wie art der daten in blob erkennen?

[himitsu]

Boar eh ... immer und immer wieder ... die sollem mal richtige Entwickler einstellen, die ihr eigenes Produckt selber benutzen.

Du kannst dich aber selber an jedes einzelne ImageFormat wenden und es fragen,
TGraphic.CanLoadFromStream

also TBitmap.CanLoadFromStream, TPngImage.CanLoadFromStream, TJPEGImage.CanLoadFromStream usw.

Ein GetFileFormats.FindFormat wäre natürlich einfacher, aber ..... mähhhhhhhhhh

Delphi-Quellcode:

unit Vcl.Graphics;

implementation  <-    was soll dieser perverse Scheiß immer?

var
  ClipboardFormats: TClipboardFormats = nil;
  FileFormats: TFileFormatsList = nil;

function GetFileFormats: TFileFormatsList;
begin
  if FileFormats = nil then FileFormats := TFileFormatsList.Create;
  Result := FileFormats;
end;

function GetClipboardFormats: TClipboardFormats;
begin
  if ClipboardFormats = nil then ClipboardFormats := TClipboardFormats.Create;
  Result := ClipboardFormats;
end;

Delphi-Quellcode:

procedure TPicture.LoadFromFile(const Filename: string);
var
  Ext: string;
  GraphicClass: TGraphicClass;
  Context: TFindGraphicClassContext;
begin
  Ext := ExtractFileExt(Filename).Remove(0, 1);
  GraphicClass := FileFormats.FindExt(Ext);

Delphi-Quellcode:

procedure TPicture.LoadFromStream(Stream: TStream);
var
  GraphicClass: TGraphicClass;
  Context: TFindGraphicClassContext;
begin
  if Stream.Size - Stream.Position = 0 then
    GraphicClass := TBitmap
  else
    GraphicClass := FileFormats.FindFormat(Stream);

Delphi-Quellcode:

procedure TPicture.LoadFromClipboardFormat(AFormat: Word; AData: THandle;
  APalette: HPALETTE);
var
  GraphicClass: TGraphicClass;
  Context: TFindGraphicClassContext;
begin
  GraphicClass := ClipboardFormats.FindFormat(AFormat);

das was öffentlich ist, ist hierfür nicht nutzbar.

Delphi-Quellcode:

function GraphicFilter(GraphicClass: TGraphicClass): string;
var
  Filters: string;
begin
  GetFileFormats.BuildFilterStrings(GraphicClass, Result, Filters);
end;

function GraphicExtension(GraphicClass: TGraphicClass): string;
var
  I: Integer;
begin
  for I := GetFileFormats.Count-1 downto 0 do
    if TFileFormatType(FileFormats[I]).GraphicClass.ClassName = GraphicClass.ClassName then
    begin
      Result := TFileFormatType(FileFormats[I]).Extension;
      Exit;
    end;
  Result := '';
end;

function GraphicFileMask(GraphicClass: TGraphicClass): string;
var
  Descriptions: string;
begin
  GetFileFormats.BuildFilterStrings(GraphicClass, Descriptions, Result);
end;