Встала задача – создать thumbnails для полноформатных изображений. В сети уйма информации, не знал за что хвататься, решил пробовать по очереди. В сущности, попробовал 2 способа более менее подробно, а остальные по верхам. Остановился на стандартном StretchDraw из Delphi, из за того, что GDI+ почему-то в дополнительном потоке рисовала белые прямоугольники. Я не стал это глубоко раскапывать, так как нужно было решать задачу.
В результате получим кучу уменьшенный фотографий практически из любых форматов. Я тестил с Jpg, PNG, Tiff, с другими думаю тоже будет работать, так как для загрузки используется twicimage.
Коды приведенные ниже иллюстрируют уменьшение большого числа изображений. Как это работает?
Выбираем директорию
Запускается отдельный поток, в котором в цикле уменьшается большое число изображений
Всё складывается в папочку \thumbnaiPics
Я использовал формат twicimage, который позволяет загружать большое число форматов, ну и в программе уже в ручную ставил фильтр на сами форматы.
Как уменьшить одно изображение с помощью библиотеки GDI+?
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... uses GDIPOBJ ... |
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//-------------Diminish one pic GDI+--------------- procedure TDiminishPicsThread.LoadAAImageFromFile(FileName: String; W,H: Integer; Pic: TBitmap); var ImageTemp: TGPImage; graphicsGDIPlus: TGPGraphics; begin if FileExists(FileName) then begin Pic.Width:=W; Pic.Height:=H; graphicsGDIPlus:=TGPGraphics.Create (Pic.Canvas.Handle); ImageTemp:=TGPImage.Create(FileName ); // Trouble here graphicsGDIPlus.DrawImage(ImageTemp , 0,0,W,H); ImageTemp.Free; graphicsGDIPlus.Free; end; end; |
В Filename отправляем путь до файла, который надо уменьшить, в Pic получаем уменьшенное изображение, которое можно как-то сохранить, например вот так…
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procedure TDiminishPicsThread.GDIplusDiminishPic(FilePath:string); var thumbnailPicsDir: string; bmp, bmpDiminished: TBItmap; twic:TWICImage; maxWidth:integer; maxHeight:integer; currentWidth:integer; currentHeight:integer; koeff:Extended; NewWidth: integer; NewHeight: integer; CurrentFileName: string; FileExtension: string; NewFileName: string; begin //Checks... if not TFile.Exists(FilePath) then exit; //Creating dir for Thumbs if not Existed thumbnailPicsDir:=ExtractFileDir(Application.ExeName)+'\thumbnailPics'; if not TDirectory.Exists( thumbnailPicsDir) then TDirectory.CreateDirectory(thumbnailPicsDir); //---- //Getting FileExtension FileExtension:=ExtractFileExt(FilePath); //Setting MaxSize On the Exit... maxWidth:=50; maxHeight:=50; twic:=TWICImage.Create; bmp:= Tbitmap.Create; bmpDiminished:= Tbitmap.Create; try twic.LoadFromFile(FilePath); bmp.Assign(twic); currentWidth:=bmp.Width; currentHeight:=bmp.Height; //Calculating koeff if (currentWidth>maxWidth) or (currentHeight>maxHeight) then koeff:=Min(maxWidth/currentWidth,maxHeight/currentHeight) else koeff:=1; // New width and height NewWidth:=Trunc(koeff*currentWidth); NewHeight:=Trunc(koeff*currentHeight); CurrentFileName:=ExtractFileName(FilePath); NewFileName:=ChangeFileext( CurrentFileName, '_thumb.'+FileExtension ); // <<NewExtension LoadAAImageFromFile(FilePath,NewWidth,NewHeight,bmpDiminished); bmpDiminished.SaveToFile(thumbnailPicsDir+'\'+NewFileName); finally FreeAndNil(bmp); FreeAndNil(bmpDiminished); FreeAndNil(twic); // ShowMessage('success'); end; end; |
Если вызвать этот код для 1 файла, то всё прекрасно отработает. Но запустить его в потоке, скажем так…
Как уменьшить много картинок в отдельном потоке с GDI+?
