/** Creates the "Example" widgets. */
void createExampleWidgets() {
/* Compute the widget style */
int style = getDefaultStyle();
if (horizontalButton.getSelection()) style |= SWT.H_SCROLL;
if (verticalButton.getSelection()) style |= SWT.V_SCROLL;
if (borderButton.getSelection()) style |= SWT.BORDER;
if (noBackgroundButton.getSelection()) style |= SWT.NO_BACKGROUND;
if (noFocusButton.getSelection()) style |= SWT.NO_FOCUS;
if (noMergePaintsButton.getSelection()) style |= SWT.NO_MERGE_PAINTS;
if (noRedrawResizeButton.getSelection()) style |= SWT.NO_REDRAW_RESIZE;
/* Create the example widgets */
paintCount = 0;
cx = 0;
cy = 0;
canvas = new Canvas(canvasGroup, style);
canvas.addPaintListener(
new PaintListener() {
public void paintControl(PaintEvent e) {
paintCount++;
GC gc = e.gc;
if (fillDamageButton.getSelection()) {
Color color = e.display.getSystemColor(colors[paintCount % colors.length]);
gc.setBackground(color);
gc.fillRectangle(e.x, e.y, e.width, e.height);
}
Point size = canvas.getSize();
gc.drawArc(cx + 1, cy + 1, size.x - 2, size.y - 2, 0, 360);
gc.drawRectangle(cx + (size.x - 10) / 2, cy + (size.y - 10) / 2, 10, 10);
}
});
canvas.addControlListener(
new ControlAdapter() {
public void controlResized(ControlEvent event) {
Point size = canvas.getSize();
maxX = size.x * 3 / 2;
maxY = size.y * 3 / 2;
resizeScrollBars();
}
});
ScrollBar bar = canvas.getHorizontalBar();
if (bar != null) {
bar.addSelectionListener(
new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
scrollHorizontal((ScrollBar) event.widget);
}
});
}
bar = canvas.getVerticalBar();
if (bar != null) {
bar.addSelectionListener(
new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
scrollVertical((ScrollBar) event.widget);
}
});
}
}
/**
* Scrolls the canvas horizontally.
*
* @param scrollBar
*/
void scrollHorizontal(ScrollBar scrollBar) {
Rectangle bounds = canvas.getClientArea();
int x = -scrollBar.getSelection();
if (x + maxX < bounds.width) {
x = bounds.width - maxX;
}
canvas.scroll(x, cy, cx, cy, maxX, maxY, false);
cx = x;
}
/**
* Scrolls the canvas vertically.
*
* @param scrollBar
*/
void scrollVertical(ScrollBar scrollBar) {
Rectangle bounds = canvas.getClientArea();
int y = -scrollBar.getSelection();
if (y + maxY < bounds.height) {
y = bounds.height - maxY;
}
canvas.scroll(cx, y, cx, cy, maxX, maxY, false);
cy = y;
}
/** Resizes the maximum and thumb of both scrollbars. */
void resizeScrollBars() {
Rectangle clientArea = canvas.getClientArea();
ScrollBar bar = canvas.getHorizontalBar();
if (bar != null) {
bar.setMaximum(maxX);
bar.setThumb(clientArea.width);
bar.setPageIncrement(clientArea.width);
}
bar = canvas.getVerticalBar();
if (bar != null) {
bar.setMaximum(maxY);
bar.setThumb(clientArea.height);
bar.setPageIncrement(clientArea.height);
}
}