X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/f172cb8200f08ba1c6735a0d507991c877c0d68f..a91a64da8ec5aa3916d06e77875d8ae5e13cfd9f:/src/msw/printwin.cpp?ds=inline diff --git a/src/msw/printwin.cpp b/src/msw/printwin.cpp index 2ccf24961c..99f2892758 100644 --- a/src/msw/printwin.cpp +++ b/src/msw/printwin.cpp @@ -39,8 +39,12 @@ #include "wx/intl.h" #include "wx/log.h" #include "wx/dcprint.h" + #include "wx/dcmemory.h" + #include "wx/image.h" #endif +#include "wx/msw/dib.h" +#include "wx/msw/dcmemory.h" #include "wx/msw/printwin.h" #include "wx/msw/printdlg.h" #include "wx/msw/private.h" @@ -282,7 +286,7 @@ bool wxWindowsPrinter::Print(wxWindow *parent, wxPrintout *printout, bool prompt wxDC *wxWindowsPrinter::PrintDialog(wxWindow *parent) { - wxDC *dc = (wxPrinterDC*) NULL; + wxDC *dc = NULL; wxWindowsPrintDialog dialog(parent, & m_printDialogData); int ret = dialog.ShowModal(); @@ -331,6 +335,9 @@ wxWindowsPrintPreview::wxWindowsPrintPreview(wxPrintout *printout, wxPrintDialogData *data) : wxPrintPreviewBase(printout, printoutForPrinting, data) { +#if wxUSE_HIGH_QUALITY_PREVIEW + m_hqPreviewFailed = false; +#endif DetermineScaling(); } @@ -339,6 +346,9 @@ wxWindowsPrintPreview::wxWindowsPrintPreview(wxPrintout *printout, wxPrintData *data) : wxPrintPreviewBase(printout, printoutForPrinting, data) { +#if wxUSE_HIGH_QUALITY_PREVIEW + m_hqPreviewFailed = false; +#endif DetermineScaling(); } @@ -419,6 +429,297 @@ void wxWindowsPrintPreview::DetermineScaling() m_previewScaleY = float(logPPIScreenY) / logPPIPrinterY; } + +#if wxUSE_HIGH_QUALITY_PREVIEW + +// The preview, as implemented in wxPrintPreviewBase (and as used prior to wx3) +// is inexact: it uses screen DC, which has much lower resolution and has +// other properties different from printer DC, so the preview is not quite +// right. +// +// To make matters worse, if the application depends heavily on GetTextExtent() +// or does text layout itself, the output in preview and on paper can be very +// different. In particular, wxHtmlEasyPrinting is affected and the preview +// can be easily off by several pages. +// +// To fix this, we attempt to render the preview into high-resolution bitmap +// using DC with same resolution etc. as the printer DC. This takes lot of +// memory, so the code is more complicated than it could be, but the results +// are much better. +// +// Finally, this code is specific to wxMSW, because it doesn't make sense to +// bother with it on other platforms. Both OSX and modern GNOME/GTK+ +// environments have builtin accurate preview (that applications should use +// instead) and the differences between screen and printer DC in wxGTK are so +// large than this trick doesn't help at all. + +namespace +{ + +// If there's not enough memory, we need to render the preview in parts. +// Unfortunately we cannot simply use wxMemoryDC, because it reports its size +// as bitmap's size, and we need to use smaller bitmap while still reporting +// original ("correct") DC size, because printing code frequently uses +// GetSize() to determine scaling factor. This DC class handles this. + +class PageFragmentDCImpl : public wxMemoryDCImpl +{ +public: + PageFragmentDCImpl(wxMemoryDC *owner, wxDC *printer, + const wxPoint& offset, + const wxSize& fullSize) + : wxMemoryDCImpl(owner, printer), + m_offset(offset), + m_fullSize(fullSize) + { + SetDeviceOrigin(0, 0); + } + + virtual void SetDeviceOrigin(wxCoord x, wxCoord y) + { + wxMemoryDCImpl::SetDeviceOrigin(x - m_offset.x, y - m_offset.y); + } + + virtual void DoGetDeviceOrigin(wxCoord *x, wxCoord *y) const + { + wxMemoryDCImpl::DoGetDeviceOrigin(x, y); + if ( x ) *x += m_offset.x; + if ( x ) *y += m_offset.y; + } + + virtual void DoGetSize(int *width, int *height) const + { + if ( width ) + *width = m_fullSize.x; + if ( height ) + *height = m_fullSize.y; + } + +private: + wxPoint m_offset; + wxSize m_fullSize; +}; + +class PageFragmentDC : public wxDC +{ +public: + PageFragmentDC(wxDC* printer, wxBitmap& bmp, + const wxPoint& offset, + const wxSize& fullSize) + : wxDC(new PageFragmentDCImpl((wxMemoryDC*)this, printer, offset, fullSize)) + { + static_cast(m_pimpl)->DoSelect(bmp); + } +}; + +// estimate how big chunks we can render, given available RAM +long ComputeFragmentSize(long printerDepth, + long width, + long height) +{ + // Compute the amount of memory needed to generate the preview. + // Memory requirements of RenderPageFragment() are as follows: + // + // (memory DC - always) + // width * height * printerDepth/8 + // (wxImage + wxDIB instance) + // width * height * (3 + 4) + // (this could be reduced to *3 if using wxGraphicsContext) + // + // So, given amount of memory M, we can render at most + // + // height = M / (width * (printerDepth/8 + F)) + // + // where F is 3 or 7 depending on whether wxGraphicsContext