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freetype2/demos/graph/graph.h

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/***************************************************************************
*
* graph.h
*
* Graphics Subsystem interface
*
* Copyright 1999 - The FreeType Development Team - www.freetype.org
*
*
*
*
***************************************************************************/
#ifndef GRAPH_H
#define GRAPH_H
#include "grevents.h"
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******** ********/
/******** GENERAL DEFINITIONS AND BLITTING ROUTINES ********/
/******** ********/
/******** ********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* define the global error variable */
extern int grError;
/* initialisation */
extern int grInit( void );
/* finalisation */
extern void grDone( void );
/* pixel mode constants */
typedef enum grPixelMode
{
gr_pixel_mode_none = 0,
gr_pixel_mode_mono, /* monochrome bitmaps */
gr_pixel_mode_pal4, /* 4-bit paletted - 16 colors */
gr_pixel_mode_pal8, /* 8-bit paletted - 256 colors */
gr_pixel_mode_gray, /* 8-bit gray levels */
gr_pixel_mode_rgb555, /* 15-bits mode - 32768 colors */
gr_pixel_mode_rgb565, /* 16-bits mode - 65536 colors */
gr_pixel_mode_rgb24, /* 24-bits mode - 16 million colors */
gr_pixel_mode_rgb32, /* 32-bits mode - 16 million colors */
gr_pixel_mode_max /* don't remove */
} grPixelMode;
/* forward declaration of the surface class */
typedef struct grSurface_ grSurface;
/*********************************************************************
*
* <Struct>
* grBitmap
*
* <Description>
* a simple bitmap descriptor
*
* <Fields>
* rows :: height in pixels
* width :: width in pixels
* pitch :: + or - the number of bytes per row
* mode :: pixel mode of bitmap buffer
* grays :: number of grays in palette for PAL8 mode. 0 otherwise
* buffer :: pointer to pixel buffer
*
* <Note>
* the 'pitch' is positive for downward flows, and negative otherwise
* Its absolute value is always the number of bytes taken by each
* bitmap row.
*
* All drawing operations will be performed within the first
* "width" pixels of each row (clipping is always performed).
*
********************************************************************/
typedef struct grBitmap_
{
int rows;
int width;
int pitch;
grPixelMode mode;
int grays;
char* buffer;
} grBitmap;
typedef long grPos;
typedef char grBool;
typedef struct grVector_
{
grPos x;
grPos y;
} grVector;
typedef union grColor_
{
long value;
unsigned char chroma[4];
} grColor;
/**********************************************************************
*
* <Function>
* grNewBitmap
*
* <Description>
* creates a new bitmap
*
* <Input>
* pixel_mode :: the target surface's pixel_mode
* num_grays :: number of grays levels for PAL8 pixel mode
* width :: width in pixels
* height :: height in pixels
*
* <Output>
* bit :: descriptor of the new bitmap
*
* <Return>
* Error code. 0 means success.
*
* <Note>
* This function really allocates a pixel buffer, zero it, then
* returns a descriptor for it.
*
* Call grDoneBitmap when you're done with it..
*
**********************************************************************/
extern int grNewBitmap( grPixelMode pixel_mode,
int num_grays,
int width,
int height,
grBitmap *bit );
/**********************************************************************
*
* <Function>
* grBlitGlyphToBitmap
*
* <Description>
* writes a given glyph bitmap to a target surface.
*
* <Input>
* target :: handle to target bitmap
* glyph :: handle to source glyph bitmap
* x :: position of left-most pixel of glyph image in target surface
* y :: position of top-most pixel of glyph image in target surface
* color :: color to be used to draw a monochrome glyph
*
* <Return>
* Error code. 0 means success
*
* <Note>
* There are only two supported source pixel modes : monochrome
* and gray. The 8-bit images can have any number of grays between
* 2 and 128, and conversions to the target surface is handled
* _automatically_.
*
* Note however that you should avoid blitting a gray glyph to a gray
* bitmap with fewer levels of grays, as this would much probably
* give unpleasant results..
*
* This function performs clipping
*
**********************************************************************/
extern int grBlitGlyphToBitmap( grBitmap* target,
grBitmap* glyph,
grPos x,
grPos y,
grColor color );
/**********************************************************************
*
* <Function>
* grFillRectangle
*
* <Description>
* this function is used to fill a given rectangle on a surface
*
* <Input>
* surface :: handle to target surface
* x :: x coordinate of the top-left corner of the rectangle
* y :: y coordinate of the top-left corner of the rectangle
* width :: rectangle width in pixels
* height :: rectangle height in pixels
* color :: fill color
*
**********************************************************************/
extern void grFillRectangle( grBitmap* surface,
grPos x,
grPos y,
grPos width,
grPos height,
grColor color );
/**********************************************************************
*
* <Function>
* grWriteCellChar
*
* <Description>
* The graphics sub-system contains an internal Latin1 8x8 font
* which can be used to display simple strings of text without
* using FreeType.
