[qt4] New Page::renderToPainter()

This new painter-based painting function ican be used for painting (with Arthur only for now) without getting an image first.
Also add a new flag type for it, with a single item telling whether do not save+restore the provided painter.

Mostly based on a patch by Matthias Fauconneau (matthias.fauconneau@gmail.com), thanks!

2 files changed, 107 insertions, 20 deletions

diff --git a/qt4/src/poppler-page.cc b/qt4/src/poppler-page.cc
index 293d09b1..1b55c33d 100644
--- a/qt4/src/poppler-page.cc
+++ b/qt4/src/poppler-page.cc
@@ -8,6 +8,7 @@
  * Copyright (C) 2009 Shawn Rutledge <shawn.t.rutledge@gmail.com>
  * Copyright (C) 2010, Guillermo Amaral <gamaral@kdab.com>
  * Copyright (C) 2010 Suzuki Toshiya <mpsuzuki@hiroshima-u.ac.jp>
+ * Copyright (C) 2010 Matthias Fauconneau <matthias.fauconneau@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -250,25 +251,7 @@ QImage Page::renderToImage(double xres, double yres, int x, int y, int w, int h,
       QImage tmpimg(w == -1 ? qRound( size.width() * xres / 72.0 ) : w, h == -1 ? qRound( size.height() * yres / 72.0 ) : h, QImage::Format_ARGB32);
 
       QPainter painter(&tmpimg);
-      if (m_page->parentDoc->m_hints & Document::Antialiasing)
-          painter.setRenderHint(QPainter::Antialiasing);
-      if (m_page->parentDoc->m_hints & Document::TextAntialiasing)
-          painter.setRenderHint(QPainter::TextAntialiasing);
-      painter.translate(x == -1 ? 0 : -x, y == -1 ? 0 : -y);
-      ArthurOutputDev arthur_output(&painter);
-      arthur_output.startDoc(m_page->parentDoc->doc->getXRef());
-      m_page->parentDoc->doc->displayPageSlice(&arthur_output,
-						 m_page->index + 1,
-						 xres,
-						 yres,
-						 rotation,
-						 false,
-						 true,
-						 false,
-						 x,
-						 y,
-						 w,
-						 h);
+      renderToPainter(&painter, xres, yres, x, y, w, h, rotate, DontSaveAndRestore);
       painter.end();
       img = tmpimg;
       break;
@@ -278,6 +261,47 @@ QImage Page::renderToImage(double xres, double yres, int x, int y, int w, int h,
   return img;
 }
 
+bool Page::renderToPainter(QPainter* painter, double xres, double yres, int x, int y, int w, int h, Rotation rotate, PainterFlags flags) const
+{
+  if (!painter)
+    return false;
+
+  switch(m_page->parentDoc->m_backend)
+  {
+    case Poppler::Document::SplashBackend:
+      return false;
+    case Poppler::Document::ArthurBackend:
+    {
+      const bool savePainter = !(flags & DontSaveAndRestore);
+      if (savePainter)
+         painter->save();
+      if (m_page->parentDoc->m_hints & Document::Antialiasing)
+          painter->setRenderHint(QPainter::Antialiasing);
+      if (m_page->parentDoc->m_hints & Document::TextAntialiasing)
+          painter->setRenderHint(QPainter::TextAntialiasing);
+      painter->translate(x == -1 ? 0 : -x, y == -1 ? 0 : -y);
+      ArthurOutputDev arthur_output(painter);
+      arthur_output.startDoc(m_page->parentDoc->doc->getXRef());
+      m_page->parentDoc->doc->displayPageSlice(&arthur_output,
+                                               m_page->index + 1,
+                                               xres,
+                                               yres,
+                                               (int)rotate * 90,
+                                               false,
+                                               true,
+                                               false,
+                                               x,
+                                               y,
+                                               w,
+                                               h);
+      if (savePainter)
+         painter->restore();
+      return true;
+    }
+  }
+  return false;
+}
+
 QImage Page::thumbnail() const
 {
   unsigned char* data = 0;
diff --git a/qt4/src/poppler-qt4.h b/qt4/src/poppler-qt4.h
index d742973b..c50e4f9f 100644
--- a/qt4/src/poppler-qt4.h
+++ b/qt4/src/poppler-qt4.h
@@ -3,9 +3,10 @@
  * Copyright (C) 2005, 2007, Brad Hards <bradh@frogmouth.net>
  * Copyright (C) 2005-2010, Albert Astals Cid <aacid@kde.org>
  * Copyright (C) 2005, Stefan Kebekus <stefan.kebekus@math.uni-koeln.de>
- * Copyright (C) 2006-2009, Pino Toscano <pino@kde.org>
+ * Copyright (C) 2006-2010, Pino Toscano <pino@kde.org>
  * Copyright (C) 2009 Shawn Rutledge <shawn.t.rutledge@gmail.com>
  * Copyright (C) 2010 Suzuki Toshiya <mpsuzuki@hiroshima-u.ac.jp>
+ * Copyright (C) 2010 Matthias Fauconneau <matthias.fauconneau@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -398,6 +399,22 @@ delete it;
 	    RawOrderLayout          ///< The text is returned without any type of processing
 	};
 
