love2d.love/src/modules/graphics/opengl/Font.h

/**
 * Copyright (c) 2006-2013 LOVE Development Team
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 **/

#ifndef LOVE_GRAPHICS_OPENGL_FONT_H
#define LOVE_GRAPHICS_OPENGL_FONT_H

// STD
#include <map>
#include <string>
#include <vector>

// LOVE
#include "common/Object.h"
#include "font/Rasterizer.h"
#include "graphics/Image.h"

#include "OpenGL.h"

namespace love
{
namespace graphics
{
namespace opengl
{

class Font : public Object, public Volatile
{
public:

	/**
	 * Default constructor.
	 *
	 * @param data The font data to construct from.
	 **/
	Font(love::font::Rasterizer *r, const Image::Filter &filter = Image::getDefaultFilter());

	virtual ~Font();

	/**
	 * Prints the text at the designated position with rotation and scaling.
	 *
	 * @param text A string.
	 * @param x The x-coordinate.
	 * @param y The y-coordinate.
	 * @param letter_spacing Additional spacing between letters.
	 * @param angle The amount of rotation.
	 * @param sx Scale along the x axis.
	 * @param sy Scale along the y axis.
	 * @param ox The origin offset along the x-axis.
	 * @param oy The origin offset along the y-axis.
	 * @param kx Shear along the x axis.
	 * @param ky Shear along the y axis.
	 **/
	void print(const std::string &text, float x, float y, float letter_spacing = 0.0f, float angle = 0.0f, float sx = 1.0f, float sy = 1.0f, float ox = 0.0f, float oy = 0.0f, float kx = 0.0f, float ky = 0.0f);

	/**
	 * Returns the height of the font.
	 **/
	float getHeight() const;

	/**
	 * Returns the width of the passed string.
	 *
	 * @param str A string of text.
	 **/
	int getWidth(const std::string &str);
	int getWidth(const char *str);

	/**
	 * Returns the width of the passed character.
	 *
	 * @param character A character.
	 **/
	int getWidth(unsigned int character);

	/**
	 * Returns the maximal width of a wrapped string
	 * and optionally the number of lines
	 *
	 * @param text The input text
	 * @param wrap The number of pixels to wrap at
	 * @param max_width Optional output of the maximum width
	 * Returns a vector with the lines.
	 **/
	std::vector<std::string> getWrap(const std::string &text, float wrap, int *max_width = 0);

	/**
	 * Sets the line height (which should be a number to multiply the font size by,
	 * example: line height = 1.2 and size = 12 means that rendered line height = 12*1.2)
	 * @param height The new line height.
	 **/
	void setLineHeight(float height);

	/**
	 * Returns the line height.
	 **/
	float getLineHeight() const;

	/**
	 * Sets the spacing modifier (changes the spacing between the characters the
	 * same way that the line height does [multiplication]).
	 * Note: The spacing must be set BEFORE the font is loaded to have any effect.
	 * @param amount The amount of modification.
	 **/
	void setSpacing(float amount);

	/**
	 * Returns the spacing modifier.
	 **/
	float getSpacing() const;

	void setFilter(const Image::Filter &f);
	const Image::Filter &getFilter();

	// Implements Volatile.
	bool loadVolatile();
	void unloadVolatile();

	// Extra font metrics
	int getAscent() const;
	int getDescent() const;
	float getBaseline() const;

private:

	enum FontType
	{
		FONT_TRUETYPE = 1,
		FONT_IMAGE,
		FONT_UNKNOWN
	};
	
	// thin wrapper for an array of 4 vertices
	struct GlyphQuad
	{
		vertex vertices[4];
	};

	struct Glyph
	{
		GLuint texture;
		int spacing;
		GlyphQuad quad;
	};

	// used to determine when to change textures in the vertex array generated when printing text
	struct GlyphArrayDrawInfo
	{
		GLuint texture;
		int startquad, numquads;

		// used when sorting with std::sort
		// sorts by texture first (binding textures is expensive) and relative position in memory second
		bool operator < (const GlyphArrayDrawInfo &other) const
		{
			if (texture != other.texture)
				return texture < other.texture;
			else
				return startquad < other.startquad;
		};
	};

	love::font::Rasterizer *rasterizer;

	int height;
	float lineHeight;
	float mSpacing; // modifies the spacing by multiplying it with this value

	int texture_size_index;
	int texture_width;
	int texture_height;

	std::vector<GLuint> textures; // vector of packed textures
	std::map<unsigned int, Glyph *> glyphs; // maps glyphs to quad information
	FontType type;
	Image::Filter filter;

	static const int NUM_TEXTURE_SIZES = 7;
	static const int TEXTURE_WIDTHS[NUM_TEXTURE_SIZES];
	static const int TEXTURE_HEIGHTS[NUM_TEXTURE_SIZES];

	static const int TEXTURE_PADDING = 1;

	int texture_x, texture_y;
	int rowHeight;

	bool initializeTexture(GLint format);
	void createTexture();
	Glyph *addGlyph(unsigned int glyph);
	Glyph *findGlyph(unsigned int glyph);
}; // Font

} // opengl
} // graphics
} // love

#endif // LOVE_GRAPHICS_OPENGL_FONT_H