Graph unit

TP compatible unit to handle screen graphics.

This document describes the GRAPH unit for Free Pascal, for all platforms. The unit was first written for dos by Florian Klaempfl, but was later completely rewritten by Carl-Eric Codere to be completely portable. The unit is provided for compatibility only: It is recommended to use more modern graphical systems. The graph unit will allow to recompile old programs. They will work to some extent, but if the application has heavy graphical needs, it's recommended to use another set of graphical routines, suited to the platform the program should work on.

Classes and records

`ArcCoordsType`	record	Describe the last arc which was drawn on screen.
`FillSettingsType`	record	Record describing fill mode.
`LineSettingsType`	record	Record describing current line drawing mode.
`PaletteType`	record	Record describing palette.
`PointType`	record	Record describing a point in a 2 dimensional plane.
`RGBRec`	record	Record describing palette RGB color.
`TextSettingsType`	record	Record describing how texts are drawn.
`TModeInfo`	record	Record describing a graphical mode.
`TResolutionRec`	record	Record describing resolution.
`ViewPortType`	record	Record describing a viewport.

Procedures and functions

`Arc`	procedure	Draw part of a circle.
`Bar`	procedure	Draw filled rectangle.
`Bar3D`	procedure	Draw filled 3-dimensional rectangle.
`ClearDevice`	procedure	Clear the complete screen.
`Closegraph`	procedure	Close graphical system.
`DetectGraph`	procedure	Detect correct graphical driver to use.
`DrawPoly`	procedure	Draw a polygon.
`Ellipse`	procedure	Draw an ellipse.
`FillEllipse`	procedure	Draw and fill an ellipse.
`FillPoly`	procedure	Draw, close and fill a polygon.
`FloodFill`	procedure	Fill an area with a given color.
`GetArcCoords`	procedure	Return coordinates of last drawn arc or ellipse.
`GetAspectRatio`	procedure	Return screen resolution.
`GetColor`	function	Return current drawing color.
`GetDefaultPalette`	procedure	Return default palette.
`GetDirectVideo`	function	Determine whether direct video mode is active.
`GetDriverName`	function	Return current driver name.
`GetFillPattern`	procedure	Return current fill pattern.
`GetFillSettings`	procedure	Return current fill settings.
`GetGraphMode`	function	Get current graphical modus.
`GetLineSettings`	procedure	Get current line drawing settings.
`GetMaxColor`	function	return maximum number of colors.
`GetMaxMode`	function	Return biggest mode for the current driver.
`GetMaxX`	function	Return maximal X coordinate.
`GetMaxY`	function	Return maximal Y coordinate.
`GetModeName`	function	Return description a modus.
`GetModeRange`	procedure	Return lowest and highest modus of current driver.
`GetPalette`	procedure	Return current palette.
`GetPaletteSize`	function	Return maximal number of entries in current palette.
`GetTextSettings`	procedure	Return current text style.
`GetViewSettings`	procedure	Return current viewport.
`GetX`	function	Return current cursor X position.
`GetY`	function	Return current cursor Y position.
`GraphDefaults`	procedure	Reset graphical mode to defaults.
`GraphErrorMsg`	function	Return a description of an error.
`GraphResult`	function	Result of last graphical operation.
`InitGraph`	procedure	Initialize graphical system.
`InstallUserDriver`	function	Install a user driver.
`InstallUserFont`	function	Install a user-defined font.
`LineRel`	procedure	Draw a line starting from current position in given direction.
`LineTo`	procedure	Draw a line starting from current position to a given point.
`MoveRel`	procedure	Move cursor relative to current position.
`MoveTo`	procedure	Move cursor to absolute position.
`OutText`	procedure	Write text on the screen at the current location.
`PieSlice`	procedure	Draw a pie-slice.
`queryadapterinfo`	function	Function called to retrieve the current video adapter settings.
`Rectangle`	procedure	Draw a rectangle on the screen.
`RegisterBGIDriver`	function	Register a new BGI driver.
`RegisterBGIfont`	function	Register a new BGI font.
`RestoreCrtMode`	procedure	Restore text screen.
`Sector`	procedure	Draw and fill a sector of an ellipse.
`SetAspectRatio`	procedure	Set aspect ration of the screen.
`SetColor`	procedure	Set foreground drawing color.
`SetDirectVideo`	procedure	Attempt to enter direct video mode.
`SetFillPattern`	procedure	Set drawing fill pattern.
`SetFillStyle`	procedure	Set drawing fill style.
`SetGraphMode`	procedure	Set graphical mode.
`SetLineStyle`	procedure	Set line drawing style.
`SetPalette`	procedure	Set palette entry using color constant.
`SetTextJustify`	procedure	Set text placement style.
`SetTextStyle`	procedure	Set text style.
`SetUserCharSize`	procedure	Set user character size for vector font.
`SetViewPort`	procedure	Set the graphical drawing window.
`SetWriteMode`	procedure	Specify binary operation to perform when drawing on screen.
`SetWriteModeEx`	procedure	Set write mode (extended version).
`TextHeight`	function	Return height (in pixels) of the given string.
`TextWidth`	function	Return width (in pixels) of the given string.

