preview.cpp

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//----------------------------------------------------------------------------
// ObjectWindows
// Copyright (c) 1992, 1996 by Borland International, All Rights Reserved
//
/// \file
/// Implementation of print preview classes
//----------------------------------------------------------------------------
#include <owl/pch.h>
#include <owl/preview.h>
#include <owl/printer.h>
#include <owl/gdiobjec.h>
#include <owl/dc.h>
#include <owl/printdia.h>
#include <math.h>
 
//
// Some inlines to provide platform independence since we drop directly to API
// calls to implement some of TPrintPreviewDC.
//
  inline bool SetWindowExt(HDC hdc, int w, int h) {return ::SetWindowExtEx(hdc, w, h, nullptr);}
  inline bool SetWindowOrg(HDC hdc, int w, int h) {return ::SetWindowOrgEx(hdc, w, h, nullptr);}
  inline bool SetViewportExt(HDC hdc, int w, int h) {return ::SetViewportExtEx(hdc, w, h, nullptr);}
  inline bool SetViewportOrg(HDC hdc, int x, int y) {return ::SetViewportOrgEx(hdc, x, y, nullptr);}
 
namespace owl {
 
OWL_DIAGINFO;
 
//
/// Constructs a basic Preview DC.
//
TPreviewDCBase::TPreviewDCBase(TDC&      screen,
                               TPrintDC& printdc)
:
  TPrintDC(screen),
  PrnDC(printdc)
{}
 
//
/// Overriden to return printer's HDC.
//
HDC
TPreviewDCBase::GetAttributeHDC() const
{
  return PrnDC;
}
 
//
/// TPrintPreviewDC's constructor takes a screen DC as well as a printer DC. The
/// screen DC is passed to the inherited constructor while the printer DC is copied
/// to the member, PrnDC.
//
TPrintPreviewDC::TPrintPreviewDC(TDC&         screen,
                                 TPrintDC&    printdc,
                                 const TRect& client,
                                 const TRect& clip)
:
  TPreviewDCBase(screen, printdc),
  PrnFont(nullptr),
  CurrentPreviewFont(nullptr)
{
  //
  // Set the initial mode & extents for the screen dc
  //
  ::SetMapMode(GetHDC(), MM_ANISOTROPIC);
  ::SetWindowExt(GetHDC(), client.Width(), client.Height());
  ::SetViewportExt(GetHDC(), client.Width(), client.Height());
 
  //
  // Static call to virtual method, but some mapping must be done now.
  //
  ReScale();
 
  //
  // Assume clip rect is in device points - DPs are same in new viewport
  //
  SelectClipRgn(clip);
  PrnFont = (HFONT)PrnDC.GetCurrentObject(OBJ_FONT);
  SyncFont();
}
 
//
/// Destroys a TPrintPreviewDC object.
//
TPrintPreviewDC::~TPrintPreviewDC()
{
  // cleanup screen dc
  //
  ::DeleteObject(::SelectObject(GetHDC(), ::GetStockObject(SYSTEM_FONT)));
  delete CurrentPreviewFont;
}
 
//
/// Selects the given font object into this DC.
///
/// Intercept setting of the printer font, making & keeping a copy of it and
/// calling SyncFont if needed to recreate the preview font.
//
void
TPrintPreviewDC::SelectObject(const TFont& newFont)
{
  if ((HFONT)newFont) {
    LOGFONT lf = newFont.GetObject();
 
    TFont*  oldPreviewF = CurrentPreviewFont;
    CurrentPreviewFont = new TFont(lf);
 
    PrnDC.SelectObject(*CurrentPreviewFont);
    delete oldPreviewF;
 
    if ((HFONT)(*CurrentPreviewFont) != PrnFont) {
      PrnFont = (HFONT)(*CurrentPreviewFont);
      SyncFont();
    }
  }
}
 
//
/// Retrieves a handle to a predefined stock font.
//
void
TPrintPreviewDC::SelectStockObject(int index)
{
  PrnDC.SelectStockObject(index);
  switch (index) {
    case ANSI_FIXED_FONT:
    case ANSI_VAR_FONT:
    case DEVICE_DEFAULT_FONT:
    case OEM_FIXED_FONT:
    case SYSTEM_FONT:
    case SYSTEM_FIXED_FONT: {
      HFONT stockFont = (HFONT)GetStockObject(index);
      if (stockFont != PrnFont) {
        PrnFont = stockFont;
        SyncFont();
      }
      break;
    }
    default:
      TPrintDC::SelectStockObject(index);
  }
}
 
//
/// Restores the original GDI font object to this DC.
//
void
TPrintPreviewDC::RestoreFont()
{
  PrnDC.RestoreFont();
  PrnFont = (HFONT)PrnDC.GetCurrentObject(OBJ_FONT);
  TPrintDC::RestoreFont();
  SyncFont();
}
 
