From c1c277684ce4534bb2267a18363bc16b04b3b6be Mon Sep 17 00:00:00 2001 From: tobigun Date: Thu, 23 Jul 2009 15:00:42 +0000 Subject: font extrusion is done by freetypes stroker API instead of pixel-by-pixel operation on the glyph bitmap -> sharper and nicer outlines git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/branches/experimental@1860 b956fd51-792f-4845-bead-9b4dfca2ff2c --- unicode/src/base/UFont.pas | 179 +++++++++++++++++++++++++++------------------ 1 file changed, 108 insertions(+), 71 deletions(-) (limited to 'unicode') diff --git a/unicode/src/base/UFont.pas b/unicode/src/base/UFont.pas index 346f4a07..ce52ed96 100644 --- a/unicode/src/base/UFont.pas +++ b/unicode/src/base/UFont.pas @@ -464,7 +464,7 @@ type * The bitmap must be 2* pixels wider and higher than the * original glyph's bitmap with the latter centered in it. *} - procedure Extrude(var TexBuffer: TGLubyteDynArray; Outset: single); + procedure StrokeBorder(var Glyph: FT_Glyph); {** * Creates an OpenGL texture (and display list) for the glyph. @@ -496,6 +496,8 @@ type property CharIndex: FT_UInt read fCharIndex; end; + TFontPart = ( fpNone, fpInner, fpOutline ); + {** * Freetype font class. *} @@ -511,6 +513,7 @@ type fLoadFlags: FT_Int32; //**< FT glpyh load-flags fFontUnitScale: TPositionDbl; //**< FT font-units to pixel ratio fUseDisplayLists: boolean; //**< true: use display-lists, false: direct drawing + fPart: TFontPart; //**< indicates the part of an outline font {** @seealso TCachedFont.LoadGlyph } function LoadGlyph(ch: UCS4Char): TGlyph; override; @@ -1416,6 +1419,7 @@ begin fOutset := Outset; fLoadFlags := LoadFlags; fUseDisplayLists := true; + fPart := fpNone; // load font information if (FT_New_Face(TFreeType.GetLibrary(), PChar(Filename), 0, fFace) <> 0) then @@ -1708,7 +1712,9 @@ begin fOutset := Outset; fInnerFont := TFTFont.Create(Filename, Size, 0.0, LoadFlags); + fInnerFont.fPart := fpInner; fOutlineFont := TFTFont.Create(Filename, Size, Outset, LoadFlags); + fOutlineFont.fPart := fpOutline; ResetIntern(); end; @@ -1970,82 +1976,113 @@ const *} cTexSmoothBorder = 1; -procedure TFTGlyph.Extrude(var TexBuffer: TGLubyteDynArray; Outset: single); +procedure TFTGlyph.StrokeBorder(var Glyph: FT_Glyph); +var + Outline: PFT_Outline; + OuterStroker, InnerStroker: FT_Stroker; + OuterNumPoints, InnerNumPoints, GlyphNumPoints: FT_UInt; + OuterNumContours, InnerNumContours, GlyphNumContours: FT_UInt; + OuterBorder, InnerBorder: FT_StrokerBorder; + OutlineFlags: FT_Int; + UseStencil: boolean; +begin + // It is possible to extrude the borders of a glyph with FT_Glyph_Stroke + // but it will extrude the border to the outside and the inside of a glyph + // although we just want to extrude to the outside. + // FT_Glyph_StrokeBorder extrudes to the outside but also fills the interior + // (this is what we need for bold fonts). + // In both cases the inner font and outline font (border) will overlap. + // Normally this does not matter but it does if alpha blending is active. + // In this case if e.g. the inner color is set to white, the outline to red + // and alpha to 0.5 the inner part will not be white it will be pink. + + InnerStroker := nil; + OuterStroker := nil; + + // If we are to create the interior of an outlined font (fInner = true) + // we have to create two borders: + // - one extruded to the outside by fOutset pixels and + // - one extruded to the inside by almost 0 zero pixels. + // The second one is used as a stencil for the first one, clearing the + // interiour of the glyph. + // The stencil is not needed to create bold fonts. + UseStencil := (fFont.fPart = fpInner); + + Outline := @FT_OutlineGlyph(Glyph).outline; + + OuterBorder := FT_Outline_GetOutsideBorder(Outline); + if (OuterBorder = FT_STROKER_BORDER_LEFT) then + InnerBorder := FT_STROKER_BORDER_RIGHT + else + InnerBorder := FT_STROKER_BORDER_LEFT; + + { extrude outer border } + + if (FT_Stroker_New(Glyph.library_, OuterStroker) <> 0) then + raise Exception.Create('FT_Stroker_New failed!'); + FT_Stroker_Set( + OuterStroker, + Round(fOutset * 64), + FT_STROKER_LINECAP_ROUND, + FT_STROKER_LINEJOIN_BEVEL, + 0); + + // similar to FT_Glyph_StrokeBorder(inner = FT_FALSE) but it is possible to + // use FT_Stroker_ExportBorder() afterwards to combine inner and outer borders + if (FT_Stroker_ParseOutline(OuterStroker, Outline, FT_FALSE) <> 0) then + raise Exception.Create('FT_Stroker_ParseOutline failed!'); - procedure SetToMax(var Val1: GLubyte; Val2: GLubyte); {$IFDEF