/**
* Method to check if the given x and y are in the picture
*
* @param column the horizontal value
* @param row the vertical value
* @return true if the row and column are in the picture and false otherwise
*/
private boolean isLocationInPicture(int column, int row) {
boolean result = false; // the default is false
if (column >= 0 && column < picture.getWidth() && row >= 0 && row < picture.getHeight())
result = true;
return result;
}
/**
* Zooms in the on picture by scaling the image. It is extremely memory intensive.
*
* @param factor the amount to zoom by
*/
public void zoom(double factor) {
// save the current zoom factor
zoomFactor = factor;
// calculate the new width and height and get an image that size
int width = (int) (picture.getWidth() * zoomFactor);
int height = (int) (picture.getHeight() * zoomFactor);
BufferedImage bimg = picture.getBufferedImage();
// set the scroll image icon to the new image
imageDisplay.setImage(bimg.getScaledInstance(width, height, Image.SCALE_DEFAULT));
imageDisplay.setCurrentX((int) (colIndex * zoomFactor));
imageDisplay.setCurrentY((int) (rowIndex * zoomFactor));
imageDisplay.revalidate();
checkScroll(); // check if need to reposition scroll
}
/**
* Method to check that the current position is in the viewing area and if not scroll to center
* the current position if possible
*/
public void checkScroll() {
// get the x and y position in pixels
int xPos = (int) (colIndex * zoomFactor);
int yPos = (int) (rowIndex * zoomFactor);
// only do this if the image is larger than normal
if (zoomFactor > 1) {
// get the rectangle that defines the current view
JViewport viewport = scrollPane.getViewport();
Rectangle rect = viewport.getViewRect();
int rectMinX = (int) rect.getX();
int rectWidth = (int) rect.getWidth();
int rectMaxX = rectMinX + rectWidth - 1;
int rectMinY = (int) rect.getY();
int rectHeight = (int) rect.getHeight();
int rectMaxY = rectMinY + rectHeight - 1;
// get the maximum possible x and y index
int macolIndexX = (int) (picture.getWidth() * zoomFactor) - rectWidth - 1;
int macolIndexY = (int) (picture.getHeight() * zoomFactor) - rectHeight - 1;
// calculate how to position the current position in the middle of the viewing
// area
int viewX = xPos - (int) (rectWidth / 2);
int viewY = yPos - (int) (rectHeight / 2);
// reposition the viewX and viewY if outside allowed values
if (viewX < 0) viewX = 0;
else if (viewX > macolIndexX) viewX = macolIndexX;
if (viewY < 0) viewY = 0;
else if (viewY > macolIndexY) viewY = macolIndexY;
// move the viewport upper left point
viewport.scrollRectToVisible(new Rectangle(viewX, viewY, rectWidth, rectHeight));
}
}