Transparency causes nonsmooth lines
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When I set transparency in the figure, the original smooth line becomes nonsmooth.
[x,y] = meshgrid(-2:.2:2);
z = x.*exp(-x.^2-y.^2);
a = gradient(z);
figure; surf(x,y,z,'AlphaData',a,'FaceAlpha','flat','FaceColor','blue');
figure; surf(x,y,z)
采纳的回答
Jan
2018-7-26
0 个投票
Transparency requires the OpenGL renderer. The line-smoothing requires the Painters renderer. As far as I can see, you observe the expected behavior.
5 个评论
bai da
2018-7-26
"Dilemma" means that it is not a "lemma", or in other words: It cannot be decided. This implies, that you cannot avoid it, because it is the nature of the different renderers.
But you can reduce the effects or find a work-around. It depends on what you want to do with the displayed graphics. Does your problem concerns the output to the screen or do you want to export a smoothed graphics file? KALYAN ACHARJYA asked already, what your question is.
Which Matlab version are you using and do you have the Image Processing toolbox?
bai da
2018-7-26
Try this:
RGB = AntiAlias(gcf, 4, 'lanczos3');
imwrite(RGB, 'File.png');
Using this function:
function Out = AntiAlias(FigH, K, Method)
% Anti-aliasing of a figure
% Reply = AntiAliasFig(FigH, K)
% FigH: Figure handle.
% K: Integer subsampling factor >= 1: The created pictures uses a K-times
% higher resolution.
% For K = 1 the output equals the original picture.
% Method: See Method of IMRESIZE: E.g. 'lanczos3'
%
% OUTPUT:
% Reply: RGB data are replied as [M x N x 3] UINT8 array.
%
% Tested: Matlab/64 9.1, Win10
% Author: Jan Simon, Heidelberg, (C) 2018
% Initialize: ==================================================================
screen_DPI = get(groot, 'ScreenPixelsPerInch');
% Do the work: =================================================================
% Wanted resolution as string:
ResolutionStr = sprintf('-r%d', round(screen_DPI * K));
% Prepare figure for hardcopy:
drawnow;
fig_Renderer = get(FigH, 'Renderer');
fig_Paperposmode = get(FigH, 'PaperPositionMode');
fig_PaperOrient = get(FigH, 'PaperOrientation');
fig_Invhardcopy = get(FigH, 'InvertHardcopy');
set(FigH, ...
'PaperPositionMode', 'auto', ...
'PaperOrientation', 'portrait', ...
'InvertHardcopy', 'off');
% Create hard copy in high resolution: -----------------------------------------
% Simulate PRINT command (save time for writing and reading image file):
% Set units of axes and text from PIXELS to POINTS to keep their sizes
% independent from from the output resolution:
% See: graphics/private/preparehg.m
root_SHH = get(groot, 'ShowHiddenHandles');
set(groot, 'ShowHiddenHandles', 'on');
text_axes_H = [findobj(FigH, 'Type', 'axes'); ...
findobj(FigH, 'Type', 'text')];
pixelObj = findobj(text_axes_H, 'Units', 'pixels');
fontPixelObj = findobj(text_axes_H, 'FontUnits', 'pixels');
set(pixelObj, 'Units', 'points');
set(fontPixelObj, 'FontUnits', 'points');
fig_ResizeFcn = get(FigH, 'ResizeFcn');
set(FigH, 'ResizeFcn', '');
% Get image as RGB array:
high = print('-RGBImage', ResolutionStr);
% Restore units of axes and text objects, and EraseMode:
set(pixelObj, 'Units', 'pixels');
set(fontPixelObj, 'FontUnits', 'pixels');
set(groot, 'ShowHiddenHandles', root_SHH);
set(FigH, 'ResizeFcn', fig_ResizeFcn);
% Restore properties of the original image:
set(FigH, ...
'InvertHardcopy', fig_Invhardcopy, ...
'PaperPositionMode', fig_Paperposmode, ...
'PaperOrientation', fig_PaperOrient, ...
'Renderer', fig_Renderer);
% Create the low resolution data and axes properties:
try
low = imresize(high, 1 / K, Method); % Hide from CheckSyntax
catch ME
if isempty(which('imresize'))
error(['*** %s: Signal-Processing-Toolbox is required.', ...
char(10), '%s'], mfilename, Mode, ME.message);
else
error(['*** %s: Unknown [Mode]: [%s]', ...
char(10), '%s'], mfilename, Mode, ME.message);
end
end
% Limit range of data:
% Slightly slower: lowres = max(min(lowres, 1), 0);
if isa(low, 'double')
low(low < 0) = 0;
low(low > 1) = 1;
end
Out = low;
end
更多回答（1 个）
Indrajit Wadgaonkar
2021-8-10
编辑：Indrajit Wadgaonkar
2021-8-10
0 个投票
Did this issue get resolved? What is the solution if I need transparency as well as smooth lines?
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