更改线条的不透明度

Posted 2023-03-06

【中文标题】更改线条的不透明度

【英文标题】：Change opacity of lines

【发布时间】：2012-07-23 06:09:42

【问题描述】：

我想改变我在 MATLAB 中绘制的线条的不透明度。我在某处读到了有关 alpha 和 facealpha 命令的信息，但不知道如何使用它们。有人可以告诉我怎么做吗？

【参考方案1】：

来自 How can I set the transparency of LINE objects in MATLAB 7.14 (R2012a)? (mirror) 上的 MathWorks 支持团队：

线系列对象不支持透明度 (alpha) 值。这 可以使用以下解决方法来克服此限制：

请参考以下 MATLAB Central 链接：http://www.mathworks.com/matlabcentral/fileexchange/36953-patchline/content/patchline.m

上述函数可用于在 LINE 对象中引入透明度，如下所示：

示例 1：

n = 10;
xs = rand(n,1);
ys = rand(n,1);
zs = rand(n,1)*3;
plot3(xs,ys,zs,'r.')
xlabel('x');ylabel('y');zlabel('z');
p  = patchline(xs,ys,zs,'linestyle','--','edgecolor','g','linewidth',3,'edgealpha',0.2);

示例 2：

t = 0:pi/64:4*pi;
p(1) = patchline(t,sin(t),'edgecolor','b','linewidth',2,'edgealpha',0.5);
p(2) = patchline(t,cos(t),'edgecolor','r','linewidth',2,'edgealpha',0.5);
l = legend('sine(t)','cosine(t)');
tmp = sort(findobj(l,'type','patch'));
for ii = 1:numel(tmp)
    set(tmp(ii),'facecolor',get(p(ii),'edgecolor'),'facealpha',get(p(ii),'edgealpha'),'edgecolor','none')
end

patchline.m（Brett Shoelson，2012 年 6 月 20 日（2016 年 9 月 1 日更新））：

function p = patchline(xs,ys,varargin)
% Plot lines as patches (efficiently)
%
% SYNTAX:
%     patchline(xs,ys)
%     patchline(xs,ys,zs,...)
%     patchline(xs,ys,zs,'PropertyName',propertyvalue,...)
%     p = patchline(...)
%
% PROPERTIES: 
%     Accepts all parameter-values accepted by PATCH.
% 
% DESCRIPTION:
%     p = patchline(xs,ys,zs,'PropertyName',propertyvalue,...)
%         Takes a vector of x-values (xs) and a same-sized
%         vector of y-values (ys). z-values (zs) are
%         supported, but optional; if specified, zs must
%         occupy the third input position. Takes all P-V
%         pairs supported by PATCH. Returns in p the handle
%         to the resulting patch object.
%         
% NOTES:
%     Note that we are drawing 0-thickness patches here,
%     represented only by their edges. FACE PROPERTIES WILL
%     NOT NOTICEABLY AFFECT THESE OBJECTS! (Modify the
%     properties of the edges instead.)
%
%     LINUX (UNIX) USERS: One test-user found that this code
%     worked well on his Windows machine, but crashed his
%     Linux box. We traced the problem to an openGL issue;
%     the problem can be fixed by calling 'opengl software'
%     in your <http://www.mathworks.com/help/techdoc/ref/startup.html startup.m>.
%     (That command is valid at startup, but not at runtime,
%     on a unix machine.)
%
% EXAMPLES:
%%% Example 1:
%
% n = 10;
% xs = rand(n,1);
% ys = rand(n,1);
% zs = rand(n,1)*3;
% plot3(xs,ys,zs,'r.')
% xlabel('x');ylabel('y');zlabel('z');
% p  = patchline(xs,ys,zs,'linestyle','--','edgecolor','g',...
%     'linewidth',3,'edgealpha',0.2);
%
%%% Example 2: (Note "hold on" not necessary here!)
%
% t = 0:pi/64:4*pi;
% p(1) = patchline(t,sin(t),'edgecolor','b','linewidth',2,'edgealpha',0.5);
% p(2) = patchline(t,cos(t),'edgecolor','r','linewidth',2,'edgealpha',0.5);
% l = legend('sine(t)','cosine(t)');
% tmp = sort(findobj(l,'type','patch'));
% for ii = 1:numel(tmp)
%     set(tmp(ii),'facecolor',get(p(ii),'edgecolor'),'facealpha',get(p(ii),'edgealpha'),'edgecolor','none')
% end
%
%%% Example 3 (requires Image Processing Toolbox):
%%%   (NOTE that this is NOT the same as showing a transparent image on 
%%%         of the existing image. (That functionality is
%%%         available using showMaskAsOverlay or imoverlay).
%%%         Instead, patchline plots transparent lines over
%%%         the image.)
%
% img = imread('rice.png');
% imshow(img)
% img = imtophat(img,strel('disk',15));
% grains = im2bw(img,graythresh(img));
% grains = bwareaopen(grains,10);
% edges = edge(grains,'canny');
% boundaries = bwboundaries(edges,'noholes');
% cmap = jet(numel(boundaries));
% ind = randperm(numel(boundaries));
% for ii = 1:numel(boundaries)
% patchline(boundariesii(:,2),boundariesii(:,1),...
%     'edgealpha',0.2,'edgecolor',cmap(ind(ii),:),'linewidth',3);
% end
%
% Written by Brett Shoelson, PhD
% [e-mail]
% 5/31/2012
% 
% Revisions:
% 6/26 Improved rice.png example, modified FEX image.
%
% Copyright 2012 MathWorks, Inc.
%
% See also: patch, line, plot

[zs,PVs] = parseInputs(varargin:);
if rem(numel(PVs),2) ~= 0
    % Odd number of inputs!
    error('patchline: Parameter-Values must be entered in valid pairs')
end

% Facecolor = 'k' is (essentially) ignored here, but syntactically necessary
if isempty(zs)
    p = patch([xs(:);NaN],[ys(:);NaN],'k');
else
    p = patch([xs(:);NaN],[ys(:);NaN],[zs(:);NaN],'k');
end

% Apply PV pairs
for ii = 1:2:numel(PVs)
    set(p,PVsii,PVsii+1)
end
if nargout == 0
    clear p
end

function [zs,PVs] = parseInputs(varargin)
if isnumeric(varargin1)
    zs = varargin1;
    PVs = varargin(2:end);
else
    PVs = varargin;
    zs = [];
end

许可证：

Copyright (c) 2016, The MathWorks, Inc.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the distribution.
    * In all cases, the software is, and all modifications and derivatives
      of the software shall be, licensed to you solely for use in conjunction
      with MathWorks products and service offerings.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.