wxWidgets/src/common/dcbase.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        dc.cpp
// Purpose:     wxDC Class
// Author:      Brian Macy
// Modified by:
// Created:     05/25/99
// RCS-ID:      $Id$
// Copyright:   (c) wxWindows team
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

#ifdef __GNUG__
#pragma implementation "dcbase.h"
#endif

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

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#include "wx/dc.h"

void wxDCBase::DoDrawCheckMark(wxCoord x1, wxCoord y1,
                               wxCoord width, wxCoord height)
{
    wxCHECK_RET( Ok(), wxT("invalid window dc") );

    wxCoord x2 = x1 + width,
            y2 = y1 + height;

    // this is to yield width of 3 for width == height == 10
    SetPen(wxPen(GetTextForeground(), (width + height + 1) / 7, wxSOLID));

    // we're drawing a scaled version of wx/generic/tick.xpm here
    wxCoord x3 = x1 + (4*width) / 10,   // x of the tick bottom
            y3 = y1 + height / 2;       // y of the left tick branch
    DoDrawLine(x1, y3, x3, y2);
    DoDrawLine(x3, y2, x2, y1);

    CalcBoundingBox(x1, y1);
    CalcBoundingBox(x2, y2);
}

void wxDCBase::DrawLines(const wxList *list, wxCoord xoffset, wxCoord yoffset)
{
    int n = list->Number();
    wxPoint *points = new wxPoint[n];

    int i = 0;
    for ( wxNode *node = list->First(); node; node = node->Next(), i++ )
    {
        wxPoint *point = (wxPoint *)node->Data();
        points[i].x = point->x;
        points[i].y = point->y;
    }

    DoDrawLines(n, points, xoffset, yoffset);

    delete [] points;
}


void wxDCBase::DrawPolygon(const wxList *list,
                           wxCoord xoffset, wxCoord yoffset,
                           int fillStyle)
{
    int n = list->Number();
    wxPoint *points = new wxPoint[n];

    int i = 0;
    for ( wxNode *node = list->First(); node; node = node->Next(), i++ )
    {
        wxPoint *point = (wxPoint *)node->Data();
        points[i].x = point->x;
        points[i].y = point->y;
    }

    DoDrawPolygon(n, points, xoffset, yoffset, fillStyle);

    delete [] points;
}


#if wxUSE_SPLINES

// TODO: this API needs fixing (wxPointList, why (!const) "wxList *"?)
void wxDCBase::DrawSpline(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2, wxCoord x3, wxCoord y3)
{
    wxList point_list;

    wxPoint *point1 = new wxPoint;
    point1->x = x1; point1->y = y1;
    point_list.Append((wxObject*)point1);

    wxPoint *point2 = new wxPoint;
    point2->x = x2; point2->y = y2;
    point_list.Append((wxObject*)point2);

    wxPoint *point3 = new wxPoint;
    point3->x = x3; point3->y = y3;
    point_list.Append((wxObject*)point3);

    DrawSpline(&point_list);

    for( wxNode *node = point_list.First(); node; node = node->Next() )
    {
        wxPoint *p = (wxPoint *)node->Data();
        delete p;
    }
}

void wxDCBase::DrawSpline(int n, wxPoint points[])
{
    wxList list;
    for (int i =0; i < n; i++)
    {
        list.Append((wxObject*)&points[i]);
    }

    DrawSpline(&list);
}

// ----------------------------------- spline code ----------------------------------------

void wx_quadratic_spline(double a1, double b1, double a2, double b2,
                         double a3, double b3, double a4, double b4);
void wx_clear_stack();
int wx_spline_pop(double *x1, double *y1, double *x2, double *y2, double *x3,
        double *y3, double *x4, double *y4);
void wx_spline_push(double x1, double y1, double x2, double y2, double x3, double y3,
          double x4, double y4);
static bool wx_spline_add_point(double x, double y);
static void wx_spline_draw_point_array(wxDCBase *dc);

wxList wx_spline_point_list;

#define                half(z1, z2)        ((z1+z2)/2.0)
#define                THRESHOLD        5

