Simplify resolution calculation

Removed unnecessary complexity with resolutions because X in 2014 isn't
telling the truth about the size of the screen. My brand-new 13" laptop
with the latest X and everything apparently has a 33" x 18" monitor. So
if the data isn't reliable, just use 96 dpi anyway which is a very
reasonable default.

Also got rid of exact resolution member variable. LibreOffice can just
always think it has exact resolution. If it doesn't, then it just means
the code needs to be smarter, not that we need a flag about whether the
data we have is "exact" or not.

Change-Id: Ic41bdc3a82dbd1fdb6a987d6dc49adad8194ce14
Reviewed-on: https://gerrit.libreoffice.org/8166Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/inc/unx/saldisp.hxx

@@ -252,7 +252,6 @@ protected:
     std::vector< ScreenData >    m_aScreens;
     ScreenData      m_aInvalidScreenData;
     Pair            aResolution_;       // [dpi]
-    bool            mbExactResolution;
     sal_uLong       nMaxRequestSize_;   // [byte]
 
     srv_vendor_t    meServerVendor;
@@ -353,7 +352,6 @@ public:
     const SalVisual&      GetVisual( SalX11Screen nXScreen ) const { return getDataForScreen(nXScreen).m_aVisual; }
     RenderEntryMap&       GetRenderEntries( SalX11Screen nXScreen ) const { return getDataForScreen(nXScreen).m_aRenderData; }
     const Pair     &GetResolution() const { return aResolution_; }
-    bool            GetExactResolution() const { return mbExactResolution; }
     sal_uLong       GetProperties() const { return PROPERTY_DEFAULT; }
     sal_uLong       GetMaxRequestSize() const { return nMaxRequestSize_; }
     XLIB_Time       GetLastUserEventTime( bool bAlwaysReget = false ) const;

vcl/unx/generic/app/saldisp.cxx

@@ -540,7 +540,7 @@ void SalDisplay::Init()
     int nDisplayScreens = ScreenCount( pDisp_ );
     m_aScreens = std::vector<ScreenData>(nDisplayScreens);
 
-    mbExactResolution = false;
+    bool bExactResolution = false;
     /*  #i15507#
      *  Xft resolution should take precedence since
      *  it is what modern desktops use.
@@ -554,27 +554,12 @@ void SalDisplay::Init()
         if( (nDPI >= 50) && (nDPI <= 500) )
         {
             aResolution_ = Pair( nDPI, nDPI );
-            mbExactResolution = true;
+            bExactResolution = true;
         }
     }
-    if( mbExactResolution == false )
+    if( bExactResolution == false )
     {
-        int nDisplayWidth = DisplayWidthMM ( pDisp_, m_nXDefaultScreen.getXScreen() );
-        int nDisplayHeight = DisplayHeightMM( pDisp_, m_nXDefaultScreen.getXScreen() );
-
-        if (nDisplayHeight == 0 || nDisplayWidth == 0)
-        {
-            aResolution_ = Pair( 96, 96 );
-            SAL_WARN("vcl", "screen width/height reported as 0!, using fallback 96dpi");
-        }
-        else
-        {
-            aResolution_     =
-                Pair( DPI( WidthOfScreen( DefaultScreenOfDisplay( pDisp_ ) ),
-                           nDisplayWidth ),
-                      DPI( HeightOfScreen( DefaultScreenOfDisplay( pDisp_ ) ),
-                           nDisplayHeight ) );
-        }
+        aResolution_ = Pair( 96, 96 );
     }
 
     nMaxRequestSize_    = XExtendedMaxRequestSize( pDisp_ ) * 4;

vcl/unx/generic/gdi/salgdi.cxx

@@ -484,12 +484,8 @@ void X11SalGraphics::GetResolution( sal_Int32 &rDPIX, sal_Int32 &rDPIY ) // cons
 
     rDPIX = pDisplay->GetResolution().A();
     rDPIY = pDisplay->GetResolution().B();
-    if( !pDisplay->GetExactResolution() && rDPIY < 96 )
-    {
-        rDPIX = Divide( rDPIX * 96, rDPIY );
-            rDPIY = 96;
-    }
-    else if ( rDPIY > 200 )
+
+    if ( rDPIY > 200 )
     {
         rDPIX = Divide( rDPIX * 200, rDPIY );
         rDPIY = 200;