src/common/graphcmn.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        src/common/graphcmn.cpp
// Purpose:     graphics context methods common to all platforms
// Author:      Stefan Csomor
// Modified by:
// Created:
// Copyright:   (c) Stefan Csomor
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#if defined(__BORLANDC__)
    #pragma hdrstop
#endif

#if wxUSE_GRAPHICS_CONTEXT

#include "wx/graphics.h"

#ifndef WX_PRECOMP
    #include "wx/icon.h"
    #include "wx/bitmap.h"
    #include "wx/dcmemory.h"
    #include "wx/region.h"
    #include "wx/log.h"
#endif

#include "wx/private/graphics.h"

//-----------------------------------------------------------------------------
// Local functions
//-----------------------------------------------------------------------------

static inline double DegToRad(double deg)
{
    return (deg * M_PI) / 180.0;
}

//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// wxGraphicsObject
//-----------------------------------------------------------------------------

IMPLEMENT_DYNAMIC_CLASS(wxGraphicsObject, wxObject)

wxGraphicsObjectRefData::wxGraphicsObjectRefData( wxGraphicsRenderer* renderer )
{
    m_renderer = renderer;
}
wxGraphicsObjectRefData::wxGraphicsObjectRefData( const wxGraphicsObjectRefData* data )
{
    m_renderer = data->m_renderer;
}
wxGraphicsRenderer* wxGraphicsObjectRefData::GetRenderer() const
{
    return m_renderer ;
}

wxGraphicsObjectRefData* wxGraphicsObjectRefData::Clone() const
{
    return new wxGraphicsObjectRefData(this);
}

wxGraphicsObject::wxGraphicsObject()
{
}

wxGraphicsObject::wxGraphicsObject( wxGraphicsRenderer* renderer )
{
    SetRefData( new wxGraphicsObjectRefData(renderer));
}

wxGraphicsObject::~wxGraphicsObject()
{
}

bool wxGraphicsObject::IsNull() const
{
    return m_refData == NULL;
}

wxGraphicsRenderer* wxGraphicsObject::GetRenderer() const
{
    return ( IsNull() ? NULL : GetGraphicsData()->GetRenderer() );
}

wxGraphicsObjectRefData* wxGraphicsObject::GetGraphicsData() const
{
    return (wxGraphicsObjectRefData*) m_refData;
}

wxObjectRefData* wxGraphicsObject::CreateRefData() const
{
    wxLogDebug(wxT("A Null Object cannot be changed"));
    return NULL;
}

wxObjectRefData* wxGraphicsObject::CloneRefData(const wxObjectRefData* data) const
{
    const wxGraphicsObjectRefData* ptr = (const wxGraphicsObjectRefData*) data;
    return ptr->Clone();
}

//-----------------------------------------------------------------------------
// pens etc.
//-----------------------------------------------------------------------------

IMPLEMENT_DYNAMIC_CLASS(wxGraphicsPen, wxGraphicsObject)
IMPLEMENT_DYNAMIC_CLASS(wxGraphicsBrush, wxGraphicsObject)
IMPLEMENT_DYNAMIC_CLASS(wxGraphicsFont, wxGraphicsObject)
IMPLEMENT_DYNAMIC_CLASS(wxGraphicsBitmap, wxGraphicsObject)

WXDLLIMPEXP_DATA_CORE(wxGraphicsPen) wxNullGraphicsPen;
WXDLLIMPEXP_DATA_CORE(wxGraphicsBrush) wxNullGraphicsBrush;
WXDLLIMPEXP_DATA_CORE(wxGraphicsFont) wxNullGraphicsFont;
WXDLLIMPEXP_DATA_CORE(wxGraphicsBitmap) wxNullGraphicsBitmap;

//-----------------------------------------------------------------------------
// matrix
//-----------------------------------------------------------------------------

IMPLEMENT_DYNAMIC_CLASS(wxGraphicsMatrix, wxGraphicsObject)
WXDLLIMPEXP_DATA_CORE(wxGraphicsMatrix) wxNullGraphicsMatrix;

