delphi – 我可以生成大于149的抗锯齿字体吗？

原始的演示应用程序在这里,但它使用的是TForm,我改为TWinControl,它没有GDI后备,只是一个例外.

http://cc.embarcadero.com/item/27491

撰写上述演示的Pawel Glowacki的讨论/博客文章如下：

http://blogs.embarcadero.com/pawelglowacki/2009/12/14/38872

此处显示了一个代码片段,其中包含来自Pawel演示的修改后的D2DUtils.pas,并添加了GDI后备功能(而不是用例说明).

uses
  Windows,Messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,Winapi.D2D1,Vcl.Direct2D;


type
   TCanvasD2D = class(TWinControl) // a base class,using TWinControl instead of TForm.
   private
      FInitFlag: Boolean;
      FGDIMode: Boolean; { Fallback }
      FD2DCanvas: TDirect2DCanvas; { Used When D2D is available and GDIMode=False }
      FGDICanvas: TCanvas; { Fallback canvas,used when FGDIMode=True }
      procedure WMEraseBkgnd(var Message: TWMEraseBkgnd); message WM_ERASEBKGND;
   protected
      procedure Resize; override;

      procedure DoPaint(AHDC: HDC); virtual;

      procedure CreateD2DResources; virtual;

      procedure PaintD2D; virtual;
      procedure PaintGDI; virtual;

      function RenderTarget: ID2D1RenderTarget; // convenience function used during D2D Paints.

      procedure PaintWindow(DC: HDC); override;

   public
      constructor Create(AOwner: TComponent); override;
      destructor Destroy; override;

      procedure Init;
      property D2DCanvas: TDirect2DCanvas read FD2DCanvas;
      property GDICanvas: TCanvas read FGDICanvas;

      property GDIMode: Boolean read FGDIMode write FGDIMode;
      { Set to true to force GDI fallback,will automatically set true if D2D is not available,also }
   end;


TCanvasD2DSample = class(TCanvasD2D) // subclass of TCanvasD2D that is a primitive "TLabel"
    private
    FFontBrush: ID2D1SolidColorBrush;// Brush generated from current value of FFontColor
    FBackgroundColor:TColor; // clWhite
    FFontColor:TColor; //clBlack;
    FTextFormat: IDWriteTextFormat;
    FFontName: string;
    FFontSize: Integer;  { Units?}
    FDisplayText: String;
    FLocale: String;


    procedure SetFontName(const Value: String);
    procedure SetFontSize(const Value: Integer);
    procedure SetDisplayText(const Value: String);

  protected
    procedure PaintD2D; override;
    procedure PaintGDI; override;
    procedure CreateD2DResources; override;

    function FontSizeToDip(FontSize:Integer ):Double;

  public
    constructor Create(AOwner: TComponent); override;

    property TextFormat:IDWriteTextFormat read FTextFormat;
    property FontSize:Integer read FFontSize write SetFontSize;
    property FontName:String read FFontName write SetFontName;
    property DisplayText: String read FDisplayText write SetDisplayText;

    property BackgroundColor:TColor read FBackgroundColor write FBackgroundColor;
    property FontColor:TColor read FFontColor write FFontColor; //clBlack;


    property Locale: String read FLocale write FLocale; // string like 'en-us'

  end;

implementation

constructor TCanvasD2D.Create(AOwner: TComponent);
begin
   inherited;

end;

destructor TCanvasD2D.Destroy;
begin
   FD2DCanvas.Free;
   FD2DCanvas := nil;
   FGDICanvas.Free;
   FGDICanvas := nil;

   inherited;
end;

procedure TCanvasD2D.Init;
begin
   if not FInitFlag then
   begin
      FInitFlag := True;

      if (not FGDIMode) and (TDirect2DCanvas.Supported) then
      begin
         if Assigned(FD2DCanvas) then
            FD2DCanvas.Free;
         FD2DCanvas := TDirect2DCanvas.Create(Handle);
         CreateD2DResources;
      end
      else
      begin
         FGDIMode := True;
         if Assigned(FGDICanvas) then
            FGDICanvas.Free;
         FGDICanvas := TCanvas.Create;
         FGDICanvas.Handle := GetDC(Self.Handle);
      end;
   end;
end;

