ColorButton: Fixed rendering color button with a checkerboard if the transparency comes from the global style.Alpha and not from the actual source color.

imgui.cpp

@@ -9433,7 +9433,7 @@ bool ImGui::ColorButton(const char* desc_id, const ImVec4& col, ImGuiColorEditFl
     float grid_step = ImMin(size.x, size.y) / 2.99f;
     float rounding = ImMin(g.Style.FrameRounding, grid_step * 0.5f);
     ImRect bb_inner = bb;
-    float off = -0.75f; // The border (using Col_FrameBg) tends to look off when color is near-opaque and rounding is enabled. This offset seemed like a good middleground to reduce those artefacts.
+    float off = -0.75f; // The border (using Col_FrameBg) tends to look off when color is near-opaque and rounding is enabled. This offset seemed like a good middle ground to reduce those artifacts.
     bb_inner.Expand(off);
     if ((flags & ImGuiColorEditFlags_AlphaPreviewHalf) && col.w < 1.0f)
     {
@@ -9443,7 +9443,12 @@ bool ImGui::ColorButton(const char* desc_id, const ImVec4& col, ImGuiColorEditFl
     }
     else
     {
-        RenderColorRectWithAlphaCheckerboard(bb_inner.Min, bb_inner.Max, GetColorU32((flags & ImGuiColorEditFlags_AlphaPreview) ? col : col_without_alpha), grid_step, ImVec2(off, off), rounding);
+        // Because GetColorU32() multiplies by the global style Alpha and we don't want to display a checkerboard if the source code had no alpha
+        ImVec4 col_source = (flags & ImGuiColorEditFlags_AlphaPreview) ? col : col_without_alpha;
+        if (col_source.w < 1.0f)
+            RenderColorRectWithAlphaCheckerboard(bb_inner.Min, bb_inner.Max, GetColorU32(col_source), grid_step, ImVec2(off, off), rounding);
+        else
+            window->DrawList->AddRectFilled(bb_inner.Min, bb_inner.Max, GetColorU32(col_source), rounding, ~0);
     }
     if (window->Flags & ImGuiWindowFlags_ShowBorders)
         RenderFrameBorder(bb.Min, bb.Max, rounding);