//
/// GetDeviceCaps returns capability information, such as font and pitch attributes,
/// about the printer DC. The index argument specifies the type of information
/// required.
//
int
TPrintPreviewDC::GetDeviceCaps(int index) const
{
  switch (index) {
    case CLIPCAPS:
    case RASTERCAPS:
    case CURVECAPS:
    case LINECAPS:
    case POLYGONALCAPS:
    case TEXTCAPS:      // report capabilities supported on both devices
      return PrnDC.GetDeviceCaps(index) & TPrintDC::GetDeviceCaps(index);
 
      // otherwise, report printer caps and let GDI sort out differences
    default:
      return PrnDC.GetDeviceCaps(index);
  }
}
 
//
//
//
inline int
GlyphHeight(TEXTMETRIC& tm)
{
  return tm.tmHeight < 0
            ? tm.tmHeight
            : -(tm.tmHeight - tm.tmInternalLeading);
}
 
/// Sets the screen font equal to the current printer font.
//
/// SyncFont performs a simple font match attempt, with a retry option if
/// the GDI selected match is too different from the selected printer font.
/// In print preview, matching the size of the characters is more important
/// than matching their appearance.  In most cases, the print preview will
/// barely be legible anyway.  Size is most important because you don't
/// want character size differences to change the line breaks or page
/// breaks of the on-screen document from what they would be on the
/// printed page.  This effect is minimized in this TPrintPreviewDC object,
/// since info reports such as GetTextMetrics and GetTextExtent are always
/// reported from the printer dc using the real font.  Internal calculations
/// should be the same for preview as for printing, but the output accuracy
/// will depend upon the accuracy of font selection.
///
/// It is also possible to take over control of the text output functions
/// through this DC object - the TextOut and other text methods are virtual.
/// You can place each character on the preview screen yourself, if you
/// desire more precision in character placement than GDI's font matching
/// can provide.  That's a lot of work, and a lot of code, and isn't
/// necessary to meet the needs of most applications.
///
/// SyncFont is virtual so that you may substitute your own font matching
/// algorythm with more font matching heuristics.
//
void
TPrintPreviewDC::SyncFont()
{
  //
  // set screen font to match current printer font.
  //
  LOGFONT lf;
  ::GetObject(PrnFont, sizeof(lf), &lf);
 
  TEXTMETRIC tm;
  PrnDC.GetTextMetrics(tm);
 
  lf.lfHeight         = GlyphHeight(tm);
  lf.lfWidth          = tm.tmAveCharWidth;
  lf.lfWeight         = tm.tmWeight;
  lf.lfItalic         = tm.tmItalic;
  lf.lfUnderline      = tm.tmUnderlined;
  lf.lfStrikeOut      = tm.tmStruckOut;
  lf.lfCharSet        = tm.tmCharSet;
  lf.lfOutPrecision   = OUT_TT_PRECIS;
  lf.lfClipPrecision  = CLIP_DEFAULT_PRECIS;
  lf.lfQuality        = DRAFT_QUALITY;
 
  // Keep just the pitch (low 2 bits). Ignore the family
  //
  lf.lfPitchAndFamily = uint8((tm.tmPitchAndFamily & 0x0003) | FF_DONTCARE);
  PrnDC.GetTextFace(sizeof(lf.lfFaceName)/sizeof(lf.lfFaceName[0]), lf.lfFaceName);
 
  ::DeleteObject(::SelectObject(GetHDC(), ::CreateFontIndirect(&lf)));
 
  //
  // if height isn't right, relax the font pitch and facename requirements
  //
  GetTextMetrics(tm);
  if (abs(abs(static_cast<int>(lf.lfHeight)) - abs(GlyphHeight(tm))) > 2) {
    if (lf.lfPitchAndFamily & FF_DECORATIVE)
      lf.lfPitchAndFamily = DEFAULT_PITCH | FF_DECORATIVE;
    else
      lf.lfPitchAndFamily = DEFAULT_PITCH | FF_DONTCARE;
    lf.lfFaceName[0] = 0;
    ::DeleteObject(::SelectObject(GetHDC(), CreateFontIndirect(&lf)));
  }
}
 
//
// Return the size of the given printer device in device units.
//
static TSize
GetPageSizeInPixels(TPrintDC& d)
{
  return TSize(d.GetDeviceCaps(HORZRES), d.GetDeviceCaps(VERTRES));
}
 
//
/// Maps the points of the printer DC to the screen DC. Sets the screen window
/// extent equal to the maximum logical pointer of the printer DC.
///
/// It is assumed that the viewport extents of the screen DC
/// are already set and represent the full previewed page.
/// The window extents are set to the page size in logical units
/// as defined by the printer DC.
//
void
TPrintPreviewDC::ReScale()
{
  // Get the extents of the screen viewport in device units (pixels).
  // This should represent the whole previewed page on the screen.
 
