"Android: Displaying Levels At Optimum Zoom" core functions for GameDevAlgorithms

DisplayHelper.java

    public TileDisplaySetup setupTileDisplay(PuzzleDisplayer puzzleDisplayer, List<Tile> tiles, ZoomableViewGroup tileContainer, Tile selectedTile, ImageView selectedTileImage, boolean isEditor) {
        tileContainer.removeAllViews();

        Setting minimumMillisForDrag = Setting.get(Constants.SETTING_MINIMUM_MILLIS_DRAG);
        int dragDelay = minimumMillisForDrag != null ? minimumMillisForDrag.getIntValue() : 200;
        Pair<Integer, Integer> maxXY = TileHelper.getMaxXY(tiles);

        DisplayValues displayValues = getDisplayValues(puzzleDisplayer.getActivity(), maxXY.first + 1, maxXY.second + 1);
        float optimumScale = displayValues.getZoomFactor();

        int topOffset = displayValues.isLeftOffset() ? 0 : displayValues.getOffset();
        int leftOffset = displayValues.isLeftOffset() ? displayValues.getOffset() : 0;

        tileContainer.setScaleFactor(optimumScale, true);
        tileContainer.removeAllViews();
        for (final Tile tile : tiles) {
            if (!puzzleDisplayer.displayEmptyTile() && tile.getTileTypeId() == Constants.TILE_EMPTY) {
                continue;
            }

            ZoomableViewGroup.LayoutParams layoutParams = new ZoomableViewGroup.LayoutParams(ZoomableViewGroup.LayoutParams.WRAP_CONTENT, ZoomableViewGroup.LayoutParams.WRAP_CONTENT);
            int leftPadding = leftOffset + (tile.getY() + tile.getX()) * (getTileWidth() / 2);
            int topPadding = topOffset + (tile.getX() + maxXY.second - tile.getY()) * (getTileHeight() / 2);
            layoutParams.setMargins(leftPadding, topPadding, 0, 0);

            int drawableId = getTileDrawableId(puzzleDisplayer.getActivity(), tile.getTileTypeId(), tile.getRotation());
            ImageView image = createTileImageView(puzzleDisplayer, tile, drawableId, dragDelay);

            // Make sure we always have a tile selected
            if (isEditor && (selectedTile == null || selectedTileImage == null)) {
                image.setAlpha(0.75f);
                image.setColorFilter(Color.RED, PorterDuff.Mode.MULTIPLY);
                selectedTileImage = image;
                selectedTile = tile;

                TextView selectedTileText = (TextView) puzzleDisplayer.getActivity().findViewById(R.id.selectedTileText);
                if (selectedTileText != null) {
                    ((TextView) puzzleDisplayer.getActivity().findViewById(R.id.selectedTileText)).setText(tile.getName());
                }
            }

            tileContainer.addView(image, layoutParams);
        }

        return new TileDisplaySetup(selectedTileImage, optimumScale);
    }

    private DisplayValues getDisplayValues(Activity activity, int xTiles, int yTiles) {
        DisplayMetrics displayMetrics = getSizes(activity);
        int screenHeight = displayMetrics.heightPixels;
        int screenWidth = displayMetrics.widthPixels;

        double totalTilesAmount = (xTiles + yTiles) / 2.0;
        int puzzleHeight = (int) (totalTilesAmount * getTileHeight());
        int puzzleWidth = (int) (totalTilesAmount * getTileWidth());

        float xZoomFactor = screenWidth / (float) (puzzleWidth);
        float yZoomFactor = (screenHeight / (float) (puzzleHeight)) / 2;
        float zoomFactor = Math.min(xZoomFactor, yZoomFactor);

        int offset = puzzleHeight / 2;
        return new DisplayValues(zoomFactor, offset, yZoomFactor < xZoomFactor);
    }