Types

`CircleProc`	procedure type	Standard circle drawing routine prototype.
`clrviewproc`	procedure type	Standard clearviewport routine prototype.
`ColorType`	type	Color type alias.
`defpixelproc`	procedure type	Standard pixel drawing routine prototype.
`ellipseproc`	procedure type	Standard ellipse drawing routine prototype.
`FillPatternType`	type	Bit pattern used when drawing lines. Set bits are drawn.
`GetBkColorProc`	procedure type	GetBKColor callback prototype.
`getimageproc`	procedure type	Standard procedure prototype.
`getpixelproc`	procedure type	Standard pixel fetching routine prototype.
`getrgbpaletteproc`	procedure type	This routine prototype is a hook for .
`getscanlineproc`	procedure type	Standard getscanline routine prototype.
`graph_float`	type	The platform's preferred floating point size for fast graph operations.
`graphfreememprc`	procedure type	Procedure prototype, used when heap memory is freed by the graph routines.
`graphgetmemprc`	procedure type	Procedure prototype, used when heap memory is needed by the graph routines.
`hlineproc`	procedure type	Standard procedure prototype to draw a single horizontal line.
`imagesizeproc`	procedure type	Standard calculation procedure prototype.
`initmodeproc`	procedure type	Standard routine prototype to initialize a mode.
`lineproc`	procedure type	Standard line drawing routine prototype.
`OutTextXYProc`	procedure type	This routine prototype is a hook for .
`patternlineproc`	procedure type	Standard procedure prototype to draw a patterned line.
`PCharsetTransTable`	type	Pointer to array.
`PModeInfo`	type	Pointer to record.
`putimageproc`	procedure type	Standard procedure prototype.
`putpixelproc`	procedure type	Standard pixel drawing routine prototype.
`restorestateproc`	procedure type	Standard routine prototype to restore the graphical state at a closegraph call.
`savestateproc`	procedure type	Standard routine prototype to save the graphical state before a mode is set.
`setactivepageproc`	procedure type	Standard procedure prototype.
`SetAllPaletteProc`	procedure type	This routine prototype is a hook for .
`SetBkColorProc`	procedure type	SetBKColor callback prototype.
`setrgbpaletteproc`	procedure type	This routine prototype is a hook for .
`setvisualpageproc`	procedure type	Standard procedure prototype.
`TCharsetTransTable`	type	Character transliteration table, with entries for 256 characters.
`vlineproc`	procedure type	Standard procedure prototype to draw a single vertical line.

