Increase size of internal shared double buffer to accommodate larger screens more typical of modern (year 2011) systems

tqtinterface/qt4/src/kernel/tqinternal.cpp

@@ -44,6 +44,11 @@
 #include "tqpainter.h"
 #include "tqcleanuphandler.h"
 
+// Modern systems (year 2011) have very large screens in excess of 1000 pixels wide
+// Some may even have screens in excess of 4000 pixels wide(!)
+// Prevent drawing artifacts on such screens
+#define USE_HUGE_QT_SHARED_DOUBLE_BUFFERS 1
+
 static TQPixmap* qdb_shared_pixmap = 0;
 static TQPixmap *qdb_force_pixmap = 0;
 static TQSharedDoubleBuffer* qdb_owner = 0;
@@ -74,9 +79,15 @@ static const int hardLimitHeight = -1;
 // static const int sharedLimitWidth = 64;
 // static const int sharedLimitHeight = 20;
 // #else
+#ifdef USE_HUGE_QT_SHARED_DOUBLE_BUFFERS
+// 24M on 32bpp
+static const int sharedLimitWidth = 6400;
+static const int sharedLimitHeight = 1000;
+#else
 // 240K on 32bpp
 static const int sharedLimitWidth = 640;
 static const int sharedLimitHeight = 100;
+#endif
 // #endif
 
 // *******************************************************************
@@ -533,8 +544,13 @@ TQPixmap *TQSharedDoubleBuffer::getPixmap()
 	    rw = 4000;	// 32MB seems reasonable enough, but the usage is likely to be wider than it is tall (think of multiple wide monitors)
 	    rh = 2000;
 #else // USE_QT4
+#ifdef USE_HUGE_QT_SHARED_DOUBLE_BUFFERS
+	    rw = TQMIN(rw, 16000);
+	    rh = TQMIN(rh, 16000);
+#else
 	    rw = TQMIN(rw, 8000);
 	    rh = TQMIN(rh, 8000);
+#endif
 #endif // USE_QT4
 	    // need to create a big pixmap and start the cleaner
 	    if ( ! qdb_force_pixmap ) {