如何在MATLAB中实现已弃用的完整十字线指针功能？

Question

我试图用一个完整的十字准线替换图表图上的指针(也就是说,一组2条垂直线,它们垂直和水平地延伸到图的边缘并跟随鼠标光标).多年前,我用这行代码完成了这个任务:

set(gcf,'Pointer','fullcross')

但是,当我尝试现在运行此行时,我收到以下消息:

Warning: Full crosshair pointer is no longer supported. A crosshair pointer will be used instead.

我真的想找到一种实现此功能的替代方法,但迄今为止无法实现.我遇到了以下功能:MYGINPUT,但它似乎没有完成我正在寻找的东西.有没有人有什么建议？

Answer 1

实际上,您可以通过'WindowButtonMotionFcn'在图形中添加一个(假设没有其他任何东西正在使用它)来实现这一点,当鼠标悬停在轴上时,它将在轴上显示十字线.这是一个为图中所有轴创建此类功能的函数:

function full_crosshair(hFigure)

  % Find axes children:
  hAxes = findall(hFigure, 'Type', 'axes');

  % Get all axes limits:
  xLimits = get(hAxes, 'XLim');
  xLimits = vertcat(xLimits{:});
  yLimits = get(hAxes, 'YLim');
  yLimits = vertcat(yLimits{:});

  % Create lines (not displayed yet due to NaNs) and listeners:
  for iAxes = 1:numel(hAxes)
    hHoriz(iAxes) = line(xLimits(iAxes, :), nan(1, 2), 'Parent', hAxes(iAxes));
    hVert(iAxes) = line(nan(1, 2), yLimits(iAxes, :), 'Parent', hAxes(iAxes));
    listenObj(iAxes) = addlistener(hAxes(iAxes), {'XLim', 'YLim'}, ...
                                   'PostSet', @(~, ~) update_limits(iAxes));
  end

  % Set callback on the axes parent to the nested function below:
  set(hFigure, 'WindowButtonMotionFcn', @show_lines);

  function update_limits(axesIndex)
    xLimits(axesIndex, :) = get(hAxes(axesIndex), 'XLim');
    yLimits(axesIndex, :) = get(hAxes(axesIndex), 'YLim');
    set(hHoriz(axesIndex), 'XData', xLimits(axesIndex, :));
    set(hVert(axesIndex), 'YData', yLimits(axesIndex, :));
  end

  function show_lines(~, ~)

    % Get current cursor positions in axes:
    cursorPos = get(hAxes, 'CurrentPoint');
    cursorPos = vertcat(cursorPos{:});
    cursorPos = cursorPos(1:2:end, 1:2);

    % Determine if the cursor is within an axes:
    inAxes = (cursorPos(:, 1) >= xLimits(:, 1)) & ...
             (cursorPos(:, 1) <= xLimits(:, 2)) & ...
             (cursorPos(:, 2) >= yLimits(:, 1)) & ...
             (cursorPos(:, 2) <= yLimits(:, 2));

    % Update lines and cursor:
    if any(inAxes)  % Cursor within an axes
      set(hFigure, 'Pointer', 'custom', 'PointerShapeCData', nan(16));
      set(hHoriz(inAxes), {'YData'}, num2cell(cursorPos(inAxes, 2)*[1 1], 2));
      set(hVert(inAxes), {'XData'}, num2cell(cursorPos(inAxes, 1)*[1 1], 2));
      set(hHoriz(~inAxes), 'YData', nan(1, 2));
      set(hVert(~inAxes), 'XData', nan(1, 2));
    else  % Cursor outside axes
      set(hFigure, 'Pointer', 'arrow');
      set(hHoriz, 'YData', nan(1, 2));
      set(hVert, 'XData', nan(1, 2));
    end

  end

end

如果您执行以下操作:

full_crosshair(gcf);

然后当您将光标移动到图中的每个轴上时,光标将消失,您将看到两条线出现并跟踪鼠标位置.如果任何轴限制发生变化,则上述代码中的事件侦听器将检测并解释它.如果在图中添加或删除轴,则需要full_crosshair再次调用以进行相应更新'WindowButtonMotionFcn'.

最后,你可以通过清除它来关闭它'WindowButtonMotionFcn':

set(gcf, 'WindowButtonMotionFcn', []);