/*
* @(#)LEFontInstance.h 1.3 00/03/15
*
* (C) Copyright IBM Corp. 1998, 1999, 2000, 2001, 2002 - All Rights Reserved
*
*/
#ifndef __LEFONTINSTANCE_H
#define __LEFONTINSTANCE_H
#include "LETypes.h"
U_NAMESPACE_BEGIN
/**
* Instances of this class are used by LEFontInstance::mapCharsToGlyphs and
* LEFontInstance::mapCharToGlyph to adjust character codes before the character
* to glyph mapping process. Examples of this are filtering out control charcters
* and character mirroring - replacing a character which has both a left and a right
* hand form with the opposite form.
*
* @draft ICU 2.2
*/
class LECharMapper /* not : public UObject because this is an interface/mixin class */ {
public:
/**
* Destructor.
* @draft ICU 2.4
*/
virtual inline ~LECharMapper() {};
/**
* This method does the adjustments.
*
* @param ch - the input charcter
*
* @return the adjusted character
*
* @draft ICU 2.2
*/
virtual LEUnicode32 mapChar(LEUnicode32 ch) const = 0;
};
/**
* This is a pure virtual base class that servers as the interface between a LayoutEngine
* and the platform font environment. It allows a LayoutEngine to access font tables, do
* character to glyph mapping, and obtain metrics information without knowing any platform
* specific details. There are also a few utility methods for converting between points,
* pixels and funits. (font design units)
*
* Each instance of an LEFontInstance represents a renerable instance of a font. (i.e. a
* single font at a particular point size, with a particular transform)
*
* @draft ICU 2.2
*/
class LEFontInstance /* not : public UObject because this is an interface/mixin class */ {
public:
/**
* This virtual destructor is here so that the subclass
* destructors can be invoked through the base class.
*
* @draft ICU 2.2
*/
virtual inline ~LEFontInstance() {};
//
// Font file access
//
/**
* This method reads a table from the font.
*
* @param tableTag - the four byte table tag
*
* @return the address of the table in memory
*
* @draft ICU 2.2
*/
virtual const void *getFontTable(LETag tableTag) const = 0;
/**
* This method is used to determine if the font can
* render the given character. This can usually be done
* by looking the character up in the font's character
* to glyph mapping.
*
* @param ch - the character to be tested
*
* @return true if the font can render ch.
*
* @draft ICU 2.2
*/
virtual le_bool canDisplay(LEUnicode32 ch) const = 0;
/**
* This method returns the number of design units in
* the font's EM square.
*
* @return the number of design units pre EM.
*
* @draft ICU 2.2
*/
virtual le_int32 getUnitsPerEM() const = 0;
/**
* This method maps an array of charcter codes to an array of glyph
* indices, using the font's character to glyph map.
*
* @param chars - the character array
* @param offset - the index of the first charcter
* @param count - the number of charcters
* @param reverse - if true, store the glyph indices in reverse order.
* @param mapper - the character mapper.
* @param glyphs - the output glyph array
*
* @see LECharMapper
*
* @draft ICU 2.2
*/
virtual void mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, const LECharMapper *mapper, LEGlyphID glyphs[]) const = 0;
/**
* This method maps a single character to a glyph index, using the
* font's charcter to glyph map.
*
* @param ch - the character
* @param mapper - the character mapper
*
* @return the glyph index
*
* @see LECharMapper
*
* @draft ICU 2.2
*/
virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch, const LECharMapper *mapper) const = 0;
/**
* This method gets a name from the font. (e.g. the family name) The encoding
* of the name is specified by the platform, the script, and the language.
*
* @param platformID - the platform id
* @param scriptID - the script id
* @param langaugeID - the language id
* @param name - the destination character array (can be null)
*
* @return the number of characters in the name
*
* @draft ICU 2.2
*/
virtual le_int32 getName(le_uint16 platformID, le_uint16 scriptID, le_uint16 languageID, le_uint16 nameID, LEUnicode *name) const = 0;
//
// Metrics
//
/**
* This method gets the X and Y advance of a particular glyph, in pixels.
*
* @param glyph - the glyph index
* @param advance - the X and Y pixel values will be stored here
*
* @draft ICU 2.2
*/
virtual void getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const = 0;
/**
* This method gets the hinted X and Y pixel coordinates of a particular
* point in the outline of the given glyph.
*
* @param glyph - the glyph index
* @param pointNumber - the number of the point
* @param point - the point's X and Y pixel values will be stored here
*
* @return true if the point coordinates could be stored.
*
* @draft ICU 2.2
*/
virtual le_bool getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const = 0;
/**
* This method returns the width of the font's EM square
* in pixels.
*
* @return the pixel width of the EM square
*
* @draft ICU 2.2
*/
virtual float getXPixelsPerEm() const = 0;
/**
* This method returns the height of the font's EM square
* in pixels.
*
* @return the pixel height of the EM square
*
* @draft ICU 2.2
*/
virtual float getYPixelsPerEm() const = 0;
/**
* This method converts font design units in the
* X direction to points.
*
* @param xUnits - design units in the X direction
*
* @return points in the X direction
*
* @draft ICU 2.2
*/
virtual float xUnitsToPoints(float xUnits) const = 0;
/**
* This method converts font design units in the
* Y direction to points.
*
* @param yUnits - design units in the Y direction
*
* @return points in the Y direction
*
* @draft ICU 2.2
*/
virtual float yUnitsToPoints(float yUunits) const = 0;
/**
* This method converts font design units to points.
*
* @param units - X and Y design units
* @param points - set to X and Y points
*
* @draft ICU 2.2
*/
virtual void unitsToPoints(LEPoint &units, LEPoint &points) const = 0;
/**
* This method converts pixels in the
* X direction to font design units.
*
* @param xPixels - pixels in the X direction
*
* @return font design units in the X direction
*
* @draft ICU 2.2
*/
virtual float xPixelsToUnits(float xPixels) const = 0;
/**
* This method converts pixels in the
* Y direction to font design units.
*
* @param yPixels - pixels in the Y direction
*
* @return font design units in the Y direction
*
* @draft ICU 2.2
*/
virtual float yPixelsToUnits(float yPixels) const = 0;
/**
* This method converts pixels to font design units.
*
* @param pixels - X and Y pixel
* @param units - set to X and Y font design units
*
* @draft ICU 2.2
*/
virtual void pixelsToUnits(LEPoint &pixels, LEPoint &units) const = 0;
/**
* This method transforms an X, Y point in font design units to a
* pixel coordinate, applying the font's transform.
*
* @param xFunits - the X coordinate in font design units
* @param yFunits - the Y coordinate in font design units
* @param pixels - the tranformed co-ordinate in pixels
*
* @draft ICU 2.2
*/
virtual void transformFunits(float xFunits, float yFunits, LEPoint &pixels) const = 0;
/**
* This is a convenience method used to convert
* values in a 16.16 fixed point format to floating point.
*
* @param fixed - the fixed point value
*
* @return the floating point value
*
* @draft ICU 2.2
*/
static float fixedToFloat(le_int32 fixed)
{
return (float) (fixed / 65536.0);
};
/**
* This is a convenience method used to convert
* floating point values to 16.16 fixed point format.
*
* @param theFloat - the floating point value
*
* @return the fixed point value
*/
static le_int32 floatToFixed(float theFloat)
{
return (le_int32) (theFloat * 65536.0);
};
};
U_NAMESPACE_END
#endif
