Direct2D (39) : 使用 IDWriteTextLayout.Draw() 方法绘制文本

使用 IDWriteTextLayout.Draw() 方法绘制文本主要是实现 IDWriteTextRenderer 接口。
IDWriteTextRenderer 接口只能是手动实现，很灵活。

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
    procedure FormResize(Sender: TObject);
  end;

  TMyWriteTextRenderer = class(TInterfacedObject, IDWriteTextRenderer)
  private
    FRenderTarge: ID2D1RenderTarget;
    FOutLineBrush,FFillBrush: ID2D1Brush;
  public
    constructor Create(ARenderTarge: ID2D1RenderTarget; AOutLineBrush,AFillBrush: ID2D1Brush);
    function IsPixelSnappingDisabled(clientDrawingContext: Pointer; var isDisabled: LongBool): HRESULT;
      stdcall;
    function GetCurrentTransform(clientDrawingContext: Pointer; var transform: DWRITE_MATRIX): HRESULT;
      stdcall;
    function GetPixelsPerDip(clientDrawingContext: Pointer; var pixelsPerDip: Single): HRESULT; stdcall;
    function DrawGlyphRun(clientDrawingContext: Pointer; baselineOriginX: Single; baselineOriginY: Single;
      measuringMode: DWRITE_MEASURING_MODE; var glyphRun: DWRITE_GLYPH_RUN;
      var glyphRunDescription: DWRITE_GLYPH_RUN_DESCRIPTION; const clientDrawingEffect: IInterface): HRESULT;
      stdcall;
    function DrawUnderline(clientDrawingContext: Pointer; baselineOriginX: Single; baselineOriginY: Single;
      var underline: DWRITE_UNDERLINE; const clientDrawingEffect: IInterface): HRESULT; stdcall;
    function DrawStrikethrough(clientDrawingContext: Pointer; baselineOriginX: Single;
      baselineOriginY: Single; var strikethrough: DWRITE_STRIKETHROUGH;
      const clientDrawingEffect: IInterface): HRESULT; stdcall;
    function DrawInlineObject(clientDrawingContext: Pointer; originX: Single; originY: Single;
      var inlineObject: IDWriteInlineObject; isSideways: LongBool; isRightToLeft: LongBool;
      const clientDrawingEffect: IInterface): HRESULT; stdcall;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


{构建 DWRITE_TEXT_RANGE 结构的函数}
function DWriteTextRange(pos,len: Cardinal): TDwriteTextRange;
begin
  Result.startPosition := pos;
  Result.length := len;
end;

{构建 DWRITE_FONT_FEATURE 结构的函数}
function DWriteFontFeature(nameTag: Integer; parameter: Cardinal): TDwriteFontFeature;
begin
  Result.nameTag := nameTag;
  Result.parameter := parameter;
end;

{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;

procedure TForm1.FormPaint(Sender: TObject);
var
  cvs: TDirect2DCanvas;
  str: string;
  iTextFormat: IDWriteTextFormat;
  iSolidColorBrush: ID2D1SolidColorBrush;
  iBitmapBrush: ID2D1BitmapBrush;
  iTextLayout: IDWriteTextLayout;
  iTypography: IDWriteTypography;
  iTextRenderer: IDWriteTextRenderer;
begin
  str := 'Hello World using DirectWrite!';
  DWriteFactory.CreateTextFormat(
    'Gabriola',
    nil,
    DWRITE_FONT_WEIGHT_REGULAR,
    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);

  DWriteFactory.CreateTextLayout(
    PWideChar(str),
    Length(str),
    iTextFormat,
    ClientWidth,
    ClientHeight,
    iTextLayout
  );

  iTextLayout.SetFontSize(100.0, DWriteTextRange(18, 6));
  iTextLayout.SetUnderline(True, DWriteTextRange(18, 11));
  iTextLayout.SetFontWeight(DWRITE_FONT_WEIGHT_BOLD, DWriteTextRange(18, 11));

  DWriteFactory.CreateTypography(iTypography);
  iTypography.AddFontFeature(DWriteFontFeature(DWRITE_FONT_FEATURE_TAG_STYLISTIC_SET_6, 1));
  iTextLayout.SetTypography(iTypography, DWriteTextRange(0, Length(str)));

  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);
  cvs.RenderTarget.CreateSolidColorBrush(D2D1ColorF(clBlack), nil, iSolidColorBrush);
  iBitmapBrush := GetBitmapBrush(cvs, 'C:\Temp\Test.bmp');
  iTextRenderer := TMyWriteTextRenderer.Create(cvs.RenderTarget, iSolidColorBrush, iBitmapBrush);
  cvs.RenderTarget.BeginDraw;
  cvs.RenderTarget.Clear(D2D1ColorF(clWhite));
  iTextLayout.Draw(nil, iTextRenderer, 0, 0);
  cvs.RenderTarget.EndDraw();
  cvs.Free;
end;

procedure TForm1.FormResize(Sender: TObject);
begin
  Repaint;
end;

