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gifimage.pas
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gifimage.pas
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unit GIFImage;
////////////////////////////////////////////////////////////////////////////////
// //
// Project: GIF Graphics Object //
// Module: gifimage //
// Description: TGraphic implementation of the GIF89a graphics format //
// Version: 2.2 //
// Release: 5 //
// Date: 23-MAY-1999 //
// Target: Win32, Delphi 2, 3, 4 & 5, C++ Builder 3 & 4 //
// Author(s): anme: Anders Melander, anders@melander.dk //
// fila: Filip Larsen //
// rps: Reinier Sterkenburg //
// Copyright: (c) 1997-99 Anders Melander. //
// All rights reserved. //
// Formatting: 2 space indent, 8 space tabs, 80 columns. //
// //
////////////////////////////////////////////////////////////////////////////////
// //
// Please read the "Conditions of use" in the release notes. //
// //
////////////////////////////////////////////////////////////////////////////////
// Known problems:
//
// * The combination of buffered, tiled and transparent draw will display the
// background incorrectly (scaled).
// If this is a problem for you, use non-buffered (goDirectDraw) drawing
// instead.
//
// * The combination of non-buffered, transparent and stretched draw is
// sometimes distorted with a pattern effect when the image is displayed
// smaller than the real size (shrinked).
//
// * Buffered display flickers when TGIFImage is used by a transparent TImage
// component.
// This is a problem with TImage caused by the fact that TImage was designed
// with static images in mind. Not much I can do about it.
//
////////////////////////////////////////////////////////////////////////////////
// To do (in rough order of priority):
// { TODO -oanme -cFeature : TImage hook for destroy notification. }
// { TODO -oanme -cFeature : TBitmap pool to limit resource consumption on Win95/98. }
// { TODO -oanme -cImprovement : Make BitsPerPixel property writable. }
// { TODO -oanme -cFeature : Visual GIF component. }
// { TODO -oanme -cImprovement : Easier method to determine DrawPainter status. }
// { TODO -oanme -cFeature : Import to 256+ color GIF. }
// { TODO -oanme -cFeature : Make some of TGIFImage's properties persistent (DrawOptions etc). }
// { TODO -oanme -cFeature : Add TGIFImage.Persistent property. Should save published properties in application extension when this options is set. }
// { TODO -oanme -cBugFix : Solution for background buffering in scrollbox. }
//
//////////////////////////////////////////////////////////////////////////////////
{$ifdef BCB}
{$ObjExportAll On}
{$endif}
interface
////////////////////////////////////////////////////////////////////////////////
//
// Conditional Compiler Symbols
//
////////////////////////////////////////////////////////////////////////////////
(*
DEBUG Must be defined if any of the DEBUG_xxx
symbols are defined.
If the symbol is defined the source will not be
optimized and overflow- and range checks will be
enabled.
DEBUG_HASHPERFORMANCE Calculates hash table performance data.
DEBUG_HASHFILLFACTOR Calculates fill factor of hash table -
Interferes with DEBUG_HASHPERFORMANCE.
DEBUG_COMPRESSPERFORMANCE Calculates LZW compressor performance data.
DEBUG_DECOMPRESSPERFORMANCE Calculates LZW decompressor performance data.
DEBUG_DITHERPERFORMANCE Calculates color reduction performance data.
DEBUG_DRAWPERFORMANCE Calculates low level drawing performance data.
The performance data for DEBUG_DRAWPERFORMANCE
will be displayed when you press the Ctrl key.
DEBUG_RENDERPERFORMANCE Calculates performance data for the GIF to
bitmap converter.
The performance data for DEBUG_DRAWPERFORMANCE
will be displayed when you press the Ctrl key.
GIF_NOSAFETY Define this symbol to disable overflow- and
range checks.
Ignored if the DEBUG symbol is defined.
STRICT_MOZILLA Define to mimic Mozilla as closely as possible.
If not defined, a slightly more "optimal"
implementation is used (IMHO).
FAST_AS_HELL Define this symbol to use strictly GIF compliant
(but too fast) animation timing.
Since our paint routines are much faster and
more precise timed than Mozilla's, the standard
GIF and Mozilla values causes animations to loop
faster than they would in Mozilla.
If the symbol is _not_ defined, an alternative
set of tweaked timing values will be used.
The tweaked values are not optimal but are based
on tests performed on my reference system:
- Windows 95
- 133 MHz Pentium
- 64Mb RAM
- Diamond Stealth64/V3000
- 1600*1200 in 256 colors
The alternate values can be modified if you are
not satisfied with my defaults (they can be
found a few pages down).