// concatenates the matrix
void wxGraphicsMatrix::Concat( const wxGraphicsMatrix *t )
{
    AllocExclusive();
    GetMatrixData()->Concat(t->GetMatrixData());
}

// sets the matrix to the respective values
void wxGraphicsMatrix::Set(wxDouble a, wxDouble b, wxDouble c, wxDouble d,
                           wxDouble tx, wxDouble ty)
{
    AllocExclusive();
    GetMatrixData()->Set(a,b,c,d,tx,ty);
}

// gets the component valuess of the matrix
void wxGraphicsMatrix::Get(wxDouble* a, wxDouble* b,  wxDouble* c,
                           wxDouble* d, wxDouble* tx, wxDouble* ty) const
{
    GetMatrixData()->Get(a, b, c, d, tx, ty);
}

// makes this the inverse matrix
void wxGraphicsMatrix::Invert()
{
    AllocExclusive();
    GetMatrixData()->Invert();
}

// returns true if the elements of the transformation matrix are equal ?
bool wxGraphicsMatrix::IsEqual( const wxGraphicsMatrix* t) const
{
    return GetMatrixData()->IsEqual(t->GetMatrixData());
}

// return true if this is the identity matrix
bool wxGraphicsMatrix::IsIdentity() const
{
    return GetMatrixData()->IsIdentity();
}

// add the translation to this matrix
void wxGraphicsMatrix::Translate( wxDouble dx , wxDouble dy )
{
    AllocExclusive();
    GetMatrixData()->Translate(dx,dy);
}

// add the scale to this matrix
void wxGraphicsMatrix::Scale( wxDouble xScale , wxDouble yScale )
{
    AllocExclusive();
    GetMatrixData()->Scale(xScale,yScale);
}

// add the rotation to this matrix (radians)
void wxGraphicsMatrix::Rotate( wxDouble angle )
{
    AllocExclusive();
    GetMatrixData()->Rotate(angle);
}

//
// apply the transforms
//

// applies that matrix to the point
void wxGraphicsMatrix::TransformPoint( wxDouble *x, wxDouble *y ) const
{
    GetMatrixData()->TransformPoint(x,y);
}

// applies the matrix except for translations
void wxGraphicsMatrix::TransformDistance( wxDouble *dx, wxDouble *dy ) const
{
    GetMatrixData()->TransformDistance(dx,dy);
}

// returns the native representation
void * wxGraphicsMatrix::GetNativeMatrix() const
{
    return GetMatrixData()->GetNativeMatrix();
}

//-----------------------------------------------------------------------------
// path
//-----------------------------------------------------------------------------

IMPLEMENT_DYNAMIC_CLASS(wxGraphicsPath, wxGraphicsObject)
WXDLLIMPEXP_DATA_CORE(wxGraphicsPath) wxNullGraphicsPath;

// convenience functions, for using wxPoint2DDouble etc

wxPoint2DDouble wxGraphicsPath::GetCurrentPoint() const
{
    wxDouble x,y;
    GetCurrentPoint(&x,&y);
    return wxPoint2DDouble(x,y);
}

void wxGraphicsPath::MoveToPoint( const wxPoint2DDouble& p)
{
    MoveToPoint( p.m_x , p.m_y);
}

void wxGraphicsPath::AddLineToPoint( const wxPoint2DDouble& p)
{
    AddLineToPoint( p.m_x , p.m_y);
}

void wxGraphicsPath::AddCurveToPoint( const wxPoint2DDouble& c1, const wxPoint2DDouble& c2, const wxPoint2DDouble& e)
{
    AddCurveToPoint(c1.m_x, c1.m_y, c2.m_x, c2.m_y, e.m_x, e.m_y);
}

void wxGraphicsPath::AddArc( const wxPoint2DDouble& c, wxDouble r, wxDouble startAngle, wxDouble endAngle, bool clockwise)
{
    AddArc(c.m_x, c.m_y, r, startAngle, endAngle, clockwise);
}

wxRect2DDouble wxGraphicsPath::GetBox() const
{
    wxDouble x,y,w,h;
    GetBox(&x,&y,&w,&h);
    return wxRect2DDouble( x,y,w,h );
}

bool wxGraphicsPath::Contains( const wxPoint2DDouble& c, wxPolygonFillMode fillStyle ) const
{
    return Contains( c.m_x, c.m_y, fillStyle);
}

