Как определить графический формат файла (не используя расширение)?

Previous  Top  Next

    
 

 

 

 

You can determine it without extention. Below is a function that reads the file header and determines the type.

Code:

function PhysicalResolveFileType(AStream: TStream): Integer;

var

p: PChar;

begin

Result := 0;

if not Assigned(AStream) then

   Exit;

GetMem(p, 10);

try

   AStream.Position := 0;

   AStream.Read(p[0], 10);

   {bitmap format}

   if (p[0] = #66) and (p[1] = #77) then

     Result := 1;

   {tiff format}

   if ((p[0] = #73) and (p[1] = #73) and (p[2] = #42) and (p[3] = #0)) or

     ((p[0] = #77) and (p[1] = #77) and (p[2] = #42) and (p[3] = #0)) then

     Result := 2;

   {jpg format}

   if (p[6] = #74) and (p[7] = #70) and (p[8] = #73) and (p[9] = #70) then

     Result := 3;

   {png format}

   if (p[0] = #137) and (p[1] = #80) and (p[2] = #78) and (p[3] = #71) and

     (p[4] = #13) and (p[5] = #10) and (p[6] = #26) and (p[7] = #10) then

     Result := 4;

   {dcx format}

   if (p[0] = #177) and (p[1] = #104) and (p[2] = #222) and (p[3] = #58) then

     Result := 5;

   {pcx format}

   if p[0] = #10 then

     Result := 6;

   {emf format}

   if (p[0] = #215) and (p[1] = #205) and (p[2] = #198) and (p[3] = #154) then

     Result := 7;

   {emf format}

   if (p[0] = #1) and (p[1] = #0) and (p[2] = #0) and (p[3] = #0) then

     Result := 7;

finally

   Freemem(p);

end;

end;

 

 

©Drkb::04290

Взято с Delphi Knowledge Base: http://www.baltsoft.com/