+ int printerWidthMM;
+ int printerHeightMM;
+ int printerXRes;
+ int printerYRes;
+ int logPPIPrinterX;
+ int logPPIPrinterY;
+
+ wxRect paperRect;
+
+ if ( printerDC.IsOk() )
+ {
+ wxPrinterDCImpl *impl = (wxPrinterDCImpl*) printerDC.GetImpl();
+ HDC dc = GetHdcOf(*impl);
+ printerWidthMM = ::GetDeviceCaps(dc, HORZSIZE);
+ printerHeightMM = ::GetDeviceCaps(dc, VERTSIZE);
+ printerXRes = ::GetDeviceCaps(dc, HORZRES);
+ printerYRes = ::GetDeviceCaps(dc, VERTRES);
+ logPPIPrinterX = ::GetDeviceCaps(dc, LOGPIXELSX);
+ logPPIPrinterY = ::GetDeviceCaps(dc, LOGPIXELSY);
+
+ paperRect = printerDC.GetPaperRect();
+
+ if ( logPPIPrinterX == 0 ||
+ logPPIPrinterY == 0 ||
+ printerWidthMM == 0 ||
+ printerHeightMM == 0 )
+ {
+ m_isOk = false;
+ }
+ }
+ else
+ {
+ // use some defaults
+ printerWidthMM = 150;
+ printerHeightMM = 250;
+ printerXRes = 1500;
+ printerYRes = 2500;
+ logPPIPrinterX = 600;
+ logPPIPrinterY = 600;
+
+ paperRect = wxRect(0, 0, printerXRes, printerYRes);
+ m_isOk = false;
+ }
+ m_pageWidth = printerXRes;
+ m_pageHeight = printerYRes;
+ m_previewPrintout->SetPageSizePixels(printerXRes, printerYRes);
+ m_previewPrintout->SetPageSizeMM(printerWidthMM, printerHeightMM);
+ m_previewPrintout->SetPaperRectPixels(paperRect);
+ m_previewPrintout->SetPPIPrinter(logPPIPrinterX, logPPIPrinterY);
+
+ // At 100%, the page should look about page-size on the screen.
+ m_previewScaleX = float(logPPIScreenX) / logPPIPrinterX;
+ 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
+{
projects / wxWidgets.git / blobdiff