REGISTER_TGIFIMAGE Define this symbol to register TGIFImage with
the TPicture class and integrate with TImage.
This is required to be able to display GIFs in
the TImage component.
The symbol is defined by default.
Undefine if you use another GIF library to
provide GIF support for TImage.
PIXELFORMAT_TOO_SLOW When this symbol is defined, the internal
PixelFormat routines are used in some places
instead of TBitmap.PixelFormat.
The current implementation (Delphi4, Builder 3)
of TBitmap.PixelFormat can in some situation
degrade performance.
The symbol is defined by default.
CREATEDIBSECTION_SLOW If this symbol is defined, TDIBWriter will
use global memory as scanline storage, instead
of a DIB section.
Benchmarks have shown that a DIB section is
twice as slow as global memory.
The symbol is defined by default.
The symbol requires that PIXELFORMAT_TOO_SLOW
is defined.
SERIALIZE_RENDER Define this symbol to serialize threaded
GIF to bitmap rendering.
When a GIF is displayed with the goAsync option
(the default), the GIF to bitmap rendering is
executed in the context of the draw thread.
If more than one thread is drawing the same GIF
or the GIF is being modified while it is
animating, the GIF to bitmap rendering should be
serialized to guarantee that the bitmap isn't
modified by more than one thread at a time. If
SERIALIZE_RENDER is defined, the draw threads
uses TThread.Synchronize to serialize GIF to
bitmap rendering.
*)
{$DEFINE REGISTER_TGIFIMAGE}
{$DEFINE PIXELFORMAT_TOO_SLOW}
{$DEFINE CREATEDIBSECTION_SLOW}
////////////////////////////////////////////////////////////////////////////////
//
// Determine Delphi and C++ Builder version
//
////////////////////////////////////////////////////////////////////////////////
// Delphi 1.x
{$IFDEF VER80}
'Error: TGIFImage does not support Delphi 1.x'
{$ENDIF}
// Delphi 2.x
{$IFDEF VER90}
{$DEFINE VER9x}
{$ENDIF}
// C++ Builder 1.x
{$IFDEF VER93}
// Good luck...
{$DEFINE VER9x}
{$ENDIF}
// Delphi 3.x
{$IFDEF VER100}
{$DEFINE VER10_PLUS}
{$DEFINE D3_BCB3}
{$ENDIF}
// C++ Builder 3.x
{$IFDEF VER110}
{$DEFINE VER10_PLUS}
{$DEFINE VER11_PLUS}
{$DEFINE D3_BCB3}
{$DEFINE BAD_STACK_ALIGNMENT}
{$ENDIF}
// Delphi 4.x
{$IFDEF VER120}
{$DEFINE VER10_PLUS}
{$DEFINE VER11_PLUS}
{$DEFINE VER12_PLUS}
{$DEFINE BAD_STACK_ALIGNMENT}
{$ENDIF}
// C++ Builder 4.x
{$IFDEF VER125}
{$DEFINE VER10_PLUS}
{$DEFINE VER11_PLUS}
{$DEFINE VER12_PLUS}
{$DEFINE VER125_PLUS}
{$DEFINE BAD_STACK_ALIGNMENT}
{$ENDIF}
// Delphi 5.x
{$IFDEF VER130}
{$DEFINE VER10_PLUS}
{$DEFINE VER11_PLUS}
{$DEFINE VER12_PLUS}
{$DEFINE VER125_PLUS}
{$DEFINE VER13_PLUS}
{$DEFINE BAD_STACK_ALIGNMENT}
{$ENDIF}
// Unknown compiler version - assume D4 compatible
{$IFNDEF VER9x}
{$IFNDEF VER10_PLUS}
{$DEFINE VER10_PLUS}
{$DEFINE VER11_PLUS}
{$DEFINE VER12_PLUS}
{$DEFINE BAD_STACK_ALIGNMENT}
{$ENDIF}
{$ENDIF}
////////////////////////////////////////////////////////////////////////////////
//
// Compiler Options required to compile this library
//
////////////////////////////////////////////////////////////////////////////////
{$A+,B-,H+,J+,K-,M-,T-,X+}
// Debug control - You can safely change these settings
{$IFDEF DEBUG}
{$C+} // ASSERTIONS
{$O-} // OPTIMIZATION
{$Q+} // OVERFLOWCHECKS
{$R+} // RANGECHECKS
{$ELSE}
{$C-} // ASSERTIONS
{$IFDEF GIF_NOSAFETY}
{$Q-}// OVERFLOWCHECKS
{$R-}// RANGECHECKS
{$ENDIF}
{$ENDIF}
// Special options for Time2Help parser
{$ifdef TIME2HELP}
{$UNDEF PIXELFORMAT_TOO_SLOW}
{$endif}
////////////////////////////////////////////////////////////////////////////////
//
// External dependecies
//
////////////////////////////////////////////////////////////////////////////////
uses
sysutils,
Windows,
Graphics,
Classes;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFImage library version
//
////////////////////////////////////////////////////////////////////////////////
const
GIFVersion = $0202;
GIFVersionMajor = 2;
GIFVersionMinor = 2;
GIFVersionRelease = 5;
////////////////////////////////////////////////////////////////////////////////
//
// Misc constants and support types
//
////////////////////////////////////////////////////////////////////////////////
const
GIFMaxColors = 256; // Max number of colors supported by GIF
// Don't bother changing this value!
