bad image quality with imageicon and listcellrenderer

Question

I needed to implement a list of images, that the user can move wth drag and drop. That's the code I'm using :

    ...
    model = new DefaultListModel();
    imageList = new JList(model);
    imageList.getSelectionModel().setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
    imageList.setTransferHandler(new ListItemTransferHandler());
    imageList.setDropMode(DropMode.INSERT);
    imageList.setDragEnabled(true);
    imageList.setLayoutOrientation(JList.HORIZONTAL_WRAP);
    imageList.setVisibleRowCount(1);
    imageList.setFixedCellWidth(405);
    imageList.setFixedCellHeight(height);
    imageList.setCellRenderer(new IconCellRenderer());

then I load my files as BufferedImages and add them to the model

my IonCellRenderer class is the following :

    class IconCellRenderer extends DefaultListCellRenderer {
    private static final long serialVersionUID = 1L;

    private int size1;
    private int size2;
    private int spostamento;
    private BufferedImage icon;

    IconCellRenderer() {
        this(400,600);
    }

    IconCellRenderer(int size1,int size2) {
        this.size1 = size1;
        this.size2 = size2;
        spostamento = 4;
        icon = new BufferedImage(size1,size2,BufferedImage.TYPE_INT_ARGB);
    }

    @Override
    public Component getListCellRendererComponent(
            JList list, 
            Object value, 
            int index, 
            boolean isSelected, 
            boolean cellHasFocus) {
        Component c = super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
        if (c instanceof JLabel && value instanceof BufferedImage) {
            JLabel l = (JLabel)c;
            l.setText("");
            BufferedImage i = (BufferedImage)value;
            l.setIcon(new ImageIcon(icon));


            Graphics2D g = icon.createGraphics();
            g.setColor(new Color(0,0,0,0));
            g.clearRect(spostamento, 0, size1, size2);
            g.drawImage(i,spostamento,0,size1,size2,this);



            g.dispose();
        }
        return c;
    }

    @Override 
    public Dimension getPreferredSize() {
        return new Dimension(size1, size2);
    }
}

However when I run the code, it works but the displayed images have such a bad quality, and also they are not displaying some lines. I don't know if it could be because of the size of the images is kind of big (i.e. 1488x2105) and I resize them to 400x600.

How can I solve?

Thanks in advice, Stefano Franchini

Single step scaling is a bad idea, take a look at [this](http://stackoverflow.com/questions/14115950/quality-of-image-after-resize-very-low-java/14116752#14116752) for more details. You should either pre-scale the image or maintain the result in some kind of cache, as scaling an image can be quite slow — MadProgrammer, May 27 '15 at 07:59

bad image quality with imageicon and listcellrenderer

0 Answers0