  TSize ve; ::GetViewportExtEx(GetHDC(), &ve);
 
  // Calculate the size of the previewed page in logical units.
 
  TSize page = GetPageSizeInPixels(PrnDC);
  TSize pve = PrnDC.GetViewportExt();
  TSize pwe = PrnDC.GetWindowExt();
  TSize we(MulDiv(page.cx, pwe.cx, pve.cx), MulDiv(page.cy, pwe.cy, pve.cy));
 
  // Set the mapping mode and scale.
 
  ::SetMapMode(GetHDC(), MM_ANISOTROPIC);
  ::SetWindowExtEx(GetHDC(), we.cx, we.cy, nullptr);
  ::SetViewportExtEx(GetHDC(), ve.cx, ve.cy, nullptr);
 
  // Set the origin for logical units.
 
  ReOrg();
}
 
//
/// Gets the x- and y- extents of the viewport, equalizes the logical and screen
/// points, and resets the x- and y- extents of the viewport.
//
void
TPrintPreviewDC::ReOrg()
{
  // Get the viewport origin of the printer DC and transform it into
  // screen device units. It is assumed that the viewport extents of
  // the screen DC represent the whole previewed page.
 
  TPoint pvo = PrnDC.GetViewportOrg();
  TSize page = GetPageSizeInPixels(PrnDC);
  TSize ve; ::GetViewportExtEx(GetHDC(), &ve); // screen extents
  TPoint vo(MulDiv(pvo.x, ve.cx, page.cx), MulDiv(pvo.y, ve.cy, page.cy));
 
  // Use the same logical origin as the printout.
 
  TPoint wo = PrnDC.GetWindowOrg();
 
  // Set the origins.
 
  ::SetWindowOrgEx(GetHDC(), wo.x, wo.y, nullptr);
  ::SetViewportOrgEx(GetHDC(), vo.x, vo.y, nullptr);
}
 
//
/// Sets the current background color of this DC to the given color value or the
/// nearest available. Returns 0x80000000 if the call fails.
//
TColor
TPrintPreviewDC::SetBkColor(const TColor& color)
{
  TColor result = PrnDC.SetBkColor(color);
  ::SetBkColor(GetHDC(), PrnDC.GetBkColor());
  return result;
}
 
//
/// Sets the current text color of this DC to the given color value. The text color
/// determines the color displayed by TDC::TextOut and TDC::ExtTextOut.
//
TColor
TPrintPreviewDC::SetTextColor(const TColor& color)
{
  TColor result = PrnDC.SetTextColor(color);
  ::SetTextColor(GetHDC(), PrnDC.GetTextColor());
  return result;
}
 
//
/// Sets the current window mapping mode of this DC to mode. Returns the previous
/// mapping mode value. The mapping mode defines how logical coordinates are mapped
/// to device coordinates. It also controls the orientation of the device's x- and
/// y-axes.
//
int
TPrintPreviewDC::SetMapMode(int mode)
{
  int result = PrnDC.SetMapMode(mode);
  ReScale();
  return result;
}
 
//
/// Sets the printer DC's viewport origin to the given origin value, and saves the
/// previous origin in oldOrg. Returns nonzero if the call is successful; otherwise
/// returns 0.
//
bool
TPrintPreviewDC::SetViewportOrg(const TPoint& origin, TPoint * oldOrg)
{
  bool result = PrnDC.SetViewportOrg(origin, oldOrg);
  ReOrg();
  return result;
}
 
//
/// Modifies this DC's viewport origin relative to the current values. The delta x-
/// and y-components are added to the previous origin and the resulting point
/// becomes the new viewport origin. The previous origin is saved in oldOrg. Returns
/// nonzero if the call is successful; otherwise, returns 0.
//
bool
TPrintPreviewDC::OffsetViewportOrg(const TPoint& delta, TPoint * oldOrg)
{
  bool result = PrnDC.OffsetViewportOrg(delta, oldOrg);
  ReOrg();
  return result;
}
 
//
/// Sets the screen's viewport x- and y-extents to the given extent values. The
/// previous extents are saved in oldExtent. Returns nonzero if the call is
/// successful; otherwise, returns 0. The extent value determines the amount of
/// stretching or compression needed in the logical coordinate system to fit the
/// device coordinate system. extent also determines the relative orientation of the
/// two coordinate systems.
//
bool
TPrintPreviewDC::SetViewportExt(const TSize& extent, TSize * oldExtent)
{
  bool result = PrnDC.SetViewportExt(extent, oldExtent);
  ReScale();
  return result;
}
 
