I want to vary how much of a plane is filled with the angle of the plane with the horizontal, any help?

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Daniel Gray 2017-7-4

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https://ww2.mathworks.cn/matlabcentral/answers/347327-i-want-to-vary-how-much-of-a-plane-is-filled-with-the-angle-of-the-plane-with-the-horizontal-any-he

编辑： Jan 2017-7-6

I am running an experiment and currently have a 300x300 zeros matrix and the lower half filled with ones to get a half-plane image. Now I want to 'tilt' this plane with different angles to see how this changes what I am testing. Is there a code I could use to do this?

Any more questions on this (cause I know this could be a bit confusing) please just drop a comment or send me a message.

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Jan 2017-7-4

编辑：Jan 2017-7-6

An angle is not enough for tilting, but you need a center of rotations also: Is it at [150.5, 150.5]?

Daniel Gray 2017-7-4

Yes sorry, because of it being a matrix, we'll just make the centre of rotation [150 150]

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回答（1 个）

Jan 2017-7-4

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/347327-i-want-to-vary-how-much-of-a-plane-is-filled-with-the-angle-of-the-plane-with-the-horizontal-any-he#answer_272855

编辑：Jan 2017-7-4

在 MATLAB Online 中打开

x = 1:300;
y = 1:300;
m = atan(30 * pi / 180);  % 30 deg
k = bsxfun(@plus, m * (x - 150), y.' - 150) > 0;  % Rotate around [150,150]
imagesc(k);

Since R2016b this is simpler:

k = (m * (x - 150)) + (y.' - 150) > 0;

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Daniel Gray 2017-7-5

Sorry yes I should have been more clear. I wanted the angle to be defined as between the horizontal across the centre and the new 'tilted plane' about the centre of rotation. If that doesn't make sense I can send you a diagram

Jan 2017-7-6

在 MATLAB Online 中打开

Well, in the code I've posted I used 30 deg as angle. You can replace the angle by a variable:

YourAngle = 17.3;  % deg 
m = atan(YourAngle * pi / 180);  % 30 deg

But if you ran the code with 45 deg, you have done this already. Therefore I do not understand, what the problem is now. What is the difference between the result my code creates and the wanted matrix?

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