/**
* Synchronize the scrollbar with the image. If the transform is out of range, it will correct it.
* This function considers only following factors :<b> transform, image size, client area</b>.
*/
public void syncScrollBars() {
if (sourceImage == null) {
redraw();
return;
}
AffineTransform af = transform;
double sx = af.getScaleX(), sy = af.getScaleY();
double tx = af.getTranslateX(), ty = af.getTranslateY();
if (tx > 0) tx = 0;
if (ty > 0) ty = 0;
ScrollBar horizontal = getHorizontalBar();
horizontal.setIncrement((int) (getClientArea().width / 20));
horizontal.setPageIncrement(getClientArea().width);
Rectangle imageBound = sourceImage.getBounds();
int cw = getClientArea().width, ch = getClientArea().height;
if (imageBound.width * sx > cw) {
/* image is wider than client area */
horizontal.setMaximum((int) (imageBound.width * sx));
horizontal.setEnabled(true);
if (((int) -tx) > horizontal.getMaximum() - cw) tx = -horizontal.getMaximum() + cw;
} else {
/* image is narrower than client area */
horizontal.setEnabled(false);
tx = (cw - imageBound.width * sx) / 2; // center if too small.
}
horizontal.setSelection((int) (-tx));
horizontal.setThumb((int) (getClientArea().width));
ScrollBar vertical = getVerticalBar();
vertical.setIncrement((int) (getClientArea().height / 20));
vertical.setPageIncrement((int) (getClientArea().height));
if (imageBound.height * sy > ch) {
/* image is higher than client area */
vertical.setMaximum((int) (imageBound.height * sy));
vertical.setEnabled(true);
if (((int) -ty) > vertical.getMaximum() - ch) ty = -vertical.getMaximum() + ch;
} else {
/* image is less higher than client area */
vertical.setEnabled(false);
ty = (ch - imageBound.height * sy) / 2; // center if too small.
}
vertical.setSelection((int) (-ty));
vertical.setThumb((int) (getClientArea().height));
/* update transform. */
af = AffineTransform.getScaleInstance(sx, sy);
af.preConcatenate(AffineTransform.getTranslateInstance(tx, ty));
transform = af;
redraw();
}
/* Initalize the scrollbar and register listeners. */
private void initScrollBars() {
ScrollBar horizontal = getHorizontalBar();
horizontal.setEnabled(false);
horizontal.addSelectionListener(
new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
scrollHorizontally((ScrollBar) event.widget);
}
});
ScrollBar vertical = getVerticalBar();
vertical.setEnabled(false);
vertical.addSelectionListener(
new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
scrollVertically((ScrollBar) event.widget);
}
});
}
/**
* This method is responsible to set the scroll bar attributes so that they reflect the size of
* the current image at the current zoom factor
*/
private void synchronizeScrollBars() {
// Syncronizing only makes sense if there is a skin being drawn
if (currentSkinImage != null) {
// Retrieves the current image and client area sizes
Rectangle imageBound = currentSkinImage.getBounds();
int cw = getClientArea().width;
int ch = getClientArea().height;
// Updates horizontal scroll bar attributes
ScrollBar horizontal = getHorizontalBar();
horizontal.setIncrement((cw / 100));
horizontal.setPageIncrement((cw / 2));
horizontal.setMaximum(imageBound.width);
horizontal.setThumb(cw);
horizontal.setSelection(displayRectangle.x);
// Updates vertical scroll bar attributes
ScrollBar vertical = getVerticalBar();
vertical.setIncrement((ch / 100));
vertical.setPageIncrement((ch / 2));
vertical.setMaximum(imageBound.height);
vertical.setThumb(ch);
vertical.setSelection(displayRectangle.y);
if (horizontal.getMaximum() > cw) // Image is wider than client area
{
horizontal.setEnabled(true);
} else {
horizontal.setEnabled(false);
}
if (vertical.getMaximum() > ch) // Image is wider than client area
{
vertical.setEnabled(true);
} else {
vertical.setEnabled(false);
}
}
}
/**
* Initialize the scroll bars This include: a) setting the initial enabled state b) adding the
* necessary listeners
*/
private void initScrollBars() {
ScrollBar horizontal = getHorizontalBar();
horizontal.setEnabled(false);
horizontal.addSelectionListener(
new SelectionAdapter() {
/** @see org.eclipse.swt.events.SelectionListener#widgetSelected(SelectionEvent) */
@Override
public void widgetSelected(SelectionEvent event) {
// Updates the translation
displayRectangle.x = ((ScrollBar) event.widget).getSelection();
// Update the UI
layout();
redraw();
}
});
ScrollBar vertical = getVerticalBar();
vertical.setEnabled(false);
vertical.addSelectionListener(
new SelectionAdapter() {
/** @see org.eclipse.swt.events.SelectionListener#widgetSelected(SelectionEvent) */
@Override
public void widgetSelected(SelectionEvent event) {
// Updates the translation
displayRectangle.y = ((ScrollBar) event.widget).getSelection();
// Update the UI
layout();
redraw();
}
});
debug("Initialized scroll bars");
}