Constants

`AndPut`	constant	Draw operation: use AND.
`AnsiToASCIITransTable`	constant	Default ansi transliteration table.
`BkSlashFill`	constant	Fill style: Diagonal (backslash) lines.
`black`	constant	Color code: black.
`blue`	constant	Color code: blue.
`BoldFont`	constant	Font number: Bold font.
`BottomText`	constant	Vertical text alignment: Align text to bottom.
`brown`	constant	Color code: brown.
`CenterLn`	constant	Line style: centered line.
`CenterText`	constant	Horizontal text alignment: Center text.
`CGA`	constant	Graphic driver for CGA cards.
`CGAC0`	constant	CGA Graphic driver mode C0.
`CGAC1`	constant	CGA Graphic driver mode C1.
`CGAC2`	constant	CGA Graphic driver mode C2.
`CGAC3`	constant	CGA Graphic driver mode C3.
`CGAHi`	constant	CGA Graphic driver Hi-res mode.
`ClipOff`	constant	Viewport clipping off.
`ClipOn`	constant	Viewport clipping on.
`CloseDotFill`	constant	Fill style: Closely spaced dotted lines.
`CopyPut`	constant	Draw operation: use Copy.
`CurrentDriver`	constant	Currently used driver.
`cyan`	constant	Color code: Cyan.
`D12bit`	constant	Mode: Depth 12 bit.
`D15bit`	constant	Mode: Depth 15 bit.
`D16bit`	constant	Mode: Depth 16 bit.
`D1bit`	constant	Mode: Depth 1 bit.
`D24bit`	constant	Mode: Depth 24 bit.
`D2bit`	constant	Mode: Depth 2 bit.
`D32bit`	constant	Mode: Depth 32 bit.
`D4bit`	constant	Mode: Depth 4 bit.
`D64bit`	constant	Mode: Depth 64 bit.
`D6bit`	constant	Mode: Depth 6 bit.
`D8bit`	constant	Mode: Depth 8 bit.
`darkgray`	constant	Color code: Dark gray.
`DashedLn`	constant	Line style: dashed line.
`Default`	constant	Default mode.
`DefaultFont`	constant	Font number: Normal font.
`Detect`	constant	Mode: Detect mode.
`detectMode`	constant	Mode: Autodetect optimal mode.
`DottedLn`	constant	Line style: Dotted line.
`DrawTextBackground`	constant	Should the background of texts be drawn or should it be left untouched ?
`EGA`	constant	Graphic driver for EGA cards.
`EGA64`	constant	Graphic driver for EGA 64 cards.
`EGA64Hi`	constant	EGA64 graphic driver high resolution mode.
`EGA64Lo`	constant	EGA64 graphic driver low resolution mode.
`EGABlack`	constant	Color code: EGA Black.
`EGABlue`	constant	Color code: EGA blue.
`EGABrown`	constant	Color code: EGA brown.
`EGACyan`	constant	Color code: EGA cyan.
`EGADarkgray`	constant	Color code: EGA dark gray.
`EGAGreen`	constant	Color code: EGA green.
`EGAHi`	constant	EGA graphic driver high resolution mode.
`EGALightblue`	constant	Color code: EGA Light blue.
`EGALightcyan`	constant	Color code: EGA Light cyan.
`EGALightgray`	constant	Color code: EGA Light gray.
`EGALightgreen`	constant	Color code: EGA Light green.
`EGALightmagenta`	constant	Color code: EGA light magenta.
`EGALightred`	constant	Color code: EGA light red.
`EGALo`	constant	EGA graphic driver low resolution mode.
`EGAMagenta`	constant	Color code: EGA magenta.
`EGAMono`	constant	Graphic driver for EGA monochrome cards.
`EGAMonoHi`	constant	EGAMono graphic driver high resolution mode.
`EGARed`	constant	Color code: EGA red.
`EGAWhite`	constant	Color code: EGA white.
`EGAYellow`	constant	Color code: EGA yellow.
`EmptyFill`	constant	Fill style: Do not fill.
`EuroFont`	constant	Font number: ?
`fillpatternTable`	constant	Table with standard fill patterns.
`G1024x768x16`	constant	Mode: Resolution 1024x768, 16 colors.
`G1024x768x16M`	constant	Mode: Resolution 1024x768, 16M colors.
`G1024x768x16M32`	constant	Mode: Resolution 1024x758, 16M 32-bit colors.
`G1024x768x256`	constant	Mode: Resolution 1024x768, 256 colors.
`G1024x768x32K`	constant	Mode: Resolution 1024x768, 32K colors.
`G1024x768x64K`	constant	Mode: Resolution 1024x768, 64K colors.
`G1152x864x16`	constant	Mode: Resolution 1152x864, 16 colors.
`G1152x864x16M`	constant	Mode: Resolution 1152x864, 16M colors.
`G1152x864x16M32`	constant	Mode: Resolution 1152x864, 16M 32-bitcolors.
