Rotate pixel array 90 degrees in C++

c++, pixel, rotation

Solution

Replace the line in the inner-most loop with:

for (int i = 0; i < 3; i++)
    tempBuffer[(x * height + destinationColumn) * 3 + i] = buffer[(offset + x) * 3 + i];

Problem

I've written the next function to rotate an unsigned char pixel array which holds a RGB image by 90 degrees. The problem I'm facing is that the rotated output is all completely garbled. ``` void rotate90(unsigned char *buffer, const unsigned int width, const unsigned int height) { const unsigned int sizeBuffer = width * height * 3; unsigned char *tempBuffer = new unsigned char[sizeBuffer]; for (int y = 0, destinationColumn = height - 1; y < height; ++y, --destinationColumn) { int offset = y * width; for (int x = 0; x < width; x++) { tempBuffer[(x * height) + destinationColumn] = buffer[offset + x]; } } // Copy rotated pixels memcpy(buffer, tempBuffer, sizeBuffer); delete[] tempBuffer; } ```

Original source