crop image for a shape

[naushadck]

It is possible to crop an image using image.get_crop().
I believe that it works for a rectangle. But not for a shape.

Is it possible to use image.get_crop() for a given shape.
(Attached the image with marked the location to crop)

More details.
Image - CImg image("sad.bmp");
cimg_library::CImg points(4, 2);
points(0, 0) = 15;
points(0, 1) = 50;
points(1, 0) = 100;
points(1, 1) = 15;
points(2, 0) = 135;
points(2, 1) = 65;
points(3, 0) = 50;
points(3, 1) = 100;
image.draw_polygon(points,rcolor, 1);

How to get the data for the above said polygon area.

[dtschump]

How would you store the pixel values for an arbitrary shape ?
What if each "scanline" of that shape has a different size ?

[naushadck]

I am not sure about it.
Somehow to get the specified area or shape.

[naushadck]

Is it possible rotate the image to required degree/angle so that the specified area will be straight(left to right scan).

[dtschump]

Yes, with CImg<T>::rotate().

[naushadck]

Thank you.
Attached the original picture(polygon) and the rotated with static(manual) angle.
How can i calculate the required rotate angle ?. So that it can calculate angle dynamically and rotate accordingly.