// Aseprite TGA Library

// Copyright (C) 2020 Igara Studio S.A.

//

// This file is released under the terms of the MIT license.

// Read LICENSE.txt for more information.

#include "tga.h"

namespace tga {

namespace details {

ImageIterator::ImageIterator()

: m_image(nullptr)

{

}

ImageIterator::ImageIterator(const Header& header, Image& image)

: m_image(&image)

, m_x(header.leftToRight() ? 0: header.width-1)

, m_y(header.topToBottom() ? 0: header.height-1)

, m_w(header.width)

, m_h(header.height)

, m_dx(header.leftToRight() ? +1: -1)

, m_dy(header.topToBottom() ? +1: -1)

{

calcPtr();

}

bool ImageIterator::advance()

{

m_x += m_dx;

m_ptr += m_dx*m_image->bytesPerPixel;

if ((m_dx < 0 && m_x < 0) ||

(m_dx > 0 && m_x == m_w)) {

m_x = (m_dx > 0 ? 0: m_w-1);

m_y += m_dy;

if ((m_dy < 0 && m_y < 0) ||

(m_dy > 0 && m_y == m_h)) {

return true;

}

calcPtr();

}

return false;

}

void ImageIterator::calcPtr()

{

m_ptr =

m_image->pixels

+ m_image->rowstride*m_y

+ m_image->bytesPerPixel*m_x;

}

} // namespace details

} // namespace tga