`G1152x864x256`	constant	Mode: Resolution 1152x864, 256 colors.
`G1152x864x32K`	constant	Mode: Resolution 1152x864, 32K colors.
`G1152x864x64K`	constant	Mode: Resolution 1152x864, 64K colors.
`G1280x1024x16`	constant	Mode: Resolution 1280x1024, 16 colors.
`G1280x1024x16M`	constant	Mode: Resolution 1280x1024, 16M colors.
`G1280x1024x16M32`	constant	Mode: Resolution 1280x1024, 16M 32-bit colors.
`G1280x1024x256`	constant	Mode: Resolution 1280x1024, 256 colors.
`G1280x1024x32K`	constant	Mode: Resolution 1280x1024, 32K colors.
`G1280x1024x64K`	constant	Mode: Resolution 1280x1024, 64K colors.
`G1600x1200x16`	constant	Mode: Resolution 1600x1200, 16 colors.
`G1600x1200x16M`	constant	Mode: Resolution 1600x1200, 16M colors.
`G1600x1200x16M32`	constant	Mode: Resolution 1600x1200, 16M 32-bit colors.
`G1600x1200x256`	constant	Mode: Resolution 1600x1200, 256 colors.
`G1600x1200x32K`	constant	Mode: Resolution 1600x1200, 32K colors.
`G1600x1200x64K`	constant	Mode: Resolution 1600x1200, 64K colors.
`G320x200x16`	constant	Mode: Resulution 320x200, 16 colors.
`G320x200x16M`	constant	Mode: Resolution 320x200, 16M colors.
`G320x200x16M32`	constant	Mode: Resolution 320x200, 16M 32-bit colors.
`G320x200x256`	constant	Mode: Resolution 320x200, 256 colors.
`G320x200x32K`	constant	Mode: Resolution 320x200, 32K colors.
`G320x200x64K`	constant	Mode: Resolution 320x200, 64K colors.
`G320x240x256`	constant	Mode: Resolution 320x240, 256 colors.
`G320x400x256`	constant	Mode: Resolution 320x400, 256 colors.
`G360x480x256`	constant	Mode: Resolution 360x480, 256 colors.
`G640x200x16`	constant	Mode: Resolution x, colors.
`G640x350x16`	constant	Mode: Resolution x, colors.
`G640x480x16`	constant	Mode: Resolution x, colors.
`G640x480x16M`	constant	Mode: Resolution 640x480, 16M colors.
`G640x480x16M32`	constant	Mode: Resolution 640x480, 16M 32-bit colors.
`G640x480x2`	constant	Mode: Resolution 640x480, 2 colors.
`G640x480x256`	constant	Mode: Resolution 640x480, 256 colors.
`G640x480x32K`	constant	Mode: Resolution 640x480, 32K colors.
`G640x480x64K`	constant	Mode: Resolution 640x480, 64K colors.
`G720x348x2`	constant	Mode: Resolution 720x348, 2 colors.
`G800x600x16`	constant	Mode: Resolution 800x600, 16 colors.
`G800x600x16M`	constant	Mode: Resolution 800x600, 16M colors.
`G800x600x16M32`	constant	Mode: Resolution 800x600, 16M 32-bit colors.
`G800x600x256`	constant	Mode: Resolution 800x600, 256 colors.
`G800x600x32K`	constant	Mode: Resolution 800x600, 32K colors.
`G800x600x64K`	constant	Mode: Resolution 800x600, 64K colors.
`GothicFont`	constant	Font number: Gothic font.
`GraphStringTransTable`	constant	Table used when transliterating strings.
`green`	constant	Color code: green.
`grError`	constant	Error: Unknown error.
`grFileNotFound`	constant	Error: File for driver not found.
`grFontNotFound`	constant	Error: font description file not found.
`grInvalidDriver`	constant	Error: Invalid driver specified.
`grInvalidFont`	constant	Error: Invalid font description.
`grInvalidFontNum`	constant	Error: Invalid font number.
`grInvalidMode`	constant	Error: Invalid mode specified.
`grInvalidVersion`	constant	Error: Invalid version.
`grIOerror`	constant	Error: Unspecified Input/Output error.
`grNoFloodMem`	constant	Error: Could not allocate memory for flood operation.
`grNoFontMem`	constant	Error: Not enough memory to load font.
`grNoInitGraph`	constant	Error: Graphical system not initialized.
`grNoLoadMem`	constant	Error: Memory error.
`grNoScanMem`	constant	Error: Could not allocate memory for scan.
`grNotDetected`	constant	Error: Graphics device not detected.
`grOk`	constant	Graphical operation went OK.
`HatchFill`	constant	Fill style: Hatch lines.
`HercMono`	constant	Mode: Hercules, mono color.
`HercMonoHi`	constant	Mode: Hercules card, monochrome, high resolution.
