{Version 9.45}
{
Copyright (c) 1995-2008 by L. David Baldwin

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Note that the source modules, HTMLGIF1.PAS, PNGZLIB1.PAS, DITHERUNIT.PAS, and
URLCON.PAS are covered by separate copyright notices located in those modules.
}

{$i htmlcons.inc}

unit HTMLGif2;

interface

uses
  {$IFNDEF LCL} Windows, mmSystem, {$ELSE} LclIntf, LMessages, Types, LclType, HtmlMisc, {$ENDIF} 
  SysUtils, Classes, Graphics, Controls, ExtCtrls, htmlUN2,
  htmlgif1;

type
  TRGBColor = packed Record
    Red,
    Green,
    Blue: Byte;
  end;

  TDisposalType = (dtUndefined,   {Take no action}
                   dtDoNothing,   {Leave graphic, next frame goes on top of it}
                   dtToBackground,{restore original background for next frame}
                   dtToPrevious); {restore image as it existed before this frame}

type
  ThtBitmap=class(TBitmap)
  protected
    htMask: TBitmap;
    htTransparent: boolean;
    procedure Draw(ACanvas: TCanvas; const Rect: TRect); override;
    procedure StretchDraw(ACanvas: TCanvas; const DestRect,
      SrcRect: TRect);
  public
    destructor Destroy; override;
  end;

  TGIFImage = class;

  TgfFrame = class
  private
    { private declarations }
    frLeft: Integer;
    frTop: Integer;
    frWidth: Integer;
    frHeight: Integer;

    frDelay: Integer;
    frDisposalMethod: TDisposalType;
    TheEnd: boolean;    {end of what gets copied}

    IsCopy: boolean;

  Public
    constructor Create;       
    constructor CreateCopy(Item: TgfFrame);
    destructor Destroy; override;
  end;

  TgfFrameList = class(TList)
  private
    function GetFrame(I: integer): TgfFrame;
  public
    {note: Frames is 1 based, goes from [1..Count]}
    property Frames[I: integer]: TgfFrame read GetFrame; default;
    end;

  TGIFImage = class(TPersistent)
  private
    { Private declarations }
    FAnimated: Boolean;
    FCurrentFrame: Integer;
    FImageWidth: Integer;
    FImageHeight: Integer;
    FNumFrames: Integer;
    FNumIterations: Integer;
    FTransparent: Boolean;
    FVisible: Boolean;
    Strip: ThtBitmap;

    TheEnd: boolean;   {copy to here}

    FBitmap: TBitmap;
    FMaskedBitmap, FMask: TBitmap;
    FAnimate: Boolean;
    FStretchedRect: TRect;
    WasDisposal: TDisposalType;

    Frames: TgfFrameList;

    CurrentIteration: Integer;
    LastTime: DWord;
    CurrentInterval: DWord;

    procedure SetAnimate(AAnimate: Boolean);
    procedure SetCurrentFrame(AFrame: Integer);
    function GetMaskedBitmap: TBitmap;
    function GetMask: TBitmap;
    function GetBitMap: TBitmap;

    procedure NextFrame(OldFrame: Integer);

  public
    ShowIt: boolean;
    IsCopy: boolean;   {set if this is a copy of one in Cache}

    { Public declarations }
    constructor Create;
    constructor CreateCopy(Item: TGIFImage);
    destructor Destroy; override;
    procedure Draw(Canvas: TCanvas; X, Y, Wid, Ht: integer);
    property Bitmap: TBitmap read GetBitmap;  
    property MaskedBitmap: TBitmap read GetMaskedBitmap;
    property Mask: TBitmap read GetMask;
    property IsAnimated: Boolean read FAnimated;
    property IsTransparent: Boolean read FTransparent;
    property NumFrames: Integer read FNumFrames;
    property NumIterations: Integer read FNumIterations;

    procedure CheckTime(WinControl: TWinControl);

    property Width: integer read FImageWidth;
    property Height: integer read FImageHeight;
    property Animate: Boolean read FAnimate write SetAnimate;
    property CurrentFrame: Integer read FCurrentFrame write SetCurrentFrame;
    property Visible: Boolean read FVisible write FVisible;
  end;

function CreateAGifFromStream(var NonAnimated: boolean;
              Stream: TStream): TGifImage;
function CreateAGif(const Name: string; var NonAnimated: boolean): TGifImage;

implementation

uses
  Styleun, htmlsubs;

function CreateBitmap(Width, Height: integer): TBitmap;
begin
Result := TBitmap.Create;
Result.Width := Width;
Result.Height := Height;
end;

function CreateAGifFromStream(var NonAnimated: boolean;
              Stream: TStream): TGifImage;
var
  AGif: TGif;
  Frame: TgfFrame;
  I: integer;
  ABitmap, AMask: TBitmap;
begin
Result := Nil;
try
  NonAnimated := True;
  AGif := TGif.Create;
  Try
    AGif.LoadFromStream(Stream);
    Result := TGifImage.Create;

