GRAPHICS(3)

NAME¶

graphics.h - compatibility header for SDL_bgi

SYNOPSIS¶

#include <graphics.h>

DESCRIPTION¶

This header file must be included by C or C++ programs that use the SDL_bgi library. graphics.h includes SDL_bgi.h, usually installed in /usr/include/SDL2, which contains all definitions and function prototypes.

SDL bgi is a graphics library (GRAPHICS.H) for C, C++, WebAssembly, and Python. It’s based on SDL2 and it’s portable on many platforms.

This library strictly emulates BGI functions, making it possible to compile SDL2 versions of programs written for Turbo C/Borland C++. ARGB colours, vector fonts, mouse support, and multiple windows are also implemented; further, native SDL2 functions may be used in SDL_bgi programs.

Python programs can use SDL_bgi by means of module sdl_bgi.py.

VARIABLES¶

extern SDL_Window   *bgi_window;
extern SDL_Renderer *bgi_renderer;
extern SDL_Texture  *bgi_texture;
extern Uint32        PALETTE_SIZE;

DEFINITIONS¶

Font definitions¶

enum {


  DEFAULT_FONT,      // 8x8 bitmap


  TRIPLEX_FONT,      // trip.h


  SMALL_FONT,        // litt.h


  SANS_SERIF_FONT,   // sans.h


  GOTHIC_FONT,       // goth.h


  SCRIPT_FONT,       // scri.h


  SIMPLEX_FONT,      // simp.h


  TRIPLEX_SCR_FONT,  // tscr.h


  COMPLEX_FONT,      // lcom.h


  EUROPEAN_FONT,     // euro.h


  BOLD_FONT,         // bold.h


  LAST_SPEC_FONT
};
enum { HORIZ_DIR, VERT_DIR };
#define USER_CHAR_SIZE 0
enum {


  LEFT_TEXT, CENTER_TEXT, RIGHT_TEXT,


  BOTTOM_TEXT = 0, TOP_TEXT = 2
};

Colour definitions¶

enum {


  BLACK        = 0,                         EGA_BLACK        = 0,


  BLUE         = 1,                         EGA_BLUE         = 1,


  GREEN        = 2,  CGA_GREEN        = 2,  EGA_GREEN        = 2,


  CYAN         = 3,  CGA_CYAN         = 3,  EGA_CYAN         = 3,


  RED          = 4,  CGA_RED          = 4,  EGA_RED          = 4,


  MAGENTA      = 5,  CGA_MAGENTA      = 5,  EGA_MAGENTA      = 5,


  BROWN        = 6,  CGA_BROWN        = 6,  EGA_BROWN        = 6,


  LIGHTGRAY    = 7,  CGA_LIGHTGRAY    = 7,  EGA_LIGHTGRAY    = 7,


  DARKGRAY     = 8,                         EGA_DARKGRAY     = 8,


  LIGHTBLUE    = 9,                         EGA_LIGHTBLUE    = 9,


  LIGHTGREEN   = 10, CGA_LIGHTGREEN   = 10, EGA_LIGHTGREEN   = 10,


  LIGHTCYAN    = 11, CGA_LIGHTCYAN    = 11, EGA_LIGHTCYAN    = 11,


  LIGHTRED     = 12, CGA_LIGHTRED     = 12, EGA_LIGHTRED     = 12,


  LIGHTMAGENTA = 13, CGA_LIGHTMAGENTA = 13, EGA_LIGHTMAGENTA = 13,


  YELLOW       = 14, CGA_YELLOW       = 14, EGA_YELLOW       = 14,


  WHITE        = 15, CGA_WHITE        = 15, EGA_WHITE        = 15,


  MAXCOLORS    = 15
};
enum {


  ARGB_FG_COL   = 16,


  ARGB_BG_COL   = 17,


  ARGB_FILL_COL = 18,


  ARGB_TMP_COL  = 19,


  TMP_COLORS    = 4
};

Drawing and filling styles¶

enum { NORM_WIDTH = 1, THICK_WIDTH = 3 };
enum { SOLID_LINE, DOTTED_LINE, CENTER_LINE, DASHED_LINE, USERBIT_LINE };
enum { COPY_PUT, XOR_PUT, OR_PUT, AND_PUT, NOT_PUT };
enum {