`highNewDriver`	constant	Mode: highest number for new driver.
`highNewMode`	constant	Mode: Highest possible value of the new modes.
`HorizDir`	constant	Text write direction: Horizontal.
`InterleaveFill`	constant	Fill style: Interleaving lines.
`LCOMFont`	constant	Font number: ?
`LeftText`	constant	Horizontal text alignment: Align text left.
`lightblue`	constant	Color code: Light blue.
`lightcyan`	constant	Color code: Light cyan.
`lightgray`	constant	Color code: Light gray.
`lightgreen`	constant	Color code: Light green.
`lightmagenta`	constant	Color code: Light magenta.
`lightred`	constant	Color code: Light red.
`LineFill`	constant	Fill style: Fill using horizontal lines.
`lowNewDriver`	constant	Mode: lowest number for new driver.
`lowNewMode`	constant	Mode: Lowest possible value of the new modes.
`LowRes`	constant	Mode: Low resolution.
`LtBkSlashFill`	constant	Fill style: Light diagonal (backslash) lines.
`LtSlashFill`	constant	Fill style: Light diagonal (slash) lines.
`m1024x768`	constant	Mode: Resolution 1024x768.
`m1280x1024`	constant	Mode: Resolution 1280x1024.
`m1600x1200`	constant	Mode: Resolution 1600x1200.
`m2048x1536`	constant	Mode: Resolution 2048x1536.
`m320x200`	constant	Mode: Resolution 320x200.
`m320x256`	constant	Mode: Resolution 320x256.
`m320x400`	constant	Mode: Resolution 320x400.
`m512x384`	constant	Mode: Resolution 512x384.
`m640x200`	constant	Mode: Resolution 640x200.
`m640x256`	constant	Mode: Resolution 640x256.
`m640x350`	constant	Mode: Resolution 640x350.
`m640x400`	constant	Mode: Resolution 640x400.
`m640x480`	constant	Mode: Resolution 640x480.
`m800x600`	constant	Mode: Resolution 800x600.
`m832x624`	constant	Mode: Resolution 832x624.
`magenta`	constant	Color code: Magenta.
`MaxColors`	constant	Max amount of colors in a palette.
`maxsmallint`	constant	Maximum value for smallint type.
`MCGA`	constant	Graphic driver for MCGA cards.
`MCGAC0`	constant	MCGA Graphic driver mode C0.
`MCGAC1`	constant	MCGA Graphic driver mode C1.
`MCGAC2`	constant	MCGA Graphic driver mode C2.
`MCGAC3`	constant	MCGA Graphic driver mode C3.
`MCGAHi`	constant	MCGA Graphic driver high resolution mode.
`MCGAMed`	constant	MCGA Graphic driver medium resolution mode.
`NormalPut`	constant	Draw operation: Use Normal (copy) operation.
`NormWidth`	constant	Line width: Normal width.
`NotPut`	constant	Draw operation: use NOT.
`OrPut`	constant	Draw operation: use OR.
`red`	constant	Color code: Red.
`resolutions`	constant	Array with actual resolutions of the new modes.
`RightText`	constant	Horizontal text alignment: Align text right.
`SansSerifFont`	constant	Font number: Sans Serif font.
`ScriptFont`	constant	Font number: Script font.
`SimpleFont`	constant	Font number: Simple font.
`SlashFill`	constant	Fill style: Diagonal (slash) lines.
`SmallFont`	constant	Font number: Small font.
`SolidFill`	constant	Fill style: Solid fill.
`SolidLn`	constant	Line style: Solid line.
`ThickWidth`	constant	Line width: double width.
`TopOff`	constant	Top off.
`TopOn`	constant	Top on.
`TopText`	constant	Vertical text alignment: Align text to top.
`TriplexFont`	constant	Font number: Triplex font.
`TSCRFont`	constant	Font number: Terminal font.
`UserBitLn`	constant	Line style: User defined.
`UserCharSize`	constant	User character size.
`UserFill`	constant	Fill style: User-defined fill.
`VertDir`	constant	Text write direction: Vertical.
`VESA`	constant	Mode: VESA graphics adaptor.
`VGA`	constant	Mode: VGA graphics adaptor.
`VGAHi`	constant	Mode: VGA high resolution (640x480).
`VGALo`	constant	Mode: VGA low resolution (640x200).
`VGAMed`	constant	Mode: VGA medium resolution (640x350).
`white`	constant	Color code: White.
`WideDotFill`	constant	Fill style: Widely spaced dotted lines.
`XHatchFill`	constant	Fill style: Heavy hatch lines.
`XORPut`	constant	Draw operation: use XOR.
`yellow`	constant	Color code: Yellow.

