fix the old code for dlerror() returning const char as well (why was it changed?)

[wxWidgets.git] / src / msw / dc.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        dc.cpp
// Purpose:     wxDC class
// Author:      Julian Smart
// Modified by:
// Created:     01/02/97
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart and Markus Holzem
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ===========================================================================
// declarations
// ===========================================================================

// ---------------------------------------------------------------------------
// headers
// ---------------------------------------------------------------------------

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

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

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#ifndef WX_PRECOMP
    #include "wx/window.h"
    #include "wx/dc.h"
    #include "wx/utils.h"
    #include "wx/dialog.h"
    #include "wx/app.h"
    #include "wx/bitmap.h"
    #include "wx/dcmemory.h"
    #include "wx/log.h"
    #include "wx/icon.h"
#endif

#include "wx/sysopt.h"
#include "wx/dcprint.h"
#include "wx/module.h"

#include <string.h>
#include <math.h>

#include "wx/msw/private.h" // needs to be before #include <commdlg.h>

#if wxUSE_COMMON_DIALOGS && !defined(__WXMICROWIN__)
    #include <commdlg.h>
#endif

#ifndef __WIN32__
    #include <print.h>
#endif

IMPLEMENT_ABSTRACT_CLASS(wxDC, wxDCBase)

// ---------------------------------------------------------------------------
// constants
// ---------------------------------------------------------------------------

static const int VIEWPORT_EXTENT = 1000;

static const int MM_POINTS = 9;
static const int MM_METRIC = 10;

// usually this is defined in math.h
#ifndef M_PI
    static const double M_PI = 3.14159265358979323846;
#endif // M_PI

// ROPs which don't have standard names (see "Ternary Raster Operations" in the
// MSDN docs for how this and other numbers in wxDC::Blit() are obtained)
#define DSTCOPY 0x00AA0029      // a.k.a. NOP operation

// ---------------------------------------------------------------------------
// private functions
// ---------------------------------------------------------------------------

// convert degrees to radians
static inline double DegToRad(double deg) { return (deg * M_PI) / 180.0; }

// ----------------------------------------------------------------------------
// private classes
// ----------------------------------------------------------------------------

// instead of duplicating the same code which sets and then restores text
// colours in each wxDC method working with wxSTIPPLE_MASK_OPAQUE brushes,
// encapsulate this in a small helper class

// wxColourChanger: changes the text colours in the ctor if required and
//                  restores them in the dtor
class wxColourChanger
{
public:
    wxColourChanger(wxDC& dc);
   ~wxColourChanger();

private:
    wxDC& m_dc;

    COLORREF m_colFgOld, m_colBgOld;

    bool m_changed;
};

// ===========================================================================
// implementation
// ===========================================================================

// ----------------------------------------------------------------------------
// wxColourChanger
// ----------------------------------------------------------------------------

wxColourChanger::wxColourChanger(wxDC& dc) : m_dc(dc)
{
    if ( dc.GetBrush().GetStyle() == wxSTIPPLE_MASK_OPAQUE )
    {
        HDC hdc = GetHdcOf(dc);
        m_colFgOld = ::GetTextColor(hdc);
        m_colBgOld = ::GetBkColor(hdc);

        // note that Windows convention is opposite to wxWindows one, this is
        // why text colour becomes the background one and vice versa
        const wxColour& colFg = dc.GetTextForeground();
        if ( colFg.Ok() )
        {
            ::SetBkColor(hdc, colFg.GetPixel());
        }

        const wxColour& colBg = dc.GetTextBackground();
        if ( colBg.Ok() )
        {
            ::SetTextColor(hdc, colBg.GetPixel());
        }

        SetBkMode(hdc,
                  dc.GetBackgroundMode() == wxTRANSPARENT ? TRANSPARENT
                                                          : OPAQUE);

        // flag which telsl us to undo changes in the dtor
        m_changed = TRUE;
    }
    else
    {
        // nothing done, nothing to undo
        m_changed = FALSE;
    }
}

wxColourChanger::~wxColourChanger()
{
    if ( m_changed )
    {
        // restore the colours we changed
        HDC hdc = GetHdcOf(m_dc);

        ::SetBkMode(hdc, TRANSPARENT);
        ::SetTextColor(hdc, m_colFgOld);
        ::SetBkColor(hdc, m_colBgOld);
    }
}