  EMPTY_FILL,       // fills area in background color


  SOLID_FILL,       // fills area in solid fill color


  LINE_FILL,        // --- fill


  LTSLASH_FILL,     // /// fill


  SLASH_FILL,       // /// fill with thick lines


  BKSLASH_FILL,     // \\\ fill with thick lines


  LTBKSLASH_FILL,   // \\\ fill


  HATCH_FILL,       // light hatch fill


  XHATCH_FILL,      // heavy cross hatch fill


  INTERLEAVE_FILL,  // interleaving line fill


  WIDE_DOT_FILL,    // Widely spaced dot fill


  CLOSE_DOT_FILL,   // Closely spaced dot fill


  USER_FILL         // user defined fill
};

Mouse buttons¶

#define WM_LBUTTONDOWN  SDL_BUTTON_LEFT
#define WM_MBUTTONDOWN  SDL_BUTTON_MIDDLE
#define WM_RBUTTONDOWN  SDL_BUTTON_RIGHT
#define WM_WHEEL        SDL_MOUSEWHEEL
#define WM_WHEELUP      SDL_USEREVENT
#define WM_WHEELDOWN    SDL_USEREVENT + 1
#define WM_MOUSEMOVE    SDL_MOUSEMOTION

Key codes¶

#define KEY_HOME        SDLK_HOME
#define KEY_LEFT        SDLK_LEFT
#define KEY_UP          SDLK_UP
#define KEY_RIGHT       SDLK_RIGHT
#define KEY_DOWN        SDLK_DOWN
#define KEY_PGUP        SDLK_PAGEUP
#define KEY_PGDN        SDLK_PAGEDOWN
#define KEY_END         SDLK_END
#define KEY_INSERT      SDLK_INSERT
#define KEY_DELETE      SDLK_DELETE
#define KEY_F1          SDLK_F1
#define KEY_F2          SDLK_F2
#define KEY_F3          SDLK_F3
#define KEY_F4          SDLK_F4
#define KEY_F5          SDLK_F5
#define KEY_F6          SDLK_F6
#define KEY_F7          SDLK_F7
#define KEY_F8          SDLK_F8
#define KEY_F9          SDLK_F9
#define KEY_F10         SDLK_F10
#define KEY_F11         SDLK_F11
#define KEY_F12         SDLK_F12
#define KEY_CAPSLOCK    SDLK_CAPSLOCK
#define KEY_LEFT_CTRL   SDLK_LCTRL
#define KEY_RIGHT_CTRL  SDLK_RCTRL
#define KEY_LEFT_SHIFT  SDLK_LSHIFT
#define KEY_RIGHT_SHIFT SDLK_RSHIFT
#define KEY_LEFT_ALT    SDLK_LALT
#define KEY_RIGHT_ALT   SDLK_RALT
#define KEY_ALT_GR      SDLK_MODE
#define KEY_LGUI        SDLK_LGUI
#define KEY_RGUI        SDLK_RGUI
#define KEY_MENU        SDLK_MENU
#define KEY_TAB         SDLK_TAB
#define KEY_BS          SDLK_BACKSPACE
#define KEY_RET         SDLK_RETURN
#define KEY_PAUSE       SDLK_PAUSE
#define KEY_SCR_LOCK    SDLK_SCROLLOCK
#define KEY_ESC         SDLK_ESCAPE
#define QUIT            SDL_QUIT

