private static void navigatePage(
jetbrains.mps.openapi.editor.EditorContext context, boolean isDown) {
EditorComponent editor = (EditorComponent) context.getEditorComponent();
jetbrains.mps.openapi.editor.cells.EditorCell selection = editor.getSelectedCell();
Rectangle rect = editor.getVisibleRect();
int height = (int) rect.getHeight();
height = isDown ? height : -height;
int caretX = selection.getCaretX();
int y = selection.getY() + (selection.getHeight() / 2);
int newY = y + height;
jetbrains.mps.openapi.editor.cells.EditorCell target = editor.findCellWeak(caretX, newY);
if (target == null) {
target =
isDown
? editor.myRootCell.findChild(CellFinders.LAST_SELECTABLE_LEAF)
: editor.myRootCell.findChild(CellFinders.FIRST_SELECTABLE_LEAF);
editor.changeSelection(target);
} else {
target.setCaretX(caretX);
editor.changeSelection(target);
}
}
