How to use

_getVisibleRegionOffset

method

in

org.eclipse.jface.text.TextViewer

/**
 * Computes the document offset underlying the given text widget coordinates.
 * This method uses a linear search as it cannot make any assumption about
 * how the document is actually presented in the widget. (Covers cases such
 * as bidirectional text.)
 *
 * @param x the horizontal coordinate inside the text widget
 * @param y the vertical coordinate inside the text widget
 * @return the document offset corresponding to the given point
 */
private int computeOffsetAtLocation(int x, int y) {
  try {
    StyledText styledText= fTextViewer.getTextWidget();
    int widgetOffset= styledText.getOffsetAtLocation(new Point(x, y));
    Point p= styledText.getLocationAtOffset(widgetOffset);
    if (p.x > x)
      widgetOffset--;
    if (fTextViewer instanceof ITextViewerExtension5) {
      ITextViewerExtension5 extension= (ITextViewerExtension5) fTextViewer;
      return extension.widgetOffset2ModelOffset(widgetOffset);
    }
    return widgetOffset + fTextViewer._getVisibleRegionOffset();
  } catch (IllegalArgumentException e) {
    return -1;
  }
}

/**
 * Computes the document offset underlying the given text widget coordinates.
 * This method uses a linear search as it cannot make any assumption about
 * how the document is actually presented in the widget. (Covers cases such
 * as bidirectional text.)
 *
 * @param x the horizontal coordinate inside the text widget
 * @param y the vertical coordinate inside the text widget
 * @return the document offset corresponding to the given point
 */
private int computeOffsetAtLocation(int x, int y) {
  try {
    StyledText styledText= fTextViewer.getTextWidget();
    int widgetOffset= styledText.getOffsetAtPoint(new Point(x, y));
    if (widgetOffset == -1) {
      return -1;
    }
    Point p= styledText.getLocationAtOffset(widgetOffset);
    if (p.x > x) {
      widgetOffset--;
    }
    if (fTextViewer instanceof ITextViewerExtension5) {
      ITextViewerExtension5 extension= (ITextViewerExtension5) fTextViewer;
      return extension.widgetOffset2ModelOffset(widgetOffset);
    }
    return widgetOffset + fTextViewer._getVisibleRegionOffset();
  } catch (IllegalArgumentException e) {
    return -1;
  }
}