Quelle  ImagePopup.java

package ch.threema.app.ui;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.ScaleAnimation;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.PopupWindow;

import androidx.annotation.NonNull;
import ch.threema.app.R;
import ch.threema.app.utils.AnimationUtil;

public class ImagePopup extends DimmingPopupWindow {
    private ImageView imageView;
    private View topLayout;
    private View parentView;
    final int[] location = new int[2];

    public ImagePopup(Context context, @NonNull View parentView) {
        super(context);
        init(context, parentView, parentView.getWidth(), parentView.getHeight());
    }

    private void init(Context context, View parentView, int screenWidth, int screenHeight) {
        this.parentView = parentView;

        topLayout = LayoutInflater.from(context).inflate(R.layout.popup_image_nomargin, null, true);

        this.imageView = topLayout.findViewById(R.id.thumbnail_view);

        int borderSize = context.getResources().getDimensionPixelSize(R.dimen.image_popup_screen_border_width);
        setContentView(topLayout);

        if (screenHeight > screenWidth) {
            // portrait
            setWidth(screenWidth - borderSize);
            setHeight(LinearLayout.LayoutParams.WRAP_CONTENT);
        } else {
            // landscape
            setWidth(LinearLayout.LayoutParams.WRAP_CONTENT);
            setHeight(screenHeight - borderSize);
        }
        setBackgroundDrawable(new BitmapDrawable());
        setAnimationStyle(0);
        setElevation(0);
        setInputMethodMode(PopupWindow.INPUT_METHOD_NOT_NEEDED);
    }

    public void show(@NonNull final View sourceView, @NonNull Bitmap bitmap) {
        this.imageView.setImageBitmap(bitmap);

        showAtLocation(parentView, Gravity.CENTER, 0, 0);
        dimBackground();
        getContentView().getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                getContentView().getViewTreeObserver().removeOnGlobalLayoutListener(this);
                AnimationUtil.getViewCenter(sourceView, getContentView(), location);

                AnimationSet animation = new AnimationSet(true);
                Animation scale = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.ABSOLUTE, location[0], Animation.ABSOLUTE, location[1]);
                Animation fade = new AlphaAnimation(0.0f, 1.0f);

                animation.addAnimation(scale);
                animation.addAnimation(fade);
                animation.setInterpolator(new DecelerateInterpolator());
                animation.setDuration(150);

                getContentView().startAnimation(animation);
            }
        });

        topLayout.setOnClickListener(v -> dismiss());
    }

    @Override
    public void dismiss() {
        AnimationUtil.popupAnimateOut(getContentView(), ImagePopup.super::dismiss);
    }
}