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Date Posted: 07:47:23 12/04/00 Mon
Author: Marcel
Subject: Re: EPS Graphic Support
In reply to: Marcel Kung 's message, "EPS Graphic Support" on 23:18:35 12/03/00 Sun


Hi Marcel,

The EPS format is a very complicated format since it is a postscript format requiring a posscript interpreter. I do not have plans to support it. An Envision user has contributed some code though, which allows viewing an EPS preview. Many EPS files under Windows have a tiff or wmf preview inside the EPS file. I don't plan to support this directly, but you want to try it out:

(*
0-3 Must be hex C5D0D3C6 (byte 0=C5).
4-7 Byte position in file for start of PostScript language code section.
8-11 Byte length of PostScript language section.
12-15 Byte position in file for start of Metafile screen representation.
16-19 Byte length of Metafile section (PSize).
20-23 Byte position of TIFF representation.
24-27 Byte length of TIFF section.
*)

type
TEPSFHeader = record
Signature,
PSStart,
PSLengh,
WMFStart,
WMFLength,
TIFFStart,
TIFFLength : Cardinal;
end;

function LoadEPSFromStream(st : TStream) : TGraphic;
var
hdr : TEPSFHeader;
ms : TMemoryStream;
start,
count : integer;
begin
result := NIL;
st.Seek(0, soFromBeginning);
st.ReadBuffer(hdr, SizeOf(hdr));
if hdr.Signature <> $C6D3D0C5 then
raise EInvalidGraphic.Create('EPS has no screen representation');
if hdr.TIFFLength > 0 then begin
start := hdr.TIFFStart;
count := hdr.TIFFLength;
result := TTiffGraphic.Create;
end else if hdr.WMFLength > 0 then begin
start := hdr.WMFStart;
count := hdr.WMFLength;
result := TMetaFile.Create;
end else
raise EInvalidGraphic.Create('EPS has no screen representation');
ms := TMemoryStream.Create;
try
ms.SetSize(count);
st.Seek(start, soFromBeginning);
if ms.CopyFrom(st, count) <> count then
raise EInvalidGraphic.Create('TIFF screen representation invalid');
ms.Seek(0, soFromBeginning);
result.LoadFromStream(ms);
finally
ms.free;
end;
end;


For other formats, there are not any short term plans, but I may consider MNG (multiple image png), FlashPix, and JBIG.

Best regards,

Michel

> Hi,
>
> We're currently using envision in a product of ours
> and one of our clients has requested support for EPS
> graphics. Does envision plan on supporting EPS
> graphics? Also what other formats does envision plan
> to support in the future?
>
> Regards
> Marcel

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