see from head to neck, not to the foot. Because the width allows that much.
XML Code
...
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ImageView
android:id="@+id/imageView5"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="matrix"
android:src="@drawable/home_screen_wallpaper_image"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
The usual scale types will not work for you. You will need to use the MATRIX scale type.
Here is how to apply it:
binding.matrixImage.doOnNextLayout {
// We will use a Matrix to shift the image left.
binding.matrixImage.scaleType = ImageView.ScaleType.MATRIX
// Compute how far to shift the image
val dx = (binding.matrixImage.drawable.intrinsicWidth - binding.matrixImage.width) / 2f
// Create and set the Matrix.
val matrix = Matrix()
matrix.postTranslate(-dx, 0f)
binding.matrixImage.imageMatrix = matrix
}