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| Unit ImageDropDown;
Interface
Uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, Jpeg, pngimage, ShellAPI, ExtCtrls;
Type
TFormatIMG = Set Of (fiJPG, fiBMP, fiPNG);
TImageDropDown<T: TGraphic, Constructor> = Class
Private
originalImageWindowProc : TWndMethod;
FImage : TImage;
FPanel : TPanel;
FIMG : T;
FFormatIMG : TFormatIMG;
FFileName : String;
FOnBeforeLoadImg, FOnAfterLoadImg: TNotifyEvent;
Procedure ImageDrop(Var Msg: TWMDROPFILES);
Public
Procedure ImageWindowProc(Var Msg: TMessage);
Procedure LoadIMG(Const sImgFileName: String);
Procedure ClearIMG;
Procedure SelectIMG;
Constructor Create(AImage: TImage; APanel: TPanel);
Destructor Destroy; Override;
Property IMG: T Read FIMG Write FIMG;
Property FormatIMG: TFormatIMG Read FFormatIMG Write FFormatIMG;
Property FileName: String Read FFileName;
Property OnBeforeLoadImg: TNotifyEvent Read FOnBeforeLoadImg Write FOnBeforeLoadImg;
Property OnAfterLoadImg: TNotifyEvent Read FOnAfterLoadImg Write FOnAfterLoadImg;
End;
Resourcestring
lng_CannotLoadLotOfImg = 'Vous ne pouvez pas déposer plusieurs images en même temps.';
lng_AllImages = 'Tous les formats images supportés';
lng_JPGImages = 'Images JPEG';
lng_BMPImages = 'Images BMP';
lng_PNGImages = 'images PNG';
lng_FileExtIsBad = 'file extension is incorrect';
Implementation
Procedure TImageDropDown<T>.ClearIMG;
Begin
FImage.Picture.Assign(NIL);
FreeAndNil(FIMG);
End;
Procedure TImageDropDown<T>.LoadIMG(Const sImgFileName: String);
Var
Bmp : TBitmap;
Jpg : TJPEGImage;
Png : TPngImage;
FileExt: String;
Begin
Try
If Assigned(OnBeforeLoadImg) Then
OnBeforeLoadImg(Self);
FileExt := ExtractFileExt(sImgFileName);
If ((FileExt = '.jpg') Or (FileExt = '.jpeg')) And (fiJPG In FormatIMG) Then
Begin
Jpg := TJPEGImage.Create;
Try
Jpg.LoadFromFile(sImgFileName);
If Not Assigned(IMG) Then
FIMG := T.Create;
// cannot assign jpg to png directly
If FIMG.ClassNameIs('TPngImage') Then
Begin
Bmp := TBitmap.Create;
Try
Bmp.Assign(Jpg);
FIMG.Assign(Bmp);
Finally
Bmp.Free;
End;
End
Else
FIMG.Assign(Jpg);
FImage.Picture.Assign(Jpg);
Finally
Jpg.Free;
End;
End
Else If (FileExt = '.bmp') And (fiBMP In FormatIMG) Then
Begin
Bmp := TBitmap.Create;
Try
Bmp.LoadFromFile(sImgFileName);
If Not Assigned(IMG) Then
FIMG := T.Create;
FIMG.Assign(Bmp);
FImage.Picture.Assign(Bmp);
Finally
Bmp.Free;
End;
End
Else If (FileExt = '.png') And (fiPNG In FormatIMG) Then
Begin
Png := TPngImage.Create;
Try
Png.LoadFromFile(sImgFileName);
If Not Assigned(IMG) Then
FIMG := T.Create;
// cannot assign png to jpg directly
If FIMG.ClassNameIs('TJPEGImage') Then
Begin
Bmp := TBitmap.Create;
Try
Bmp.Assign(Png);
FIMG.Assign(Bmp);
Finally
Bmp.Free;
End;
End
Else
FIMG.Assign(Png);
FImage.Picture.Assign(Png);
Finally
Png.Free;
End;
End
Else
Raise Exception.Create(lng_FileExtIsBad);
FFileName := ExtractFileName(sImgFileName);
If Assigned(OnAfterLoadImg) Then
OnAfterLoadImg(Self);