// ---------------------------------------------------------------------------
// wxDC
// ---------------------------------------------------------------------------

// Default constructor
wxDC::wxDC()
{
    m_canvas = NULL;

    m_oldBitmap = 0;
    m_oldPen = 0;
    m_oldBrush = 0;
    m_oldFont = 0;
#if wxUSE_PALETTE
    m_oldPalette = 0;
#endif // wxUSE_PALETTE

    m_bOwnsDC = FALSE;
    m_hDC = 0;

    m_windowExtX = VIEWPORT_EXTENT;
    m_windowExtY = VIEWPORT_EXTENT;
}


wxDC::~wxDC()
{
    if ( m_hDC != 0 )
    {
        SelectOldObjects(m_hDC);

        // if we own the HDC, we delete it, otherwise we just release it

        if ( m_bOwnsDC )
        {
            ::DeleteDC(GetHdc());
        }
        else // we don't own our HDC
        {
            if (m_canvas)
            {
                ::ReleaseDC(GetHwndOf(m_canvas), GetHdc());
            }
            else
            {
                // Must have been a wxScreenDC
                ::ReleaseDC((HWND) NULL, GetHdc());
            }
        }
    }
}

// This will select current objects out of the DC,
// which is what you have to do before deleting the
// DC.
void wxDC::SelectOldObjects(WXHDC dc)
{
    if (dc)
    {
        if (m_oldBitmap)
        {
            ::SelectObject((HDC) dc, (HBITMAP) m_oldBitmap);
            if (m_selectedBitmap.Ok())
            {
                m_selectedBitmap.SetSelectedInto(NULL);
            }
        }
        m_oldBitmap = 0;
        if (m_oldPen)
        {
            ::SelectObject((HDC) dc, (HPEN) m_oldPen);
        }
        m_oldPen = 0;
        if (m_oldBrush)
        {
            ::SelectObject((HDC) dc, (HBRUSH) m_oldBrush);
        }
        m_oldBrush = 0;
        if (m_oldFont)
        {
            ::SelectObject((HDC) dc, (HFONT) m_oldFont);
        }
        m_oldFont = 0;

#if wxUSE_PALETTE
        if (m_oldPalette)
        {
            ::SelectPalette((HDC) dc, (HPALETTE) m_oldPalette, FALSE);
        }
        m_oldPalette = 0;
#endif // wxUSE_PALETTE
    }

    m_brush = wxNullBrush;
    m_pen = wxNullPen;
#if wxUSE_PALETTE
    m_palette = wxNullPalette;
#endif // wxUSE_PALETTE
    m_font = wxNullFont;
    m_backgroundBrush = wxNullBrush;
    m_selectedBitmap = wxNullBitmap;
}

// ---------------------------------------------------------------------------
// clipping
// ---------------------------------------------------------------------------

void wxDC::UpdateClipBox()
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    RECT rect;
    GetClipBox(GetHdc(), &rect);

    m_clipX1 = (wxCoord) XDEV2LOG(rect.left);
    m_clipY1 = (wxCoord) YDEV2LOG(rect.top);
    m_clipX2 = (wxCoord) XDEV2LOG(rect.right);
    m_clipY2 = (wxCoord) YDEV2LOG(rect.bottom);
}

void wxDC::DoSetClippingRegion(wxCoord x, wxCoord y, wxCoord w, wxCoord h)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    m_clipping = TRUE;

    // the region coords are always the device ones, so do the translation
    // manually
    //
    // FIXME: possible +/-1 error here, to check!
    HRGN hrgn = ::CreateRectRgn(LogicalToDeviceX(x),
                                LogicalToDeviceY(y),
                                LogicalToDeviceX(x + w),
                                LogicalToDeviceY(y + h));
    if ( !hrgn )
    {
        wxLogLastError(_T("CreateRectRgn"));
    }
    else
    {
        if ( ::SelectClipRgn(GetHdc(), hrgn) == ERROR )
        {
            wxLogLastError(_T("SelectClipRgn"));
        }
        DeleteObject(hrgn);

        UpdateClipBox();
    }
}

void wxDC::DoSetClippingRegionAsRegion(const wxRegion& region)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    wxCHECK_RET( GetHrgnOf(region), wxT("invalid clipping region") );

    m_clipping = TRUE;