Graphics modes¶

enum {


  DETECT = -1,


  SDL = 0,


  // all modes @ 320x200


  SDL_320x200 = 1, SDL_CGALO = 1, CGA = 1, CGAC0 = 1, CGAC1 = 1,


  CGAC2 = 1, CGAC3 = 1, MCGAC0 = 1, MCGAC1 = 1, MCGAC2 = 1,


  MCGAC3 = 1, ATT400C0 = 1, ATT400C1 = 1, ATT400C2 = 1, ATT400C3 = 1,


  // all modes @ 640x200


  SDL_640x200 = 2, SDL_CGAHI = 2, CGAHI = 2, MCGAMED = 2,


  EGALO = 2, EGA64LO = 2,


  // all modes @ 640x350


  SDL_640x350 = 3, SDL_EGA = 3, EGA = 3, EGAHI = 3,


  EGA64HI = 3, EGAMONOHI = 3,


  // all modes @ 640x480


  SDL_640x480 = 4, SDL_VGA = 4, VGA = 4, MCGAHI = 4, VGAHI = 4,


  IBM8514LO = 4,


  // all modes @ 720x348


  SDL_720x348 = 5, SDL_HERC = 5,


  // all modes @ 720x350


  SDL_720x350 = 6, SDL_PC3270 = 6, HERCMONOHI = 6,


  // all modes @ 800x600


  SDL_800x600 = 7, SDL_SVGALO = 7, SVGA = 7,


  // all modes @ 1024x768


  SDL_1024x768 = 8, SDL_SVGAMED1 = 8,


  // all modes @ 1152x900


  SDL_1152x900 = 9, SDL_SVGAMED2 = 9,


  // all modes @ 1280x1024


  SDL_1280x1024 = 10, SDL_SVGAHI = 10,


  // all modes @ 1366x768


  SDL_1366x768 = 11, SDL_WXGA = 11,


  // other


  SDL_USER = 12, SDL_FULLSCREEN = 13
};

Error messages¶

enum graphics_errors {


  grOk               =   0,


  grNoInitGraph      =  -1,


  grNotDetected      =  -2,


  grFileNotFound     =  -3,


  grInvalidDriver    =  -4,


  grNoLoadMem        =  -5,


  grNoScanMem        =  -6,


  grNoFloodMem       =  -7,


  grFontNotFound     =  -8,


  grNoFontMem        =  -9,


  grInvalidMode      = -10,


  grError            = -11,


  grIOerror          = -12,


  grInvalidFont      = -13,


  grInvalidFontNum   = -14,


  grInvalidVersion   = -18
};

Struct definitions¶

struct arccoordstype {


  int x;


  int y;


  int xstart;


  int ystart;


  int xend;


  int yend;
};
struct date {


  int da_year;


  int da_day;


  int da_mon;
};
struct fillsettingstype {


  int pattern;


  int color;
};
struct linesettingstype {


  int linestyle;


  unsigned int upattern;


  int thickness;
};
struct palettetype {


  unsigned char size;


  signed char colors[MAXCOLORS + 1];
};
// SDL_bgi extension
struct rgbpalettetype {


  Uint32 size;


  Uint32 *colors;
};
struct textsettingstype {


  int font;


  int direction;


  int charsize;


  int horiz;


  int vert;
};
struct viewporttype {


  int left;


  int top;


  int right;


  int bottom;


  int clip;
};