BitmapAllocationThreshold = 500000; // Bitmap pixel count limit at which
// a newly allocated bitmap will be
// converted to 1 bit format before
// being resized and converted to 8 bit.
var
{$IFDEF FAST_AS_HELL}
GIFDelayExp: integer = 10; // Delay multiplier in mS.
{$ELSE}
GIFDelayExp: integer = 12; // Delay multiplier in mS. Tweaked.
{$ENDIF}
// * GIFDelayExp:
// The following delay values should all
// be multiplied by this value to
// calculate the effective time (in mS).
// According to the GIF specs, this
// value should be 10.
// Since our paint routines are much
// faster than Mozilla's, you might need
// to increase this value if your
// animations loops too fast. The
// optimal value is impossible to
// determine since it depends on the
// speed of the CPU, the viceo card,
// memory and many other factors.
GIFDefaultDelay: integer = 10; // * GIFDefaultDelay:
// Default animation delay.
// This value is used if no GCE is
// defined.
// (10 = 100 mS)
{$IFDEF FAST_AS_HELL}
GIFMinimumDelay: integer = 1; // Minimum delay (from Mozilla source).
// (1 = 10 mS)
{$ELSE}
GIFMinimumDelay: integer = 3; // Minimum delay - Tweaked.
{$ENDIF}
// * GIFMinimumDelay:
// The minumum delay used in the Mozilla
// source is 10mS. This corresponds to a
// value of 1. However, since our paint
// routines are much faster than
// Mozilla's, a value of 3 or 4 gives
// better results.
GIFMaximumDelay: integer = 1000; // * GIFMaximumDelay:
// Maximum delay when painter is running
// in main thread (goAsync is not set).
// This value guarantees that a very
// long and slow GIF does not hang the
// system.
// (1000 = 10000 mS = 10 Seconds)
type
TGIFVersion = (gvUnknown, gv87a, gv89a);
TGIFVersionRec = array[0..2] of char;
const
GIFVersions : array[gv87a..gv89a] of TGIFVersionRec = ('87a', '89a');
type
// TGIFImage mostly throws exceptions of type GIFException
GIFException = class(EInvalidGraphic);
// Severity level as indicated in the Warning methods and the OnWarning event
TGIFSeverity = (gsInfo, gsWarning, gsError);
////////////////////////////////////////////////////////////////////////////////
//
// Delphi 2.x support
//
////////////////////////////////////////////////////////////////////////////////
{$IFDEF VER9x}
// Delphi 2 doesn't support TBitmap.PixelFormat
{$DEFINE PIXELFORMAT_TOO_SLOW}
type
// TThreadList from Delphi 3 classes.pas
TThreadList = class
private
FList: TList;
FLock: TRTLCriticalSection;
public
constructor Create;
destructor Destroy; override;
procedure Add(Item: Pointer);
procedure Clear;
function LockList: TList;
procedure Remove(Item: Pointer);
procedure UnlockList;
end;
// From Delphi 3 sysutils.pas
EOutOfMemory = class(Exception);
// From Delphi 3 classes.pas
EOutOfResources = class(EOutOfMemory);
// From Delphi 3 windows.pas
PMaxLogPalette = ^TMaxLogPalette;
TMaxLogPalette = packed record
palVersion: Word;
palNumEntries: Word;
palPalEntry: array [Byte] of TPaletteEntry;
end; { TMaxLogPalette }
// From Delphi 3 graphics.pas. Used by the D3 TGraphic class.