*
* This function writes a single 8x8 character on the target bitmap.
*
* <Input>
* target :: handle to target surface
* x :: x pixel position of character cell's top left corner
* y :: y pixel position of character cell's top left corner
* charcode :: Latin-1 character code
* color :: color to be used to draw the character
*
**********************************************************************/
extern
void grWriteCellChar( grBitmap* target,
int x,
int y,
int charcode,
grColor color );
/**********************************************************************
*
* <Function>
* grWriteCellString
*
* <Description>
* The graphics sub-system contains an internal Latin1 8x8 font
* which can be used to display simple strings of text without
* using FreeType.
*
* This function writes a string with the internal font
*
* <Input>
* target :: handle to target bitmap
* x :: x pixel position of string's top left corner
* y :: y pixel position of string's top left corner
* string :: Latin-1 text string
* color :: color to be used to draw the character
*
**********************************************************************/
extern
void grWriteCellString( grBitmap* target,
int x,
int y,
const char* string,
grColor color );
/**********************************************************************
*
* <Function>
* grDoneBitmap
*
* <Description>
* destroys a bitmap
*
* <Input>
* bitmap :: handle to bitmap descriptor
*
* <Note>
* This function does NOT release the bitmap descriptor, only
* the pixel buffer.
*
**********************************************************************/
extern void grDoneBitmap( grBitmap* bit );
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******** ********/
/******** DEVICE-SPECIFIC DEFINITIONS AND ROUTINES ********/
/******** ********/
/******** ********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* forward declaration - the definition of grDevice is not visible */
/* to clients.. */
typedef struct grDevice_ grDevice;
/**********************************************************************
*
* <Struct>
* grDeviceChain
*
* <Description>
* a simple structure used to implement a linked list of
* graphics device descriptors. The list is called a
* "device chain"
*
* <Fields>
* name :: ASCII name of the device, e.g. "x11", "os2pm", etc..
* device :: handle to the device descriptor.
* next :: next element in chain
*
* <Note>
* the 'device' field is a blind pointer; it is thus unusable by
* client applications..
*
**********************************************************************/
typedef struct grDeviceChain_ grDeviceChain;
struct grDeviceChain_
{
const char* name;
grDevice* device;
grDeviceChain* next;
};
/**********************************************************************
*
* <Function>
* grInitDevices
*
* <Description>
* This function is in charge of initialising all system-specific
* devices. A device is responsible for creating and managing one
* or more "surfaces". A surface is either a window or a screen,
* depending on the system.
*
* <Return>
* a pointer to the first element of a device chain. The chain can
* be parsed to find the available devices on the current system
*
* <Note>
* If a device cannot be initialised correctly, it is not part of
* the device chain returned by this function. For example, if an
* X11 device was compiled in the library, it will be part of
* the returned device chain only if a connection to the display
* could be establisged
*
* If no driver could be initialised, this function returns NULL.
*
**********************************************************************/
extern
grDeviceChain* grInitDevices( void );
/**********************************************************************
*
* <Function>
* grGetDeviceModes
*
* <Description>
* queries the available pixel modes for a device.
*
* <Input>
* device_name :: name of device to be used. 0 for the default
* device. For a list of available devices, see
* grInitDevices.
*
* <Output>
* num_modes :: number of available modes. 0 in case of error,
* which really is an invalid device name.
*
* pixel_modes :: array of available pixel modes for this device
* this table is internal to the device and should
* not be freed by client applications.
*
* <Return>
* error code. 0 means success. invalid device name otherwise
*
* <Note>
* All drivers are _required_ to support at least the following
* pixel formats :
*
* - gr_pixel_mode_mono : i.e. monochrome bitmaps
* - gr_pixel_mode_gray : with any number of gray levels between
* 2 and 256.
*
* the pixel modes do not provide the number of grays in the case
* of "gray" devices. You should try to create a surface with the
* maximal number (256, that is) and see the value returned in
* the bitmap descriptor.
*
**********************************************************************/
extern void grGetDeviceModes( const char* device_name,
int *num_modes,
grPixelMode* *pixel_modes );
/**********************************************************************
*
* <Function>
* grNewSurface
*
* <Description>
* creates a new device-specific surface. A surface is either
* a window or a screen, depending on the device.