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procedure TDiminishPicsThread.Execute; var iTick:integer; i: Integer; begin Synchronize( procedure begin FThreadStarter.ProgressBar.Max:=High(PicsInDir); end ); iTick:=GetTickCount; for i := 0 to High(PicsInDir) do begin // Anonymously updating progressBar Synchronize( procedure begin FThreadStarter.ProgressBar.Position:= FThreadStarter.ProgressBar.Position+1; end ); // DiminishPic(PicsInDir[i]); ( GDIplusDiminishPic(FilesInDir[i])); // <<Works unstable Randomly // Anonymously updating caption Synchronize( procedure begin ThreadStarter.Caption:= 'Npics / total = '+i.ToString+' / ' +length(FPicsArray).ToString+ ' Time(ms)='+IntToStr(GetTickCount-iTick); end ); end; fEx := ExceptObject as Exception; Synchronize( QueryError ); end; |
Код запуска дополнительного потока из основного
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procedure TfTestDiminshPics.bMultiDiminishPicsClick(Sender: TObject); var FilesInDir,FilesInDirFiltered:TStringDynArray; i: Integer; Ext: string; DiminishPicsThread:TDiminishPicsThread; AllowedExtensions:string; begin AllowedExtensions:='.bmp,.jpg,.jpeg,.png,.tiff'; //Choosing only folders FileOpenDialog.Options := [fdoPickFolders]; // Getting All files from dir if FileOpenDialog.Execute then FilesInDir:= TDirectory.GetFiles(FileOpenDialog.FileName); //Filtering only pics... in FilesInDirFiltered SetLength(FilesInDirFiltered,0); // nulling... for i := 0 to High(FilesInDir) do begin Ext:=AnsiLowerCase(ExtractFileExt(FilesInDir[i])); if Pos(Ext,AllowedExtensions)>0 then begin SetLength(FilesInDirFiltered,Length(FilesInDirFiltered)+1); FilesInDirFiltered[ High(FilesInDirFiltered) ]:=FilesInDir[i]; end; end; //--------------Starting additional thread if Length(FilesInDir)>0 then begin ProgressBar.Position:=0; //Creating additional thread DiminishPicsThread:=TDiminishPicsThread.Create(true); DiminishPicsThread.FreeOnTerminate:=true; DiminishPicsThread.Priority:=tpHigher; //Transferring params to additional thread DiminishPicsThread.ThreadStarter:=Self; DiminishPicsThread.PicsInDir:=FilesInDirFiltered; DiminishPicsThread.MaxWidth:=50; DiminishPicsThread.MaxHeight:=50; DiminishPicsThread.Start; end; end; |
то в моем случае, этот код стал давать белые прямоугольники вместо картинок… Немного поэкспериментировав, я пришел к тому, что стандартная StretchDraw функция из Delphi вполне выполняет мою задачу.
Как уменьшить много картинок в отдельном потоке при помощи StretchDraw?
Код запуска потока (точно такой же)
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procedure TfTestDiminshPics.bMultiDiminishPicsClick(Sender: TObject); var FilesInDir,FilesInDirFiltered:TStringDynArray; i: Integer; Ext: string; DiminishPicsThread:TDiminishPicsThread; AllowedExtensions:string; begin AllowedExtensions:='.bmp,.jpg,.jpeg,.png,.tiff'; //Choosing only folders FileOpenDialog.Options := [fdoPickFolders]; // Getting All files from dir if FileOpenDialog.Execute then FilesInDir:= TDirectory.GetFiles(FileOpenDialog.FileName); //Filtering only pics... in FilesInDirFiltered SetLength(FilesInDirFiltered,0); // nulling... for i := 0 to High(FilesInDir) do begin Ext:=AnsiLowerCase(ExtractFileExt(FilesInDir[i])); if Pos(Ext,AllowedExtensions)>0 then begin SetLength(FilesInDirFiltered,Length(FilesInDirFiltered)+1); FilesInDirFiltered[ High(FilesInDirFiltered) ]:=FilesInDir[i]; end; end; //--------------Starting additional thread if Length(FilesInDir)>0 then begin ProgressBar.Position:=0; //Creating additional thread DiminishPicsThread:=TDiminishPicsThread.Create(true); DiminishPicsThread.FreeOnTerminate:=true; DiminishPicsThread.Priority:=tpHigher; //Transferring params to additional thread DiminishPicsThread.ThreadStarter:=Self; DiminishPicsThread.PicsInDir:=FilesInDirFiltered; DiminishPicsThread.MaxWidth:=50; DiminishPicsThread.MaxHeight:=50; DiminishPicsThread.Start; end; end; |