    Result.FNumFrames := AGif.ImageCount;
    Result.FAnimated := Result.FNumFrames > 1;
    NonAnimated := not Result.FAnimated;
    Result.FImageWidth := AGif.Width;
    Result.FImageHeight := AGif.Height;
    Result.FNumIterations:= AGif.LoopCount;
    if Result.FNumIterations < 0 then    {-1 means no loop block}     
      Result.FNumIterations := 1
    else if Result.FNumIterations > 0 then
      Inc(Result.FNumIterations);    {apparently this is the convention}
    Result.FTransparent := AGif.Transparent;

    with Result do
      begin
      Strip := ThtBitmap.Create;
      ABitmap := AGif.GetStripBitmap(AMask);   
      try
        Strip.Assign(ABitmap);
        Strip.htMask := AMask;
        Strip.htTransparent := Assigned(AMask);
      finally
        ABitmap.Free;
        end;
      if Result.Strip.Palette <> 0 then
        DeleteObject(Result.Strip.ReleasePalette);     
      Result.Strip.Palette := CopyPalette(ThePalette);
      end;

    for I := 0 to Result.FNumFrames-1 do
      begin
      Frame := TgfFrame.Create;
      try
        Frame.frDisposalMethod := TDisposalType(AGif.ImageDisposal[I]);
        Frame.frLeft := AGif.ImageLeft[I];
        Frame.frTop := AGif.ImageTop[I];
        Frame.frWidth := AGif.ImageWidth[I];
        Frame.frHeight := AGif.ImageHeight[I];
        Frame.frDelay := IntMax(30, AGif.ImageDelay[I] * 10);  
      except
        Frame.Free;
        Raise;
        end;
      Result.Frames.Add(Frame);
      end;
    if Result.IsAnimated then
      Result.WasDisposal := dtToBackground;
  finally
    AGif.Free;
    end;
except
  FreeAndNil(Result);
  end;
end;

function CreateAGif(const Name: string; var NonAnimated: boolean): TGifImage;
var
  Stream: TFileStream;
begin
Result := Nil;    
try
  Stream := TFileStream.Create(Name, fmOpenRead or fmShareDenyWrite);
  try
    Result := CreateAGifFromStream(NonAnimated, Stream);
  finally
    Stream.Free;
    end;
except
  end;
end;

{----------------TgfFrame.Create}
constructor TgfFrame.Create;
begin
inherited Create;
end;

constructor TgfFrame.CreateCopy(Item: TgfFrame);
begin
inherited Create;
System.Move(Item.frLeft, frLeft, DWord(@TheEnd)-DWord(@frLeft));
IsCopy := True;
end;

{----------------TgfFrame.Destroy}
destructor TgfFrame.Destroy;
begin
inherited Destroy;
end;

{----------------TGIFImage.Create}
constructor TGIFImage.Create;
begin
  inherited Create;
  FVisible := True;
  FCurrentFrame := 1;
  Frames := TgfFrameList.Create;
  CurrentIteration := 1;
end;

constructor TGIFImage.CreateCopy(Item: TGIFImage);
var
  I: integer;
begin
inherited Create;
FImageWidth := Item.Width;
FimageHeight := Item.Height;
System.Move(Item.FAnimated, FAnimated, DWord(@TheEnd)-DWord(@FAnimated));
IsCopy := True;

Frames := TgfFrameList.Create;
for I := 1 to FNumFrames do
  Frames.Add(TgfFrame.CreateCopy(Item.Frames[I]));
FCurrentFrame := 1;
CurrentIteration := 1;
if FAnimated then
  WasDisposal := dtToBackground;
end;

{----------------TGIFImage.Destroy}
destructor TGIFImage.Destroy;
var
  I: Integer;
begin
for I := Frames.Count downto 1 do     
  Frames[I].Free;
Frames.Free;
FreeAndNil(FBitmap);
if not IsCopy then
  FreeAndNil(Strip);
FMaskedBitmap.Free;
FreeAndNil(FMask);
inherited Destroy;
end;

