hyperion.ng/libsrc/hyperion/BlackBorderDetector.cpp

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// Local-Hyperion includes
#include "BlackBorderDetector.h"
using namespace hyperion;
BlackBorderDetector::BlackBorderDetector()
{
// empty
}
BlackBorder BlackBorderDetector::process(const RgbImage& image)
{
// only test the topleft third of the image
int width = image.width() /3;
int height = image.height() / 3;
int maxSize = std::max(width, height);
int firstNonBlackXPixelIndex = -1;
int firstNonBlackYPixelIndex = -1;
// find some pixel of the image
for (int i = 0; i < maxSize; ++i)
{
int x = std::min(i, width);
int y = std::min(i, height);
const RgbColor& color = image(x, y);
if (!isBlack(color))
{
firstNonBlackXPixelIndex = x;
firstNonBlackYPixelIndex = y;
break;
}
}
// expand image to the left
for(; firstNonBlackXPixelIndex > 0; --firstNonBlackXPixelIndex)
{
const RgbColor& color = image(firstNonBlackXPixelIndex-1, firstNonBlackYPixelIndex);
if (isBlack(color))
{
break;
}
}
// expand image to the top
for(; firstNonBlackYPixelIndex > 0; --firstNonBlackYPixelIndex)
{
const RgbColor& color = image(firstNonBlackXPixelIndex, firstNonBlackYPixelIndex-1);
if (isBlack(color))
{
break;
}
}
// Construct result
BlackBorder detectedBorder;
detectedBorder.unknown = firstNonBlackXPixelIndex == -1 || firstNonBlackYPixelIndex == -1;
detectedBorder.horizontalSize = firstNonBlackYPixelIndex;
detectedBorder.verticalSize = firstNonBlackXPixelIndex;
return detectedBorder;
}