headless: optimize DrawWaveLine / drawPixel.

ImplDrawWaveLine - used to render colored lines under mis-spelled
and/or grammatically interesting sections uses (for better or worse)
'drawPixel' to draw the line.

Implementing drawPixel with a tiny B2DPolyPolygon is easy reading
but triggers the unbelievably expensive SystemDependentDataHolder
paths as well as some big chunks of logic for very large numbers
of pixels (if you have lots of mis-spelling this can make typing
visibly slower.).

Change-Id: Ie6ad513e27f820bcad5030579428374c8d22fb3d

1 files changed, 6 insertions, 14 deletions

diff --git a/vcl/headless/svpgdi.cxx b/vcl/headless/svpgdi.cxx
index b0f6f530e8bd..9c8a4bb97900 100644
--- a/vcl/headless/svpgdi.cxx
+++ b/vcl/headless/svpgdi.cxx
@@ -709,22 +709,14 @@ void SvpSalGraphics::drawPixel( long nX, long nY )
     }
 }
 
-void SvpSalGraphics::drawPixel( long nX, long nY, Color nColor )
+void SvpSalGraphics::drawPixel( long nX, long nY, Color aColor )
 {
-    Color aOrigFillColor = m_aFillColor;
-    Color aOrigLineColor = m_aLineColor;
-
-    basegfx::B2DPolygon aRect = basegfx::utils::createPolygonFromRect(basegfx::B2DRectangle(nX, nY, nX+1, nY+1));
-    m_aLineColor = SALCOLOR_NONE;
-    m_aFillColor = nColor;
-
-    drawPolyPolygon(
-        basegfx::B2DHomMatrix(),
-        basegfx::B2DPolyPolygon(aRect),
-        0.0);
+    cairo_t* cr = getCairoContext(true);
+    clipRegion(cr);
 
-    m_aFillColor = aOrigFillColor;
-    m_aLineColor = aOrigLineColor;
+    cairo_rectangle(cr, nX, nY, 1, 1);
+    applyColor(cr, aColor, 0.0);
+    cairo_fill(cr);
 }
 
 void SvpSalGraphics::drawRect( long nX, long nY, long nWidth, long nHeight )