{----------------TGIFImage.Draw}
procedure TGIFImage.Draw(Canvas: TCanvas; X, Y, Wid, Ht: integer);
var
  SRect: TRect;
  ALeft: integer;
begin
FStretchedRect := Rect(X, Y, X+Wid, Y+Ht);

SetStretchBltMode(Canvas.Handle, ColorOnColor);
if (FVisible) and (FNumFrames > 0) then
  begin
  with Frames[FCurrentFrame] do
    begin
    ALeft := (FCurrentFrame-1)*Width;
    SRect := Rect(ALeft, 0, ALeft+Width, Height); {current frame location in Strip bitmap}
    end;

  Canvas.CopyMode := cmSrcCopy;
  {draw the correct portion of the strip}
  Strip.StretchDraw(Canvas, FStretchedRect, SRect);
  end;
end;

{----------------TGifImage.CheckTime}
procedure TGifImage.CheckTime(WinControl: TWinControl);
var
  ThisTime: DWord;
begin
if not FAnimate then Exit;

ThisTime := timeGetTime;
if ThisTime - LastTime < CurrentInterval then
   Exit;

LastTime := ThisTime;

if (FCurrentFrame = FNumFrames) then
  begin
  if (FNumIterations > 0) and (CurrentIteration >= FNumIterations) then
    begin
    SetAnimate(False);
    Exit;
    end;
  Inc(CurrentIteration);
  end;
NextFrame(FCurrentFrame);
Inc(FCurrentFrame);
if (FCurrentFrame > FNumFrames) or (FCurrentFrame <= 0) then
  FCurrentFrame := 1;

InvalidateRect(WinControl.Handle, @FStretchedRect, True);

CurrentInterval := IntMax(Frames[FCurrentFrame].frDelay, 1);
end;

{----------------TGIFImage.SetAnimate}
procedure TGIFImage.SetAnimate(AAnimate: Boolean);
begin
  if AAnimate = FAnimate then Exit;

  FAnimate := AAnimate;
  if AAnimate and (FNumFrames > 1) then
    begin
    CurrentInterval := IntMax(Frames[FCurrentFrame].frDelay, 1);
    LastTime := timeGetTime;
    end;
end;

{----------------TGIFImage.SetCurrentFrame}
procedure TGIFImage.SetCurrentFrame(AFrame: Integer);
begin
if AFrame = FCurrentFrame then Exit;

NextFrame(FCurrentFrame);
if AFrame > FNumFrames then FCurrentFrame := 1
else if AFrame < 1 then FCurrentFrame := FNumFrames
else FCurrentFrame := AFrame;
if FAnimated then
  WasDisposal := dtToBackground;
end;

{----------------TGIFImage.GetBitmap}
function TGIFImage.GetBitmap: TBitmap;
begin
Result := GetMaskedBitmap;
end;

{----------------TGIFImage.GetMaskedBitmap:}
function TGIFImage.GetMaskedBitmap: TBitmap;
{This returns frame 1}
begin
if not Assigned(FMaskedBitmap) then
  begin
  FMaskedBitmap := TBitmap.Create;
  FMaskedBitmap.Assign(Strip);
  FMaskedBitmap.Width := FImageWidth;
  if Strip.htTransparent then
    begin
    FMask := TBitmap.Create;
    FMask.Assign(Strip.htMask);
    FMask.Width := FImageWidth;
    end;
  FMaskedBitmap.Transparent := False;
  end;
Result := FMaskedBitmap;
end;

{----------------TGIFImage.GetMask:}
function TGIFImage.GetMask: TBitmap;
{This returns mask for frame 1.  Content is black, background is white}
begin
if not FTransparent then
  Result := nil
else
  begin
  if not Assigned(FMask) then
    GetMaskedBitmap;
  Result := FMask;
  end;
end;

{----------------TGIFImage.NextFrame}
procedure TGIFImage.NextFrame(OldFrame: Integer);
begin
WasDisposal := Frames[OldFrame].frDisposalMethod;
end;

{----------------TgfFrameList.GetFrame}
function TgfFrameList.GetFrame(I: integer): TgfFrame;
begin
Assert((I <= Count) and (I >= 1   ), 'Frame index out of range');
Result := TgfFrame(Items[I-1]);
end;

{ ThtBitmap }
var
  AHandle: THandle;

destructor ThtBitmap.Destroy;
begin
htMask.Free;
inherited;
end;  