TProgressStage = (psStarting, psRunning, psEnding);
TProgressEvent = procedure (Sender: TObject; Stage: TProgressStage;
PercentDone: Byte; RedrawNow: Boolean; const R: TRect; const Msg: string) of object;
// From Delphi 3 windows.pas
PRGBTriple = ^TRGBTriple;
{$ENDIF}
////////////////////////////////////////////////////////////////////////////////
//
// Forward declarations
//
////////////////////////////////////////////////////////////////////////////////
type
TGIFImage = class;
TGIFSubImage = class;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFItem
//
////////////////////////////////////////////////////////////////////////////////
TGIFItem = class(TPersistent)
private
FGIFImage: TGIFImage;
protected
function GetVersion: TGIFVersion; virtual;
procedure Warning(Severity: TGIFSeverity; Message: string); virtual;
public
constructor Create(GIFImage: TGIFImage); virtual;
procedure SaveToStream(Stream: TStream); virtual; abstract;
procedure LoadFromStream(Stream: TStream); virtual; abstract;
procedure SaveToFile(const Filename: string); virtual;
procedure LoadFromFile(const Filename: string); virtual;
property Version: TGIFVersion read GetVersion;
property Image: TGIFImage read FGIFImage;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFList
//
////////////////////////////////////////////////////////////////////////////////
TGIFList = class(TPersistent)
private
FItems: TList;
FImage: TGIFImage;
protected
function GetItem(Index: Integer): TGIFItem;
procedure SetItem(Index: Integer; Item: TGIFItem);
function GetCount: Integer;
procedure Warning(Severity: TGIFSeverity; Message: string); virtual;
public
constructor Create(Image: TGIFImage);
destructor Destroy; override;
function Add(Item: TGIFItem): Integer;
procedure Clear;
procedure Delete(Index: Integer);
procedure Exchange(Index1, Index2: Integer);
function First: TGIFItem;
function IndexOf(Item: TGIFItem): Integer;
procedure Insert(Index: Integer; Item: TGIFItem);
function Last: TGIFItem;
procedure Move(CurIndex, NewIndex: Integer);
function Remove(Item: TGIFItem): Integer;
procedure SaveToStream(Stream: TStream); virtual;
procedure LoadFromStream(Stream: TStream; Parent: TObject); virtual; abstract;
property Items[Index: Integer]: TGIFItem read GetItem write SetItem; default;
property Count: Integer read GetCount;
property List: TList read FItems;
property Image: TGIFImage read FImage;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFColorMap
//
////////////////////////////////////////////////////////////////////////////////
// One way to do it:
// TBaseColor = (bcRed, bcGreen, bcBlue);
// TGIFColor = array[bcRed..bcBlue] of BYTE;
// Another way:
TGIFColor = packed record
Red: byte;
Green: byte;
Blue: byte;
end;
TColorMap = packed array[0..GIFMaxColors-1] of TGIFColor;
PColorMap = ^TColorMap;
TUsageCount = record
Count : integer; // # of pixels using color index
Index : integer; // Color index
end;
TColormapHistogram = array[0..255] of TUsageCount;
TColormapReverse = array[0..255] of byte;
TGIFColorMap = class(TPersistent)
private
FColorMap : PColorMap;
FCount : integer;
FCapacity : integer;
FOptimized : boolean;
protected
function GetColor(Index: integer): TColor;
procedure SetColor(Index: integer; Value: TColor);
function GetBitsPerPixel: integer;
function DoOptimize: boolean;
procedure SetCapacity(Size: integer);
procedure Warning(Severity: TGIFSeverity; Message: string); virtual; abstract;
procedure BuildHistogram(var Histogram: TColormapHistogram); virtual; abstract;
procedure MapImages(var Map: TColormapReverse); virtual; abstract;
public
constructor Create;
destructor Destroy; override;
class function Color2RGB(Color: TColor): TGIFColor;
class function RGB2Color(Color: TGIFColor): TColor;
procedure SaveToStream(Stream: TStream);
procedure LoadFromStream(Stream: TStream; Count: integer);
procedure Assign(Source: TPersistent); override;
function IndexOf(Color: TColor): integer;
function Add(Color: TColor): integer;
function AddUnique(Color: TColor): integer;
procedure Delete(Index: integer);
procedure Clear;
function Optimize: boolean; virtual; abstract;
procedure Changed; virtual; abstract;
procedure ImportPalette(Palette: HPalette);
procedure ImportColorTable(Pal: pointer; Count: integer);
