具有固定x / y比率的裁剪图像 [英] crop image with fixed x/y ratio

问题描述

我想使用以下代码裁剪图像。但我希望用户只能选择具有预定义x / y比率的裁剪区域。例如，如果x = 2，y = 2，则用户只能使用鼠标选择（x / y）= 1比率的区域。

I want to crop image using following code. but i want to user only can select the crop area with a predefined x/y ratio.for example if x=2,y=2 ,then user can only use mouse to select an area with (x/y)=1 ratio.

I = imread('image.jpg');
[rows columns numberOfColorBands] = size(I);
I2 = imcrop(I);
imshow(I), figure, imshow(I2)

推荐答案

您可以使用imrect生成坐标，然后将它们传递给imcrop。

You could use imrect to produce the coordinates, and then pass those into imcrop.

figure, imshow(I);
h = imrect(gca,[10 10 100 100]); 
setFixedAspectRatio(h,1); % this fixes the aspect ratio; user can now change size/position
position = wait(h); % returns coordinates in "position" when user doubleclicks on rectangle
I2 = imcrop(I,position);
figure, imshow(I2);

在实际代码中，您必须更换[10 10 100 100]适合您图像的尺寸/宽高比。您可能希望添加其他约束以进行修改（例如，阻止用户将矩形移动到实际图像之外）。

In the actual code, you'll have to replace [10 10 100 100] with something of the appropriate size/aspect ratio for your images. You may want to add other constraints to imrect (for example to stop the user moving the rectangle outside the actual image).

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