/// Modifies this DC's viewport extents relative to the current values. The new
/// extents are derived as follows:
/// \code
/// xNewVE = (xOldVE * xNum)/ xDenom
/// yNewVE = (yOldVE * yNum)/ yDenom
/// \endcode
/// The previous extents are saved in oldExtent. Returns nonzero if the call is
/// successful; otherwise returns 0.
bool
TPrintPreviewDC::ScaleViewportExt(int xNum, int xDenom, int yNum, int yDenom,
                                  TSize * oldExtent)
{
  bool result = PrnDC.ScaleViewportExt( xNum, xDenom, yNum, yDenom, oldExtent);
  ReScale();
  return result;
}
 
/// Sets the DC's window x- and y-extents to the given extent values. The previous
/// extents are saved in oldExtent. Returns nonzero if the call is successful;
/// otherwise, returns 0. The extent value determines the amount of stretching or
/// compression needed in the logical coordinate system to fit the device coordinate
/// system. extent also determines the relative orientation of the two coordinate
/// systems.
//
bool
TPrintPreviewDC::SetWindowExt(const TSize& extent, TSize * oldExtent)
{
  bool result = PrnDC.SetWindowExt(extent, oldExtent);
  ReScale();
  return result;
}
 
//
/// Modifies this DC's window extents relative to the current values. The new
/// extents are derived as follows:
/// \code
/// xNewWE = (xOldWE * xNum)/ xDenom
/// yNewWE = (yOldWE * yNum)/ yDenom
/// \endcode
/// The previous extents are saved in oldExtent. Returns nonzero if the call is
/// successful; otherwise returns 0.
//
bool
TPrintPreviewDC::ScaleWindowExt(int xNum, int xDenom, int yNum, int yDenom,
                                TSize * oldExtent)
{
  bool result = PrnDC.ScaleWindowExt(xNum, xDenom, yNum, yDenom, oldExtent);
  ReScale();
  return result;
}
 
 
DEFINE_RESPONSE_TABLE1(TPreviewPage, TWindow)
  EV_WM_SIZE,
END_RESPONSE_TABLE;
 
//
/// Constructs a TPreviewPage object where parent is the parent window, printout is
/// a reference to the corresponding TPrintout object, prndc is a reference to the
/// TPrintPreviewDC object, printExtent is the extent (width and height) in logical
/// units of the printed page, and pagenum is the number of the preview page.
/// TPreviewPage has the attributes of a visible child window with a thin border.
/// Sets the background color of the preview page window to white.
//
TPreviewPage::TPreviewPage(TWindow* parent, TPrintout& printout,
                           TPrintDC& prndc, TSize& printExtent, int pagenum)
:
  TWindow(parent),
  PageNum(pagenum),
  PrintExtent(printExtent),
  Printout(printout),
  PrintDC(prndc)
{
  Attr.Style = WS_CHILD | WS_BORDER | WS_VISIBLE;
  SetBkgndColor(TColor::White);
}
 
//
/// Sets newNum to the number of the page currently displayed in the preview window.
//
void
TPreviewPage::SetPageNumber(int newNum)
{
  PageNum = newNum;
  if (GetHandle())
    Invalidate();
}
 
//
/// Using a TPrintPreviewDC, 'print' the current page (PageNum) of Printout
/// onto the window DC provided
///
/// Displays the page in the preview window. To determine the preview page's
/// attributes (line width, and so on), Paint calls several of TPrintout's member
/// functions. Then, to adjust the printer object for previewing, Paint determines
/// if the page fits in the preview window or if clipping is necessary. Finally,
/// Paint passes clipping and banding information to TPrintout's PrintPage function,
/// which is called to display the page in the preview window.
//
void
TPreviewPage::Paint(TDC& dc, bool, TRect& clip)
{
  TPrintPreviewDC pdc(dc, PrintDC, GetClientRect(), clip);
  Printout.SetPrintParams(&pdc, PrintExtent);
 
  if (Printout.HasPage(PageNum)) {
    Printout.BeginPrinting();
    Printout.BeginDocument(PageNum, PageNum, pfBoth);
 
    // Change clip rect into the shared logical coordinate space, & print
    //
    pdc.SDPtoLP(clip);
    Printout.PrintPage(PageNum, clip, pfBoth);
 
    Printout.EndDocument();
    Printout.EndPrinting();
  }
  else
    dc.PatBlt(0, 0, Attr.W, Attr.H, WHITENESS);
}
 
//
/// Invalidates the entire window when the size of the page displayed in the preview
/// window changes.
//
void
TPreviewPage::EvSize(uint sizeType, const TSize& size)
{
  Invalidate();
  TWindow::EvSize(sizeType, size);
}
 
} // OWL namespace
/* ========================================================================== */