Merge pull request #555 from varnie/master
Image::flipVertically(), Image::flipHorizontally() optimizations
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commit
e9334db424
@ -271,20 +271,19 @@ void Image::flipHorizontally()
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{
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if (!m_pixels.empty())
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{
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std::vector<Uint8> before = m_pixels;
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for (unsigned int y = 0; y < m_size.y; ++y)
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{
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const Uint8* source = &before[y * m_size.x * 4];
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Uint8* dest = &m_pixels[(y + 1) * m_size.x * 4 - 4];
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for (unsigned int x = 0; x < m_size.x; ++x)
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{
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dest[0] = source[0];
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dest[1] = source[1];
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dest[2] = source[2];
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dest[3] = source[3];
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std::size_t rowSize = m_size.x * 4;
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source += 4;
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dest -= 4;
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for (std::size_t y = 0; y < m_size.y; ++y)
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{
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std::vector<Uint8>::iterator left = m_pixels.begin() + y * rowSize;
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std::vector<Uint8>::iterator right = m_pixels.begin() + (y + 1) * rowSize - 4;
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for (std::size_t x = 0; x < m_size.x / 2; ++x)
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{
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std::swap_ranges(left, left + 4, right);
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left += 4;
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right -= 4;
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}
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}
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}
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@ -296,16 +295,17 @@ void Image::flipVertically()
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{
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if (!m_pixels.empty())
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{
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std::vector<Uint8> before = m_pixels;
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const Uint8* source = &before[m_size.x * (m_size.y - 1) * 4];
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Uint8* dest = &m_pixels[0];
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std::size_t rowSize = m_size.x * 4;
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for (unsigned int y = 0; y < m_size.y; ++y)
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std::vector<Uint8>::iterator top = m_pixels.begin();
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std::vector<Uint8>::iterator bottom = m_pixels.end() - rowSize;
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for (std::size_t y = 0; y < m_size.y / 2; ++y)
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{
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std::memcpy(dest, source, rowSize);
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source -= rowSize;
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dest += rowSize;
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std::swap_ranges(top, top + rowSize, bottom);
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top += rowSize;
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bottom -= rowSize;
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}
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}
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}
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