{ TMyWriteTextRenderer }

constructor TMyWriteTextRenderer.Create(ARenderTarge: ID2D1RenderTarget; AOutLineBrush,
  AFillBrush: ID2D1Brush);
begin
  FRenderTarge := ARenderTarge;
  FOutLineBrush := AOutLineBrush;
  FFillBrush := AFillBrush;
end;

function TMyWriteTextRenderer.DrawGlyphRun(clientDrawingContext: Pointer; baselineOriginX,
  baselineOriginY: Single; measuringMode: DWRITE_MEASURING_MODE; var glyphRun: DWRITE_GLYPH_RUN;
  var glyphRunDescription: DWRITE_GLYPH_RUN_DESCRIPTION; const clientDrawingEffect: IInterface): HRESULT;
var
  iPathGeometry: ID2D1PathGeometry;
  iGeometrySink: ID2D1GeometrySink;
  iTransformedGeometry: ID2D1TransformedGeometry;
begin
  D2DFactory.CreatePathGeometry(iPathGeometry);
  iPathGeometry.Open(iGeometrySink);
  glyphRun.fontFace.GetGlyphRunOutline(
    glyphRun.fontEmSize,
    glyphRun.glyphIndices,
    glyphRun.glyphAdvances,
    glyphRun.glyphOffsets,
    glyphRun.glyphCount,
    glyphRun.isSideways,
    longBool(glyphRun.bidiLevel div 2),
    iGeometrySink
  );
  iGeometrySink.Close;

  D2DFactory.CreateTransformedGeometry(
    iPathGeometry,
    TD2DMatrix3x2F.Translation(baselineOriginX, baselineOriginY),
    iTransformedGeometry
  );

  FRenderTarge.DrawGeometry(iTransformedGeometry, FOutLineBrush);
  FRenderTarge.FillGeometry(iTransformedGeometry, FFillBrush);
  Result := S_OK;
end;

function TMyWriteTextRenderer.DrawInlineObject(clientDrawingContext: Pointer; originX, originY: Single;
  var inlineObject: IDWriteInlineObject; isSideways, isRightToLeft: LongBool;
  const clientDrawingEffect: IInterface): HRESULT;
begin
  Result := E_NOTIMPL; //未实现
end;

function TMyWriteTextRenderer.DrawStrikethrough(clientDrawingContext: Pointer; baselineOriginX,
  baselineOriginY: Single; var strikethrough: DWRITE_STRIKETHROUGH;
  const clientDrawingEffect: IInterface): HRESULT;
var
  rRectF: TD2DRectF;
  iRectangleGeometry: ID2D1RectangleGeometry;
  iTransformedGeometry: ID2D1TransformedGeometry;
begin
  rRectF := D2D1RectF(
    0,
    strikethrough.offset,
    strikethrough.width,
    strikethrough.offset + strikethrough.thickness
  );

  D2DFactory.CreateRectangleGeometry(rRectF, iRectangleGeometry);
  D2DFactory.CreateTransformedGeometry(
    iRectangleGeometry,
    TD2DMatrix3x2F.Translation(baselineOriginX, baselineOriginY),
    iTransformedGeometry
  );

  FRenderTarge.DrawGeometry(iTransformedGeometry, FOutLineBrush);
  FRenderTarge.FillGeometry(iTransformedGeometry, FFillBrush);
  Result := S_OK;
end;

function TMyWriteTextRenderer.DrawUnderline(clientDrawingContext: Pointer; baselineOriginX,
  baselineOriginY: Single; var underline: DWRITE_UNDERLINE; const clientDrawingEffect: IInterface): HRESULT;
var
  rRectF: TD2DRectF;
  iRectangleGeometry: ID2D1RectangleGeometry;
  iTransformedGeometry: ID2D1TransformedGeometry;
begin
  rRectF := D2D1RectF(
    0,
    underline.offset,
    underline.width,
    underline.offset + underline.thickness
  );

  D2DFactory.CreateRectangleGeometry(rRectF, iRectangleGeometry);
  D2DFactory.CreateTransformedGeometry(
    iRectangleGeometry,
    TD2DMatrix3x2F.Translation(baselineOriginX, baselineOriginY),
    iTransformedGeometry
  );