FUNCTIONS¶

Standard BGI functions¶

void arc (int x, int y, int stangle, int endangle, int radius);: Draws a circular arc centered at (x, y), with a radius given by radius, traveling counterclockwise from stangle to endangle.
void bar (int left, int top, int right, int bottom);: Draws a filled-in rectangle (bar), using the current fill colour and fill pattern.
void bar3d (int left, int top, int right, int bottom, int depth, int topflag);: Draws a three-dimensional, filled-in rectangle (bar), using the current fill colour and fill pattern.
void circle (int x, int y, int radius);: Draws a circle of the given radius at (x, y).
void cleardevice (void);: Clears the graphics screen, filling it with the current background colour.
void clearviewport (void);: Clears the viewport, filling it with the current background colour.
void closegraph (void);: Closes the graphics system.
void delay (int millisec): Waits for millisec milliseconds.
void detectgraph (int *graphdriver, int *graphmode);: Detects the default graphics driver and graphics mode to use; SDL and SDL_FULLSCREEN, respectively.
void drawpoly (int numpoints, int *polypoints);: Draws a polygon of numpoints vertices.
void ellipse (int x, int y, int stangle, int endangle, int xradius, int yradius);: Draws an elliptical arc centered at (x, y), with axes given by xradius and yradius, traveling from stangle to endangle.
void fillellipse (int x, int y, int xradius, int yradius);: Draws an elliptical arc centered at (x, y), with axes given by xradius and yradius, and fills it using the current fill colour and fill pattern.
void fillpoly (int numpoints, int *polypoints);: Draws a polygon of numpoints vertices and fills it using the current fill colour.
void floodfill (int x, int y, int border);: Fills an enclosed area, starting from point (x, y) bounded by the border colour. The area is filled using the current fill colour.
int getactivepage (void);: Returns the active page number.
void getarccoords (struct arccoordstype *arccoords);: Gets the coordinates of the last call to arc(), filling the arccoords structure.
void getaspectratio (int *xasp, int *yasp);: Retrieves the current graphics mode’s aspect ratio. xasp and yasp are always 10000 (i.e. pixels are square).
int getbkcolor (void);: Returns the current background colour.
int getch (void);: Waits for a key and returns its ASCII or key code.
int getcolor (void);: Returns the current drawing (foreground) colour.
struct palettetype* getdefaultpalette (void);: Returns the default palette definition structure.
char* getdrivername (void);: Returns a pointer to a string containing the name of the current graphics driver.
void getfillpattern (char *pattern);: Copies the user-defined fill pattern, as set by setfillpattern(), into the 8-byte area pointed to by pattern.
void getfillsettings (struct fillsettingstype *fillinfo);: Fills the fillsettingstype structure pointed to by fillinfo with information about the current fill pattern and fill colour.
int getgraphmode (void);: Returns the current graphics mode.
void getimage (int left, int top, int right, int bottom, void *bitmap);: Copies a bit image of the specified region into the memory pointed to by bitmap.
void getlinesettings (struct linesettingstype *lineinfo);: Fills the linesettingstype structure pointed to by lineinfo with information about the current line style, pattern, and thickness.
int getmaxcolor (void);: Returns the maximum colour value available (MAXCOLORS). If ARGB colours are being used, it returns PALETTE_SIZE (default is 4096).
int getmaxmode (void);: Returns the maximum mode number for the current driver. In SDL_bgi, the default is SDL_FULLSCREEN.
int getmaxx (void);: Returns the maximum x screen coordinate.
int getmaxy (void);: Returns the maximum y screen coordinate.
char* getmodename (int mode_number);: Returns a pointer to a string containing the name of the specified graphics mode.
void getmoderange (int graphdriver, int *lomode, int *himode);: Returns the range of valid graphics modes. The graphdriver parameter is ignored.
void getpalette (struct palettetype *palette);: Fills the palettetype structure pointed to by palette with information about the current palette size and colours.
int getpalettesize (void);: Returns the size of the palette (MAXCOLORS + 1 or MAXRGBCOLORS + 1).
unsigned int getpixel (int x, int y);: Returns the colour of the pixel located at (x, y).
void gettextsettings (struct textsettingstype *texttypeinfo);: Fills the textsettingstype structure pointed to by texttypeinfo with information about the current text font, direction, size, and justification.
void getviewsettings (struct viewporttype *viewport);: Fills the viewporttype structure pointed to by viewport with information about the current viewport.
int getvisualpage (void);: Returns the visual page number.
