From 9b0e1a6716a05a52795006d38efa529d60539511 Mon Sep 17 00:00:00 2001
From: Martin Ecker <me@martinecker.com>
Date: Tue, 18 Aug 2026 08:54:45 -0700
Subject: [PATCH] Fix double application of FillAlpha in shaded plots

ImPlot already applies FillAlpha to the constant fill color in BeginItem. The shaded render paths applied the same value again through
GetterConstColor, making fills too transparent due to the double application.

To fix stop passing FillAlpha a second time for constant-color fills in:
- shaded PlotLine calls
- shaded PlotStairs calls
- PlotShaded calls
---
 implot_items.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/implot_items.cpp b/implot_items.cpp
index 1c1fa709..b4d8f0db 100644
--- a/implot_items.cpp
+++ b/implot_items.cpp
@@ -1929,7 +1929,7 @@ void PlotLineEx(const char* label_id, const _Getter& getter, const ImPlotSpec& s
                     RenderPrimitives3<RendererShaded>(getter,getter2,color_getter);
                 } else {
                     const ImU32 col_fill = ImGui::GetColorU32(s.Spec.FillColor);
-                    GetterConstColor color_getter(col_fill, s.Spec.FillAlpha);
+                    GetterConstColor color_getter(col_fill);
                     RenderPrimitives3<RendererShaded>(getter,getter2,color_getter);
                 }
             }
@@ -2200,7 +2200,7 @@ void PlotStairsEx(const char* label_id, const Getter& getter, const ImPlotSpec&
                         GetterIdxColor color_getter(s.Spec.FillColors, getter.Count, s.Spec.FillAlpha);
                         RenderPrimitives2<RendererStairsPreShaded>(getter, color_getter);
                     } else {
-                        GetterConstColor color_getter(col_fill, s.Spec.FillAlpha);
+                        GetterConstColor color_getter(col_fill);
                         RenderPrimitives2<RendererStairsPreShaded>(getter, color_getter);
                     }
                 } else {
@@ -2208,7 +2208,7 @@ void PlotStairsEx(const char* label_id, const Getter& getter, const ImPlotSpec&
                         GetterIdxColor color_getter(s.Spec.FillColors, getter.Count, s.Spec.FillAlpha);
                         RenderPrimitives2<RendererStairsPostShaded>(getter, color_getter);
                     } else {
-                        GetterConstColor color_getter(col_fill, s.Spec.FillAlpha);
+                        GetterConstColor color_getter(col_fill);
                         RenderPrimitives2<RendererStairsPostShaded>(getter, color_getter);
                     }
                 }
@@ -2286,7 +2286,7 @@ void PlotShadedEx(const char* label_id, const Getter1& getter1, const Getter2& g
                 RenderPrimitives3<RendererShaded>(getter1,getter2,color_getter);
             } else {
                 const ImU32 col = ImGui::GetColorU32(s.Spec.FillColor);
-                GetterConstColor color_getter(col, s.Spec.FillAlpha);
+                GetterConstColor color_getter(col);
                 RenderPrimitives3<RendererShaded>(getter1,getter2,color_getter);
             }
         }