// true redirections

// begins a new subpath at (x,y)
void wxGraphicsPath::MoveToPoint( wxDouble x, wxDouble y )
{
    AllocExclusive();
    GetPathData()->MoveToPoint(x,y);
}

// adds a straight line from the current point to (x,y)
void wxGraphicsPath::AddLineToPoint( wxDouble x, wxDouble y )
{
    AllocExclusive();
    GetPathData()->AddLineToPoint(x,y);
}

// adds a cubic Bezier curve from the current point, using two control points and an end point
void wxGraphicsPath::AddCurveToPoint( wxDouble cx1, wxDouble cy1, wxDouble cx2, wxDouble cy2, wxDouble x, wxDouble y )
{
    AllocExclusive();
    GetPathData()->AddCurveToPoint(cx1,cy1,cx2,cy2,x,y);
}

// adds another path
void wxGraphicsPath::AddPath( const wxGraphicsPath& path )
{
    AllocExclusive();
    GetPathData()->AddPath(path.GetPathData());
}

// closes the current sub-path
void wxGraphicsPath::CloseSubpath()
{
    AllocExclusive();
    GetPathData()->CloseSubpath();
}

// gets the last point of the current path, (0,0) if not yet set
void wxGraphicsPath::GetCurrentPoint( wxDouble* x, wxDouble* y) const
{
    GetPathData()->GetCurrentPoint(x,y);
}

// adds an arc of a circle centering at (x,y) with radius (r) from startAngle to endAngle
void wxGraphicsPath::AddArc( wxDouble x, wxDouble y, wxDouble r, wxDouble startAngle, wxDouble endAngle, bool clockwise )
{
    AllocExclusive();
    GetPathData()->AddArc(x,y,r,startAngle,endAngle,clockwise);
}

//
// These are convenience functions which - if not available natively will be assembled
// using the primitives from above
//

// adds a quadratic Bezier curve from the current point, using a control point and an end point
void wxGraphicsPath::AddQuadCurveToPoint( wxDouble cx, wxDouble cy, wxDouble x, wxDouble y )
{
    AllocExclusive();
    GetPathData()->AddQuadCurveToPoint(cx,cy,x,y);
}

// appends a rectangle as a new closed subpath
void wxGraphicsPath::AddRectangle( wxDouble x, wxDouble y, wxDouble w, wxDouble h )
{
    AllocExclusive();
    GetPathData()->AddRectangle(x,y,w,h);
}

// appends an ellipsis as a new closed subpath fitting the passed rectangle
void wxGraphicsPath::AddCircle( wxDouble x, wxDouble y, wxDouble r )
{
    AllocExclusive();
    GetPathData()->AddCircle(x,y,r);
}

// appends a an arc to two tangents connecting (current) to (x1,y1) and (x1,y1) to (x2,y2), also a straight line from (current) to (x1,y1)
void wxGraphicsPath::AddArcToPoint( wxDouble x1, wxDouble y1 , wxDouble x2, wxDouble y2, wxDouble r )
{
    GetPathData()->AddArcToPoint(x1,y1,x2,y2,r);
}

// appends an ellipse
void wxGraphicsPath::AddEllipse( wxDouble x, wxDouble y, wxDouble w, wxDouble h)
{
    AllocExclusive();
    GetPathData()->AddEllipse(x,y,w,h);
}