*
* <Input>
* device :: name of the device to use. A value of NULL means
* the default device (which depends on the system).
* for a list of available devices, see grInitDevices.
*
* <InOut>
* bitmap :: handle to a bitmap descriptor containing the
* requested pixel mode, number of grays and dimensions
* for the surface. the bitmap's 'pitch' and 'buffer'
* fields are ignored on input.
*
* On output, the bitmap describes the surface's image
* completely. It is possible to write directly in it
* with grBlitGlyphToBitmap, even though the use of
* grBlitGlyphToSurface is recommended.
*
* <Return>
* handle to the corresponding surface object. 0 in case of error
*
* <Note>
* All drivers are _required_ to support at least the following
* pixel formats :
*
* - gr_pixel_mode_mono : i.e. monochrome bitmaps
* - gr_pixel_mode_gray : with any number of gray levels between
* 2 and 256.
*
* This function might change the bitmap descriptor's fields. For
* example, when displaying a full-screen surface, the bitmap's
* dimensions will be set to those of the screen (e.g. 640x480
* or 800x600); also, the bitmap's 'buffer' field might point to
* the Video Ram depending on the mode requested..
*
* The surface contains a copy of the returned bitmap descriptor,
* you can thus discard the 'bitmap' parameter after the call.
*
**********************************************************************/
extern grSurface* grNewSurface( const char* device,
grBitmap* bitmap );
/**********************************************************************
*
* <Function>
* grRefreshRectangle
*
* <Description>
* this function is used to indicate that a given surface rectangle
* was modified and thus needs re-painting. It really is useful for
* windowed or gray surfaces.
*
* <Input>
* surface :: handle to target surface
* x :: x coordinate of the top-left corner of the rectangle
* y :: y coordinate of the top-left corner of the rectangle
* width :: rectangle width in pixels
* height :: rectangle height in pixels
*
**********************************************************************/
extern void grRefreshRectangle( grSurface* surface,
grPos x,
grPos y,
grPos width,
grPos height );
/**********************************************************************
*
* <Function>
* grRefreshSurface
*
* <Description>
* a variation of grRefreshRectangle which repaints the whole surface
* to the screen.
*
* <Input>
* surface :: handle to target surface
*
**********************************************************************/
extern void grRefreshSurface( grSurface* surface );
/**********************************************************************
*
* <Function>
* grWriteSurfaceChar
*
* <Description>
* This function is equivalent to calling grWriteCellChar on the
* surface's bitmap, then invoking grRefreshRectangle.
*
* The graphics sub-system contains an internal Latin1 8x8 font
* which can be used to display simple strings of text without
* using FreeType.
*
* This function writes a single 8x8 character on the target bitmap.
*
* <Input>
* target :: handle to target surface
* x :: x pixel position of character cell's top left corner
* y :: y pixel position of character cell's top left corner
* charcode :: Latin-1 character code
* color :: color to be used to draw the character
*
**********************************************************************/
extern
void grWriteSurfaceChar( grSurface* target,
int x,
int y,
int charcode,
grColor color );
/**********************************************************************
*
* <Function>
* grWriteSurfaceString
*
* <Description>
* This function is equivalent to calling grWriteCellString on the
* surface's bitmap, then invoking grRefreshRectangle.
*
* The graphics sub-system contains an internal Latin1 8x8 font
* which can be used to display simple strings of text without
* using FreeType.
*
* This function writes a string with the internal font
*
* <Input>
* target :: handle to target bitmap
* x :: x pixel position of string's top left corner
* y :: y pixel position of string's top left corner
* string :: Latin-1 text string
* color :: color to be used to draw the character
*
**********************************************************************/
extern
void grWriteSurfaceString( grSurface* target,
int x,
int y,
const char* string,
grColor color );
/**********************************************************************
*
* <Function>
* grSetTitle
*
* <Description>
* set the window title of a given windowed surface.
*
* <Input>
* surface :: handle to target surface
* title_string :: the new title
*
**********************************************************************/
extern void grSetTitle( grSurface* surface,
const char* title_string );
/**********************************************************************
*
* <Function>
* grListenSurface
*
* <Description>
* listen the events for a given surface
*
* <Input>
* surface :: handle to target surface
* event_mask :: the event mask (mode)
*
* <Output>
* event :: the returned event
*
* <Note>
* XXX : For now, only keypresses are supported.
*
**********************************************************************/
extern
int grListenSurface( grSurface* surface,
int event_mask,
grEvent *event );
#endif /* GRAPH_H */
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