Variables

`Circle`	variable	Draw a complete circle.
`ClearViewPort`	variable	Clear the current viewport.
`DirectPutPixel`	variable	Hook to directly draw a pixel on the screen.
`GetBkColor`	variable	Return current background color.
`GetImage`	variable	Return a copy of a screen area.
`GetPixel`	variable	Return color of pixel.
`GetRGBPalette`	variable	Hook to set a RGB palette entries.
`GetScanLine`	variable	Hook to get a scan line from the screen.
`GraphFreeMemPtr`	variable	Hook to free heap memory.
`GraphGetMemPtr`	variable	Hook to get heap memory.
`HLine`	variable	Hook to draw a solid horizontal line.
`ImageSize`	variable	Return size to store image.
`InternalEllipse`	variable	Hook to draw an ellipse.
`Line`	variable	Draw a line between 2 points.
`OutTextXY`	variable	Write text on the screen on given position.
`PatternLine`	variable	Hook to draw a patterned line.
`PutImage`	variable	Draw an in-memory image to the screen.
`PutPixel`	variable	Draw a pixel on the screen.
`RestoreVideoState`	variable	Hook to restore a saved video mode.
`SaveVideoState`	variable	Hook to save the current video state.
`SetActivePage`	variable	Set active graphical page.
`SetAllPalette`	variable	Specify a complete new palette.
`SetBkColor`	variable	Set background drawing color.
`SetRGBPalette`	variable	Set palette entry using RGB value.
`SetVisualPage`	variable	Set video page which is displayed.
`VLine`	variable	Hook to draw a solid vertical line.

Topics

`FuncColorManagement`	topic	Categorized functions: Color management.
`FuncDrawing`	topic	Categorized functions: Drawing primitives.
`FuncFilledDrawing`	topic	Categorized functions: Filled drawings.
`FuncInitializion`	topic	Categorized functions: Initialization.
`FuncScreen`	topic	Categorized functions: Screen management.
`FuncTextHandling`	topic	Categorized functions: Text and font handling.
`Modes`	topic	A word about mode selection.
`Requirements`	topic	Requirements.
`TargetIssuesDos`	topic	Target specific issues: DOS.
`TargetIssuesWindows`	topic	Target specific issues: Linux.

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.