LibreOffice Module vcl (master)  1
vcllayout.hxx
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19 
20 #ifndef INCLUDED_VCL_VCLLAYOUT_HXX
21 #define INCLUDED_VCL_VCLLAYOUT_HXX
22 
24 #include <tools/gen.hxx>
25 #include <vcl/devicecoordinate.hxx>
26 #include <vcl/dllapi.h>
27 
28 class ImplLayoutArgs;
29 class PhysicalFontFace;
30 class SalGraphics;
31 class GlyphItem;
32 class SalLayoutGlyphs;
33 
34 // all positions/widths are in font units
35 // one exception: drawposition is in pixel units
36 
37 // Unfortunately there is little documentation to help implementors of
38 // new classes derived from SalLayout ("layout engines"), and the code
39 // and data structures are far from obvious.
40 
41 // For instance, I *think* the important virtual functions in the
42 // layout engines are called in this order:
43 
44 // * InitFont()
45 // * LayoutText()
46 // * AdjustLayout(), any number of times (but presumably
47 // usually not at all or just once)
48 // * Optionally, DrawText()
49 
50 // Functions that just return information like GetTexWidth() and
51 // FillDXArray() are called after LayoutText() and before DrawText().
52 
53 // Another important questions is which parts of an ImplLayoutArgs can
54 // be changed by callers between LayoutText() and AdjustLayout()
55 // calls. It probably makes sense only if one assumes that the "string
56 // related inputs" part are not changed after LayoutText().
57 
58 // But why use the same ImplLayoutArgs structure as parameter for both
59 // LayoutText() and AdjustLayout() in the first place? And why
60 // duplicate some of the fields in both SalLayout and ImplLayoutArgs
61 // (mnMinCharPos, mnEndCharPos, mnLayoutFlags==mnFlags,
62 // mnOrientation)? Lost in history...
63 
65 {
66 public:
67  virtual ~SalLayout();
68  // used by upper layers
69  Point& DrawBase() { return maDrawBase; }
70  const Point& DrawBase() const { return maDrawBase; }
71  Point& DrawOffset() { return maDrawOffset; }
72  const Point& DrawOffset() const { return maDrawOffset; }
73  Point GetDrawPosition( const Point& rRelative = Point(0,0) ) const;
74 
75  virtual bool LayoutText( ImplLayoutArgs&, const SalLayoutGlyphs* ) = 0; // first step of layouting
76  virtual void AdjustLayout( ImplLayoutArgs& ); // adjusting after fallback etc.
77  virtual void InitFont() const {}
78  virtual void DrawText( SalGraphics& ) const = 0;
79 
80  int GetUnitsPerPixel() const { return mnUnitsPerPixel; }
81  int GetOrientation() const { return mnOrientation; }
82 
83  // methods using string indexing
84  virtual sal_Int32 GetTextBreak(DeviceCoordinate nMaxWidth, DeviceCoordinate nCharExtra, int nFactor) const = 0;
85  virtual DeviceCoordinate FillDXArray( DeviceCoordinate* pDXArray ) const = 0;
86  virtual DeviceCoordinate GetTextWidth() const { return FillDXArray( nullptr ); }
87  virtual void GetCaretPositions( int nArraySize, long* pCaretXArray ) const = 0;
88  virtual bool IsKashidaPosValid ( int /*nCharPos*/ ) const { return true; } // i60594
89 
90  // methods using glyph indexing
91  virtual bool GetNextGlyph(const GlyphItem** pGlyph, Point& rPos, int& nStart,
92  const PhysicalFontFace** pFallbackFont = nullptr,
93  int* const pFallbackLevel = nullptr) const = 0;
94  virtual bool GetOutline(basegfx::B2DPolyPolygonVector&) const;
95  bool GetBoundRect(tools::Rectangle&) const;
96 
97  virtual const SalLayoutGlyphs* GetGlyphs() const;
98 
99 protected:
100  // used by layout engines
101  SalLayout();
102 
103 private:
104  SalLayout(const SalLayout&) = delete;
105  SalLayout& operator=(const SalLayout&) = delete;
106 
107 protected:
110 
113 
116 };
117 
118 #endif // INCLUDED_VCL_VCLLAYOUT_HXX
119 
120 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
int GetUnitsPerPixel() const
Definition: vcllayout.hxx:80
#define VCL_DLLPUBLIC
Definition: dllapi.h:29
virtual DeviceCoordinate GetTextWidth() const
Definition: vcllayout.hxx:86
Point maDrawBase
Definition: vcllayout.hxx:115
const Point & DrawBase() const
Definition: vcllayout.hxx:70
long DeviceCoordinate
abstract base class for physical font faces
int mnEndCharPos
Definition: vcllayout.hxx:109
virtual void InitFont() const
Definition: vcllayout.hxx:77
Point & DrawBase()
Definition: vcllayout.hxx:69
int GetOrientation() const
Definition: vcllayout.hxx:81
int mnUnitsPerPixel
Definition: vcllayout.hxx:111
int mnOrientation
Definition: vcllayout.hxx:112
virtual bool IsKashidaPosValid(int) const
Definition: vcllayout.hxx:88
const Point & DrawOffset() const
Definition: vcllayout.hxx:72
int mnMinCharPos
Definition: vcllayout.hxx:108
Point maDrawOffset
Definition: vcllayout.hxx:114
Point & DrawOffset()
Definition: vcllayout.hxx:71
::std::vector< B2DPolyPolygon > B2DPolyPolygonVector