// appends a rounded rectangle
void wxGraphicsPath::AddRoundedRectangle( wxDouble x, wxDouble y, wxDouble w, wxDouble h, wxDouble radius)
{
    AllocExclusive();
    GetPathData()->AddRoundedRectangle(x,y,w,h,radius);
}

// returns the native path
void * wxGraphicsPath::GetNativePath() const
{
    return GetPathData()->GetNativePath();
}

// give the native path returned by GetNativePath() back (there might be some deallocations necessary)
void wxGraphicsPath::UnGetNativePath(void *p)const
{
    GetPathData()->UnGetNativePath(p);
}

// transforms each point of this path by the matrix
void wxGraphicsPath::Transform( const wxGraphicsMatrix& matrix )
{
    AllocExclusive();
    GetPathData()->Transform(matrix.GetMatrixData());
}

// gets the bounding box enclosing all points (possibly including control points)
void wxGraphicsPath::GetBox(wxDouble *x, wxDouble *y, wxDouble *w, wxDouble *h) const
{
    GetPathData()->GetBox(x,y,w,h);
}

bool wxGraphicsPath::Contains( wxDouble x, wxDouble y, wxPolygonFillMode fillStyle ) const
{
    return GetPathData()->Contains(x,y,fillStyle);
}

//
// Emulations, these mus be implemented in the ...Data classes in order to allow for proper overrides
//

void wxGraphicsPathData::AddQuadCurveToPoint( wxDouble cx, wxDouble cy, wxDouble x, wxDouble y )
{
    // calculate using degree elevation to a cubic bezier
    wxPoint2DDouble c1;
    wxPoint2DDouble c2;

    wxPoint2DDouble start;
    GetCurrentPoint(&start.m_x,&start.m_y);
    wxPoint2DDouble end(x,y);
    wxPoint2DDouble c(cx,cy);
    c1 = wxDouble(1/3.0) * start + wxDouble(2/3.0) * c;
    c2 = wxDouble(2/3.0) * c + wxDouble(1/3.0) * end;
    AddCurveToPoint(c1.m_x,c1.m_y,c2.m_x,c2.m_y,x,y);
}

void wxGraphicsPathData::AddRectangle( wxDouble x, wxDouble y, wxDouble w, wxDouble h )
{
    MoveToPoint(x,y);
    AddLineToPoint(x,y+h);
    AddLineToPoint(x+w,y+h);
    AddLineToPoint(x+w,y);
    CloseSubpath();
}

void wxGraphicsPathData::AddCircle( wxDouble x, wxDouble y, wxDouble r )
{
    MoveToPoint(x+r,y);
    AddArc( x,y,r,0,2*M_PI,false);
    CloseSubpath();
}

void wxGraphicsPathData::AddEllipse( wxDouble x, wxDouble y, wxDouble w, wxDouble h)
{
    if (w <= 0. || h <= 0.)
      return;

    wxDouble rw = w/2;
    wxDouble rh = h/2;
    wxDouble xc = x + rw;
    wxDouble yc = y + rh;
    wxGraphicsMatrix m = GetRenderer()->CreateMatrix();
    m.Translate(xc,yc);
    m.Scale(rw/rh,1.0);
    wxGraphicsPath p = GetRenderer()->CreatePath();
    p.AddCircle(0,0,rh);
    p.Transform(m);
    AddPath(p.GetPathData());
}

void wxGraphicsPathData::AddRoundedRectangle( wxDouble x, wxDouble y, wxDouble w, wxDouble h, wxDouble radius)
{
    if ( radius == 0 )
        AddRectangle(x,y,w,h);
    else
    {
        MoveToPoint( x + w, y + h / 2);
        AddArcToPoint(x + w, y + h, x + w / 2, y + h, radius);
        AddArcToPoint(x, y + h, x, y + h / 2, radius);
        AddArcToPoint(x, y , x + w / 2, y, radius);
        AddArcToPoint(x + w, y, x + w, y + h / 2, radius);
        CloseSubpath();
    }
}

