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 <tools/degree.hxx>
26 #include <vcl/devicecoordinate.hxx>
27 #include <vcl/glyphitem.hxx>
28 #include <vcl/dllapi.h>
29 
31 namespace vcl::text { class ImplLayoutArgs; }
32 class PhysicalFontFace;
33 class SalGraphics;
34 class GlyphItem;
35 
36 // all positions/widths are in font units
37 // one exception: drawposition is in pixel units
38 
39 // Unfortunately there is little documentation to help implementors of
40 // new classes derived from SalLayout ("layout engines"), and the code
41 // and data structures are far from obvious.
42 
43 // For instance, I *think* the important virtual functions in the
44 // layout engines are called in this order:
45 
46 // * InitFont()
47 // * LayoutText()
48 // * AdjustLayout(), any number of times (but presumably
49 // usually not at all or just once)
50 // * Optionally, DrawText()
51 
52 // Functions that just return information like GetTexWidth() and
53 // FillDXArray() are called after LayoutText() and before DrawText().
54 
55 // Another important questions is which parts of an ImplLayoutArgs can
56 // be changed by callers between LayoutText() and AdjustLayout()
57 // calls. It probably makes sense only if one assumes that the "string
58 // related inputs" part are not changed after LayoutText().
59 
60 // But why use the same ImplLayoutArgs structure as parameter for both
61 // LayoutText() and AdjustLayout() in the first place? And why
62 // duplicate some of the fields in both SalLayout and ImplLayoutArgs
63 // (mnMinCharPos, mnEndCharPos, mnLayoutFlags==mnFlags,
64 // mnOrientation)? Lost in history...
65 
67 {
68 public:
69  virtual ~SalLayout();
70  // used by upper layers
71  Point& DrawBase() { return maDrawBase; }
72  const Point& DrawBase() const { return maDrawBase; }
73  Point& DrawOffset() { return maDrawOffset; }
74  const Point& DrawOffset() const { return maDrawOffset; }
75  Point GetDrawPosition( const Point& rRelative = Point(0,0) ) const;
76 
77  virtual bool LayoutText( vcl::text::ImplLayoutArgs&, const SalLayoutGlyphsImpl* ) = 0; // first step of layouting
78  virtual void AdjustLayout( vcl::text::ImplLayoutArgs& ); // adjusting after fallback etc.
79  virtual void InitFont() const {}
80  virtual void DrawText( SalGraphics& ) const = 0;
81 
82  int GetUnitsPerPixel() const { return mnUnitsPerPixel; }
83  Degree10 GetOrientation() const { return mnOrientation; }
84 
85  // methods using string indexing
86  virtual sal_Int32 GetTextBreak(DeviceCoordinate nMaxWidth, DeviceCoordinate nCharExtra, int nFactor) const = 0;
87  virtual DeviceCoordinate FillDXArray( std::vector<DeviceCoordinate>* pDXArray ) const = 0;
88  virtual DeviceCoordinate GetTextWidth() const { return FillDXArray( nullptr ); }
89  virtual void GetCaretPositions( int nArraySize, tools::Long* pCaretXArray ) const = 0;
90  virtual bool IsKashidaPosValid ( int /*nCharPos*/ ) const { return true; } // i60594
91 
92  // methods using glyph indexing
93  virtual bool GetNextGlyph(const GlyphItem** pGlyph, Point& rPos, int& nStart,
94  const LogicalFontInstance** ppGlyphFont = nullptr,
95  const PhysicalFontFace** pFallbackFont = nullptr) const = 0;
96  virtual bool GetOutline(basegfx::B2DPolyPolygonVector&) const;
97  bool GetBoundRect(tools::Rectangle&) const;
98 
99  virtual SalLayoutGlyphs GetGlyphs() const;
100 
101 protected:
102  // used by layout engines
103  SalLayout();
104 
105 private:
106  SalLayout(const SalLayout&) = delete;
107  SalLayout& operator=(const SalLayout&) = delete;
108 
109 protected:
112 
115 
118 };
119 
120 #endif // INCLUDED_VCL_VCLLAYOUT_HXX
121 
122 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
int GetUnitsPerPixel() const
Definition: vcllayout.hxx:82
#define VCL_DLLPUBLIC
Definition: dllapi.h:29
long Long
virtual DeviceCoordinate GetTextWidth() const
Definition: vcllayout.hxx:88
Point maDrawBase
Definition: vcllayout.hxx:117
const Point & DrawBase() const
Definition: vcllayout.hxx:72
abstract base class for physical font faces
int mnEndCharPos
Definition: vcllayout.hxx:111
virtual void InitFont() const
Definition: vcllayout.hxx:79
Degree10 GetOrientation() const
Definition: vcllayout.hxx:83
tools::Long DeviceCoordinate
Point & DrawBase()
Definition: vcllayout.hxx:71
int mnUnitsPerPixel
Definition: vcllayout.hxx:113
Degree10 mnOrientation
Definition: vcllayout.hxx:114
virtual bool IsKashidaPosValid(int) const
Definition: vcllayout.hxx:90
const Point & DrawOffset() const
Definition: vcllayout.hxx:74
int mnMinCharPos
Definition: vcllayout.hxx:110
Point maDrawOffset
Definition: vcllayout.hxx:116
Point & DrawOffset()
Definition: vcllayout.hxx:73
::std::vector< B2DPolyPolygon > B2DPolyPolygonVector