#ifdef __WIN16__
    SelectClipRgn(GetHdc(), GetHrgnOf(region));
#else // Win32
    ExtSelectClipRgn(GetHdc(), GetHrgnOf(region), RGN_AND);
#endif // Win16/32

    UpdateClipBox();
}

void wxDC::DestroyClippingRegion()
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    if (m_clipping && m_hDC)
    {
        // TODO: this should restore the previous clipping region,
        // so that OnPaint processing works correctly, and the update clipping region
        // doesn't get destroyed after the first DestroyClippingRegion.
        HRGN rgn = CreateRectRgn(0, 0, 32000, 32000);
        SelectClipRgn(GetHdc(), rgn);
        DeleteObject(rgn);
    }

    m_clipping = FALSE;
}

// ---------------------------------------------------------------------------
// query capabilities
// ---------------------------------------------------------------------------

bool wxDC::CanDrawBitmap() const
{
    return TRUE;
}

bool wxDC::CanGetTextExtent() const
{
#ifdef __WXMICROWIN__
    // TODO Extend MicroWindows' GetDeviceCaps function
    return TRUE;
#else
    // What sort of display is it?
    int technology = ::GetDeviceCaps(GetHdc(), TECHNOLOGY);

    return (technology == DT_RASDISPLAY) || (technology == DT_RASPRINTER);
#endif
}

int wxDC::GetDepth() const
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return 16;
#endif

    return (int)::GetDeviceCaps(GetHdc(), BITSPIXEL);
}

// ---------------------------------------------------------------------------
// drawing
// ---------------------------------------------------------------------------

void wxDC::Clear()
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    RECT rect;
    if ( m_canvas )
    {
        GetClientRect((HWND) m_canvas->GetHWND(), &rect);
    }
    else
    {
        // No, I think we should simply ignore this if printing on e.g.
        // a printer DC.
        // wxCHECK_RET( m_selectedBitmap.Ok(), wxT("this DC can't be cleared") );
        if (!m_selectedBitmap.Ok())
            return;

        rect.left = 0; rect.top = 0;
        rect.right = m_selectedBitmap.GetWidth();
        rect.bottom = m_selectedBitmap.GetHeight();
    }

    (void) ::SetMapMode(GetHdc(), MM_TEXT);

    DWORD colour = GetBkColor(GetHdc());
    HBRUSH brush = CreateSolidBrush(colour);
    FillRect(GetHdc(), &rect, brush);
    DeleteObject(brush);

    ::SetMapMode(GetHdc(), MM_ANISOTROPIC);
    ::SetViewportExtEx(GetHdc(), VIEWPORT_EXTENT, VIEWPORT_EXTENT, NULL);
    ::SetWindowExtEx(GetHdc(), m_windowExtX, m_windowExtY, NULL);
    ::SetViewportOrgEx(GetHdc(), (int)m_deviceOriginX, (int)m_deviceOriginY, NULL);
    ::SetWindowOrgEx(GetHdc(), (int)m_logicalOriginX, (int)m_logicalOriginY, NULL);
}

void wxDC::DoFloodFill(wxCoord x, wxCoord y, const wxColour& col, int style)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    if ( !::ExtFloodFill(GetHdc(), XLOG2DEV(x), YLOG2DEV(y),
                         col.GetPixel(),
                         style == wxFLOOD_SURFACE ? FLOODFILLSURFACE
                                                  : FLOODFILLBORDER) )
    {
        // quoting from the MSDN docs:
        //
        //      Following are some of the reasons this function might fail:
        //
        //      * The filling could not be completed.
        //      * The specified point has the boundary color specified by the
        //        crColor parameter (if FLOODFILLBORDER was requested).
        //      * The specified point does not have the color specified by
        //        crColor (if FLOODFILLSURFACE was requested)
        //      * The point is outside the clipping region that is, it is not
        //        visible on the device.
        //
        wxLogLastError(wxT("ExtFloodFill"));
    }

    CalcBoundingBox(x, y);
}

bool wxDC::DoGetPixel(wxCoord x, wxCoord y, wxColour *col) const
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return FALSE;
#endif

    wxCHECK_MSG( col, FALSE, _T("NULL colour parameter in wxDC::GetPixel") );

