Moved black border detection code to seperate library

Former-commit-id: 590029949b79689ea05409149677e51b748cb64f

include/blackborder/BlackBorderDetector.h

@@ -0,0 +1,136 @@
+
+#pragma once
+
+// Utils includes
+#include <utils/Image.h>
+
+namespace hyperion
+{
+	///
+	/// Result structure of the detected blackborder.
+	///
+	struct BlackBorder
+	{
+		/// Falg indicating if the border is unknown
+		bool unknown;
+
+		/// The size of the detected horizontal border
+		int horizontalSize;
+
+		/// The size of the detected vertical border
+		int verticalSize;
+
+		///
+		/// Compares this BlackBorder to the given other BlackBorder
+		///
+		/// @param[in] other  The other BlackBorder
+		///
+		/// @return True if this is the same border as other
+		///
+		inline bool operator== (const BlackBorder& other) const
+		{
+			if (unknown)
+			{
+				return other.unknown;
+			}
+
+			return other.unknown==false && horizontalSize==other.horizontalSize && verticalSize==other.verticalSize;
+		}
+	};
+
+	///
+	/// The BlackBorderDetector performs detection of black-borders on a single image.
+	/// The detector will search for the upper left corner of the picture in the frame.
+	/// Based on detected black pixels it will give an estimate of the black-border.
+	///
+	class BlackBorderDetector
+	{
+	public:
+		///
+		/// Constructs a black-border detector
+		/// @param[in] blackborderThreshold The threshold which the blackborder detector should use
+		///
+		BlackBorderDetector(uint8_t blackborderThreshold);
+
+		///
+		/// Performs the actual black-border detection on the given image
+		///
+		/// @param[in] image  The image on which detection is performed
+		///
+		/// @return The detected (or not detected) black border info
+		///
+		template <typename Pixel_T>
+		BlackBorder process(const Image<Pixel_T> & 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 Pixel_T & color = image(x, y);
+				if (!isBlack(color))
+				{
+					firstNonBlackXPixelIndex = x;
+					firstNonBlackYPixelIndex = y;
+					break;
+				}
+			}
+
+			// expand image to the left
+			for(; firstNonBlackXPixelIndex > 0; --firstNonBlackXPixelIndex)
+			{
+				const Pixel_T & color = image(firstNonBlackXPixelIndex-1, firstNonBlackYPixelIndex);
+				if (isBlack(color))
+				{
+					break;
+				}
+			}
+
+			// expand image to the top
+			for(; firstNonBlackYPixelIndex > 0; --firstNonBlackYPixelIndex)
+			{
+				const Pixel_T & 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;
+		}
+
+	private:
+
+		///
+		/// Checks if a given color is considered black and therefor could be part of the border.
+		///
+		/// @param[in] color  The color to check
+		///
+		/// @return True if the color is considered black else false
+		///
+		template <typename Pixel_T>
+		inline bool isBlack(const Pixel_T & color)
+		{
+			// Return the simple compare of the color against black
+			return color.red < _blackborderThreshold && color.green < _blackborderThreshold && color.green < _blackborderThreshold;
+		}
+
+	private:
+		/// Threshold for the blackborder detector [0 .. 255]
+		const uint8_t _blackborderThreshold;
+	};
+} // end namespace hyperion