int getx (void);: Returns the current CP x coordinate, relative to the viewport.
int gety (void);: Returns the current CP y coordinate, relative to the viewport.
void graphdefaults (void);: Resets all graphics settings to their default values.
char* grapherrormsg (int errorcode);: Returns a pointer to the error message string associated with errorcode, returned by graphresult().
int graphresult (void);: Returns the error code for the last unsuccessful graphics operation and resets the error level to grOk.
unsigned imagesize (int left, int top, int right, int bottom);: Returns the size in bytes of the memory area required to store a bit image.
void initgraph (int *graphdriver, int *graphmode, char *pathtodriver);: Initializes the graphics system. Use initgraph (NULL, NULL, ""); for default settings.
int installuserdriver (char *name, int huge (*detect)(void));: Unimplemented.
int installuserfont (char *name);: Loads and installs a CHR font from disk. The function returns an integer to be used as first argument in settextstyle().
int kbhit (void);: Returns 1 when a key is pressed, excluding special keys (Ctrl, Shift, etc.)
int lastkey (void);: Returns the last key that was detected by kbhit().
void line (int x1, int y1, int x2, int y2);: Draws a line between two specified points.
void linerel (int dx, int dy);: Draws a line from the CP to a point that is (dx, dy) pixels from the CP. The CP is then advanced by (dx, dy).
void lineto (int x, int y);: Draws a line from the CP to (x, y), then moves the CP to (dx, dy).
void moverel (int dx, int dy);: Moves the CP by (dx, dy) pixels.
void moveto (int x, int y);: Moves the CP to the position (x, y), relative to the viewport.
void outtext (char *textstring);: Outputs textstring at the CP.
void outtextxy (int x, int y, char *textstring);: Outputs textstring at (x, y).
void pieslice (int x, int y, int stangle, int endangle, int radius);: Draws and fills a pie slice centered at (x, y), with a radius given by radius, traveling from stangle to endangle.
void putimage (int left, int top, void *bitmap, int op);: Puts the bit image pointed to by bitmap onto the screen, with the upper left corner of the image placed at (left, top). op specifies the drawing mode (COPY_PUT, etc).
void putpixel (int x, int y, int color);: Plots a pixel at (x, y) using color.
int random (int range) (macro): Returns an integer random number between 0 and range - 1.
void rectangle (int left, int top, int right, int bottom);: Draws a rectangle delimited by (left, top) and (right, bottom).
int registerbgidriver (void (*driver)(void));: Unimplemented; not used by SDL_bgi.
int registerbgifont (void (*font)(void));: Unimplemented; not used by SDL_bgi.
void restorecrtmode (void);: Hides the graphics window.
void sector (int x, int y, int stangle, int endangle, int xradius, int yradius);: Draws and fills an elliptical pie slice centered at (x, y), horizontal and vertical radii given by xradius and yradius, traveling from stangle to endangle.
void setactivepage (int page);: Makes page the active page for all subsequent graphics output.
void setallpalette (struct palettetype *palette);: Sets the current palette to the values given in palette.
void setaspectratio (int xasp, int yasp);: Changes the default aspect ratio of the graphics.
void setbkcolor (int color);: Sets the current background colour.
void setcolor (int color);: Sets the current drawing colour.
void setfillpattern (char *upattern, int color);: Sets a user-defined fill pattern.
void setfillstyle (int pattern, int color);: Sets the fill pattern and fill colour.
unsigned setgraphbufsize (unsigned bufsize);: Unimplemented; not used by SDL_bgi.
void setgraphmode (int mode);: Shows the window that was hidden by restorecrtmode().
void setlinestyle (int linestyle, unsigned upattern, int thickness);: Sets the line width and style.
void setpalette (int colornum, int color);: Changes the standard palette colornum to color, which can also be specified using the COLOR() function.
void settextjustify (int horiz, int vert);: Sets text justification. Text output will be justified around the CP horizontally and vertically.
void settextstyle (int font, int direction, int charsize);: Sets the text style.
void setusercharsize (int multx, int divx, int multy, int divy);: Lets the user change the character width and height.
void setviewport (int left, int top, int right, int bottom, int clip);: Sets the current viewport for graphics output.
void setvisualpage (int page);: Sets the visual graphics page number to page.
void setwritemode (int mode);: Sets the writing mode for line drawing (COPY_PUT, etc.)
int textheight (char *textstring);: Returns the height in pixels textstring.
int textwidth (char *textstring);: Returns the width in pixels of textstring.