procedure ImportDIBColors(Handle: HDC);
procedure ImportColorMap(Map: TColorMap; Count: integer);
function ExportPalette: HPalette;
property Colors[Index: integer]: TColor read GetColor write SetColor; default;
property Data: PColorMap read FColorMap;
property Count: integer read FCount;
property Optimized: boolean read FOptimized write FOptimized;
property BitsPerPixel: integer read GetBitsPerPixel;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFHeader
//
////////////////////////////////////////////////////////////////////////////////
TLogicalScreenDescriptor = packed record
ScreenWidth: word; { logical screen width }
ScreenHeight: word; { logical screen height }
PackedFields: byte; { packed fields }
BackgroundColorIndex: byte; { index to global color table }
AspectRatio: byte; { actual ratio = (AspectRatio + 15) / 64 }
end;
TGIFHeader = class(TGIFItem)
private
FLogicalScreenDescriptor: TLogicalScreenDescriptor;
FColorMap : TGIFColorMap;
procedure Prepare;
protected
function GetVersion: TGIFVersion; override;
function GetBackgroundColor: TColor;
procedure SetBackgroundColor(Color: TColor);
procedure SetBackgroundColorIndex(Index: BYTE);
function GetBitsPerPixel: integer;
function GetColorResolution: integer;
public
constructor Create(GIFImage: TGIFImage); override;
destructor Destroy; override;
procedure Assign(Source: TPersistent); override;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
procedure Clear;
property Version: TGIFVersion read GetVersion;
property Width: WORD read FLogicalScreenDescriptor.ScreenWidth
write FLogicalScreenDescriptor.ScreenWidth;
property Height: WORD read FLogicalScreenDescriptor.ScreenHeight
write FLogicalScreenDescriptor.Screenheight;
property BackgroundColorIndex: BYTE read FLogicalScreenDescriptor.BackgroundColorIndex
write SetBackgroundColorIndex;
property BackgroundColor: TColor read GetBackgroundColor
write SetBackgroundColor;
property AspectRatio: BYTE read FLogicalScreenDescriptor.AspectRatio
write FLogicalScreenDescriptor.AspectRatio;
property ColorMap: TGIFColorMap read FColorMap;
property BitsPerPixel: integer read GetBitsPerPixel;
property ColorResolution: integer read GetColorResolution;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFExtension
//
////////////////////////////////////////////////////////////////////////////////
TGIFExtensionType = BYTE;
TGIFExtension = class;
TGIFExtensionClass = class of TGIFExtension;
TGIFGraphicControlExtension = class;
TGIFExtension = class(TGIFItem)
private
FSubImage: TGIFSubImage;
protected
function GetExtensionType: TGIFExtensionType; virtual; abstract;
function GetVersion: TGIFVersion; override;
function DoReadFromStream(Stream: TStream): TGIFExtensionType;
class procedure RegisterExtension(elabel: BYTE; eClass: TGIFExtensionClass);
class function FindExtension(Stream: TStream): TGIFExtensionClass;
class function FindSubExtension(Stream: TStream): TGIFExtensionClass; virtual;
public
// Ignore compiler warning about hiding base class constructor
constructor Create(ASubImage: TGIFSubImage); {$IFDEF VER12_PLUS} reintroduce; {$ENDIF} virtual;
destructor Destroy; override;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
property ExtensionType: TGIFExtensionType read GetExtensionType;
property SubImage: TGIFSubImage read FSubImage;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFSubImage
//
////////////////////////////////////////////////////////////////////////////////
TGIFExtensionList = class(TGIFList)
protected
function GetExtension(Index: Integer): TGIFExtension;
procedure SetExtension(Index: Integer; Extension: TGIFExtension);
public
procedure LoadFromStream(Stream: TStream; Parent: TObject); override;
property Extensions[Index: Integer]: TGIFExtension read GetExtension write SetExtension; default;
end;
TImageDescriptor = packed record
Separator: byte; { fixed value of ImageSeparator }
Left: word; { Column in pixels in respect to left edge of logical screen }
Top: word; { row in pixels in respect to top of logical screen }
Width: word; { width of image in pixels }
Height: word; { height of image in pixels }
PackedFields: byte; { Bit fields }
end;
TGIFSubImage = class(TGIFItem)
private
FBitmap : TBitmap;
FMask : HBitmap;
FNeedMask : boolean;