Метод уменьшения одной картинки при помощи StretchDraw
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//-------------Diminish one pic Stretch--------------- procedure TDiminishPicsThread.DiminishPic(FilePath:string); var thumbnailPicsDir: string; bmp, bmpDiminished: TBItmap; twic:TWICImage; maxWidth:integer; maxHeight:integer; currentWidth:integer; currentHeight:integer; koeff:Extended; NewWidth: integer; NewHeight: integer; CurrentFileName: string; FileExtension: string; NewFileName: string; Picture:TPicture; ms: TMemoryStream; size:int64; begin //Checks... if not TFile.Exists(FilePath) then exit; //Creating dir for Thumbs if not Existed thumbnailPicsDir:=ExtractFileDir(Application.ExeName)+'\thumbnailPics'; if not TDirectory.Exists( thumbnailPicsDir) then TDirectory.CreateDirectory(thumbnailPicsDir); //---- //Getting FileExtension FileExtension:=ExtractFileExt(FilePath); //Setting MaxSize On the Exit... maxWidth:=FMaxWidth; maxHeight:=FMaxHeight; twic:=TWICImage.Create; bmp:= Tbitmap.Create; //bmp.PixelFormat:=pf32bit; bmp.AlphaFormat:=afDefined; bmpDiminished:= Tbitmap.Create; //bmpDiminished.PixelFormat:=pf32bit; bmpDiminished.AlphaFormat:=afDefined; try twic.LoadFromFile(FilePath); bmp.Assign(twic); currentWidth:=bmp.Width; currentHeight:=bmp.Height; //Calculating koeff if (currentWidth>maxWidth) or (currentHeight>maxHeight) then koeff:=Min(maxWidth/currentWidth,maxHeight/currentHeight) else koeff:=1; // New width and height NewWidth:=Trunc(koeff*currentWidth); NewHeight:=Trunc(koeff*currentHeight); CurrentFileName:=ExtractFileName(FilePath); NewFileName:=ChangeFileext( CurrentFileName, '_thumb'+FileExtension ); // <<NewExtension bmpDiminished.Width:=NewWidth; bmpDiminished.Height:=NewHeight; bmpDiminished.Canvas.StretchDraw(Rect(0, 0, NewWidth, NewHeight), bmp); bmpDiminished.SaveToFile(thumbnailPicsDir+'\'+NewFileName); finally FreeAndNil(twic); FreeAndNil(bmp); FreeAndNil(bmpDiminished); // ShowMessage('success'); end; end; |
Модуль потока – полностью (на всякий случай)
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unit uDiminishPicsThread; interface uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Buttons,GDIPOBJ,Math, System.IOUtils,System.Types, Vcl.ComCtrls,uTestDiminishPics; type TDiminishPicsThread = class(TThread) private FThreadStarter:TfTestDiminshPics; fEx : Exception; FPicsArray:TStringDynArray; FMaxWidth:integer; FMaxHeight:integer; procedure QueryError; procedure GDIplusDiminishPic(FilePath: string); procedure LoadAAImageFromFile(FileName: String; W, H: Integer; Pic: TBitmap); procedure LoadFromFile(FilePath: string; var twic:twicimage); procedure DiminishPic(FilePath: string); public property PicsInDir:TStringDynArray read FPicsArray write FPicsArray; property ThreadStarter:TfTestDiminshPics read FThreadStarter write FThreadStarter; property MaxWidth:integer read FMaxWidth write FMaxWidth; property MaxHeight:integer read FMaxHeight write FMaxHeight; protected procedure Execute; override; end; implementation { TDiminishPicsThread } procedure TDiminishPicsThread.Execute; var iTick:integer; i: Integer; begin FThreadStarter.ProgressBar.Max:=High(PicsInDir); iTick:=GetTickCount; for i := 0 to High(PicsInDir) do begin // Anonymously updating progressBar Synchronize( procedure begin FThreadStarter.ProgressBar.Position:= FThreadStarter.ProgressBar.Position+1; end ); DiminishPic(PicsInDir[i]); // ( GDIplusDiminishPic(FilesInDir[i])); // <<Works unstable Randomly // Anonymously updating caption Synchronize( procedure begin ThreadStarter.Caption:= 'Npics / total = '+i.ToString+' / ' +length(FPicsArray).ToString+ ' Time(ms)='+IntToStr(GetTickCount-iTick); end ); end; fEx := ExceptObject as Exception; Synchronize( QueryError ); end; procedure TDiminishPicsThread.LoadFromFile(FilePath:string; var twic:twicimage); begin twic.LoadFromFile(FilePath); end; procedure TDiminishPicsThread.QueryError; begin Application.OnException(Self,fex); end; procedure