is used or not + + wxMemorySize memAvail = wxGetFreeMemory(); + if ( memAvail == -1 ) + { + // we don't know; 10meg shouldn't be a problem hopefully + memAvail = 10000000; + } + else + { + // limit ourselves to half of available RAM to have a margin for other + // apps, for our rendering code, and for miscalculations + memAvail /= 2; + } + + const float perPixel = float(printerDepth)/8 + (3 + 4); + + const long perLine = long(width * perPixel); + const long maxstep = (memAvail / perLine).GetValue(); + const long step = wxMin(height, maxstep); + + wxLogTrace("printing", + "using %liMB of RAM (%li lines) for preview, %li %lipx fragments", + long((memAvail >> 20).GetValue()), + maxstep, + (height+step-1) / step, + step); + + return step; +} + +} // anonymous namespace + + +bool wxWindowsPrintPreview::RenderPageFragment(float scaleX, float scaleY, + int *nextFinalLine, + wxPrinterDC& printer, + wxMemoryDC& finalDC, + const wxRect& rect, + int pageNum) +{ + // compute 'rect' equivalent in the small final bitmap: + const wxRect smallRect(wxPoint(0, *nextFinalLine), + wxPoint(int(rect.GetRight() * scaleX), + int(rect.GetBottom() * scaleY))); + wxLogTrace("printing", + "rendering fragment of page %i: [%i,%i,%i,%i] scaled down to [%i,%i,%i,%i]", + pageNum, + rect.x, rect.y, rect.GetRight(), rect.GetBottom(), + smallRect.x, smallRect.y, smallRect.GetRight(), smallRect.GetBottom() + ); + + // create DC and bitmap compatible with printer DC: + wxBitmap large(rect.width, rect.height, printer); + if ( !large.IsOk() ) + return false; + + // render part of the page into it: + { + PageFragmentDC memoryDC(&printer, large, + rect.GetPosition(), + wxSize(m_pageWidth, m_pageHeight)); + if ( !memoryDC.IsOk() ) + return false; + + memoryDC.Clear(); + + if ( !RenderPageIntoDC(memoryDC, pageNum) ) + return false; + } // release bitmap from memoryDC + + // now scale the rendered part down and blit it into final output: + + wxImage img; + { + wxDIB dib(large); + if ( !dib.IsOk() ) + return false; + large = wxNullBitmap; // free memory a.s.a.p. + img = dib.ConvertToImage(); + } // free the DIB now that it's no longer needed, too + + if ( !img.IsOk() ) + return false; + + img.Rescale(smallRect.width, smallRect.height, wxIMAGE_QUALITY_HIGH); + if ( !img.IsOk() ) + return false; + + wxBitmap bmp(img); + if ( !bmp.IsOk() ) + return false; + + img = wxNullImage; + finalDC.DrawBitmap(bmp, smallRect.x, smallRect.y); + if ( bmp.IsOk() ) + { + *nextFinalLine += smallRect.height; + return true; + } + + return false; +} + +bool wxWindowsPrintPreview::RenderPageIntoBitmapHQ(wxBitmap& bmp, int pageNum) +{ + wxLogTrace("printing", "rendering HQ preview of page %i", pageNum); + + wxPrinterDC printerDC(m_printDialogData.GetPrintData()); + if ( !printerDC.IsOk() ) + return false; + + // compute scale factor + const float scaleX = float(bmp.GetWidth()) / float(m_pageWidth); + const float scaleY = float(bmp.GetHeight()) / float(m_pageHeight); + + wxMemoryDC bmpDC; + bmpDC.SelectObject(bmp); + bmpDC.Clear(); + + const int initialStep = ComputeFragmentSize(printerDC.GetDepth(), + m_pageWidth, m_pageHeight); + + wxRect todo(0, 0, m_pageWidth, initialStep); // rect to render + int nextFinalLine = 0; // first not-yet-rendered output line + + while ( todo.y < m_pageHeight ) + { + todo.SetBottom(wxMin(todo.GetBottom(), m_pageHeight - 1)); + + if ( !RenderPageFragment(scaleX, scaleY, + &nextFinalLine, + printerDC, + bmpDC, + todo, + pageNum) ) + { + if ( todo.height < 20 ) + { + // something is very wrong if we can't render even at this + // slow space, let's bail out and fall back to low quality + // preview + wxLogTrace("printing", + "it seems that HQ preview doesn't work at all"); + return false; + } + + // it's possible our memory calculation was off, or conditions + // changed, or there's not enough _bitmap_ resources; try if using + // smaller bitmap would help: + todo.height /= 2; + + wxLogTrace("printing", + "preview of fragment failed, reducing height to %ipx", + todo.height); + + continue; // retry at the same position again + } + + // move to the next segment + todo.Offset(0, todo.height); + } + + return true; +} + +bool wxWindowsPrintPreview::RenderPageIntoBitmap(wxBitmap& bmp, int pageNum) +{ + // try high quality rendering first: + if ( !m_hqPreviewFailed ) + { + if ( RenderPageIntoBitmapHQ(bmp, pageNum) ) + { + return true; + } + else + { + wxLogTrace("printing", + "high-quality preview failed, falling back to normal"); + m_hqPreviewFailed = true; // don't bother re-trying + } + } + + // if it fails, use the generic method that is less resource intensive, + // but inexact + return wxPrintPreviewBase::RenderPageIntoBitmap(bmp, pageNum); +} + +#endif // wxUSE_HIGH_QUALITY_PREVIEW + /**************************************************************************** FUNCTION: wxAbortProc()