SDL_bgi extensions¶

int ALPHA_VALUE (int color);: Returns the alpha (transparency) component of color in the ARGB palette.
int BLUE_VALUE (int color);: Returns the blue component of color in the ARGB palette.
void closewindow (int id);: Closes the window identified by id.
int COLOR (int r, int g, int b);: Can be used as an argument for putpixel(), setalpha(), setcolor(), setbkcolor(), setfillpattern(), and setfillstyle() to set a colour specifying its ARGB components.
int COLOR32 (Uint32 color);: Can be used as an argument for putpixel(), setalpha(), setcolor(), setbkcolor(), setfillpattern(), and setfillstyle() to set a colour as ARGB integer.
char * colorname (int color);: Returns a string containing the colour name.
Uint32 colorRGB (int r, int g, int b) (macro): Can be used to compose a 32 bit colour with r g b components.
void copysurface (SDL_Surface *surface, int x1, int y1, int x2, int y2);: Copies surface to the rectangle defined by x1, y1, x2, y2.
int doubleclick (void);: Returns 1 if the last mouse click was a double click.
int edelay (int msec);: Waits for msec milliseconds. This function returns 1 if an event occurs during the delay, otherwise it returns 0.
int event (void);: Returns 1 if an event (mouse click, key press, or QUIT) has occurred.
int eventtype (void);: Returns the type of the last event: SDL_KEYDOWN, SDL_MOUSEMOTION, SDL_MOUSEBUTTONDOWN, SDL_MOUSEBUTTONUP, SDL_MOUSEWHEEL, SDL_QUIT
void fputpixel (int x, int y);: Plots a point at (x, y) using the current drawing colour.
void getbuffer (Uint32 *buffer);: Copies the contents of the active window to buffer.
int getclick (void);: Waits for a mouse button click and returns its code.
int getcurrentwindow (void);: Returns the id of the current window.
int getevent (void);: Waits for a keypress, mouse click, or SDL_QUIT event, and returns the code of the key, mouse button, or SDL_QUIT.
void getleftclick (void);: Waits for the left mouse button to be clicked and released.
void getlinebuffer (int y, Uint32 *linebuffer);: Copies the y-th screen line to linebuffer.
int getmaxheight (void);: Returns the maximum possible height for a new window (actual screen height in pixels).
int getmaxwidth (void);: Returns the maximum possible width for a new window (actual screen width in pixels).
void getmiddleclick (void);: Waits for the middle mouse button to be clicked and released.
void getmouseclick (int btn, int *x, int *y);: Sets the x, y coordinates of the last btn button click expected by ismouseclick().
void getrgbpalette (struct rgbpalettetype* palette, int size);: Fills the rgbpalettetype structure pointed to by palette with information about the current ARGB palette’s size and colours.
int getrgbpalettesize (void);: Returns the current size of the ARGB palette.
void getrightclick (void);: Waits for the right mouse button to be clicked and released.
void getscreensize (int *width, int *height);: Reports the screen width and height in width and height, regardless of current window dimensions.
void getwindowheight ();: Equivalent to getmaxy() (WinBGIm compatibility).
void getwindowwidth ();: Equivalent to getmaxx() (WinBGIm compatibility).
int GREEN_VALUE (int color);: Returns the green component of color in the ARGB palette.
void initpalette (void);: Initialises the BGI palette to the standard 16 colours.
int initwindow (int width, int height);: Initializes the graphics system, opening a width x height window. Set width or height equal to 0 for fullscreen.
int IS_BGI_COLOR (int color);: Returns 1 if the current drawing colour is a standard BGI colour (that is, not ARGB). The color argument is actually redundant.
int ismouseclick (int btn);: Returns 1 if the btn mouse button was clicked.
int IS_RGB_COLOR (int color);: Returns 1 if the current drawing colour is ARGB. The color argument is actually redundant.
int kdelay (int msec);: Waits for msec milliseconds. This function returns 1 if a key is pressed during the delay, otherwise it returns 0.
int mouseclick (void);: Returns the code of the mouse button that is being clicked, or SDL_MOUSEMOTION, or 0.
int mousex (void);: Returns the X coordinate of the last mouse click.
int mousey (void);: Returns the Y coordinate of the last mouse click.
void putbuffer (Uint32 *buffer);: Copies buffer to the current window.
void putlinebuffer (int y, Uint32 *linebuffer);: Copies linebuffer to the y coordinate in the current window.
void _putpixel* (int x, int y);: Same as fputpixel().
void readimagefile (char *filename, int x1, int y1, int x2, int y2);: Reads a .bmp file and displays it immediately at (x1, y1).
int RED_VALUE (int color);: Returns the red component of color in the ARGB palette.
void refresh (void);: Updates the screen contents, i.e. displays all graphics.
void resetwinoptions (int id, char *title, int x, int y);: Resets title and position of window id to title, (x, y).
int resizepalette (Uint32 newsize);: Resizes the ARGB palette to newsize; returns 0 if successful, 1 otherwise.
int RGBPALETTE (int color);: Can be used as an argument for putpixel(), setalpha(), setcolor(), setbkcolor(), setfillpattern(), and setfillstyle() to set a colour from the ARGB palette color entry.
void sdlbgiauto (void);: Triggers auto mode, i.e. refresh() is performed automatically.
void sdlbgifast (void);: Triggers fast mode, i.e. refresh() is needed to display graphics.
void sdlbgislow (void);: Triggers slow mode i.e. refresh() is not needed to display graphics.
void setallrgbpalette (struct rgbpalettetype *palette);: Sets the current ARGB palette to the values given in palette.
void setalpha (int col, Uint8 alpha);: Sets alpha transparency for colour col to alpha (0-255); 0 means full transparecy, 255 full opacity.
void setbkrgbcolor (int color);: Sets the current background colour to the color entry in the ARGB palette.
void setblendmode (int blendmode);: Sets the blend mode to be used with screen refresh; either SDL_BLENDMODE_NONE or SDL_BLENDMODE_BLEND.
void setcurrentwindow (int id);: Sets the current active window to id.
void setrgbcolor (int color);: Sets the current drawing colour to the color entry in the ARGB palette.
void setrgbpalette (int colornum, int red, int green, int blue);: Sets the colornum entry in the ARGB palette specifying the r, g, and b components.
void setwinoptions (char *title, int x, int y, Uint32 flags);: Sets the window title title, the initial position to (x, y), and SDL2 flags OR’ed together.
void setwintitle (int id, char *title);: Sets the title of the window identified by id.
void showerrorbox (const char *message);: Opens an error message box with the specified message.
void showinfobox (const char *message);: Opens an information message box with the specified message.
void swapbuffers (void);: Swaps the current active and the current visual graphics pages.
void writeimagefile (char *filename, int left, int top, int right, int bottom);: Writes a .bmp file from the screen rectangle defined by left, top, right, bottom.
int xkbhit (void);: Returns 1 when any key is pressed, including special keys (Ctrl, Shift, etc.)