// draws a an arc to two tangents connecting (current) to (x1,y1) and (x1,y1) to (x2,y2), also a straight line from (current) to (x1,y1)
void wxGraphicsPathData::AddArcToPoint( wxDouble x1, wxDouble y1 , wxDouble x2, wxDouble y2, wxDouble r )
{
    wxPoint2DDouble current;
    GetCurrentPoint(&current.m_x,&current.m_y);
    wxPoint2DDouble p1(x1,y1);
    wxPoint2DDouble p2(x2,y2);

    wxPoint2DDouble v1 = current - p1;
    v1.Normalize();
    wxPoint2DDouble v2 = p2 - p1;
    v2.Normalize();

    wxDouble alpha = v1.GetVectorAngle() - v2.GetVectorAngle();

    if ( alpha < 0 )
        alpha = 360 + alpha;
    // TODO obtuse angles

    alpha = DegToRad(alpha);

    wxDouble dist = r / sin(alpha/2) * cos(alpha/2);
    // calculate tangential points
    wxPoint2DDouble t1 = dist*v1 + p1;

    wxPoint2DDouble nv1 = v1;
    nv1.SetVectorAngle(v1.GetVectorAngle()-90);
    wxPoint2DDouble c = t1 + r*nv1;

    wxDouble a1 = v1.GetVectorAngle()+90;
    wxDouble a2 = v2.GetVectorAngle()-90;

    AddLineToPoint(t1.m_x,t1.m_y);
    AddArc(c.m_x,c.m_y,r,DegToRad(a1),DegToRad(a2),true);
    AddLineToPoint(p2.m_x,p2.m_y);
}

//-----------------------------------------------------------------------------
// wxGraphicsGradientStops
//-----------------------------------------------------------------------------

void wxGraphicsGradientStops::Add(const wxGraphicsGradientStop& stop)
{
    for ( wxVector<wxGraphicsGradientStop>::iterator it = m_stops.begin();
          it != m_stops.end();
          ++it )
    {
        if ( stop.GetPosition() < it->GetPosition() )
        {
            if ( it != m_stops.begin() )
            {
                m_stops.insert(it, stop);
            }
            else // we shouldn't be inserting it at the beginning
            {
                wxFAIL_MSG( "invalid gradient stop position < 0" );
            }

            return;
        }
    }

    if ( stop.GetPosition() == 1. )
    {
        m_stops.insert(m_stops.end() - 1, stop);
    }
    else
    {
        wxFAIL_MSG( "invalid gradient stop position > 1" );
    }
}

void * wxGraphicsBitmap::GetNativeBitmap() const
{
    return GetBitmapData()->GetNativeBitmap();
}

//-----------------------------------------------------------------------------
// wxGraphicsContext Convenience Methods
//-----------------------------------------------------------------------------

IMPLEMENT_ABSTRACT_CLASS(wxGraphicsContext, wxObject)


wxGraphicsContext::wxGraphicsContext(wxGraphicsRenderer* renderer) :
    wxGraphicsObject(renderer),
      m_antialias(wxANTIALIAS_DEFAULT),
      m_composition(wxCOMPOSITION_OVER),
      m_interpolation(wxINTERPOLATION_DEFAULT),
      m_enableOffset(false)
{
}

wxGraphicsContext::~wxGraphicsContext()
{
}

bool wxGraphicsContext::StartDoc(const wxString& WXUNUSED(message))
{
    return true;
}

void wxGraphicsContext::EndDoc()
{
}

void wxGraphicsContext::StartPage(wxDouble WXUNUSED(width),
                                  wxDouble WXUNUSED(height))
{
}

void wxGraphicsContext::EndPage()
{
}

void wxGraphicsContext::Flush()
{
}

void wxGraphicsContext::EnableOffset(bool enable)
{
    m_enableOffset = enable;
}

