hyperion.ng/include/hyperion/ImageToLedsMap.h

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#pragma once
// STL includes
#include <cassert>
#include <sstream>
// hyperion-utils includes
#include <utils/Image.h>
// hyperion includes
#include <hyperion/LedString.h>
namespace hyperion
{
///
/// The ImageToLedsMap holds a mapping of indices into an image to leds. It can be used to
/// calculate the average (or mean) color per led for a specific region.
///
class ImageToLedsMap
{
public:
///
/// Constructs an mapping from the absolute indices in an image to each led based on the border
/// definition given in the list of leds. The map holds absolute indices to any given image,
/// provided that it is row-oriented.
/// The mapping is created purely on size (width and height). The given borders are excluded
/// from indexing.
///
/// @param[in] width The width of the indexed image
/// @param[in] height The width of the indexed image
/// @param[in] horizontalBorder The size of the horizontal border (0=no border)
/// @param[in] verticalBorder The size of the vertical border (0=no border)
/// @param[in] leds The list with led specifications
///
ImageToLedsMap(
const unsigned width,
const unsigned height,
const unsigned horizontalBorder,
const unsigned verticalBorder,
const std::vector<Led> & leds);
///
/// Returns the width of the indexed image
///
/// @return The width of the indexed image [pixels]
///
unsigned width() const;
///
/// Returns the height of the indexed image
///
/// @return The height of the indexed image [pixels]
///
unsigned height() const;
const unsigned horizontalBorder() const { return _horizontalBorder; };
const unsigned verticalBorder() const { return _verticalBorder; };
///
/// Determines the mean-color for each led using the mapping the image given
/// at construction.
///
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/// @param[in] image The image from which to extract the led colors
///
/// @return ledColors The vector containing the output
///
template <typename Pixel_T>
std::vector<ColorRgb> getMeanLedColor(const Image<Pixel_T> & image) const
{
std::vector<ColorRgb> colors(mColorsMap.size(), ColorRgb{0,0,0});
getMeanLedColor(image, colors);
return colors;
}
///
/// Determines the mean color for each led using the mapping the image given
/// at construction.
///
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/// @param[in] image The image from which to extract the led colors
/// @param[out] ledColors The vector containing the output
///
template <typename Pixel_T>
void getMeanLedColor(const Image<Pixel_T> & image, std::vector<ColorRgb> & ledColors) const
{
// Sanity check for the number of leds
assert(mColorsMap.size() == ledColors.size());
// Iterate each led and compute the mean
auto led = ledColors.begin();
for (auto ledColors = mColorsMap.begin(); ledColors != mColorsMap.end(); ++ledColors, ++led)
{
const ColorRgb color = calcMeanColor(image, *ledColors);
*led = color;
}
}
private:
/// The width of the indexed image
const unsigned _width;
/// The height of the indexed image
const unsigned _height;
const unsigned _horizontalBorder;
const unsigned _verticalBorder;
/// The absolute indices into the image for each led
std::vector<std::vector<unsigned>> mColorsMap;
///
/// Calculates the 'mean color' of the given list. This is the mean over each color-channel
/// (red, green, blue)
///
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/// @param[in] image The image a section from which an average color must be computed
/// @param[in] colors The list with colors
///
/// @return The mean of the given list of colors (or black when empty)
///
template <typename Pixel_T>
ColorRgb calcMeanColor(const Image<Pixel_T> & image, const std::vector<unsigned> & colors) const
{
if (colors.size() == 0)
{
return ColorRgb::BLACK;
}
// Accumulate the sum of each seperate color channel
uint_fast16_t cummRed = 0;
uint_fast16_t cummGreen = 0;
uint_fast16_t cummBlue = 0;
for (const unsigned colorOffset : colors)
{
const Pixel_T& pixel = image.memptr()[colorOffset];
cummRed += pixel.red;
cummGreen += pixel.green;
cummBlue += pixel.blue;
}
// Compute the average of each color channel
const uint8_t avgRed = uint8_t(cummRed/colors.size());
const uint8_t avgGreen = uint8_t(cummGreen/colors.size());
const uint8_t avgBlue = uint8_t(cummBlue/colors.size());
// Return the computed color
return {avgRed, avgGreen, avgBlue};
}
};
} // end namespace hyperion