/** 
 * @file llfontgl.h
 * @author Doug Soo
 * @brief Wrapper around FreeType
 *
 * $LicenseInfo:firstyear=2001&license=viewergpl$
 * 
 * Copyright (c) 2001-2009, Linden Research, Inc.
 * 
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
 * to you under the terms of the GNU General Public License, version 2.0
 * ("GPL"), unless you have obtained a separate licensing agreement
 * ("Other License"), formally executed by you and Linden Lab.  Terms of
 * the GPL can be found in doc/GPL-license.txt in this distribution, or
 * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
 * 
 * There are special exceptions to the terms and conditions of the GPL as
 * it is applied to this Source Code. View the full text of the exception
 * in the file doc/FLOSS-exception.txt in this software distribution, or
 * online at
 * http://secondlifegrid.net/programs/open_source/licensing/flossexception
 * 
 * By copying, modifying or distributing this software, you acknowledge
 * that you have read and understood your obligations described above,
 * and agree to abide by those obligations.
 * 
 * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
 * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
 * COMPLETENESS OR PERFORMANCE.
 * $/LicenseInfo$
 */

#ifndef LL_LLFONTGL_H
#define LL_LLFONTGL_H

#include "llcoord.h"
#include "llfontregistry.h"
#include "llimagegl.h"
#include "llpointer.h"
#include "llrect.h"
#include "v2math.h"

class LLColor4;
// Key used to request a font.
class LLFontDescriptor;
class LLFontFreetype;

// Structure used to store previously requested fonts.
class LLFontRegistry;

class LLFontGL
{
public:
	enum HAlign
	{
		// Horizontal location of x,y coord to render.
		LEFT = 0,		// Left align
		RIGHT = 1,		// Right align
		HCENTER = 2,	// Center
	};

	enum VAlign
	{
		// Vertical location of x,y coord to render.
		TOP = 3,		// Top align
		VCENTER = 4,	// Center
		BASELINE = 5,	// Baseline
		BOTTOM = 6		// Bottom
	};

	enum StyleFlags
	{
		// text style to render.  May be combined (these are bit flags)
		NORMAL    = 0x00,	
		BOLD      = 0x01,
		ITALIC    = 0x02,
		UNDERLINE = 0x04
	};

	enum ShadowType
	{
		NO_SHADOW,
		DROP_SHADOW,
		DROP_SHADOW_SOFT
	};

	LLFontGL();
	~LLFontGL();


	void reset(); // Reset a font after GL cleanup.  ONLY works on an already loaded font.

	void destroyGL();

	BOOL loadFace(const std::string& filename, F32 point_size, const F32 vert_dpi, const F32 horz_dpi, const S32 components, BOOL is_fallback);

	S32 render(const LLWString &text, S32 begin_offset, F32 x, F32 y, const LLColor4 &color, HAlign halign = LEFT,  VAlign valign = BASELINE, U8 style = NORMAL,
	           ShadowType shadow = NO_SHADOW, S32 max_chars = S32_MAX, S32 max_pixels = S32_MAX, F32* right_x=NULL, BOOL use_ellipses = FALSE) const;
	S32 render(const LLWString &text, S32 begin_offset, F32 x, F32 y, const LLColor4 &color) const;

	// renderUTF8 does a conversion, so is slower!
	S32 renderUTF8(const std::string &text, S32 begin_offset, F32 x, F32 y, const LLColor4 &color, HAlign halign,  VAlign valign, U8 style, ShadowType shadow, S32 max_chars, S32 max_pixels,  F32* right_x, BOOL use_ellipses) const;
	S32 renderUTF8(const std::string &text, S32 begin_offset, S32 x, S32 y, const LLColor4 &color) const;
	S32 renderUTF8(const std::string &text, S32 begin_offset, S32 x, S32 y, const LLColor4 &color, HAlign halign, VAlign valign, U8 style = NORMAL, ShadowType shadow = NO_SHADOW) const;

	// font metrics - override for LLFontFreetype that returns units of virtual pixels
	F32 getLineHeight() const;
	F32 getAscenderHeight() const;
	F32 getDescenderHeight() const;

