include/vcl/vcllayout.hxx

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  19
  20 #pragma once
  21
  22 #include <basegfx/polygon/b2dpolypolygon.hxx>
  23 #include <i18nlangtag/languagetag.hxx>
  24 #include <tools/gen.hxx>
  25 #include <tools/degree.hxx>
  26
  27 #include <vcl/devicecoordinate.hxx>
  28 #include <vcl/glyphitem.hxx>
  29 #include <vcl/dllapi.h>
  30
  31 class LogicalFontInstance;
  32 namespace vcl::text { class ImplLayoutArgs; }
  33 namespace vcl::font { class PhysicalFontFace; }
  34 class SalGraphics;
  35 class GlyphItem;
  36
  37 // all positions/widths are in font units
  38 // one exception: drawposition is in pixel units
  39
  40 // Unfortunately there is little documentation to help implementors of
  41 // new classes derived from SalLayout ("layout engines"), and the code
  42 // and data structures are far from obvious.
  43
  44 // For instance, I *think* the important virtual functions in the
  45 // layout engines are called in this order:
  46
  47 // * InitFont()
  48 // * LayoutText()
  49 // * AdjustLayout(), any number of times (but presumably
  50 // usually not at all or just once)
  51 // * Optionally, DrawText()
  52
  53 // Functions that just return information like GetTexWidth() and
  54 // FillDXArray() are called after LayoutText() and before DrawText().
  55
  56 // Another important questions is which parts of an ImplLayoutArgs can
  57 // be changed by callers between LayoutText() and AdjustLayout()
  58 // calls. It probably makes sense only if one assumes that the "string
  59 // related inputs" part are not changed after LayoutText().
  60
  61 // But why use the same ImplLayoutArgs structure as parameter for both
  62 // LayoutText() and AdjustLayout() in the first place? And why
  63 // duplicate some of the fields in both SalLayout and ImplLayoutArgs
  64 // (mnMinCharPos, mnEndCharPos, mnLayoutFlags==mnFlags,
  65 // mnOrientation)? Lost in history...
  66
  67 class VCL_DLLPUBLIC SalLayout
  68 {
  69 public:
  70     virtual         ~SalLayout();
  71     // used by upper layers
  72     DevicePoint&    DrawBase()                              { return maDrawBase; }
  73     const DevicePoint& DrawBase() const                     { return maDrawBase; }
  74     Point&          DrawOffset()                            { return maDrawOffset; }
  75     const Point&    DrawOffset() const                      { return maDrawOffset; }
  76     DevicePoint     GetDrawPosition( const DevicePoint& rRelative = DevicePoint(0,0) ) const;
  77
  78     virtual bool    LayoutText( vcl::text::ImplLayoutArgs&, const SalLayoutGlyphsImpl* ) = 0;  // first step of layouting
  79     virtual void    AdjustLayout( vcl::text::ImplLayoutArgs& );    // adjusting after fallback etc.
  80     virtual void    InitFont() const {}
  81     virtual void    DrawText( SalGraphics& ) const = 0;
  82
  83     Degree10        GetOrientation() const                  { return mnOrientation; }
  84
  85     void            SetTextRenderModeForResolutionIndependentLayout(bool bTextRenderModeForResolutionIndependentLayout)
  86     {
  87         mbTextRenderModeForResolutionIndependentLayout = bTextRenderModeForResolutionIndependentLayout;
  88     }
  89
  90     bool            GetTextRenderModeForResolutionIndependentLayout() const
  91     {
  92         return mbTextRenderModeForResolutionIndependentLayout;
  93     }
  94
  95     // methods using string indexing
  96     virtual sal_Int32 GetTextBreak(DeviceCoordinate nMaxWidth, DeviceCoordinate nCharExtra, int nFactor) const = 0;
  97     virtual DeviceCoordinate FillDXArray( std::vector<DeviceCoordinate>* pDXArray, const OUString& rStr ) const = 0;
  98     virtual DeviceCoordinate GetTextWidth() const { return FillDXArray( nullptr, {} ); }
  99     virtual void    GetCaretPositions( int nArraySize, sal_Int32* pCaretXArray ) const = 0;
 100     virtual bool    IsKashidaPosValid ( int /*nCharPos*/, int /*nNextCharPos*/ ) const = 0; // i60594
 101
 102     // methods using glyph indexing
 103     virtual bool    GetNextGlyph(const GlyphItem** pGlyph, DevicePoint& rPos, int& nStart,
 104                                  const LogicalFontInstance** ppGlyphFont = nullptr) const = 0;
 105     virtual bool GetOutline(basegfx::B2DPolyPolygonVector&) const;
 106     bool GetBoundRect(tools::Rectangle&) const;
 107
 108     virtual SalLayoutGlyphs GetGlyphs() const;
 109
 110 protected:
 111     // used by layout engines
 112     SalLayout();
 113
 114 private:
 115     SalLayout(const SalLayout&) = delete;
 116     SalLayout& operator=(const SalLayout&) = delete;
 117
 118 protected:
 119     int             mnMinCharPos;
 120     int             mnEndCharPos;
 121     LanguageTag     maLanguageTag;
 122
 123     Degree10        mnOrientation;
 124
 125     mutable Point   maDrawOffset;
 126     DevicePoint     maDrawBase;
 127
 128     bool            mbTextRenderModeForResolutionIndependentLayout;
 129 };
 130
 131 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */