why the coordinates start from 800. want it to start from 0 . and the origin point in the left down like usual.

2 次查看（过去 30 天）

显示更早的评论

Mustafa Alhandhali 2019-3-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/449460-why-the-coordinates-start-from-800-want-it-to-start-from-0-and-the-origin-point-in-the-left-down

评论： Mustafa Alhandhali 2019-3-24

采纳的回答： Adam Danz

在 MATLAB Online 中打开

this the code i use

%load the image called test1 
rgbImage = imread('test1.JPG');
% Get the dimensions of the image.  numberOfColorBands should be = 3.
[rows, columns, numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 2, 1);
imshow(rgbImage);
axis on; grid on
title('Original Color Image');

采纳的回答

Adam Danz 2019-3-11

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/449460-why-the-coordinates-start-from-800-want-it-to-start-from-0-and-the-origin-point-in-the-left-down#answer_364865

在 MATLAB Online 中打开

The funtion imshow() flips the y axis. To make the y-axis normal again.

ax = gca;
ax.YDir = 'normal'; 

However, your image will also flip its y direction.

6 个评论
显示 4更早的评论隐藏 4更早的评论

dpb 2019-3-12

在 MATLAB Online 中打开

Yes, I know what he wants...but sometimes we can't always have what we want and this is one of those times.

As said, you could fake it by simply writing the tick labels as the reverse or

hAx=gca;
ytk=hAx.YTick;
hAx.YTickLabel=max(ytk)-ytk;

Mustafa Alhandhali 2019-3-24

thank you it works now

请先登录，再进行评论。

更多回答（1 个）

dpb 2019-3-11

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/449460-why-the-coordinates-start-from-800-want-it-to-start-from-0-and-the-origin-point-in-the-left-down#answer_364869

编辑：dpb 2019-3-11

在 MATLAB Online 中打开

imshow by default uses size() of the image x- and y- dimensions +/-0.5 as the axis x- and y-limits. The data are plotted on the axes from 1:Nx and 1:Ny so If you actually make the limits to be 0, you'll have a little background area outside the actual image data.

And, it always shows images with origin at top left. You can flip the axes, but unless you also flip() the image data in the y-direction, the image will be displayed upside down.

imshow(flipud(rgbImage))      % show the image in reversed y-direction
hAx=gca;                        % the parent axes handle
hAx.YDir='normal';              % invert the axis to go from bottom up so is displayed right side up