Bar plot with a hatched fill pattern

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Corymbiamaculata 2022-3-13

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1670649-bar-plot-with-a-hatched-fill-pattern

评论： dpb 2024-8-1

采纳的回答： DGM

在 MATLAB Online 中打开

I have a grouped bar plot, bb:

bb = bar(ax, x, y)

where 'ax' is the axis handle, x is a 1x7 datetime vector and y is a 5x7 double vector. For each of the seven dates, I get five bars with data.

I then specify the color of the bars:

for i = 1:5
    bb(i).FaceColor = colmapLight(i,:);
    bb(i).EdgeColor = colmapDark(i,:);
end

In addition to specifying the colors, I want to use a hatched fill pattern, e.g. horizontal lines in the first two bars in each group, and dots in the last three. I tried using the functions mentioned in this post (https://blogs.mathworks.com/pick/2011/07/15/creating-hatched-patches/), but I haven't managed to make any of them work. I think the hatchfill function (https://se.mathworks.com/matlabcentral/fileexchange/30733-hatchfill) suits my needs best (I want to keep my custom bar colors; plus I don't need a bitmap copy of the figure, want to keep it as a fig). However, the function works on 'patch' objects and I don't know how to get their handles. The following:

hPatch = findobj(bb, 'Type', 'patch');

returns an empty, 0x0 GraphicsPlaceholder.

Does anyone know a way to solve this? Thanks in advance!

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采纳的回答

DGM 2022-3-13

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1670649-bar-plot-with-a-hatched-fill-pattern#answer_916574

在 MATLAB Online 中打开

hatchfill2.m

You'd want to avoid hatchfill(). That's so old that it predates the current graphics system. Things like contour and bar plots are constructed differently than they were prior to R2014. There is an updated version that seems to work okay for this.

https://www.mathworks.com/matlabcentral/fileexchange/53593-hatchfill2

y = 0.5*randn(3,5)+2; % a simplified example

hp = bar(y);

cm = colororder; % or replace with the desired colormap

hatchfill2(hp(1),'single','HatchAngle',0,'hatchcolor',cm(1,:));

hatchfill2(hp(2),'cross','HatchAngle',45,'hatchcolor',cm(2,:));

hatchfill2(hp(3),'single','HatchAngle',45,'hatchcolor',cm(3,:));

hatchfill2(hp(4),'single','HatchAngle',-45,'hatchcolor',cm(4,:));

hatchfill2(hp(5),'cross','HatchAngle',30,'hatchcolor',cm(5,:));

for b = 1:numel(hp)

hp(b).FaceColor = 'none';

end

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DGM 2022-3-14

编辑：DGM 2022-3-14

在 MATLAB Online 中打开

hatchfill2.m

it seems to work for me

y = 0.5*randn(3,5)+2; % a simplified example

hp = bar(y);

hatchfill2(hp(1),'single','HatchAngle',0,'hatchcolor','k');

hatchfill2(hp(2),'cross','HatchAngle',45,'hatchcolor','k');

hatchfill2(hp(3),'single','HatchAngle',45,'hatchcolor','k');

hatchfill2(hp(4),'single','HatchAngle',-45,'hatchcolor','k');

hatchfill2(hp(5),'cross','HatchAngle',30,'hatchcolor','k');

EDIT: The way I'd set the hatch colors in the first example was based off of the figure's 'colororder' property, which is what is normally used for the bar face color. The default map used for colororder is lines(7).

If you didn't change the colormap that was being specified for the hatching, then it would've simply been the same color as the bar's face color.

y = 0.5*randn(3,5)+2; % a simplified example

hp = bar(y);

cm = hsv(6); % a colormap other than the one specified in 'colororder'

hatchfill2(hp(1),'single','HatchAngle',0,'hatchcolor',cm(1,:));

hatchfill2(hp(2),'cross','HatchAngle',45,'hatchcolor',cm(2,:));

hatchfill2(hp(3),'single','HatchAngle',45,'hatchcolor',cm(3,:));

hatchfill2(hp(4),'single','HatchAngle',-45,'hatchcolor',cm(4,:));

hatchfill2(hp(5),'cross','HatchAngle',30,'hatchcolor',cm(5,:));

DGM 2023-3-1

编辑：DGM 2023-3-1

在 MATLAB Online 中打开

hatchfill2.m

I don't really think there's a way of doing that conveniently. The vertex data used to place the lines describes the vertices of all the bars. They aren't separate at an object level like the CData is

Here are two ideas:

% simple bar setup

y = 0.5*randn(1,4)+2;

hb = bar(y);

% get vertex data for second bar

% the vertex list for N bars is 3x(N*4)

% where rows are [x; y; z]

drawnow

vertdat = hb.Face.VertexData(:,5:8);

% create a patch overlay

% this is required to provide the extents for hatching,

% but it can also be used as a means to change the face color

hp = patch(vertdat(1,:),vertdat(2,:),'g');

% otherwise, you can make the patch invisible

% and set the CData of the bar object as before

%hp.FaceColor = 'none';

%hp.EdgeColor = 'none';

% fill the patch object instead of the bar

hhf = hatchfill2(hp,'cross','HatchAngle',20,'hatchcolor','k');

Alternatively, the bar object can be filled and the relevant lines removed afterward.