#if 0
void wxGraphicsContext::SetAlpha( wxDouble WXUNUSED(alpha) )
{
}

wxDouble wxGraphicsContext::GetAlpha() const
{
    return 1.0;
}
#endif

void wxGraphicsContext::GetDPI( wxDouble* dpiX, wxDouble* dpiY)
{
    *dpiX = 72.0;
    *dpiY = 72.0;
}

// sets the pen
void wxGraphicsContext::SetPen( const wxGraphicsPen& pen )
{
    m_pen = pen;
}

void wxGraphicsContext::SetPen( const wxPen& pen )
{
    if ( !pen.IsOk() || pen.GetStyle() == wxPENSTYLE_TRANSPARENT )
        SetPen( wxNullGraphicsPen );
    else
        SetPen( CreatePen( pen ) );
}

// sets the brush for filling
void wxGraphicsContext::SetBrush( const wxGraphicsBrush& brush )
{
    m_brush = brush;
}

void wxGraphicsContext::SetBrush( const wxBrush& brush )
{
    if ( !brush.IsOk() || brush.GetStyle() == wxBRUSHSTYLE_TRANSPARENT )
        SetBrush( wxNullGraphicsBrush );
    else
        SetBrush( CreateBrush( brush ) );
}

// sets the brush for filling
void wxGraphicsContext::SetFont( const wxGraphicsFont& font )
{
    m_font = font;
}

void wxGraphicsContext::SetFont( const wxFont& font, const wxColour& colour )
{
    if ( font.IsOk() )
        SetFont( CreateFont( font, colour ) );
    else
        SetFont( wxNullGraphicsFont );
}

void wxGraphicsContext::DrawPath( const wxGraphicsPath& path, wxPolygonFillMode fillStyle )
{
    FillPath( path , fillStyle );
    StrokePath( path );
}

void
wxGraphicsContext::DoDrawRotatedText(const wxString &str,
                                     wxDouble x,
                                     wxDouble y,
                                     wxDouble angle)
{
    Translate(x,y);
    Rotate( -angle );
    DrawText( str , 0, 0 );
    Rotate( angle );
    Translate(-x,-y);
}

void
wxGraphicsContext::DoDrawFilledText(const wxString &str,
                                    wxDouble x,
                                    wxDouble y,
                                    const wxGraphicsBrush& backgroundBrush)
{
    wxGraphicsBrush formerBrush = m_brush;
    wxGraphicsPen formerPen = m_pen;
    wxDouble width;
    wxDouble height;
    wxDouble descent;
    wxDouble externalLeading;
    GetTextExtent( str , &width, &height, &descent, &externalLeading );
    SetBrush( backgroundBrush );
    // to make sure our 'OffsetToPixelBoundaries' doesn't move the fill shape
    SetPen( wxNullGraphicsPen );

    DrawRectangle(x , y, width, height);

    DrawText( str, x ,y);
    SetBrush( formerBrush );
    SetPen( formerPen );
}

void
wxGraphicsContext::DoDrawRotatedFilledText(const wxString &str,
                                           wxDouble x, wxDouble y,
                                           wxDouble angle,
                                           const wxGraphicsBrush& backgroundBrush)
{
    wxGraphicsBrush formerBrush = m_brush;
    wxGraphicsPen formerPen = m_pen;

    wxDouble width;
    wxDouble height;
    wxDouble descent;
    wxDouble externalLeading;
    GetTextExtent( str , &width, &height, &descent, &externalLeading );
    SetBrush( backgroundBrush );
    // to make sure our 'OffsetToPixelBoundaries' doesn't move the fill shape
    SetPen( wxNullGraphicsPen );

    wxGraphicsPath path = CreatePath();
    path.MoveToPoint( x , y );
    path.AddLineToPoint( (int) (x + sin(angle) * height) , (int) (y + cos(angle) * height) );
    path.AddLineToPoint(
        (int) (x + sin(angle) * height + cos(angle) * width) ,
        (int) (y + cos(angle) * height - sin(angle) * width));
    path.AddLineToPoint((int) (x + cos(angle) * width) , (int) (y - sin(angle) * width) );
    FillPath( path );
    DrawText( str, x ,y, angle);
    SetBrush( formerBrush );
    SetPen( formerPen );
}