HasInline}inline;{$ENDIF} + FT_Stroker_GetBorderCounts(OuterStroker, OuterBorder, OuterNumPoints, OuterNumContours); + + { extrude inner border (= stencil) } + + if (UseStencil) then begin - if (Val1 < Val2) then - Val1 := Val2; + if (FT_Stroker_New(Glyph.library_, InnerStroker) <> 0) then + raise Exception.Create('FT_Stroker_New failed!'); + FT_Stroker_Set( + InnerStroker, + 63, // extrude at most one pixel to avoid a black border + FT_STROKER_LINECAP_ROUND, + FT_STROKER_LINEJOIN_BEVEL, + 0); + + if (FT_Stroker_ParseOutline(InnerStroker, Outline, FT_FALSE) <> 0) then + raise Exception.Create('FT_Stroker_ParseOutline failed!'); + + FT_Stroker_GetBorderCounts(InnerStroker, InnerBorder, InnerNumPoints, InnerNumContours); + end else begin + InnerNumPoints := 0; + InnerNumContours := 0; end; -var - I, X, Y: integer; - SrcBuffer,TmpBuffer: TGLubyteDynArray; - TexLine, TexLinePrev, TexLineNext: PGLubyteArray; - SrcLine: PGLubyteArray; - AlphaScale: single; - Value, ValueNeigh, ValueDiag: GLubyte; -const - // square-root of 2 used for diagonal neighbor pixels - cSqrt2 = 1.4142; - // number of ignored pixels on each edge of the bitmap. Consists of: - // - border used for font smoothing and - // - outer (extruded) bitmap pixel (because it is just written but never read) - cBorder = cTexSmoothBorder + 1; -begin - // allocate memory for temporary buffer - SetLength(SrcBuffer, Length(TexBuffer)); - FillChar(SrcBuffer[0], Length(TexBuffer), 0); - - // extrude pixel by pixel - for I := 1 to Ceil(Outset) do - begin - // swap arrays - TmpBuffer := TexBuffer; - TexBuffer := SrcBuffer; - SrcBuffer := TmpBuffer; - - // as long as we add an entire pixel of outset, use a solid color. - // If the fractional part is reached blend, e.g. outline=3.2 -> 3 solid - // pixels and one blended with alpha=0.2. - // For the fractional part I = Ceil(Outset) is always true. - if (I <= Outset) then - AlphaScale := 1 - else - AlphaScale := Outset - Trunc(Outset); - - // copy data to the expanded bitmap. - for Y := cBorder to fTexSize.Height - 2*cBorder do - begin - TexLine := @TexBuffer[Y*fTexSize.Width]; - TexLinePrev := @TexBuffer[(Y-1)*fTexSize.Width]; - TexLineNext := @TexBuffer[(Y+1)*fTexSize.Width]; - SrcLine := @SrcBuffer[Y*fTexSize.Width]; + { combine borders (subtract: OuterBorder - InnerBorder) } - // expand current line's pixels - for X := cBorder to fTexSize.Width - 2*cBorder do - begin - Value := SrcLine[X]; - ValueNeigh := Round(Value * AlphaScale); - ValueDiag := Round(ValueNeigh / cSqrt2); + GlyphNumPoints := InnerNumPoints + OuterNumPoints; + GlyphNumContours := InnerNumContours + OuterNumContours; - SetToMax(TexLine[X], Value); - SetToMax(TexLine[X-1], ValueNeigh); - SetToMax(TexLine[X+1], ValueNeigh); + // save flags before deletion (TODO: set them on the resulting outline) + OutlineFlags := Outline.flags; - SetToMax(TexLinePrev[X], ValueNeigh); - SetToMax(TexLinePrev[X-1], ValueDiag); - SetToMax(TexLinePrev[X+1], ValueDiag); + // resize glyph outline to hold inner and outer border + FT_Outline_Done(Glyph.Library_, Outline); + if (FT_Outline_New(Glyph.Library_, GlyphNumPoints, GlyphNumContours, Outline) <> 0) then + raise Exception.Create('FT_Outline_New failed!'); - SetToMax(TexLineNext[X], ValueNeigh); - SetToMax(TexLineNext[X-1], ValueDiag); - SetToMax(TexLineNext[X+1], ValueDiag); - end; - end; - end; + Outline.n_points := 0; + Outline.n_contours := 0; - TmpBuffer := nil; - SetLength(SrcBuffer, 0); + // add points to outline. The inner-border is used as a stencil. + FT_Stroker_ExportBorder(OuterStroker, OuterBorder, Outline); + if (UseStencil) then + FT_Stroker_ExportBorder(InnerStroker, InnerBorder, Outline); + if (FT_Outline_Check(outline) <> 0) then + raise Exception.Create('FT_Stroker_ExportBorder failed!'); + + if (InnerStroker <> nil) then + FT_Stroker_Done(InnerStroker); + if (OuterStroker <> nil) then + FT_Stroker_Done(OuterStroker); end; procedure TFTGlyph.CreateTexture(LoadFlags: FT_Int32); @@ -2068,6 +2105,9 @@ begin if (FT_Get_Glyph(fFont.Face^.glyph, Glyph) <> 0) then raise Exception.Create('FT_Get_Glyph failed'); + if (fOutset > 0) then + StrokeBorder(Glyph); + // store scaled advance width/height in glyph-object fAdvance.X := fFont.Face^.glyph^.advance.x / 64 + fOutset*2; fAdvance.Y := fFont.Face^.glyph^.advance.y / 64 + fOutset*2; @@ -2149,9 +2189,6 @@ begin end; end; - if (fOutset > 0) then - Extrude(TexBuffer, fOutset); - // allocate resources for textures and display lists glGenTextures(1, @fTexture); -- cgit v1.2.3