% simple bar setup

y = 0.5*randn(1,4)+2;

hb = bar(y);

hb.FaceColor = 'flat';

hb.CData(2,:) = [0 1 0];

% apply the hatching to all bars

hhf = hatchfill2(hb(1),'cross','HatchAngle',20,'hatchcolor','k');

% find the indices of the relevant line segments

idx = find(isnan(hhf.ZData)); % bars are separated by a trailing NaN

idx = idx(1)+1:idx(2)-1; % to pick the second bar

% get rid of unwanted lines

hhf.XData = hhf.XData(idx);

hhf.YData = hhf.YData(idx);

hhf.ZData = hhf.ZData(idx);

... well, at least that works on my computer. I don't know why it doesn't work on the forum editor. It successfully deleted the line vertices, but it's persisting to draw them regardless. Forcing a redraw doesn't do anything. Setting the unwanted vertices to NaN doesn't do anything.

Walter Roberson 2023-9-11

编辑：Walter Roberson 2023-9-11

Shoudn't the angles and the spacing be consistent throughout?

No. The code assumed a certain size and aspect ratio for the drawing area in the legend. You manually resized the drawing area, violating the assumptions of the code.

The only way to draw the representative sample in the legend area is to have an axes to draw into. line() coordinates are always in data units. If you change the shape of the axes without adjusting the axes XLim and YLim then you are going to distort the relationship between data coordinates and physical coordinates. And if you do adjust XLim and YLim to keep the relationship consistent, then you cannot expect that the lines will extend to full width or height of the new axes size.

legend() has never [deliberately] provided any callback mechanism to provide hooks to redraw the representative sample icons when the legend is resized. It would be possible to set a listener on a resize event for the axes used by legend... but only when the two-output "legacy" version of legend() is used (the newer single-output version does not give access to the drawing area.)

DGM 2024-8-1

编辑：DGM 2024-8-1

在 MATLAB Online 中打开

Yeah, pretty much.

EDIT: I figured I could make it even more ridiculous by reverting to raster composition. (No I'm not serious)

% say you have any collection of colored plot objects
y = round(0.5*randn(3,5)+2);
hp = bar(y,'stacked');
legend({'meow','trill','purr','hiss','growl'},'location','eastoutside')
title('cat utterances')
xlabel('subject')
% take a raster screenshot
saveas(gcf,'myscreenshot.png')

% load it
inpict = imread('myscreenshot.png');
% these are the colors used in the image
% need the colors in the same class
CT = im2uint8(lines(5)); % there are 5 colors used
% patterns to use for the fills
% these are included with MIMT
pats = {imread('sources/patterns/ospat/OldSchool_A6_165.png');
        imread('sources/patterns/ospat/OldSchool_A6_046.png');
        imread('sources/patterns/ospat/OldSchool_A6_064.png');
        imread('sources/patterns/ospat/OldSchool_A6_089.png');
        imread('sources/patterns/ospat/OldSchool_A6_108.png')};
% FG colors
fgct = ccmap('hsyp',5); % MIMT
% BG colors
bgct = zeros(5,3); % all black
% replace the colored regions as specified
szo = size(inpict,1:3);
outpict = inpict;
for k = 1:size(CT,1)
    % i'm assuming we can get an exact mask
    % i.e. that there's no antialiasing or JPG crust
    % i make this assumption on the basis that this example
    % is ridiculous anyway
    regionmk = all(inpict == permute(CT(k,:),[1 3 2]),3);
    
    % create a pattern fill
    patmask = ptile(im2gray(pats{k}),szo); % MIMT
    patfill = replacepixels(fgct(k,:),bgct(k,:),patmask); % MIMT
    
    % fill the selected region
    outpict = replacepixels(patfill,outpict,regionmk); % MIMT
end
imwrite(outpict,'sillyhatch.png')

It's fun to use these old pattern fills again, but nobody would work at an appropriately low resolution for them to render well. I suppose the same method would work with larger pattern tiles, but it loses the charm.

... but maybe there's no accounting for taste.

As an aside, I think a lot of people regard hatch fills as antiquated, or maybe just cluttered. I see hatch fills mostly as a practical compromise for printability, and I think that's still a justifiable solution 30 years later. I assume the biggest factor against the need for hatch fills would be simply that fewer things get physically printed, but fewer isn't none. I suppose catering to colorblindness accessibility is probably more of a concern today than it was in the past, and hatch fills can have some utility there too.

dpb 2024-8-1

" I think a lot of people regard hatch fills as antiquated..."

Apparently Mathworks is among them... :(

At the time, I was working where needed black/white presentation materials; color gradations eventually wash out into indistinguishable shades. I don't know that has completely gone away, either.

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