Except
FreeAndNil(FIMG);
Raise;
End;
End;
Procedure TImageDropDown<T>.SelectIMG;
Var
sFileMask: String;
Begin
sFileMask := '';
If fiJPG In FormatIMG Then
sFileMask := sFileMask + '*.jpg;*.jpeg;';
If fiBMP In FormatIMG Then
sFileMask := sFileMask + '*.bmp;';
If fiPNG In FormatIMG Then
sFileMask := sFileMask + '*.png';
If (sFileMask <> '') And (sFileMask[Length(sFileMask) - 1] = ';') Then
SetLength(sFileMask, -1);
// if vista or +
If Win32MajorVersion >= 6 Then
Begin
With TFileOpenDialog.Create(NIL) Do
Try
If fiJPG In FormatIMG Then
DefaultExtension := 'jpg'
Else If fiBMP In FormatIMG Then
DefaultExtension := 'bmp'
Else If fiPNG In FormatIMG Then
DefaultExtension := 'png';
With FileTypes.Add Do
Begin
DisplayName := lng_AllImages;
FileMask := sFileMask;
End;
If fiJPG In FormatIMG Then
Begin
With FileTypes.Add Do
Begin
DisplayName := lng_JPGImages;
FileMask := '*.jpg;*.jpeg';
End;
End;
If fiBMP In FormatIMG Then
Begin
With FileTypes.Add Do
Begin
DisplayName := lng_BMPImages;
FileMask := '*.bmp';
End;
End;
If fiPNG In FormatIMG Then
Begin
With FileTypes.Add Do
Begin
DisplayName := lng_PNGImages;
FileMask := '*.png';
End;
End;
If Execute Then
LoadIMG(FileName);
Finally
Free;
End;
End
Else
Begin
With TOpenDialog.Create(NIL) Do
Try
sFileMask := lng_AllImages + '|' + sFileMask + '|';
If fiJPG In FormatIMG Then
sFileMask := sFileMask + lng_JPGImages + '|*.jpg;*.jpeg|';
If fiBMP In FormatIMG Then
sFileMask := sFileMask + lng_BMPImages + '|*.bmp|';;
If fiPNG In FormatIMG Then
sFileMask := sFileMask + lng_PNGImages + '|*.png';
If (sFileMask <> '') And (sFileMask[Length(sFileMask) - 1] = '|') Then
SetLength(sFileMask, -1);
Filter := sFileMask;
Options := [ofHideReadOnly, ofFileMustExist, ofEnableSizing];
If Execute Then
LoadIMG(FileName);
Finally
Free;
End;
End;
End;
Procedure TImageDropDown<T>.ImageWindowProc(Var Msg: TMessage);
Begin
If Msg.Msg = WM_DROPFILES Then
ImageDrop(TWMDROPFILES(Msg))
Else
originalImageWindowProc(Msg);
End;
Constructor TImageDropDown<T>.Create(AImage: TImage; APanel: TPanel);
Begin
FormatIMG := [fiJPG, fiBMP, fiPNG];
FImage := AImage;
FPanel := APanel;
FFileName := '';
FOnBeforeLoadImg := NIL;
FOnAfterLoadImg := NIL;
originalImageWindowProc := APanel.WindowProc;
APanel.WindowProc := ImageWindowProc;
DragAcceptFiles(APanel.Handle, True);
End;
Destructor TImageDropDown<T>.Destroy;
Begin
If Assigned(FPanel) Then
Begin
FPanel.WindowProc := originalImageWindowProc;
DragAcceptFiles(FPanel.Handle, False);
End;
If Assigned(FIMG) Then
FIMG.Free;
Inherited;
End;
Procedure TImageDropDown<T>.ImageDrop(Var Msg: TWMDROPFILES);
Var
numFiles: Longint;
Buffer : Array [0 .. MAX_PATH] Of Char;
Begin
numFiles := DragQueryFile(Msg.Drop, $FFFFFFFF, NIL, 0);
If numFiles = 1 Then
Begin
DragQueryFile(Msg.Drop, 0, @Buffer, sizeof(Buffer));
LoadIMG(Buffer);
End
Else
Raise Exception.Create(lng_CannotLoadLotOfImg);
End;
End. |
10/01/2011, 20h10
Alexandre 
[Delphi] Drag Drop image conversion
00
