improve the rendering of databar gradients

Change-Id: Ie4a0e1b9193ca1fe230e8a0a69bef757d442fbee
Reviewed-on: https://gerrit.libreoffice.org/36311
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
diff --git a/sc/source/ui/view/output.cxx b/sc/source/ui/view/output.cxx
index 943b4af..f896179 100644
--- a/sc/source/ui/view/output.cxx
+++ b/sc/source/ui/view/output.cxx
@@ -857,6 +857,7 @@ void drawDataBars(vcl::RenderContext& rRenderContext, const ScDataBarInfo* pOldD
    {
        rRenderContext.SetLineColor(pOldDataBarInfo->maColor);
        Gradient aGradient(GradientStyle::Linear, pOldDataBarInfo->maColor, COL_TRANSPARENT);
        aGradient.SetSteps(255);

        if(pOldDataBarInfo->mnLength < 0)
            aGradient.SetAngle(2700);