void wxGraphicsContext::StrokeLine( wxDouble x1, wxDouble y1, wxDouble x2, wxDouble y2)
{
    wxGraphicsPath path = CreatePath();
    path.MoveToPoint(x1, y1);
    path.AddLineToPoint( x2, y2 );
    StrokePath( path );
}

void wxGraphicsContext::DrawRectangle( wxDouble x, wxDouble y, wxDouble w, wxDouble h)
{
    wxGraphicsPath path = CreatePath();
    path.AddRectangle( x , y , w , h );
    DrawPath( path );
}

void wxGraphicsContext::DrawEllipse( wxDouble x, wxDouble y, wxDouble w, wxDouble h)
{
    wxGraphicsPath path = CreatePath();
    path.AddEllipse(x,y,w,h);
    DrawPath(path);
}

void wxGraphicsContext::DrawRoundedRectangle( wxDouble x, wxDouble y, wxDouble w, wxDouble h, wxDouble radius)
{
    wxGraphicsPath path = CreatePath();
    path.AddRoundedRectangle(x,y,w,h,radius);
    DrawPath(path);
}

void wxGraphicsContext::StrokeLines( size_t n, const wxPoint2DDouble *points)
{
    wxASSERT(n > 1);
    wxGraphicsPath path = CreatePath();
    path.MoveToPoint(points[0].m_x, points[0].m_y);
    for ( size_t i = 1; i < n; ++i)
        path.AddLineToPoint( points[i].m_x, points[i].m_y );
    StrokePath( path );
}

void wxGraphicsContext::DrawLines( size_t n, const wxPoint2DDouble *points, wxPolygonFillMode fillStyle)
{
    wxASSERT(n > 1);
    wxGraphicsPath path = CreatePath();
    path.MoveToPoint(points[0].m_x, points[0].m_y);
    for ( size_t i = 1; i < n; ++i)
        path.AddLineToPoint( points[i].m_x, points[i].m_y );
    DrawPath( path , fillStyle);
}

void wxGraphicsContext::StrokeLines( size_t n, const wxPoint2DDouble *beginPoints, const wxPoint2DDouble *endPoints)
{
    wxASSERT(n > 0);
    wxGraphicsPath path = CreatePath();
    for ( size_t i = 0; i < n; ++i)
    {
        path.MoveToPoint(beginPoints[i].m_x, beginPoints[i].m_y);
        path.AddLineToPoint( endPoints[i].m_x, endPoints[i].m_y );
    }
    StrokePath( path );
}

// create a 'native' matrix corresponding to these values
wxGraphicsMatrix wxGraphicsContext::CreateMatrix( wxDouble a, wxDouble b, wxDouble c, wxDouble d,
    wxDouble tx, wxDouble ty) const
{
    return GetRenderer()->CreateMatrix(a,b,c,d,tx,ty);
}

wxGraphicsPath wxGraphicsContext::CreatePath() const
{
    return GetRenderer()->CreatePath();
}

wxGraphicsPen wxGraphicsContext::CreatePen(const wxPen& pen) const
{
    return GetRenderer()->CreatePen(pen);
}

wxGraphicsBrush wxGraphicsContext::CreateBrush(const wxBrush& brush ) const
{
    return GetRenderer()->CreateBrush(brush);
}

wxGraphicsBrush
wxGraphicsContext::CreateLinearGradientBrush(
    wxDouble x1, wxDouble y1,
    wxDouble x2, wxDouble y2,
    const wxColour& c1, const wxColour& c2) const
{
    return GetRenderer()->CreateLinearGradientBrush
                          (
                            x1, y1,
                            x2, y2,
                            wxGraphicsGradientStops(c1,c2)
                          );
}

