Merge branch 'rightlib' into merge-libs-250514-0050

1 files changed, 85 insertions, 0 deletions

diff --git a/contrib/python/matplotlib/py3/src/agg_workaround.h b/contrib/python/matplotlib/py3/src/agg_workaround.h
new file mode 100644
index 00000000000..47621951928
--- /dev/null
+++ b/contrib/python/matplotlib/py3/src/agg_workaround.h
@@ -0,0 +1,85 @@
+#ifndef MPL_AGG_WORKAROUND_H
+#define MPL_AGG_WORKAROUND_H
+
+#include "agg_pixfmt_rgba.h"
+
+/**********************************************************************
+ WORKAROUND: This class is to workaround a bug in Agg SVN where the
+ blending of RGBA32 pixels does not preserve enough precision
+*/
+
+template<class ColorT, class Order>
+struct fixed_blender_rgba_pre : agg::conv_rgba_pre<ColorT, Order>
+{
+    typedef ColorT color_type;
+    typedef Order order_type;
+    typedef typename color_type::value_type value_type;
+    typedef typename color_type::calc_type calc_type;
+    typedef typename color_type::long_type long_type;
+    enum base_scale_e
+    {
+        base_shift = color_type::base_shift,
+        base_mask  = color_type::base_mask
+    };
+
+    //--------------------------------------------------------------------
+    static AGG_INLINE void blend_pix(value_type* p,
+                                     value_type cr, value_type cg, value_type cb,
+                                     value_type alpha, agg::cover_type cover)
+    {
+        blend_pix(p,
+                  color_type::mult_cover(cr, cover),
+                  color_type::mult_cover(cg, cover),
+                  color_type::mult_cover(cb, cover),
+                  color_type::mult_cover(alpha, cover));
+    }
+
+    //--------------------------------------------------------------------
+    static AGG_INLINE void blend_pix(value_type* p,
+                                     value_type cr, value_type cg, value_type cb,
+                                     value_type alpha)
+    {
+        alpha = base_mask - alpha;
+        p[Order::R] = (value_type)(((p[Order::R] * alpha) >> base_shift) + cr);
+        p[Order::G] = (value_type)(((p[Order::G] * alpha) >> base_shift) + cg);
+        p[Order::B] = (value_type)(((p[Order::B] * alpha) >> base_shift) + cb);
+        p[Order::A] = (value_type)(base_mask - ((alpha * (base_mask - p[Order::A])) >> base_shift));
+    }
+};
+
+
+template<class ColorT, class Order>
+struct fixed_blender_rgba_plain : agg::conv_rgba_plain<ColorT, Order>
+{
+    typedef ColorT color_type;
+    typedef Order order_type;
+    typedef typename color_type::value_type value_type;
+    typedef typename color_type::calc_type calc_type;
+    typedef typename color_type::long_type long_type;
+    enum base_scale_e { base_shift = color_type::base_shift };
+
+    //--------------------------------------------------------------------
+    static AGG_INLINE void blend_pix(value_type* p,
+                                     value_type cr, value_type cg, value_type cb, value_type alpha, agg::cover_type cover)
+    {
+        blend_pix(p, cr, cg, cb, color_type::mult_cover(alpha, cover));
+    }
+
+    //--------------------------------------------------------------------
+    static AGG_INLINE void blend_pix(value_type* p,
+                                     value_type cr, value_type cg, value_type cb, value_type alpha)
+    {
+        if(alpha == 0) return;
+        calc_type a = p[Order::A];
+        calc_type r = p[Order::R] * a;
+        calc_type g = p[Order::G] * a;
+        calc_type b = p[Order::B] * a;
+        a = ((alpha + a) << base_shift) - alpha * a;
+        p[Order::A] = (value_type)(a >> base_shift);
+        p[Order::R] = (value_type)((((cr << base_shift) - r) * alpha + (r << base_shift)) / a);
+        p[Order::G] = (value_type)((((cg << base_shift) - g) * alpha + (g << base_shift)) / a);
+        p[Order::B] = (value_type)((((cb << base_shift) - b) * alpha + (b << base_shift)) / a);
+    }
+};
+
+#endif