FLocalPalette : HPalette;
FData : PChar;
FDataSize : integer;
FColorMap : TGIFColorMap;
FImageDescriptor : TImageDescriptor;
FExtensions : TGIFExtensionList;
FTransparent : boolean;
FGCE : TGIFGraphicControlExtension;
procedure Prepare;
procedure Compress(Stream: TStream);
procedure Decompress(Stream: TStream);
protected
function GetVersion: TGIFVersion; override;
function GetInterlaced: boolean;
procedure SetInterlaced(Value: boolean);
function GetColorResolution: integer;
function GetBitsPerPixel: integer;
procedure AssignTo(Dest: TPersistent); override;
function DoGetBitmap: TBitmap;
function DoGetDitherBitmap: TBitmap;
function GetBitmap: TBitmap;
procedure SetBitmap(Value: TBitmap);
procedure FreeMask;
function GetEmpty: Boolean;
function GetPalette: HPALETTE;
procedure SetPalette(Value: HPalette);
function GetActiveColorMap: TGIFColorMap;
function GetBoundsRect: TRect;
procedure SetBoundsRect(const Value: TRect);
procedure DoSetBounds(ALeft, ATop, AWidth, AHeight: integer);
function GetClientRect: TRect;
function GetPixel(x, y: integer): BYTE;
function GetScanline(y: integer): pointer;
procedure NewBitmap;
procedure FreeBitmap;
procedure NewImage;
procedure FreeImage;
procedure NeedImage;
function ScaleRect(DestRect: TRect): TRect;
function HasMask: boolean;
function GetBounds(Index: integer): WORD;
procedure SetBounds(Index: integer; Value: WORD);
function GetHasBitmap: boolean;
procedure SetHasBitmap(Value: boolean);
public
constructor Create(GIFImage: TGIFImage); override;
destructor Destroy; override;
procedure Clear;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
procedure Assign(Source: TPersistent); override;
procedure Draw(ACanvas: TCanvas; const Rect: TRect;
DoTransparent, DoTile: boolean);
procedure StretchDraw(ACanvas: TCanvas; const Rect: TRect;
DoTransparent, DoTile: boolean);
procedure Crop;
procedure Merge(Previous: TGIFSubImage);
property HasBitmap: boolean read GetHasBitmap write SetHasBitmap;
property Left: WORD index 1 read GetBounds write SetBounds;
property Top: WORD index 2 read GetBounds write SetBounds;
property Width: WORD index 3 read GetBounds write SetBounds;
property Height: WORD index 4 read GetBounds write SetBounds;
property BoundsRect: TRect read GetBoundsRect write SetBoundsRect;
property ClientRect: TRect read GetClientRect;
property Interlaced: boolean read GetInterlaced write SetInterlaced;
property ColorMap: TGIFColorMap read FColorMap;
property ActiveColorMap: TGIFColorMap read GetActiveColorMap;
property Data: PChar read FData;
property DataSize: integer read FDataSize;
property Extensions: TGIFExtensionList read FExtensions;
property Version: TGIFVersion read GetVersion;
property ColorResolution: integer read GetColorResolution;
property BitsPerPixel: integer read GetBitsPerPixel;
property Bitmap: TBitmap read GetBitmap write SetBitmap;
property Mask: HBitmap read FMask;
property Palette: HPALETTE read GetPalette write SetPalette;
property Empty: boolean read GetEmpty;
property Transparent: boolean read FTransparent;
property GraphicControlExtension: TGIFGraphicControlExtension read FGCE;
property Pixels[x, y: integer]: BYTE read GetPixel;
property Scanline[y: integer]: pointer read GetScanline;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFTrailer
//
////////////////////////////////////////////////////////////////////////////////
TGIFTrailer = class(TGIFItem)
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFGraphicControlExtension
//
////////////////////////////////////////////////////////////////////////////////
// Graphic Control Extension block a.k.a GCE
TGIFGCERec = packed record
BlockSize: byte; { should be 4 }
PackedFields: Byte;
DelayTime: Word; { in centiseconds }
TransparentColorIndex: Byte;
Terminator: Byte;
end;
TDisposalMethod = (dmNone, dmNoDisposal, dmBackground, dmPrevious);
TGIFGraphicControlExtension = class(TGIFExtension)
private
FGCExtension: TGIFGCERec;
protected
function GetExtensionType: TGIFExtensionType; override;
function GetTransparent: boolean;
procedure SetTransparent(Value: boolean);
function GetTransparentColor: TColor;
procedure SetTransparentColor(Color: TColor);
function GetTransparentColorIndex: BYTE;
procedure SetTransparentColorIndex(Value: BYTE);