procedure TCanvasD2D.CreateD2DResources;
begin
   // create Direct2D resources in descendant class
end;

function TCanvasD2D.RenderTarget: ID2D1RenderTarget;
begin
   Result := D2DCanvas.RenderTarget;
end;

procedure TCanvasD2D.Resize;
var
   HwndTarget: ID2D1HwndRenderTarget;
   ASize: TD2D1SizeU;
begin
   inherited;

   if Assigned(D2DCanvas) then
      if Supports(RenderTarget,ID2D1HwndRenderTarget,HwndTarget) then
      begin
         ASize := D2D1SizeU(ClientWidth,ClientHeight);
         HwndTarget.Resize(ASize);
      end;

   Invalidate;
end;

procedure TCanvasD2D.WMEraseBkgnd(var Message: TWMEraseBkgnd);
begin
   if (not FGDIMode) then
      // avoid flicker as described here:
      // http://chrisbensen.blogspot.com/2009/09/touch-demo-part-i.html
      Message.Result := 1
   else
      inherited;
end;

procedure TCanvasD2D.DoPaint(AHDC: HDC);
begin
   Init;
   if FGDIMode then
   begin
      FGDICanvas.Handle := AHDC;
      PaintGDI;
   end
   else
   begin
      D2DCanvas.BeginDraw;
      try
         PaintD2D;
      finally
         D2DCanvas.EndDraw;
      end;
   end;
end;

procedure TCanvasD2D.PaintD2D;
begin
   // implement painting code in descendant class
end;

procedure TCanvasD2D.PaintGDI;
begin
   // implement in descendant.
end;

procedure TCanvasD2D.PaintWindow(DC: HDC);
begin
   DoPaint(DC);
   inherited;

end;




{ Custom Control Subclass }
procedure TCanvasD2DSample.CreateD2DResources;

begin
  inherited;

  D2DCanvas.RenderTarget.CreateSolidColorBrush(
    D2D1ColorF(FFontColor,1),nil,FFontBrush
    );

  DWriteFactory.CreateTextFormat(
    PWideChar(FontName),DWRITE_FONT_WEIGHT_REGULAR,DWRITE_FONT_STYLE_NORMAL,DWRITE_FONT_STRETCH_NORMAL,FontSizeToDip( FontSize),PWideChar(FLocale),FTextFormat
   );

   FTextFormat.SetTextAlignment(DWRITE_TEXT_ALIGNMENT_CENTER);
   FTextFormat.SetParagraphAlignment(DWRITE_PARAGRAPH_ALIGNMENT_CENTER);
end;



function TCanvasD2DSample.FontSizeToDip(FontSize: Integer): Double;
begin
   result := FontSize * (96.0 / 72.0); { TODO: 96.0 should not be hard coded? }
end;

procedure TCanvasD2DSample.PaintD2D;
var
  aRect: TD2D1RectF;
//  ASize:D2D_SIZE_F;
begin

  // fill with white color the whole window
  RenderTarget.Clear(D2D1ColorF(FBackgroundColor));



  RenderTarget.DrawText(
    PWideChar(FDisplayText),Length(FDisplayText),FTextFormat,D2D1RectF(0,ClientWidth,ClientHeight),FFontBrush
    );

  //  RenderTarget.GetSize(ASize);
end;

procedure TCanvasD2DSample.PaintGDI;
begin
  { FALLBACK PAINT MODE}
  GDICanvas.Lock;
  GDICanvas.Font.Name := FFontName;
  GDICanvas.Font.Size := FFontSize;
  GDICanvas.Font.Color := FFontColor;
  GDICanvas.Brush.Style := bsSolid;
  GDICanvas.Brush.Color := FBackgroundColor;
  GDICanvas.Rectangle(Self.ClientRect);


  GDICanvas.TextOut(0,FDisplayText);
GDICanvas.Unlock;
end;

procedure TCanvasD2DSample.SetDisplayText(const Value: String);
begin
   if Value<>FDisplayText then
   begin
    FDisplayText := Value;
    Invalidate;
   end;
end;

procedure TCanvasD2DSample.SetFontName(const Value: String);
begin
  FFontName := Value;
end;

procedure TCanvasD2DSample.SetFontSize(const Value: Integer);
begin
  FFontSize := Value;
end;