{----------------ThtBitmap.Draw}
procedure ThtBitmap.Draw(ACanvas: TCanvas; const Rect: TRect);
var
  OldPalette: HPalette;
  RestorePalette: Boolean;
  DoHalftone: Boolean;
  Pt: TPoint;
  BPP: Integer;
  MaskDC: HDC;
  Save: THandle;
begin
  with Rect do
  begin
    AHandle := ACanvas.Handle;  {LDB}
    PaletteNeeded;
    OldPalette := 0;
    RestorePalette := False;

    if Palette <> 0 then
    begin
      OldPalette := SelectPalette(ACanvas.Handle, Palette, True);
      RealizePalette(ACanvas.Handle);
      RestorePalette := True;
    end;
    BPP := GetDeviceCaps(ACanvas.Handle, BITSPIXEL) *
      GetDeviceCaps(ACanvas.Handle, PLANES);
    DoHalftone := (BPP <= 8) and (PixelFormat in [pf15bit, pf16bit, pf24bit]);
    if DoHalftone then
    begin
      GetBrushOrgEx(ACanvas.Handle, pt);
      SetStretchBltMode(ACanvas.Handle, HALFTONE);
      SetBrushOrgEx(ACanvas.Handle, pt.x, pt.y, @pt);
    end else if not Monochrome then
      SetStretchBltMode(ACanvas.Handle, STRETCH_DELETESCANS);
    try
      AHandle := Canvas.Handle;   {LDB}
      if htTransparent then
      begin
        Save := 0;
        MaskDC := 0;
        try
          MaskDC := CreateCompatibleDC(0);  {LDB}
          Save := SelectObject(MaskDC, MaskHandle);
          TransparentStretchBlt(ACanvas.Handle, Left, Top, Right - Left,
            Bottom - Top, Canvas.Handle, 0, 0, Width,
            Height, htMask.Canvas.Handle, 0, 0);   {LDB}
        finally
          if Save <> 0 then SelectObject(MaskDC, Save);
          if MaskDC <> 0 then DeleteDC(MaskDC);
        end;
      end
      else
        StretchBlt(ACanvas.Handle, Left, Top, Right - Left, Bottom - Top,
          Canvas.Handle, 0, 0, Width,
          Height, ACanvas.CopyMode);
    finally
      if RestorePalette then
        SelectPalette(ACanvas.Handle, OldPalette, True);
    end;
  end;
end;

procedure ThtBitmap.StretchDraw(ACanvas: TCanvas; const DestRect, SrcRect: TRect);
{Draw parts of this bitmap on ACanvas}
var
  OldPalette: HPalette;
  RestorePalette: Boolean;
  DoHalftone: Boolean;
  Pt: TPoint;
  BPP: Integer;
begin
  with DestRect do
  begin
    AHandle := ACanvas.Handle;  {LDB}
    PaletteNeeded;
    OldPalette := 0;
    RestorePalette := False;

    if Palette <> 0 then
    begin
      OldPalette := SelectPalette(ACanvas.Handle, Palette, True);
      RealizePalette(ACanvas.Handle);
      RestorePalette := True;
    end;
    BPP := GetDeviceCaps(ACanvas.Handle, BITSPIXEL) *
      GetDeviceCaps(ACanvas.Handle, PLANES);
    DoHalftone := (BPP <= 8) and (PixelFormat in [pf15bit, pf16bit, pf24bit]);
    if DoHalftone then
    begin
      GetBrushOrgEx(ACanvas.Handle, pt);
      SetStretchBltMode(ACanvas.Handle, HALFTONE);
      SetBrushOrgEx(ACanvas.Handle, pt.x, pt.y, @pt);
    end else if not Monochrome then
      SetStretchBltMode(ACanvas.Handle, STRETCH_DELETESCANS);
    try
      AHandle := Canvas.Handle;   {LDB}
      if htTransparent then
        TransparentStretchBlt(ACanvas.Handle, Left, Top, Right - Left,
            Bottom - Top, Canvas.Handle,
            SrcRect.Left, SrcRect.Top, SrcRect.Right - SrcRect.Left, SrcRect.Bottom - SrcRect.Top,
            htMask.Canvas.Handle, SrcRect.Left, SrcRect.Top)   {LDB}
      else
        StretchBlt(ACanvas.Handle, Left, Top, Right - Left, Bottom - Top,
          Canvas.Handle,
          SrcRect.Left, SrcRect.Top, SrcRect.Right - SrcRect.Left, SrcRect.Bottom - SrcRect.Top,
          ACanvas.CopyMode);
    finally
      if RestorePalette then
        SelectPalette(ACanvas.Handle, OldPalette, True);
    end;
  end;
end;

end.