+        /**
+           Additional flags for the renderToPainter method
+           \since 0.16
+        */
+        enum PainterFlag {
+            /**
+               Do not save/restore the caller-owned painter.
+
+               renderToPainter() by default preserves, using save() + restore(),
+               the state of the painter specified; if this is not needed, this
+               flag can avoid this job
+             */
+            DontSaveAndRestore = 0x00000001
+        };
+        Q_DECLARE_FLAGS( PainterFlags, PainterFlag )
+
 	/** 
 	   Render the page to a QImage using the current
 	   \link Document::renderBackend() Document renderer\endlink.
@@ -438,6 +455,51 @@ delete it;
         */
 	QImage renderToImage(double xres=72.0, double yres=72.0, int x=-1, int y=-1, int w=-1, int h=-1, Rotation rotate = Rotate0) const;
 
+        /**
+           Render the page to the specified QPainter using the current
+           \link Document::renderBackend() Document renderer\endlink.
+
+           If \p x = \p y = \p w = \p h = -1, the method will automatically
+           compute the size of the page area from the horizontal and vertical
+           resolutions specified in \p xres and \p yres. Otherwise, the
+           method renders only a part of the page, specified by the
+           parameters (\p x, \p y, \p w, \p h) in pixel coordinates.
+
+           \param painter the painter to paint on
+
+           \param x specifies the left x-coordinate of the box, in
+           pixels.
+
+           \param y specifies the top y-coordinate of the box, in
+           pixels.
+
+           \param w specifies the width of the box, in pixels.
+
+           \param h specifies the height of the box, in pixels.
+
+           \param xres horizontal resolution of the graphics device,
+           in dots per inch
+
+           \param yres vertical resolution of the graphics device, in
+           dots per inch
+
+           \param rotate how to rotate the page
+
+           \param flags additional painter flags
+
+           \warning The parameter (\p x, \p y, \p w, \p h) are not
+           well-tested. Unusual or meaningless parameters may lead to
+           rather unexpected results.
+
+           \returns whether the painting succeeded
+
+           \note This method is only supported for Arthur
+
+           \since 0.16
+        */
+        bool renderToPainter(QPainter* painter, double xres=72.0, double yres=72.0, int x=-1, int y=-1, int w=-1, int h=-1,
+                             Rotation rotate = Rotate0, PainterFlags flags = 0) const;
+
 	/**
 	   Get the page thumbnail if it exists.
 
@@ -1626,6 +1688,7 @@ height = dummy.height();
 
 }
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(Poppler::Page::PainterFlags)
 Q_DECLARE_OPERATORS_FOR_FLAGS(Poppler::Document::RenderHints)
 Q_DECLARE_OPERATORS_FOR_FLAGS(Poppler::PDFConverter::PDFOptions)
 Q_DECLARE_OPERATORS_FOR_FLAGS(Poppler::PSConverter::PSOptions)