ENVIRONMENT¶

Native code and Python:

SDL_BGI_RES: when set to VGA, default resolution will be 640 x 480 instead of default 800 x 600.

SDL_BGI_RATE: when set to auto, automatic screen refresh will be performed.

SDL_BGI_PALETTE: when set to BGI, the first 16 colours will use the same RGB values as Turbo C 2.01.

Compiling programs with emscripten, variables SDL_BGI_RES and SDL_BGI_PALETTE can be replaced by files by the same name, possibly containing the strings VGA and BGI.

When run in a browser, the user can provide “environment files” in the assets directory. These text files have the same name as the corresponding environment variable, and contain the desired value (e.g. VGA for assets/SDL_BGI_RES).

KNOWN BUGS¶

•: Visualisation problems on NVIDIA GK208BM (GeForce 920M) with nvidia-driver-* on GNU/Linux. As far as I can say, this is an NVIDIA driver problem.
•: On Raspios 10 ARM, the letter `p' is drawn incorrectly in SCRIPT_FONT. This bug does not affect Raspios 10 i386.

Please report bugs if you find any.

EXAMPLE¶

#include <graphics.h>
int main (int argc, char *argv[])
{


  int i, gd = DETECT, gm;


  initgraph (&gd, &gm, "");


  setbkcolor (BLACK);


  cleardevice ();


  outtextxy (0, 0, "Drawing 1000 lines...");


  for (i = 0; i < 1000; i++) {


    setcolor (1 + random (15));


    line (random(getmaxx()), random(getmaxy()),


    random (getmaxx()), random(getmaxy()) );


  }


  getch ();


  closegraph ();


  return 0;
}

To compile this program on GNU/Linux, macOS, or Raspios:

$ gcc -o program program.c -lSDL_bgi -lSDL2

To compile this program on MSYS2 + mingw-w64:

$ gcc -o program.exe program.c -lmingw32 -L/mingw64/bin \


  -lSDL_bgi -lSDL2main -lSDL2 # -mwindows

To compile this program to WebAssembly using emcc:

$ emcc --emrun -o program.html program.c -lSDL_bgi \


    -std=gnu99 -O2 -Wall -lm \


    -s USE_SDL=2 -s ALLOW_MEMORY_GROWTH=1 -s ASYNCIFY -s SINGLE_FILE

To initialise the graphics, you may try one of the following methods:

// open a 400x300 window
initwindow (400, 300);
// open a 400x300 window, setting position, title, and flags
setwinoptions ("SDL_bgi window", 100, 100, SDL_WINDOW_BORDERLESS);
initwindow (400, 300);
// go fullscreen
initwindow (0, 0);
// go fullscreen or VGA if SDL_BGI_RES is set
gd = DETECT;
gm = getmaxmode ();
initgraph(&gd, &gm, "");
// go fullscreen with non native resolution
setwinoptions ("", -1, -1, SDL_WINDOW_FULLSCREEN);
initwindow (800, 600);

AUTHORS¶

Main library: Guido Gonzato, PhD guido dot gonzato at gmail dot com

Automatic refresh patch, CHR font support: Marco Diego Aurélio Mesquita, marcodiegomesquita at gmail dot com

LICENSE¶

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.

AUTHORS¶

November 2022

SDL_bgi 3.0.0

Source file:	graphics.3.en.gz (from libSDL_bgi-devel 3.0.0-2.2)
Source last updated:	2024-02-28T20:16:32Z
Converted to HTML:	2024-04-27T02:04:31Z