A panel that draws an image. The standard (and currently only supported) * mode is to draw the specified image starting at position 0,0 in the * panel. The component&s preferred size is based on the image, unless * explicitly set by the user.
* *In the future, the JXImagePanel will also support tiling of images, * scaling, resizing, cropping, segways etc.
* *This component also supports allowing the user to set the image. If the
* JXImagePanel is editable, then when the user clicks on the
* JXImagePanel a FileChooser is shown allowing the user to pick
* some other image to use within the JXImagePanel.
Images to be displayed can be set based on URL, Image, etc.
*
* @author rbair
*/
public class JXImagePanel extends JXPanel {
public static enum Style {CENTERED, TILED, SCALED, SCALED_KEEP_ASPECT_RATIO}
private static final Logger LOG = Logger.getLogger(JXImagePanel.class
.getName());
/**
* Text informing the user that clicking on this component will allow them to set the image
*/
private static final String TEXT = "Click here
to set the image";
/**
* The image to draw
*/
private Image img;
/**
* If true, then the image can be changed. Perhaps a better name is
* "readOnly", but editable was chosen to be more consistent
* with other Swing components.
*/
private boolean editable = false;
/**
* The mouse handler that is used if the component is editable
*/
private MouseHandler mhandler = new MouseHandler();
/**
* If not null, then the user has explicitly set the preferred size of
* this component, and this should be honored
*/
private Dimension preferredSize;
/**
* Specifies how to draw the image, i.e. what kind of Style to use
* when drawing
*/
private Style style = Style.CENTERED;
public JXImagePanel() {
}
public JXImagePanel(URL imageUrl) {
try {
setImage(ImageIO.read(imageUrl));
} catch (Exception e) {
//TODO need convert to something meaningful
LOG.log(Level.WARNING, "", e);
}
}
/**
* Sets the image to use for the background of this panel. This image is
* painted whether the panel is opaque or translucent.
* @param image if null, clears the image. Otherwise, this will set the
* image to be painted. If the preferred size has not been explicitly set,
* then the image dimensions will alter the preferred size of the panel.
*/
public void setImage(Image image) {
if (image != img) {
Image oldImage = img;
img = image;
firePropertyChange("image", oldImage, img);
invalidate();
repaint();
}
}
/**
* @return the image used for painting the background of this panel
*/
public Image getImage() {
return img;
}
/**
* @param editable
*/
public void setEditable(boolean editable) {
if (editable != this.editable) {
//if it was editable, remove the mouse handler
if (this.editable) {
removeMouseListener(mhandler);
}
this.editable = editable;
//if it is now editable, add the mouse handler
if (this.editable) {
addMouseListener(mhandler);
}
setToolTipText(editable ? TEXT : "");
firePropertyChange("editable", !editable, editable);
repaint();
}
}
/**
* @return whether the image for this panel can be changed or not via
* the UI. setImage may still be called, even if isEditable
* returns false.
*/
public boolean isEditable() {
return editable;
}
/**
* Sets what style to use when painting the image
*
* @param s
*/
public void setStyle(Style s) {
if (style != s) {
Style oldStyle = style;
style = s;
firePropertyChange("style", oldStyle, s);
repaint();
}
}
/**
* @return the Style used for drawing the image (CENTERED, TILED, etc).
*/
public Style getStyle() {
return style;
}
public void setPreferredSize(Dimension pref) {
preferredSize = pref;
super.setPreferredSize(pref);
}
public Dimension getPreferredSize() {
if (preferredSize == null && img != null) {
//it has not been explicitly set, so return the width/height of the image
int width = img.getWidth(null);
int height = img.getHeight(null);
if (width == -1 || height == -1) {
return super.getPreferredSize();
}
Insets insets = getInsets();
width += insets.left + insets.right;
height += insets.top + insets.bottom;
return new Dimension(width, height);
} else {
return super.getPreferredSize();
}
}
/**
* Overridden to paint the image on the panel
* @param g
*/
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
if (img != null) {
final int imgWidth = img.getWidth(null);
final int imgHeight = img.getHeight(null);
if (imgWidth == -1 || imgHeight == -1) {
//image hasn't completed loading, return
return;
}
Insets insets = getInsets();
final int pw = getWidth() - insets.left - insets.right;
final int ph = getHeight() - insets.top - insets.bottom;
switch (style) {
case CENTERED:
Rectangle clipRect = g2.getClipBounds();
int imageX = (pw - imgWidth) / 2 + insets.left;
int imageY = (ph - imgHeight) / 2 + insets.top;
Rectangle r = SwingUtilities.computeIntersection(imageX, imageY, imgWidth, imgHeight, clipRect);
if (r.x == 0 && r.y == 0 && (r.width == 0 || r.height == 0)) {
return;
}
//I have my new clipping rectangle "r" in clipRect space.
//It is therefore the new clipRect.
clipRect = r;
//since I have the intersection, all I need to do is adjust the
//x & y values for the image
int txClipX = clipRect.x - imageX;
int txClipY = clipRect.y - imageY;
int txClipW = clipRect.width;
int txClipH = clipRect.height;
g2.drawImage(img, clipRect.x, clipRect.y, clipRect.x + clipRect.width, clipRect.y + clipRect.height,
txClipX, txClipY, txClipX + txClipW, txClipY + txClipH, null);
break;
case TILED:
g2.translate(insets.left, insets.top);
Rectangle clip = g2.getClipBounds();
g2.setClip(0, 0, pw, ph);
int totalH = 0;
while (totalH < ph) {
int totalW = 0;
while (totalW < pw) {
g2.drawImage(img, totalW, totalH, null);
totalW += img.getWidth(null);
}
totalH += img.getHeight(null);
}
g2.setClip(clip);
g2.translate(-insets.left, -insets.top);
break;
case SCALED:
g2.drawImage(img, insets.left, insets.top, pw, ph, null);
break;
case SCALED_KEEP_ASPECT_RATIO:
int w = pw;
int h = ph;
final float ratioW = ((float) w) / ((float) imgWidth);
final float ratioH = ((float) h) / ((float) imgHeight);
if (ratioW < ratioH) {
h = (int)(imgHeight * ratioW);
} else {
w = (int)(imgWidth * ratioH);
}
final int x = (pw - w) / 2 + insets.left;
final int y = (ph - h) / 2 + insets.top;
g2.drawImage(img, x, y, w, h, null);
break;
default:
LOG.fine("unimplemented");
g2.drawImage(img, insets.left, insets.top, this);
break;
}
}
}
/**
* Handles click events on the component
*/
private class MouseHandler extends MouseAdapter {
private Cursor oldCursor;
private JFileChooser chooser;
public void mouseClicked(MouseEvent evt) {
if (chooser == null) {
chooser = new JFileChooser();
}
int retVal = chooser.showOpenDialog(JXImagePanel.this);
if (retVal == JFileChooser.APPROVE_OPTION) {
File file = chooser.getSelectedFile();
try {
setImage(new ImageIcon(file.toURI().toURL()).getImage());
} catch (Exception ex) {
}
}
}
public void mouseEntered(MouseEvent evt) {
if (oldCursor == null) {
oldCursor = getCursor();
setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
}
}
public void mouseExited(MouseEvent evt) {
if (oldCursor != null) {
setCursor(oldCursor);
oldCursor = null;
}
}
}
}