  FRenderTarge.DrawGeometry(iTransformedGeometry, FOutLineBrush);
  FRenderTarge.FillGeometry(iTransformedGeometry, FFillBrush);
  Result := S_OK;
end;

function TMyWriteTextRenderer.GetCurrentTransform(clientDrawingContext: Pointer;
  var transform: DWRITE_MATRIX): HRESULT;
begin
  FRenderTarge.GetTransform(TD2D1Matrix3x2F(transform));
  Result := S_OK;
end;

function TMyWriteTextRenderer.GetPixelsPerDip(clientDrawingContext: Pointer;
  var pixelsPerDip: Single): HRESULT;
var
  x,y: Single;
begin
  FRenderTarge.GetDpi(x, y);
  pixelsPerDip := x / 96;
  Result := S_OK;
end;

function TMyWriteTextRenderer.IsPixelSnappingDisabled(clientDrawingContext: Pointer;
  var isDisabled: LongBool): HRESULT;
begin
  isDisabled := False;
  Result := S_OK;
end;

end.

---

效果图：

---

简化一下，只描绘文本的轮廓：

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
    procedure FormResize(Sender: TObject);
  end;

  TMyWriteTextRenderer = class(TInterfacedObject, IDWriteTextRenderer)
  private
    FRenderTarge: ID2D1RenderTarget;
    FOutLineBrush: ID2D1Brush;
  public
    constructor Create(ARenderTarge: ID2D1RenderTarget; AOutLineBrush: ID2D1Brush);
    function IsPixelSnappingDisabled(clientDrawingContext: Pointer; var isDisabled: LongBool): HRESULT;
      stdcall;
    function GetCurrentTransform(clientDrawingContext: Pointer; var transform: DWRITE_MATRIX): HRESULT;
      stdcall;
    function GetPixelsPerDip(clientDrawingContext: Pointer; var pixelsPerDip: Single): HRESULT; stdcall;
    function DrawGlyphRun(clientDrawingContext: Pointer; baselineOriginX: Single; baselineOriginY: Single;
      measuringMode: DWRITE_MEASURING_MODE; var glyphRun: DWRITE_GLYPH_RUN;
      var glyphRunDescription: DWRITE_GLYPH_RUN_DESCRIPTION; const clientDrawingEffect: IInterface): HRESULT;
      stdcall;
    function DrawUnderline(clientDrawingContext: Pointer; baselineOriginX: Single; baselineOriginY: Single;
      var underline: DWRITE_UNDERLINE; const clientDrawingEffect: IInterface): HRESULT; stdcall;
    function DrawStrikethrough(clientDrawingContext: Pointer; baselineOriginX: Single;
      baselineOriginY: Single; var strikethrough: DWRITE_STRIKETHROUGH;
      const clientDrawingEffect: IInterface): HRESULT; stdcall;
    function DrawInlineObject(clientDrawingContext: Pointer; originX: Single; originY: Single;
      var inlineObject: IDWriteInlineObject; isSideways: LongBool; isRightToLeft: LongBool;
      const clientDrawingEffect: IInterface): HRESULT; stdcall;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


{构建 DWRITE_TEXT_RANGE 结构的函数}
function DWriteTextRange(pos,len: Cardinal): TDwriteTextRange;
begin
  Result.startPosition := pos;
  Result.length := len;
end;

{构建 DWRITE_FONT_FEATURE 结构的函数}
function DWriteFontFeature(nameTag: Integer; parameter: Cardinal): TDwriteFontFeature;
begin
  Result.nameTag := nameTag;
  Result.parameter := parameter;
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  cvs: TDirect2DCanvas;
  str: string;
  iTextFormat: IDWriteTextFormat;
  iSolidColorBrush: ID2D1SolidColorBrush;
  iTextLayout: IDWriteTextLayout;
  iTypography: IDWriteTypography;
  iTextRenderer: IDWriteTextRenderer;
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);

  DWriteFactory.CreateTextLayout(
    PWideChar(str),
    Length(str),
    iTextFormat,
    ClientWidth,
    ClientHeight,
    iTextLayout
  );

  iTextLayout.SetFontSize(100.0, DWriteTextRange(18, 6));
  iTextLayout.SetUnderline(True, DWriteTextRange(18, 11));
  iTextLayout.SetFontWeight(DWRITE_FONT_WEIGHT_BOLD, DWriteTextRange(18, 11));

  DWriteFactory.CreateTypography(iTypography);
  iTypography.AddFontFeature(DWriteFontFeature(DWRITE_FONT_FEATURE_TAG_STYLISTIC_SET_6, 1));
  iTextLayout.SetTypography(iTypography, DWriteTextRange(0, Length(str)));