    // get the color of the pixel
    COLORREF pixelcolor = ::GetPixel(GetHdc(), XLOG2DEV(x), YLOG2DEV(y));

    wxRGBToColour(*col, pixelcolor);

    return TRUE;
}

void wxDC::DoCrossHair(wxCoord x, wxCoord y)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    wxCoord x1 = x-VIEWPORT_EXTENT;
    wxCoord y1 = y-VIEWPORT_EXTENT;
    wxCoord x2 = x+VIEWPORT_EXTENT;
    wxCoord y2 = y+VIEWPORT_EXTENT;

    (void)MoveToEx(GetHdc(), XLOG2DEV(x1), YLOG2DEV(y), NULL);
    (void)LineTo(GetHdc(), XLOG2DEV(x2), YLOG2DEV(y));

    (void)MoveToEx(GetHdc(), XLOG2DEV(x), YLOG2DEV(y1), NULL);
    (void)LineTo(GetHdc(), XLOG2DEV(x), YLOG2DEV(y2));

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

void wxDC::DoDrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    (void)MoveToEx(GetHdc(), XLOG2DEV(x1), YLOG2DEV(y1), NULL);
    (void)LineTo(GetHdc(), XLOG2DEV(x2), YLOG2DEV(y2));

    // Normalization: Windows doesn't draw the last point of the line.
    // But apparently neither does GTK+, so we take it out again.
//    (void)LineTo(GetHdc(), XLOG2DEV(x2) + 1, YLOG2DEV(y2));

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

// Draws an arc of a circle, centred on (xc, yc), with starting point (x1, y1)
// and ending at (x2, y2)
void wxDC::DoDrawArc(wxCoord x1, wxCoord y1,
                     wxCoord x2, wxCoord y2,
                     wxCoord xc, wxCoord yc)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    wxColourChanger cc(*this); // needed for wxSTIPPLE_MASK_OPAQUE handling

    double dx = xc - x1;
    double dy = yc - y1;
    double radius = (double)sqrt(dx*dx+dy*dy);
    wxCoord r = (wxCoord)radius;

    // treat the special case of full circle separately
    if ( x1 == x2 && y1 == y2 )
    {
        DrawEllipse(xc - r, yc - r, 2*r, 2*r);
        return;
    }

    wxCoord xx1 = XLOG2DEV(x1);
    wxCoord yy1 = YLOG2DEV(y1);
    wxCoord xx2 = XLOG2DEV(x2);
    wxCoord yy2 = YLOG2DEV(y2);
    wxCoord xxc = XLOG2DEV(xc);
    wxCoord yyc = YLOG2DEV(yc);
    wxCoord ray = (wxCoord) sqrt(double((xxc-xx1)*(xxc-xx1)+(yyc-yy1)*(yyc-yy1)));

    wxCoord xxx1 = (wxCoord) (xxc-ray);
    wxCoord yyy1 = (wxCoord) (yyc-ray);
    wxCoord xxx2 = (wxCoord) (xxc+ray);
    wxCoord yyy2 = (wxCoord) (yyc+ray);

    if ( m_brush.Ok() && m_brush.GetStyle() != wxTRANSPARENT )
    {
        // Have to add 1 to bottom-right corner of rectangle
        // to make semi-circles look right (crooked line otherwise).
        // Unfortunately this is not a reliable method, depends
        // on the size of shape.
        // TODO: figure out why this happens!
        Pie(GetHdc(),xxx1,yyy1,xxx2+1,yyy2+1, xx1,yy1,xx2,yy2);
    }
    else
    {
        Arc(GetHdc(),xxx1,yyy1,xxx2,yyy2, xx1,yy1,xx2,yy2);
    }

    CalcBoundingBox(xc - r, yc - r);
    CalcBoundingBox(xc + r, yc + r);
}

void wxDC::DoDrawCheckMark(wxCoord x1, wxCoord y1,
                           wxCoord width, wxCoord height)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

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

#if defined(__WIN32__) && !defined(__SC__) && !defined(__WXMICROWIN__)
    RECT rect;
    rect.left   = x1;
    rect.top    = y1;
    rect.right  = x2;
    rect.bottom = y2;