/* iterative version */

void wx_quadratic_spline(double a1, double b1, double a2, double b2, double a3, double b3, double a4,
                 double b4)
{
    register double  xmid, ymid;
    double           x1, y1, x2, y2, x3, y3, x4, y4;

    wx_clear_stack();
    wx_spline_push(a1, b1, a2, b2, a3, b3, a4, b4);

    while (wx_spline_pop(&x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4)) {
        xmid = (double)half(x2, x3);
        ymid = (double)half(y2, y3);
        if (fabs(x1 - xmid) < THRESHOLD && fabs(y1 - ymid) < THRESHOLD &&
            fabs(xmid - x4) < THRESHOLD && fabs(ymid - y4) < THRESHOLD) {
            wx_spline_add_point( x1, y1 );
            wx_spline_add_point( xmid, ymid );
        } else {
            wx_spline_push(xmid, ymid, (double)half(xmid, x3), (double)half(ymid, y3),
                 (double)half(x3, x4), (double)half(y3, y4), x4, y4);
            wx_spline_push(x1, y1, (double)half(x1, x2), (double)half(y1, y2),
                 (double)half(x2, xmid), (double)half(y2, ymid), xmid, ymid);
        }
    }
}

/* utilities used by spline drawing routines */

typedef struct wx_spline_stack_struct {
    double           x1, y1, x2, y2, x3, y3, x4, y4;
} Stack;

#define         SPLINE_STACK_DEPTH             20
static Stack    wx_spline_stack[SPLINE_STACK_DEPTH];
static Stack   *wx_stack_top;
static int      wx_stack_count;

void wx_clear_stack()
{
    wx_stack_top = wx_spline_stack;
    wx_stack_count = 0;
}

void wx_spline_push(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)
{
    wx_stack_top->x1 = x1;
    wx_stack_top->y1 = y1;
    wx_stack_top->x2 = x2;
    wx_stack_top->y2 = y2;
    wx_stack_top->x3 = x3;
    wx_stack_top->y3 = y3;
    wx_stack_top->x4 = x4;
    wx_stack_top->y4 = y4;
    wx_stack_top++;
    wx_stack_count++;
}

int wx_spline_pop(double *x1, double *y1, double *x2, double *y2,
                  double *x3, double *y3, double *x4, double *y4)
{
    if (wx_stack_count == 0)
        return (0);
    wx_stack_top--;
    wx_stack_count--;
    *x1 = wx_stack_top->x1;
    *y1 = wx_stack_top->y1;
    *x2 = wx_stack_top->x2;
    *y2 = wx_stack_top->y2;
    *x3 = wx_stack_top->x3;
    *y3 = wx_stack_top->y3;
    *x4 = wx_stack_top->x4;
    *y4 = wx_stack_top->y4;
    return (1);
}

static bool wx_spline_add_point(double x, double y)
{
  wxPoint *point = new wxPoint ;
  point->x = (int) x;
  point->y = (int) y;
  wx_spline_point_list.Append((wxObject*)point);
  return TRUE;
}

static void wx_spline_draw_point_array(wxDCBase *dc)
{
  dc->DrawLines(&wx_spline_point_list, 0, 0 );
  wxNode *node = wx_spline_point_list.First();
  while (node)
  {
    wxPoint *point = (wxPoint *)node->Data();
    delete point;
    delete node;
    node = wx_spline_point_list.First();
  }
}

void wxDCBase::DoDrawSpline( wxList *points )
{
    wxCHECK_RET( Ok(), wxT("invalid window dc") );

    wxPoint *p;
    double           cx1, cy1, cx2, cy2, cx3, cy3, cx4, cy4;
    double           x1, y1, x2, y2;

    wxNode *node = points->First();
    p = (wxPoint *)node->Data();

    x1 = p->x;
    y1 = p->y;

    node = node->Next();
    p = (wxPoint *)node->Data();

    x2 = p->x;
    y2 = p->y;
    cx1 = (double)((x1 + x2) / 2);
    cy1 = (double)((y1 + y2) / 2);
    cx2 = (double)((cx1 + x2) / 2);
    cy2 = (double)((cy1 + y2) / 2);

    wx_spline_add_point(x1, y1);

    while ((node = node->Next()) != NULL)
    {
        p = (wxPoint *)node->Data();
        x1 = x2;
        y1 = y2;
        x2 = p->x;
        y2 = p->y;
        cx4 = (double)(x1 + x2) / 2;
        cy4 = (double)(y1 + y2) / 2;
        cx3 = (double)(x1 + cx4) / 2;
        cy3 = (double)(y1 + cy4) / 2;

        wx_quadratic_spline(cx1, cy1, cx2, cy2, cx3, cy3, cx4, cy4);

        cx1 = cx4;
        cy1 = cy4;
        cx2 = (double)(cx1 + x2) / 2;
        cy2 = (double)(cy1 + y2) / 2;
    }

    wx_spline_add_point( cx1, cy1 );
    wx_spline_add_point( x2, y2 );

    wx_spline_draw_point_array( this );
}

#endif // wxUSE_SPLINES