pdf转换图片

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unit MainFrm;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, PdfiumCore, ExtCtrls, StdCtrls, PdfiumCtrl, jpeg, PdfiumLib, Spin,
  ComCtrls,ShellAPI;

type
  TfrmMain = class(TForm)
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    btnStart: TButton;
    Label1: TLabel;
    edtFile: TEdit;
    btnOpen: TButton;
    GroupBox1: TGroupBox;
    rbAll: TRadioButton;
    rbJS: TRadioButton;
    rbOS: TRadioButton;
    rbZDY: TRadioButton;
    seStart: TSpinEdit;
    seEnd: TSpinEdit;
    Label2: TLabel;
    GroupBox2: TGroupBox;
    RichEdit1: TRichEdit;
    ProgressBar1: TProgressBar;
    Label3: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure btnStartClick(Sender: TObject);
    procedure btnOpenClick(Sender: TObject);
  private
    FDocument: TPdfDocument;
  public
    { Public-Deklarationen }
  end;

var
  frmMain: TfrmMain;

implementation

uses
  TypInfo, Printers;

{$R *.dfm}

procedure TfrmMain.FormCreate(Sender: TObject);
begin
  PDFiumDllDir := ExtractFilePath(ParamStr(0));
  FDocument := TPdfDocument.Create;
  seStart.MinValue := 1;
  seEnd.MinValue := 1;
  seStart.MaxValue := 1;
  seEnd.MaxValue := 1;
  ForceDirectories(PDFiumDllDir + '图片');
end;

function ColorToARGB(Color: TColor; Alpha: Byte = $FF): FPDF_DWORD;
const
  clSystemColor = $FF000000;
var
  RGBColor: DWORD;
begin
  if (DWORD(Color) and clSystemColor) = clSystemColor then
    RGBColor := GetSysColor(DWORD(Color) and $FFFFFF)
  else
    RGBColor := DWORD(Color);

  Result := FPDF_ARGB(Alpha, RGBColor and $FF, (RGBColor and $FF00) shr 8, (RGBColor and $FF0000) shr 16);
end;

procedure ToBitmap(Bitmap: FPDF_BITMAP; Result: TBitmap);
var
  Format, Width, Height, Stride, BytesPerPixel, Y: Integer;
  Buffer: Pointer;
begin
  Format := FPDFBitmap_GetFormat(Bitmap);
  Width := FPDFBitmap_GetWidth(Bitmap);
  Height := FPDFBitmap_GetHeight(Bitmap);
  Stride := FPDFBitmap_GetStride(Bitmap);
  Buffer := FPDFBitmap_GetBuffer(Bitmap);
  case Format of
    FPDFBitmap_Unknown:
      Exit;

    FPDFBitmap_Gray:
      begin
        Result.PixelFormat := pf8bit;
        BytesPerPixel := 1;
      end;

    FPDFBitmap_BGR:
      begin
        Result.PixelFormat := pf24bit;
        BytesPerPixel := 3;
      end;

  else
    begin
      Result.PixelFormat := pf32bit;
      BytesPerPixel := 4;
    end;
  end;

  Result.Width := Width;
  Result.Height := Height;

  for Y := 0 to Height - 1 do
  begin
    Move(Buffer^, Result.ScanLine[Y]^, BytesPerPixel * Width);
    Inc(PByte(Buffer), Stride);
  end;
end;

procedure TfrmMain.btnOpenClick(Sender: TObject);
begin
  if OpenDialog1.Execute then
  begin
    edtFile.Text := OpenDialog1.FileName;
    FDocument.LoadFromFile(edtFile.Text);
    seStart.MaxValue := FDocument.PageCount;
    seEnd.MaxValue := FDocument.PageCount;
    seEnd.Value := seEnd.MaxValue;
  end;
end;

procedure TfrmMain.btnStartClick(Sender: TObject);
var
  i: Integer;
var
  JpegImage: TJpegImage;
  pdfBitmap: TPdfBitmap;
  Bitmap: TBitmap;
  w, h: integer;
begin
  RichEdit1.Clear;
  ProgressBar1.Max := FDocument.PageCount;
  for i := 0 to FDocument.PageCount - 1 do
  begin
    ProgressBar1.Position := i + 1;
    if rbJS.Checked then
    begin
      if (i + 1) mod 2 = 0 then
      begin
        Continue;
      end;
    end;
    if rbOS.Checked then
    begin
      if (i + 1) mod 2 <> 0 then
      begin
        Continue;
      end;
    end;
    if rbZDY.Checked then
    begin
      if not ((i + 1) in [seStart.Value..seEnd.Value]) then
      begin
        Continue;
      end;
    end;
    try
      JpegImage := TJpegImage.Create;
      Bitmap := TBitmap.Create;
      JpegImage.CompressionQuality := 100;
      w := Round(150 * FDocument.Pages[i].Width / 72.0);
      h := Round(150 * FDocument.Pages[i].Height / 72.0);
      w := Round(100 * FDocument.Pages[i].Width / 72.0);
      h := Round(100 * FDocument.Pages[i].Height / 72.0);

      pdfBitmap := TPdfBitmap.Create(w, h, True);
      pdfBitmap.FillRect(0, 0, w, h, ColorToARGB(clWhite));
      FDocument.Pages[i].DrawToPdfBitmap(pdfBitmap, 0, 0, w, h, prNormal, [proAnnotations, proPrinting]);
      ToBitmap(pdfBitmap.Bitmap, Bitmap);
      JpegImage.Assign(Bitmap);
      JpegImage.SaveToFile(ExtractFilePath(ParamStr(0)) +'图片\' + IntToStr(i + 1) + '.jpg');
      RichEdit1.Lines.Add(IntToStr(i + 1) + '.jpg 转换成功！');
      PostMessage(RichEdit1.Handle, WM_VSCROLL, SB_BOTTOM, 0);
    finally
      JpegImage.Free;
      Bitmap.Free;
      pdfBitmap.free;
    end;
  end;
  ShellExecute(0,'open','Explorer.exe',PWideChar(ExtractFilePath(ParamStr(0)) + '图片'),nil,SW_NORMAL);
  RichEdit1.Lines.Add('转换完成！');
end;

end.