wxGraphicsBrush
wxGraphicsContext::CreateLinearGradientBrush(
    wxDouble x1, wxDouble y1,
    wxDouble x2, wxDouble y2,
    const wxGraphicsGradientStops& gradientStops) const
{
    return GetRenderer()->CreateLinearGradientBrush(x1,y1,x2,y2, gradientStops);
}

wxGraphicsBrush
wxGraphicsContext::CreateRadialGradientBrush(
        wxDouble xo, wxDouble yo,
        wxDouble xc, wxDouble yc, wxDouble radius,
        const wxColour &oColor, const wxColour &cColor) const
{
    return GetRenderer()->CreateRadialGradientBrush
                          (
                            xo, yo,
                            xc, yc, radius,
                            wxGraphicsGradientStops(oColor, cColor)
                          );
}

wxGraphicsBrush
wxGraphicsContext::CreateRadialGradientBrush(
        wxDouble xo, wxDouble yo,
        wxDouble xc, wxDouble yc, wxDouble radius,
        const wxGraphicsGradientStops& gradientStops) const
{
    return GetRenderer()->CreateRadialGradientBrush
                          (
                            xo, yo,
                            xc, yc, radius,
                            gradientStops
                          );
}

wxGraphicsFont wxGraphicsContext::CreateFont( const wxFont &font , const wxColour &col ) const
{
    return GetRenderer()->CreateFont(font,col);
}

wxGraphicsFont
wxGraphicsContext::CreateFont(double size,
                              const wxString& facename,
                              int flags,
                              const wxColour& col) const
{
    return GetRenderer()->CreateFont(size, facename, flags, col);
}

wxGraphicsBitmap wxGraphicsContext::CreateBitmap( const wxBitmap& bmp ) const
{
    return GetRenderer()->CreateBitmap(bmp);
}

#if wxUSE_IMAGE
wxGraphicsBitmap wxGraphicsContext::CreateBitmapFromImage(const wxImage& image) const
{
    return GetRenderer()->CreateBitmapFromImage(image);
}
#endif // wxUSE_IMAGE

wxGraphicsBitmap wxGraphicsContext::CreateSubBitmap( const wxGraphicsBitmap &bmp, wxDouble x, wxDouble y, wxDouble w, wxDouble h   ) const
{
    return GetRenderer()->CreateSubBitmap(bmp,x,y,w,h);
}

/* static */ wxGraphicsContext* wxGraphicsContext::Create( const wxWindowDC& dc)
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(dc);
}

/* static */ wxGraphicsContext* wxGraphicsContext::Create( const wxMemoryDC& dc)
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(dc);
}

#if wxUSE_PRINTING_ARCHITECTURE
/* static */ wxGraphicsContext* wxGraphicsContext::Create( const wxPrinterDC& dc)
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(dc);
}
#endif

#ifdef __WXMSW__
#if wxUSE_ENH_METAFILE
/* static */ wxGraphicsContext* wxGraphicsContext::Create( const wxEnhMetaFileDC& dc)
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(dc);
}
#endif
#endif

wxGraphicsContext* wxGraphicsContext::CreateFromNative( void * context )
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContextFromNativeContext(context);
}

wxGraphicsContext* wxGraphicsContext::CreateFromNativeWindow( void * window )
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContextFromNativeWindow(window);
}

wxGraphicsContext* wxGraphicsContext::Create( wxWindow* window )
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContext(window);
}

#if wxUSE_IMAGE
/* static */ wxGraphicsContext* wxGraphicsContext::Create(wxImage& image)
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateContextFromImage(image);
}
#endif // wxUSE_IMAGE

wxGraphicsContext* wxGraphicsContext::Create()
{
    return wxGraphicsRenderer::GetDefaultRenderer()->CreateMeasuringContext();
}

//-----------------------------------------------------------------------------
// wxGraphicsRenderer
//-----------------------------------------------------------------------------

IMPLEMENT_ABSTRACT_CLASS(wxGraphicsRenderer, wxObject)

#endif // wxUSE_GRAPHICS_CONTEXT