function GetDelay: WORD;
procedure SetDelay(Value: WORD);
function GetUserInput: boolean;
procedure SetUserInput(Value: boolean);
function GetDisposal: TDisposalMethod;
procedure SetDisposal(Value: TDisposalMethod);
public
constructor Create(ASubImage: TGIFSubImage); override;
destructor Destroy; override;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
property Delay: WORD read GetDelay write SetDelay;
property Transparent: boolean read GetTransparent write SetTransparent;
property TransparentColorIndex: BYTE read GetTransparentColorIndex
write SetTransparentColorIndex;
property TransparentColor: TColor read GetTransparentColor write SetTransparentColor;
property UserInput: boolean read GetUserInput write SetUserInput;
property Disposal: TDisposalMethod read GetDisposal write SetDisposal;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFTextExtension
//
////////////////////////////////////////////////////////////////////////////////
TGIFPlainTextExtensionRec = packed record
BlockSize: byte; { should be 12 }
Left, Top, Width, Height: Word;
CellWidth, CellHeight: Byte;
TextFGColorIndex,
TextBGColorIndex: Byte;
end;
TGIFTextExtension = class(TGIFExtension)
private
FText : TStrings;
FPlainTextExtension : TGIFPlainTextExtensionRec;
protected
function GetExtensionType: TGIFExtensionType; override;
function GetForegroundColor: TColor;
procedure SetForegroundColor(Color: TColor);
function GetBackgroundColor: TColor;
procedure SetBackgroundColor(Color: TColor);
function GetBounds(Index: integer): WORD;
procedure SetBounds(Index: integer; Value: WORD);
function GetCharWidthHeight(Index: integer): BYTE;
procedure SetCharWidthHeight(Index: integer; Value: BYTE);
function GetColorIndex(Index: integer): BYTE;
procedure SetColorIndex(Index: integer; Value: BYTE);
public
constructor Create(ASubImage: TGIFSubImage); override;
destructor Destroy; override;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
property Left: WORD index 1 read GetBounds write SetBounds;
property Top: WORD index 2 read GetBounds write SetBounds;
property GridWidth: WORD index 3 read GetBounds write SetBounds;
property GridHeight: WORD index 4 read GetBounds write SetBounds;
property CharWidth: BYTE index 1 read GetCharWidthHeight write SetCharWidthHeight;
property CharHeight: BYTE index 2 read GetCharWidthHeight write SetCharWidthHeight;
property ForegroundColorIndex: BYTE index 1 read GetColorIndex write SetColorIndex;
property ForegroundColor: TColor read GetForegroundColor;
property BackgroundColorIndex: BYTE index 2 read GetColorIndex write SetColorIndex;
property BackgroundColor: TColor read GetBackgroundColor;
property Text: TStrings read FText write FText;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFCommentExtension
//
////////////////////////////////////////////////////////////////////////////////
TGIFCommentExtension = class(TGIFExtension)
private
FText : TStrings;
protected
function GetExtensionType: TGIFExtensionType; override;
public
constructor Create(ASubImage: TGIFSubImage); override;
destructor Destroy; override;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
property Text: TStrings read FText;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFApplicationExtension
//
////////////////////////////////////////////////////////////////////////////////
TGIFIdentifierCode = array[0..7] of char;
TGIFAuthenticationCode = array[0..2] of char;
TGIFApplicationRec = packed record
Identifier : TGIFIdentifierCode;
Authentication : TGIFAuthenticationCode;
end;
TGIFApplicationExtension = class;
TGIFAppExtensionClass = class of TGIFApplicationExtension;
TGIFApplicationExtension = class(TGIFExtension)
private
FIdent : TGIFApplicationRec;
function GetAuthentication: string;
function GetIdentifier: string;
protected
function GetExtensionType: TGIFExtensionType; override;
procedure SetAuthentication(const Value: string);
procedure SetIdentifier(const Value: string);
procedure SaveData(Stream: TStream); virtual; abstract;
procedure LoadData(Stream: TStream); virtual; abstract;
public
constructor Create(ASubImage: TGIFSubImage); override;
destructor Destroy; override;
procedure SaveToStream(Stream: TStream); override;
procedure LoadFromStream(Stream: TStream); override;
