Aegisub/src/audio_colorscheme.h

// Copyright (c) 2009-2010, Niels Martin Hansen
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/// @file audio_colorscheme.h
/// @see audio_colorscheme.cpp
/// @ingroup audio_ui
///
/// Manage colour schemes for the audio display


#include <vector>

#include <wx/colour.h>

#include "utils.h"


/// @class AudioSpectrumColorMap
/// @brief Provides colour maps for audio display rendering
///
/// Maps values from floats in range 0..1 into RGB colour values.
///
/// First create an instance of this class, then call an initialisation function
/// in it to fill the palette with a colour map.
class AudioColorScheme {
	/// The palette data for the map
	std::vector<unsigned char> palette;

	/// Factor to multiply 0..1 values by to map them into the palette range
	size_t factor;

	/// @brief Get a floating point value's colour as a 24-bit RGB pixel
	/// @param val The value to map from
	const unsigned char *get_color(float val) const
	{
		return &palette[mid<size_t>(0, val * factor, factor) * 3];
	}

public:
	/// @brief Constructor
	/// @param prec Bit precision to create the colour map with
	/// @param scheme_name Name of the colour scheme to use
	/// @param audio_rendering_style AudioRenderingStyle to init this colorscheme for
	///
	/// Allocates the palette array to 2^prec entries
	AudioColorScheme(int prec, std::string const& scheme_name, int audio_rendering_style);

	/// @brief Map a floating point value to RGB
	/// @param val   [in] The value to map from
	/// @param pixel [out] First byte of the pixel to write
	///
	/// Writes into the XRGB pixel (assumed 32 bit without alpha) passed.
	/// The pixel format is assumed to be the same as that in the palette.
	void map(float val, unsigned char *pixel) const
	{
		// Find the colour in the palette
		const unsigned char *color = get_color(val);
		// Copy to the destination.
		// Has to be done one byte at a time since we're writing RGB and not RGBX or RGBA
		// data, and we otherwise write past the end of the pixel we're writing, possibly
		// hitting adjacent memory blocks or just overwriting the start of the following
		// scanline in the image.
		// As the image is 24 bpp, 3 of every 4 uint32_t writes would  be unaligned anyway.
		pixel[0] = color[0];
		pixel[1] = color[1];
		pixel[2] = color[2];
	}

	/// @brief Get a floating point value's colour as a wxColour
	/// @param val The value to map from
	/// @return The corresponding wxColour
	wxColour get(float val) const
	{
		const unsigned char *color = get_color(val);
		return wxColour(color[0], color[1], color[2]);
	}
};