Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>So, the basic idea, is when you change the scale, rather then allowing the entire change to be added/subtracted from the width/height, you need to divide it between the location and the size...</p> <pre><code>public void mouseWheelMoved(MouseWheelEvent e) { int notches = e.getWheelRotation(); // Get the current/old size... double oldWidth = image.getWidth() * scaleFactor; double oldHeight = image.getHeight() * scaleFactor; scaleFactor = scaleFactor + notches / 10.0; if (scaleFactor &lt; 0.5) { scaleFactor = 0.5; } else if (scaleFactor &gt; 3.0) { scaleFactor = 3.0; } // Get the new size double newWidth = image.getWidth() * scaleFactor; double newHeight = image.getHeight() * scaleFactor; // Calculate the difference (and divide it by 2) double difWidth = (oldWidth - newWidth) / 2; double difHeight = (oldHeight - newHeight) / 2; // Add it to the image position... imageX += difWidth; imageY += difHeight; revalidate(); repaint(); } </code></pre> <p><strong>Updated with working example</strong></p> <p>Okay, so the basic idea is you're dealing with a virtual space, where the image sits. This virtual space has a size (the component size x the scale factor). This allows you to center the virtual space within the actual space.</p> <p>After that, you simply need to calculate the x/y offset of the virtual space (within the real space) and the virtual location of the image.</p> <p>In this example, I removed the <code>AffineTransformation#setLocation</code> in favor of generating a scaled instance of the image, it simply made it easier to place the image.</p> <pre><code>import java.awt.*; import javax.imageio.ImageIO; import javax.swing.*; import java.awt.event.*; import java.awt.geom.*; import java.awt.image.BufferedImage; import java.net.URL; public class MoveImageExample extends JFrame { ShowCanvas canvas; public MoveImageExample() throws Exception { super(); Container container = getContentPane(); canvas = new ShowCanvas( "http://cdn.smosh.com/sites/default/files/bloguploads/funny-iphone-5-bruce-lee.jpg"); container.add(canvas); pack(); setVisible(true); } public static void main(String arg[]) throws Exception { new MoveImageExample(); } } @SuppressWarnings("serial") final class ShowCanvas extends JPanel { int imageX = 0, imageY = 0; int lastMouseX = 0, lastMouseY = 0; int centerX = 225; int centerY = 225; int canvasWidth = 450; int canvasHeight = 450; double scaleFactor = 1.0; boolean firstMouseDrag = true; BufferedImage image; private BufferedImage scaled; public ShowCanvas(String imagePath) throws Exception { setBackground(Color.white); MouseMotionHandler mouseHandler = new MouseMotionHandler(); addMouseMotionListener(mouseHandler); addMouseListener(mouseHandler); addMouseWheelListener(mouseHandler); URL url = new URL(imagePath); Image rawImage = ImageIO.read(url); image = new BufferedImage(rawImage.getWidth(this), rawImage.getHeight(this), BufferedImage.TYPE_INT_ARGB); setSize(image.getWidth(), image.getHeight()); Graphics2D g2 = image.createGraphics(); g2.drawImage(rawImage, imageX, imageY, this); } @Override public Dimension getPreferredSize() { return new Dimension((int) (image.getWidth()), (int) (image.getHeight())); } protected BufferedImage getScaledInstance() { if (scaled == null) { int width = (int) (image.getWidth() * scaleFactor); int height = (int) (image.getHeight() * scaleFactor); scaled = new BufferedImage(width, height, image.getType()); Graphics2D g2d = scaled.createGraphics(); AffineTransform transformer = new AffineTransform(); transformer.scale(scaleFactor, scaleFactor); // scale by 2x on x and y g2d.setTransform(transformer); g2d.drawImage(image, 0, 0, this); g2d.dispose(); } return scaled; } public Dimension getVirtualSize() { return new Dimension( (int)(getWidth() * scaleFactor), (int)(getHeight() * scaleFactor)); } public Point getVirtualPoint(int x, int y) { return new Point( (int)(x * scaleFactor), (int)(y * scaleFactor)); } public void paintComponent(Graphics g) { super.paintComponent(g); Dimension vitualSize = getVirtualSize(); int xOffset = (getWidth() - vitualSize.width) / 2; int yOffset = (getHeight() - vitualSize.height) / 2; Graphics2D g2D = (Graphics2D) g.create(); g2D.setColor(Color.gray); g.fillRect(0, 0, image.getWidth(), image.getHeight()); g2D.setColor(Color.GREEN); g2D.drawRect(xOffset, yOffset, vitualSize.width, vitualSize.height); g2D.setColor(Color.RED); g2D.drawLine(getWidth() / 2, 0, getWidth() / 2, getHeight()); g2D.drawLine(0, getHeight() / 2, getWidth(), getHeight() / 2); Point virtualPoint = getVirtualPoint(imageX, imageY); System.out.println(virtualPoint); g2D.drawImage(getScaledInstance(), virtualPoint.x + xOffset, virtualPoint.y + yOffset, this); g2D.dispose(); } class MouseMotionHandler extends MouseMotionAdapter implements MouseListener, MouseWheelListener { public void mousePressed(MouseEvent e) { lastMouseX = e.getX(); lastMouseY = e.getY(); } public void mouseDragged(MouseEvent e) { int xDiff = e.getX() - lastMouseX; int yDiff = e.getY() - lastMouseY; imageX = imageX + xDiff; imageY = imageY + yDiff; lastMouseX = e.getX(); lastMouseY = e.getY(); repaint(); } public void mouseWheelMoved(MouseWheelEvent e) { scaled = null; int notches = e.getWheelRotation(); scaleFactor = scaleFactor + notches / 10.0; if (scaleFactor &lt; 0.5) { scaleFactor = 0.5; } else if (scaleFactor &gt; 3.0) { scaleFactor = 3.0; } repaint(); } public void mouseReleased(MouseEvent e) { } public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent e) { } public void mouseClicked(MouseEvent e) { } } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow do I make this panel zoom toward the middle of the panel?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USMadProgrammer
    1. USMadProgrammer
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow do I make this panel zoom toward the middle of the panel?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    1. COReally really good solution... it's just not quite what I needed exactly. I need it to zoom in on the center of what's in the panel and not necessarily the image. I don't really know how to explain that, but if, say, the top left corner of the panel is in the center point of the panel, the panel needs to zoom in on that one part.
      singulars
      1. PO
      1. USidungotnosn
    2. COYeah I just tripped over that part. I'm not quite sure I understand how it's suppose to work
      singulars
      1. PO
      1. USMadProgrammer
    3. COAllow me to clarify... Zooming should be done relative to the center point of the currently visible area. That is, as zooming occurs, the point at the center of the view should remain fixed.
      singulars
      1. PO
      1. USidungotnosn
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload