为什么在这个带有export_fig的Matlab Polar演示文稿中有Gap？

Question

为什么在这个带有export_fig的Matlab Polar演示文稿中有Gap？

Léo*_* 준영 1 matlab matlab-figure polar-coordinates

从origo(0,0)到(1,0)的行产生间隙的代码,如果C尺寸达到无穷大,它似乎达到零; 但是,我不能用任何尺寸的小尺寸得到它,C所以我认为工件可能是由Matlab图形内部特征或图像数据本身(AnderBiguri)引起的,因为它似乎不会发生img=imread('peppers.png').制作图像的代码,存储它export_fig并将其从笛卡尔映射到工件发生的极地

close all; clear all; clc;

%% Make image
f1=figure;
hax=axes(f1);
x = rand(1,6);
y = exp(rand(1,181));
C = rand(3613,3613);
imagesc(hax, x, y, C); 
box(hax, 'off');
axis(hax, 'off');
set(hax, 'yTickLabel', []);
set(hax, 'xTickLabel', []); % for polar presentation
set(hax, 'Ticklength', [0 0]); % http://stackoverflow.com/a/15529630/54964
filename='/home/masi/Images/testi';
% by default, export_fig has cropping
[img, alpha] = export_fig(filename, '-png', '-native', '-q101', '-a1', '-m1', '-RGB', '-nofontswap', '-dpng', hax);
close all; 

%% Read Image
img=imread('/home/masi/Images/testi.png');
% http://stackoverflow.com/a/7586650/54964
[h,w,~] = size(img);
s = min(h,w)/2; % have here .../1, some phenomenon occurs
[rho,theta] = meshgrid(linspace(0,s-1,s), linspace(0,2*pi,s));
[x,y] = pol2cart(theta, rho);
z = zeros(size(x));
subplot(121), imshow(img)
subplot(122), warp(x, y, z, img)
view(2), axis square tight off

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图1输出时size(C)=[3613 3613],图2输出时size(C)=[36130 36130]