matlab – 在现有轴内显示新图像,无需删除颜色条

2019年7月22日 243次阅读

我正在开发一个GUI,通过创建几个
axes以及每个的隐形
colorbar进行初始化(这样做是为了使轴保持其预定义的
Position)
1.存储所有轴和颜色条的手柄.

与UI的交互可能导致在任何一个轴上绘制图像.我希望通过适当地设置所有颜色条的可见属性,只在任何给定时间显示活动轴的颜色条.

我遇到了这种方法的问题,因为我使用imagesc来更新我的轴,这会删除与轴关联的任何颜色条,使存储的句柄无效.

我的问题是：如何在不删除颜色条的情况下使用imagesc或image来更新与颜色条关联的轴？

以下是重现此问题的方法：

dbclear in newplot %// Needed for the code to be properly re-runnable
%// Create an example figure containing a colorbar:
figure(); imagesc(imread('cameraman.tif')); colorbar;
%// "Refreshing" the displayed image:
uiwait(msgbox('The image will now be refreshed. A breakpoint will be set in newplot.m'));
dbstop in newplot at 124 %// The line responsible for deleting the colorbar in R2015A/B
imagesc(imread('cameraman.tif'));

newplot.m中设置断点的行读取：

cla(ax, 'reset', hsave);

这是(un)令人惊讶的一种未记录的方式来调用cla(带有3个参数)来保留在hsave中找到句柄的对象.

我假设使用彩条删除的一些想法是不可避免的(如果找不到“理智”的解决方案,我会追求这种想法)：

>将DeleteFcn绑定到将其数据保存到某个结构的颜色条.在imagesc完成后创建一个新的颜色条,然后迭代结构的字段并将所有属性分配给新的颜色条对象.
>使用findall(hFig,’type’,’colorbar’)检查所有颜色条中的“偶尔”,或者验证每个轴是否具有有效的ColorbarPeerHandle,如下面的附录所示.如果无效,重新创建CB.
>当不同的轴变为活动状态时删除所有颜色条,并仅创建我想要显示的CB.

附录 – ColorBar / Axes关联：

>处理与某个轴相关的颜色条hAx可以使用以下方式获得(在hg2中)：

hCb = getappdata(hAx,'ColorbarPeerHandle');

>处理与颜色条对象关联的轴hCb可以使用2获得：

hAx = hCb.Axes;

最佳答案 我设法提出了几个解决方案：

> safeUpdateImage1 – 基于在使用hold之后通过在轴内创建新Image对象来规避cla(…).这对于轴中不一定存在图像的情况很有用.
> safeUpdateImage2 – 遵循mikkola’s suggestion,基于更新现有的Image对象.这适用于已有ColorBar和与轴关联的Image的情况.

以下是两个解决方案与原始问题的演示：

function [] = Problem
dbclear in newplot %// Needed for the code to be properly re-runnable
%// Create an example figure containing a colorbar:
Img = imread('cameraman.tif');
figure(); imagesc(Img); hAx = gca; colorbar;
%// Refreshing the displayed image (comment/uncomment as needed):
switch questdlg('Please select an image update method:','Update method selection',...
                'Broken','Safe1','Safe2','Safe1')
  case 'Broken'
    brokenUpdateImage(hAx,255-Img);
  case 'Safe1'
    safeUpdateImage1(hAx,255-Img);
  case 'Safe2'
  safeUpdateImage2(hAx,255-Img);  
end
end

function brokenUpdateImage(hAx,newImg)
uiwait(msgbox('The image will now be refreshed. A breakpoint will be set in NEWPLOT'));
dbstop in newplot at 124 %// The line responsible for deleting the colorbar in R2015A/B
imagesc(newImg,'Parent',hAx);
end

% For cases when the only desired child is an Image and the axes contents are unknown
function safeUpdateImage1(hAx,newImg,imgType,imgUpdateFcn)
if nargin < 4 || isempty(imgUpdateFcn)
  imgUpdateFcn = @imagesc;
end
if nargin < 3 || isempty(imgType)
  imgType = 'Image';  
end
if strcmp(hAx.NextPlot,'replace') %// Equivalent to checking "ishold == false"
  hAx.NextPlot = 'add'; %// Equivalent to "hold on"
  %// hCurrImgs = get(hAx,'Children'); %// Deletes all types of Children
  hCurrImgs = findall(hAx,'type','Image'); %// Deletes only graphical objects of type 
                                           %// "matlab.graphics.primitive.Image"
  for ind1=1:numel(hCurrImgs)
    delete(hCurrImgs(ind1));
  end
  imgUpdateFcn(newImg,'Parent',hAx);
  if strcmpi(imgType,'Image')
    axis(hAx,'tight','ij');    
%// 'tight' - XLimMode, YLimMode, and ZLimMode change to 'auto'. The limits automatic- 
%//           ally update to incorporate new data added to the axes. To keep the limits
%//           from changing when using hold on, use axis tight manual.
%// 'ij'  —   Reverse direction. For axes with a 2-D view, the y-axis is vertical with
%//           values increasing from top to bottom.    
  end
end
end

%// When it's known that the axes contains at least one Image:
function safeUpdateImage2(hAx,newImg,~,~)
%// <Input checking code>
hCurrImgs = findall(hAx,'type','Image');
%// <Optional code to decide which Image child to update>
hCurrImgs(1).CData = newImg; %// In this example, only update the "topmost" child
end
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