Direct2D (37) : 使用不同画刷绘制文本

uses Direct2D, D2D1;



{建立位图画刷的函数}

function GetBitmapBrush(Canvas: TDirect2DCanvas; filePath: string): ID2D1BitmapBrush;

var

  rBBP: TD2D1BitmapBrushProperties;

  bit: TBitmap;

begin

  bit := TBitmap.Create;

  bit.LoadFromFile(filePath);

  rBBP.extendModeX := D2D1_EXTEND_MODE_WRAP;

  rBBP.extendModeY := D2D1_EXTEND_MODE_WRAP;

  rBBP.interpolationMode := D2D1_BITMAP_INTERPOLATION_MODE_NEAREST_NEIGHBOR;

  Canvas.RenderTarget.CreateBitmapBrush(Canvas.CreateBitmap(bit), @rBBP, nil, Result);

  bit.Free;

end;



{建立线性渐变画刷的函数}

function GetLinearGradientBrush(RenderTarget: ID2D1RenderTarget; Colors: array of TColor): ID2D1LinearGradientBrush;

var

  rLinear: TD2D1LinearGradientBrushProperties;

  rGradientStops: array of TD2D1GradientStop;

  iGradientStops: ID2D1GradientStopCollection;

  rSizeF: TD2DSizeF;

  count,i: Integer;

begin

  RenderTarget.GetSize(rSizeF);

  rLinear.startPoint := D2D1PointF(0, rSizeF.height/2);

  rLinear.endPoint := D2D1PointF(rSizeF.width, rSizeF.height/2);

  count := Length(Colors);

  SetLength(rGradientStops, count);

  for i := 0 to count - 1 do

  begin

    rGradientStops[i].position := i * (1 / (count-1));

    rGradientStops[i].color := D2D1ColorF(Colors[i]);

  end;

  RenderTarget.CreateGradientStopCollection(

    @rGradientStops[0], count, D2D1_GAMMA_2_2, D2D1_EXTEND_MODE_CLAMP, iGradientStops

  );

  RenderTarget.CreateLinearGradientBrush(rLinear, nil, iGradientStops, Result);

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  cvs: TDirect2DCanvas;

  str: string;

  iTextFormat: IDWriteTextFormat;

  iBrush: ID2D1Brush;

begin

  str := 'Hello World using DirectWrite!';

  DWriteFactory.CreateTextFormat(

    'Gabriola',

    nil,

    DWRITE_FONT_WEIGHT_ULTRA_BLACK,

    DWRITE_FONT_STYLE_NORMAL,

    DWRITE_FONT_STRETCH_NORMAL,

    72.0,

    'en-us',

    iTextFormat

  );

  iTextFormat.SetTextAlignment(DWRITE_TEXT_ALIGNMENT_CENTER);

  iTextFormat.SetParagraphAlignment(DWRITE_PARAGRAPH_ALIGNMENT_CENTER);



  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);

  cvs.RenderTarget.BeginDraw;

  cvs.RenderTarget.Clear(D2D1ColorF(clWhite));



  if Tag = 0 then

    iBrush := GetLinearGradientBrush(cvs.RenderTarget, [clRed, clYellow])

  else

    iBrush := GetBitmapBrush(cvs, 'C:\Temp\Test.bmp'); //!



  cvs.RenderTarget.DrawText(PWideChar(str), Length(str), iTextFormat, ClientRect, iBrush);

  cvs.RenderTarget.EndDraw();

  cvs.Free;

end;



{鼠标单击转换画刷}

procedure TForm1.FormClick(Sender: TObject);

begin

  Tag := not Tag;

  Repaint;

end;



procedure TForm1.FormResize(Sender: TObject);

begin

  Repaint;

end;

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效果图：

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