    DrawFrameControl(GetHdc(), &rect, DFC_MENU, DFCS_MENUCHECK);
#else // Win16
    // In WIN16, draw a cross
    HPEN blackPen = ::CreatePen(PS_SOLID, 1, RGB(0, 0, 0));
    HPEN whiteBrush = (HPEN)::GetStockObject(WHITE_BRUSH);
    HPEN hPenOld = (HPEN)::SelectObject(GetHdc(), blackPen);
    HPEN hBrushOld = (HPEN)::SelectObject(GetHdc(), whiteBrush);
    ::SetROP2(GetHdc(), R2_COPYPEN);
    Rectangle(GetHdc(), x1, y1, x2, y2);
    MoveToEx(GetHdc(), x1, y1, NULL);
    LineTo(GetHdc(), x2, y2);
    MoveToEx(GetHdc(), x2, y1, NULL);
    LineTo(GetHdc(), x1, y2);
    ::SelectObject(GetHdc(), hPenOld);
    ::SelectObject(GetHdc(), hBrushOld);
    ::DeleteObject(blackPen);
#endif // Win32/16

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

void wxDC::DoDrawPoint(wxCoord x, wxCoord y)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    COLORREF color = 0x00ffffff;
    if (m_pen.Ok())
    {
        color = m_pen.GetColour().GetPixel();
    }

    SetPixel(GetHdc(), XLOG2DEV(x), YLOG2DEV(y), color);

    CalcBoundingBox(x, y);
}

void wxDC::DoDrawPolygon(int n, wxPoint points[], wxCoord xoffset, wxCoord yoffset,int fillStyle)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    wxColourChanger cc(*this); // needed for wxSTIPPLE_MASK_OPAQUE handling

    // Do things less efficiently if we have offsets
    if (xoffset != 0 || yoffset != 0)
    {
        POINT *cpoints = new POINT[n];
        int i;
        for (i = 0; i < n; i++)
        {
            cpoints[i].x = (int)(points[i].x + xoffset);
            cpoints[i].y = (int)(points[i].y + yoffset);

            CalcBoundingBox(cpoints[i].x, cpoints[i].y);
        }
        int prev = SetPolyFillMode(GetHdc(),fillStyle==wxODDEVEN_RULE?ALTERNATE:WINDING);
        (void)Polygon(GetHdc(), cpoints, n);
        SetPolyFillMode(GetHdc(),prev);
        delete[] cpoints;
    }
    else
    {
        int i;
        for (i = 0; i < n; i++)
            CalcBoundingBox(points[i].x, points[i].y);

        int prev = SetPolyFillMode(GetHdc(),fillStyle==wxODDEVEN_RULE?ALTERNATE:WINDING);
        (void)Polygon(GetHdc(), (POINT*) points, n);
        SetPolyFillMode(GetHdc(),prev);
    }
}

void wxDC::DoDrawLines(int n, wxPoint points[], wxCoord xoffset, wxCoord yoffset)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    // Do things less efficiently if we have offsets
    if (xoffset != 0 || yoffset != 0)
    {
        POINT *cpoints = new POINT[n];
        int i;
        for (i = 0; i < n; i++)
        {
            cpoints[i].x = (int)(points[i].x + xoffset);
            cpoints[i].y = (int)(points[i].y + yoffset);

            CalcBoundingBox(cpoints[i].x, cpoints[i].y);
        }
        (void)Polyline(GetHdc(), cpoints, n);
        delete[] cpoints;
    }
    else
    {
        int i;
        for (i = 0; i < n; i++)
            CalcBoundingBox(points[i].x, points[i].y);

        (void)Polyline(GetHdc(), (POINT*) points, n);
    }
}

void wxDC::DoDrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
{
#ifdef __WXMICROWIN__
    if (!GetHDC()) return;
#endif

    wxColourChanger cc(*this); // needed for wxSTIPPLE_MASK_OPAQUE handling

    wxCoord x2 = x + width;
    wxCoord y2 = y + height;

    if ((m_logicalFunction == wxCOPY) && (m_pen.GetStyle() == wxTRANSPARENT))
    {
        RECT rect;
        rect.left = XLOG2DEV(x);
        rect.top = YLOG2DEV(y);
        rect.right = XLOG2DEV(x2);
        rect.bottom = YLOG2DEV(y2);
        (void)FillRect(GetHdc(), &rect, (HBRUSH)m_brush.GetResourceHandle() );
    }
    else
    {
        // Windows draws the filled rectangles without outline (i.e. drawn with a
        // transparent pen) one pixel smaller in both directions and we want them
        // to have the same size regardless of which pen is used - adjust