/**
* Calls layout() on the rootBox until the y-coordinate of a caret at the given offset converges,
* i.e. is less than LAYOUT_TOLERANCE pixels from the last call.
*
* @param offset Offset around which we should lay out boxes.
*/
private void iterateLayout(int offset) {
int repaintStart = Integer.MAX_VALUE;
int repaintEnd = 0;
Graphics g = this.hostComponent.createDefaultGraphics();
LayoutContext context = this.createLayoutContext(g);
int layoutY = this.rootBox.getCaret(context, offset).getY();
while (true) {
int oldLayoutY = layoutY;
IntRange repaintRange =
this.rootBox.layout(context, layoutY - LAYOUT_WINDOW / 2, layoutY + LAYOUT_WINDOW / 2);
if (repaintRange != null) {
repaintStart = Math.min(repaintStart, repaintRange.getStart());
repaintEnd = Math.max(repaintEnd, repaintRange.getEnd());
}
layoutY = this.rootBox.getCaret(context, offset).getY();
if (Math.abs(layoutY - oldLayoutY) < LAYOUT_TOLERANCE) {
break;
}
}
g.dispose();
if (repaintStart < repaintEnd) {
Rectangle viewport = this.hostComponent.getViewport();
if (repaintStart < viewport.getY() + viewport.getHeight() && repaintEnd > viewport.getY()) {
int start = Math.max(repaintStart, viewport.getY());
int end = Math.min(repaintEnd, viewport.getY() + viewport.getHeight());
this.hostComponent.repaint(viewport.getX(), start, viewport.getWidth(), end - start);
}
}
}
/** Repaints the area of the caret. */
private void repaintCaret() {
if (this.caret != null) {
// caret may be null when document is first set
Rectangle bounds = this.caret.getBounds();
this.hostComponent.repaint(
bounds.getX(), bounds.getY(), bounds.getWidth(), bounds.getHeight());
}
}