使用OpenCV在C中进行图像旋转

Question

for the needs of a project I have to make a function that rotate an image in C with the OpenCV library. I know that this library has some function to do that but I can only use the library to load the picture and print it in a window. I already have some code but OpenCV throw me an error and I don't understand why. Here is the error message: http://pastebin.com/5Y8Wc1SF

Also here is the code of my functions: http://pastebin.com/w0AAeqyc

Can somebody help me to resolve it please?

Answer 1

Your trig function results are assigned to the wrong type

int cosd = cos(angle);
int sind = sin(angle);

They need to be

double cosd = cos(angle);
double sind = sin(angle);

or float . But when that is corrected, you can be getting negative image dimensions from these statements:

int new_width = (int)((img->width) * cosd + (img->height) * sind);
int new_height = (int)((img->height) * cosd + (img->width) * sind);

But seeing as it is unclear what axis is being rotated, I can't offer a solution.