	S32 getWidth(const std::string& utf8text) const;
	S32 getWidth(const llwchar* wchars) const;
	S32 getWidth(const std::string& utf8text, S32 offset, S32 max_chars ) const;
	S32 getWidth(const llwchar* wchars, S32 offset, S32 max_chars) const;

	F32 getWidthF32(const std::string& utf8text) const;
	F32 getWidthF32(const llwchar* wchars) const;
	F32 getWidthF32(const std::string& text, S32 offset, S32 max_chars ) const;
	F32 getWidthF32(const llwchar* wchars, S32 offset, S32 max_chars) const;

	// The following are called often, frequently with large buffers, so do not use a string interface
	
	// Returns the max number of complete characters from text (up to max_chars) that can be drawn in max_pixels
	S32	maxDrawableChars(const llwchar* wchars, F32 max_pixels, S32 max_chars = S32_MAX, BOOL end_on_word_boundary = FALSE) const;

	// Returns the index of the first complete characters from text that can be drawn in max_pixels
	// given that the character at start_pos should be the last character (or as close to last as possible).
	S32	firstDrawableChar(const llwchar* wchars, F32 max_pixels, S32 text_len, S32 start_pos=S32_MAX, S32 max_chars = S32_MAX) const;

	// Returns the index of the character closest to pixel position x (ignoring text to the right of max_pixels and max_chars)
	S32 charFromPixelOffset(const llwchar* wchars, S32 char_offset, F32 x, F32 max_pixels=F32_MAX, S32 max_chars = S32_MAX, BOOL round = TRUE) const;

	BOOL addChar(const llwchar wch) const;

	const LLFontDescriptor& getFontDesc() const;


	static void initClass(F32 screen_dpi, F32 x_scale, F32 y_scale, const std::string& app_dir, const std::vector<std::string>& xui_paths, bool create_gl_textures = true);

	// Load sans-serif, sans-serif-small, etc.
	// Slow, requires multiple seconds to load fonts.
	static bool loadDefaultFonts();
	static void	destroyDefaultFonts();
	static void destroyAllGL();

	// Takes a string with potentially several flags, i.e. "NORMAL|BOLD|ITALIC"
	static U8 getStyleFromString(const std::string &style);

	static std::string nameFromFont(const LLFontGL* fontp);

	static std::string nameFromHAlign(LLFontGL::HAlign align);
	static LLFontGL::HAlign hAlignFromName(const std::string& name);

	static std::string nameFromVAlign(LLFontGL::VAlign align);
	static LLFontGL::VAlign vAlignFromName(const std::string& name);

	static void setFontDisplay(BOOL flag) { sDisplayFont = flag; }
		
	static LLFontGL* getFontMonospace();
	static LLFontGL* getFontSansSerifSmall();
	static LLFontGL* getFontSansSerif();
	static LLFontGL* getFontSansSerifBig();
	static LLFontGL* getFontSansSerifHuge();
	static LLFontGL* getFontSansSerifBold();
	static LLFontGL* getFontExtChar();
	static LLFontGL* getFont(const LLFontDescriptor& desc);
	// Use with legacy names like "SANSSERIF_SMALL" or "OCRA"
	static LLFontGL* getFontByName(const std::string& name);

	static std::string getFontPathLocal();
	static std::string getFontPathSystem();

	static LLCoordFont sCurOrigin;
	static std::vector<LLCoordFont> sOriginStack;

	static LLColor4 sShadowColor;

	static F32 sVertDPI;
	static F32 sHorizDPI;
	static F32 sScaleX;
	static F32 sScaleY;
	static BOOL sDisplayFont ;
	static std::string sAppDir;			// For loading fonts

private:
	friend class LLFontRegistry;
	friend class LLTextBillboard;
	friend class LLHUDText;

	LLFontGL(const LLFontGL &source);
	LLFontGL &operator=(const LLFontGL &source);

	LLFontDescriptor mFontDescriptor;
	LLPointer<LLFontFreetype> mFontFreetype;

	void renderQuad(const LLRectf& screen_rect, const LLRectf& uv_rect, F32 slant_amt) const;
	void drawGlyph(const LLRectf& screen_rect, const LLRectf& uv_rect, const LLColor4& color, U8 style, ShadowType shadow, F32 drop_shadow_fade) const;

	// Registry holds all instantiated fonts.
	static LLFontRegistry* sFontRegistry;
};

#endif