Unbreak compilation of the iOS vcl code

Note that this is code basically copy-pasted from the MacOSX ("aqua")
back-end with some small edits, and it is not clear at all that it
will eventually be used in this form at all. But until then, let's
keep it compiling.

Change-Id: Ia1bd63f2ecc621cd4ce699ffc754cab423321d42

vcl/inc/ios/salgdi.h

@@ -123,8 +123,12 @@ public:
     virtual sal_Bool drawPolygonBezier( sal_uLong nPoints, const SalPoint* pPtAry, const sal_uInt8* pFlgAry );
     virtual sal_Bool drawPolyPolygonBezier( sal_uLong nPoly, const sal_uLong* pPoints,
                                             const SalPoint* const* pPtAry, const sal_uInt8* const* pFlgAry );
-    virtual bool drawPolyLine( const ::basegfx::B2DPolygon&, double fTransparency,
-                               const ::basegfx::B2DVector& rLineWidths, basegfx::B2DLineJoin );
+    virtual bool        drawPolyLine(
+        const ::basegfx::B2DPolygon&,
+        double fTransparency,
+        const ::basegfx::B2DVector& rLineWidths,
+        basegfx::B2DLineJoin,
+        com::sun::star::drawing::LineCap eLineCap);
 
     // CopyArea --> No RasterOp, but ClipRegion
     virtual void copyArea( long nDestX, long nDestY, long nSrcX, long nSrcY, long nSrcWidth,

vcl/ios/source/gdi/salgdicommon.cxx

@@ -662,7 +662,8 @@ void IosSalGraphics::drawPixel( long nX, long nY, SalColor nSalColor )
 bool IosSalGraphics::drawPolyLine( const ::basegfx::B2DPolygon& rPolyLine,
                                     double fTransparency,
                                     const ::basegfx::B2DVector& rLineWidths,
-                                    basegfx::B2DLineJoin eLineJoin )
+                                    basegfx::B2DLineJoin eLineJoin,
+                                    com::sun::star::drawing::LineCap eLineCap )
 {
     // short circuit if there is nothing to do
     const int nPointCount = rPolyLine.count();
@@ -694,6 +695,28 @@ bool IosSalGraphics::drawPolyLine( const ::basegfx::B2DPolygon& rPolyLine,
     case ::basegfx::B2DLINEJOIN_ROUND: aCGLineJoin = kCGLineJoinRound; break;
     }
 
+    // setup cap attribute
+    CGLineCap aCGLineCap(kCGLineCapButt);
+
+    switch(eLineCap)
+    {
+        default: // com::sun::star::drawing::LineCap_BUTT:
+        {
+            aCGLineCap = kCGLineCapButt;
+            break;
+        }
+        case com::sun::star::drawing::LineCap_ROUND:
+        {
+            aCGLineCap = kCGLineCapRound;
+            break;
+        }
+        case com::sun::star::drawing::LineCap_SQUARE:
+        {
+            aCGLineCap = kCGLineCapSquare;
+            break;
+        }
+    }
+
     // setup poly-polygon path
     CGMutablePathRef xPath = CGPathCreateMutable();
     AddPolygonToPath( xPath, rPolyLine, rPolyLine.isClosed(), !getAntiAliasB2DDraw(), true );
@@ -711,6 +734,7 @@ bool IosSalGraphics::drawPolyLine( const ::basegfx::B2DPolygon& rPolyLine,
         CGContextSetShouldAntialias( mrContext, true );
         CGContextSetAlpha( mrContext, 1.0 - fTransparency );
         CGContextSetLineJoin( mrContext, aCGLineJoin );
+        CGContextSetLineCap( mrContext, aCGLineCap );
         CGContextSetLineWidth( mrContext, rLineWidths.getX() );
         CGContextDrawPath( mrContext, kCGPathStroke );
         CGContextRestoreGState( mrContext );