TDiminishPicsThread.GDIplusDiminishPic(FilePath:string); var thumbnailPicsDir: string; bmp, bmpDiminished: TBItmap; twic:TWICImage; maxWidth:integer; maxHeight:integer; currentWidth:integer; currentHeight:integer; koeff:Extended; NewWidth: integer; NewHeight: integer; CurrentFileName: string; FileExtension: string; NewFileName: string; begin //Checks... if not TFile.Exists(FilePath) then exit; //Creating dir for Thumbs if not Existed thumbnailPicsDir:=ExtractFileDir(Application.ExeName)+'\thumbnailPics'; if not TDirectory.Exists( thumbnailPicsDir) then TDirectory.CreateDirectory(thumbnailPicsDir); //---- //Getting FileExtension FileExtension:=ExtractFileExt(FilePath); //Setting MaxSize On the Exit... maxWidth:=50; maxHeight:=50; twic:=TWICImage.Create; bmp:= Tbitmap.Create; bmpDiminished:= Tbitmap.Create; try twic.LoadFromFile(FilePath); bmp.Assign(twic); currentWidth:=bmp.Width; currentHeight:=bmp.Height; //Calculating koeff if (currentWidth>maxWidth) or (currentHeight>maxHeight) then koeff:=Min(maxWidth/currentWidth,maxHeight/currentHeight) else koeff:=1; // New width and height NewWidth:=Trunc(koeff*currentWidth); NewHeight:=Trunc(koeff*currentHeight); CurrentFileName:=ExtractFileName(FilePath); NewFileName:=ChangeFileext( CurrentFileName, '_thumb.'+FileExtension ); // <<NewExtension LoadAAImageFromFile(FilePath,NewWidth,NewHeight,bmpDiminished); bmpDiminished.SaveToFile(thumbnailPicsDir+'\'+NewFileName); finally FreeAndNil(bmp); FreeAndNil(bmpDiminished); FreeAndNil(twic); // ShowMessage('success'); end; end; //-------------Diminish one pic GDI+--------------- procedure TDiminishPicsThread.LoadAAImageFromFile(FileName: String; W,H: Integer; Pic: TBitmap); var ImageTemp: TGPImage; graphicsGDIPlus: TGPGraphics; begin if FileExists(FileName) then begin Pic.Width:=W; Pic.Height:=H; graphicsGDIPlus:=TGPGraphics.Create (Pic.Canvas.Handle); ImageTemp:=TGPImage.Create(FileName ); // Trouble here graphicsGDIPlus.DrawImage(ImageTemp , 0,0,W,H); ImageTemp.Free; graphicsGDIPlus.Free; end; end; //-------------Diminish one pic Stretch--------------- procedure TDiminishPicsThread.DiminishPic(FilePath:string); var thumbnailPicsDir: string; bmp, bmpDiminished: TBItmap; twic:TWICImage; maxWidth:integer; maxHeight:integer; currentWidth:integer; currentHeight:integer; koeff:Extended; NewWidth: integer; NewHeight: integer; CurrentFileName: string; FileExtension: string; NewFileName: string; Picture:TPicture; ms: TMemoryStream; size:int64; begin //Checks... if not TFile.Exists(FilePath) then exit; //Creating dir for Thumbs if not Existed thumbnailPicsDir:=ExtractFileDir(Application.ExeName)+'\thumbnailPics'; if not TDirectory.Exists( thumbnailPicsDir) then TDirectory.CreateDirectory(thumbnailPicsDir); //---- //Getting FileExtension FileExtension:=ExtractFileExt(FilePath); //Setting MaxSize On the Exit... maxWidth:=FMaxWidth; maxHeight:=FMaxHeight; twic:=TWICImage.Create; bmp:= Tbitmap.Create; //bmp.PixelFormat:=pf32bit; bmp.AlphaFormat:=afDefined; bmpDiminished:= Tbitmap.Create; //bmpDiminished.PixelFormat:=pf32bit; bmpDiminished.AlphaFormat:=afDefined; try twic.LoadFromFile(FilePath); bmp.Assign(twic); currentWidth:=bmp.Width; currentHeight:=bmp.Height; //Calculating koeff if (currentWidth>maxWidth) or (currentHeight>maxHeight) then koeff:=Min(maxWidth/currentWidth,maxHeight/currentHeight) else koeff:=1; // New width and height NewWidth:=Trunc(koeff*currentWidth); NewHeight:=Trunc(koeff*currentHeight); CurrentFileName:=ExtractFileName(FilePath); NewFileName:=ChangeFileext( CurrentFileName, '_thumb'+FileExtension ); // <<NewExtension bmpDiminished.Width:=NewWidth; bmpDiminished.Height:=NewHeight; bmpDiminished.Canvas.StretchDraw(Rect(0, 0, NewWidth, NewHeight), bmp); bmpDiminished.SaveToFile(thumbnailPicsDir+'\'+NewFileName); finally FreeAndNil(twic); FreeAndNil(bmp); FreeAndNil(bmpDiminished); // FreeAndNil(twic); // ShowMessage('success'); end; end; end. |
Исходники