  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);
  cvs.RenderTarget.CreateSolidColorBrush(D2D1ColorF(clRed), nil, iSolidColorBrush);
  iTextRenderer := TMyWriteTextRenderer.Create(cvs.RenderTarget, iSolidColorBrush);
  cvs.RenderTarget.BeginDraw;
  cvs.RenderTarget.Clear(D2D1ColorF(clWhite));
  iTextLayout.Draw(nil, iTextRenderer, 0, 0);
  cvs.RenderTarget.EndDraw();
  cvs.Free;
end;

procedure TForm1.FormResize(Sender: TObject);
begin
  Repaint;
end;

{ TMyWriteTextRenderer }

constructor TMyWriteTextRenderer.Create(ARenderTarge: ID2D1RenderTarget; AOutLineBrush: ID2D1Brush);
begin
  FRenderTarge := ARenderTarge;
  FOutLineBrush := AOutLineBrush;
end;

function TMyWriteTextRenderer.DrawGlyphRun(clientDrawingContext: Pointer; baselineOriginX,
  baselineOriginY: Single; measuringMode: DWRITE_MEASURING_MODE; var glyphRun: DWRITE_GLYPH_RUN;
  var glyphRunDescription: DWRITE_GLYPH_RUN_DESCRIPTION; const clientDrawingEffect: IInterface): HRESULT;
var
  iPathGeometry: ID2D1PathGeometry;
  iGeometrySink: ID2D1GeometrySink;
  iTransformedGeometry: ID2D1TransformedGeometry;
begin
  D2DFactory.CreatePathGeometry(iPathGeometry);
  iPathGeometry.Open(iGeometrySink);
  glyphRun.fontFace.GetGlyphRunOutline(
    glyphRun.fontEmSize,
    glyphRun.glyphIndices,
    glyphRun.glyphAdvances,
    glyphRun.glyphOffsets,
    glyphRun.glyphCount,
    glyphRun.isSideways,
    longBool(glyphRun.bidiLevel div 2),
    iGeometrySink
  );
  iGeometrySink.Close;

  D2DFactory.CreateTransformedGeometry(
    iPathGeometry,
    TD2DMatrix3x2F.Translation(baselineOriginX, baselineOriginY),
    iTransformedGeometry
  );

  FRenderTarge.DrawGeometry(iTransformedGeometry, FOutLineBrush);
  Result := S_OK;
end;

function TMyWriteTextRenderer.DrawInlineObject(clientDrawingContext: Pointer; originX, originY: Single;
  var inlineObject: IDWriteInlineObject; isSideways, isRightToLeft: LongBool;
  const clientDrawingEffect: IInterface): HRESULT;
begin
  Result := E_NOTIMPL;
end;

function TMyWriteTextRenderer.DrawStrikethrough(clientDrawingContext: Pointer; baselineOriginX,
  baselineOriginY: Single; var strikethrough: DWRITE_STRIKETHROUGH;
  const clientDrawingEffect: IInterface): HRESULT;
begin
  Result := E_NOTIMPL;
end;

function TMyWriteTextRenderer.DrawUnderline(clientDrawingContext: Pointer; baselineOriginX,
  baselineOriginY: Single; var underline: DWRITE_UNDERLINE; const clientDrawingEffect: IInterface): HRESULT;
var
  rRectF: TD2DRectF;
  iRectangleGeometry: ID2D1RectangleGeometry;
  iTransformedGeometry: ID2D1TransformedGeometry;
begin
  rRectF := D2D1RectF(
    0,
    underline.offset,
    underline.width,
    underline.offset + underline.thickness
  );

  D2DFactory.CreateRectangleGeometry(rRectF, iRectangleGeometry);
  D2DFactory.CreateTransformedGeometry(
    iRectangleGeometry,
    TD2DMatrix3x2F.Translation(baselineOriginX, baselineOriginY),
    iTransformedGeometry
  );

  FRenderTarge.DrawGeometry(iTransformedGeometry, FOutLineBrush);
  Result := S_OK;
end;

function TMyWriteTextRenderer.GetCurrentTransform(clientDrawingContext: Pointer;
  var transform: DWRITE_MATRIX): HRESULT;
begin
  FRenderTarge.GetTransform(TD2D1Matrix3x2F(transform));
  Result := S_OK;
end;

function TMyWriteTextRenderer.GetPixelsPerDip(clientDrawingContext: Pointer;
  var pixelsPerDip: Single): HRESULT;
var
  x,y: Single;
begin
  FRenderTarge.GetDpi(x, y);
  pixelsPerDip := x / 96;
  Result := S_OK;
end;

function TMyWriteTextRenderer.IsPixelSnappingDisabled(clientDrawingContext: Pointer;
  var isDisabled: LongBool): HRESULT;
begin
  isDisabled := False;
  Result := S_OK;
end;

end.

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效果图：

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