class procedure RegisterExtension(eIdent: TGIFApplicationRec; eClass: TGIFAppExtensionClass);
class function FindSubExtension(Stream: TStream): TGIFExtensionClass; override;
property Identifier: string read GetIdentifier write SetIdentifier;
property Authentication: string read GetAuthentication write SetAuthentication;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFUnknownAppExtension
//
////////////////////////////////////////////////////////////////////////////////
TGIFBlock = class(TObject)
private
FSize : BYTE;
FData : pointer;
public
constructor Create(ASize: integer);
destructor Destroy; override;
procedure SaveToStream(Stream: TStream);
procedure LoadFromStream(Stream: TStream);
property Size: BYTE read FSize;
property Data: pointer read FData;
end;
TGIFUnknownAppExtension = class(TGIFApplicationExtension)
private
FBlocks : TList;
protected
procedure SaveData(Stream: TStream); override;
procedure LoadData(Stream: TStream); override;
public
constructor Create(ASubImage: TGIFSubImage); override;
destructor Destroy; override;
property Blocks: TList read FBlocks;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFAppExtNSLoop
//
////////////////////////////////////////////////////////////////////////////////
TGIFAppExtNSLoop = class(TGIFApplicationExtension)
private
FLoops : WORD;
FBufferSize : DWORD;
protected
procedure SaveData(Stream: TStream); override;
procedure LoadData(Stream: TStream); override;
public
constructor Create(ASubImage: TGIFSubImage); override;
property Loops: WORD read FLoops write FLoops;
property BufferSize: DWORD read FBufferSize write FBufferSize;
end;
////////////////////////////////////////////////////////////////////////////////
//
// TGIFImage
//
////////////////////////////////////////////////////////////////////////////////
TGIFImageList = class(TGIFList)
protected
function GetImage(Index: Integer): TGIFSubImage;
procedure SetImage(Index: Integer; SubImage: TGIFSubImage);
public
procedure LoadFromStream(Stream: TStream; Parent: TObject); override;
procedure SaveToStream(Stream: TStream); override;
property SubImages[Index: Integer]: TGIFSubImage read GetImage write SetImage; default;
end;
// Compression algorithms
TGIFCompression =
(gcLZW, // Normal LZW compression
gcRLE // GIF compatible RLE compression
);
// Color reduction methods
TColorReduction =
(rmNone, // Do not perform color reduction
rmWindows20, // Reduce to the Windows 20 color system palette
rmWindows256, // Reduce to the Windows 256 color halftone palette (Only works in 256 color display mode)
rmWindowsGray, // Reduce to the Windows 4 grayscale colors
rmMonochrome, // Reduce to a black/white monochrome palette
rmGrayScale, // Reduce to a uniform 256 shade grayscale palette
rmNetscape, // Reduce to the Netscape 216 color palette
rmQuantize, // Reduce to optimal 2^n color palette
rmQuantizeWindows, // Reduce to optimal 256 color windows palette
rmPalette // Reduce to custom palette
);
TDitherMode =
(dmNearest, // Nearest color matching w/o error correction
dmFloydSteinberg, // Floyd Steinberg Error Diffusion dithering
dmStucki, // Stucki Error Diffusion dithering
dmSierra, // Sierra Error Diffusion dithering
dmJaJuNI, // Jarvis, Judice & Ninke Error Diffusion dithering
dmSteveArche, // Stevenson & Arche Error Diffusion dithering
dmBurkes // Burkes Error Diffusion dithering
// dmOrdered, // Ordered dither
);
// Optimization options
TGIFOptimizeOption =
(ooCrop, // Crop animated GIF frames
ooMerge, // Merge pixels of same color
ooCleanup, // Remove comments and application extensions
ooColorMap, // Sort color map by usage and remove unused entries
ooReduceColors // Reduce color depth ***NOT IMPLEMENTED***
);
TGIFOptimizeOptions = set of TGIFOptimizeOption;
TGIFDrawOption =
(goAsync, // Asyncronous draws (paint in thread)
goTransparent, // Transparent draws
goAnimate, // Animate draws
goLoop, // Loop animations
goLoopContinously, // Ignore loop count and loop forever
goValidateCanvas, // Validate canvas in threaded paint ***NOT IMPLEMENTED***
goDirectDraw, // Draw() directly on canvas
goClearOnLoop, // Clear animation on loop
goTile, // Tiled display
goDither, // Dither to Netscape palette
goAutoDither // Only dither on 256 color systems
);