Add backdrop.color to libf3d and a f3d option

application/F3DOptionsTools.h

@@ -96,6 +96,7 @@ static inline const std::map<std::string_view, std::string_view> LibOptionsNames
   { "font-scale", "ui.scale" },
   { "font-color", "ui.font_color" },
   { "backdrop-opacity", "ui.backdrop.opacity" },
+  { "backdrop-color", "ui.backdrop.color" },
   { "normal-glyphs", "model.normal_glyphs.enable" },
   { "normal-glyphs-scale", "model.normal_glyphs.scale" },
   { "point-sprites-size", "model.point_sprites.size" },

application/testing/tests.features.cmake

@@ -308,6 +308,7 @@ f3d_test(NAME TestAnimationInputChangePointSprites DATA v_rock2.mdl ARGS --point
 f3d_test(NAME TestBackdropOpacityOpaque DATA suzanne.ply ARGS -n --backdrop-opacity=1.0 UI)
 f3d_test(NAME TestBackdropOpacityTransparent DATA suzanne.ply ARGS -n --backdrop-opacity=0.0 UI)
 f3d_test(NAME TestBackdropOpacityMedium DATA suzanne.ply ARGS -n --backdrop-opacity=0.5 UI)
+f3d_test(NAME TestBackdropColor DATA suzanne.ply ARGS -n --backdrop-color=0.5,1.0,0.5 UI)
 
 if(VTK_VERSION VERSION_GREATER_EQUAL 9.5.20251001)
   f3d_test(NAME TestDefaultConfigFileHDRIFilename DATA dragon.vtu CONFIG config_build ARGS -j --hdri-file=${F3D_SOURCE_DIR}/testing/data/palermo_park_1k.hdr UI LONG_TIMEOUT)

doc/libf3d/03-OPTIONS.md

@@ -581,6 +581,12 @@ Space separated custom key bindings to display in the drop zone.
 
 Display the logo. Needs ui.drop_zone.enable to be true.
 
+### `ui.backdrop.color` (_color_, default: `f3d_black`)
+
+Set the color of the backdrop behind the UI elements.
+
+CLI: `--backdrop-color`.
+
 ### `ui.backdrop.opacity` (_double_, default: `0.9`)
 
 Set the opacity of the backdrop behind the UI elements. Value is between 0.0 (fully transparent) and 1.0 (fully opaque).

doc/user/03-OPTIONS.md

@@ -224,6 +224,10 @@ Only supported on Windows platform.
 Provide a script file containing a list of [commands](07-COMMANDS.md) to be executed sequentially.
 Allows automation of multiple commands or pre-defined tasks.
 
+### `--backdrop-color=<color>` (_color_, default: `f3d_black`)
+
+Set the color of the backdrop behind text information such as FPS, filename, metadata or cheatsheet.
+
 ### `--backdrop-opacity=<opacity>` (_double_, default: `0.9`)
 
 Set the opacity of the backdrop behind text information such as FPS, filename, metadata or cheatsheet.

library/options.json

@@ -183,6 +183,10 @@
       "opacity": {
         "type": "double",
         "default_value": "0.9"
+      },
+      "color": {
+        "type": "color",
+        "parsed_default_value": "f3d_black"
       }
     },
     "axis": {

library/src/window_impl.cxx

@@ -453,6 +453,7 @@ void window_impl::UpdateDynamicOptions()
   renderer->ShowMinimalConsole(opt.ui.minimal_console);
   renderer->ShowDropZone(opt.ui.drop_zone.enable);
   renderer->ShowDropZoneLogo(opt.ui.drop_zone.show_logo);
+  renderer->SetBackdropColor(opt.ui.backdrop.color);
   renderer->SetBackdropOpacity(opt.ui.backdrop.opacity);
   renderer->ShowNotification(opt.ui.notifications.enable);
   renderer->ShowBindings(opt.ui.notifications.show_bindings);

resources/cli-options.json

@@ -307,6 +307,12 @@
           "valueHelper": "<value>",
           "conditional": "F3D_MODULE_UI"
         },
+        {
+          "longName": "backdrop-color",
+          "helpText": "UI backdrop color",
+          "valueHelper": "<color>",
+          "conditional": "F3D_MODULE_UI"
+        },
         {
           "longName": "command-script",
           "helpText": "Path to a script file containing commands to execute",

vtkext/private/module/vtkF3DImguiActor.cxx

@@ -587,7 +587,9 @@ void vtkF3DImguiActor::RenderSceneHierarchy(vtkOpenGLRenderWindow* renWin)
   ImGui::SetNextWindowSize(ImVec2(defaultWidth, winHeight), ImGuiCond_FirstUseEver);
   ImGui::SetNextWindowSizeConstraints(
     ImVec2(10.f, winHeight), ImVec2(std::numeric_limits<float>::max(), winHeight));
-  ImGui::SetNextWindowBgAlpha(this->BackdropOpacity);
+  ImGuiStyle& style = ImGui::GetStyle();
+  style.Colors[ImGuiCol_WindowBg] = ImVec4(
+    this->BackdropColor[0], this->BackdropColor[1], this->BackdropColor[2], this->BackdropOpacity);
 
   ImGuiWindowFlags flags = ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoCollapse |
     ImGuiWindowFlags_NoBringToFrontOnFocus | ImGuiWindowFlags_NoSavedSettings |
@@ -826,7 +828,9 @@ void vtkF3DImguiActor::RenderFileName()
     }
 
     ::SetupNextWindow(ImVec2(viewport->GetWorkCenter().x - 0.5f * totalWidth, margin), winSize);
-    ImGui::SetNextWindowBgAlpha(this->BackdropOpacity);
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.Colors[ImGuiCol_WindowBg] = ImVec4(this->BackdropColor[0], this->BackdropColor[1],
+      this->BackdropColor[2], this->BackdropOpacity);
 
     ImGuiWindowFlags flags = ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoSavedSettings |
       ImGuiWindowFlags_NoFocusOnAppearing | ImGuiWindowFlags_NoNav | ImGuiWindowFlags_NoMove;
@@ -851,7 +855,9 @@ void vtkF3DImguiActor::RenderMetaData()
   ::SetupNextWindow(ImVec2(viewport->WorkSize.x - winSize.x - margin,
                       viewport->GetWorkCenter().y - 0.5f * winSize.y),
     winSize);
-  ImGui::SetNextWindowBgAlpha(this->BackdropOpacity);
+  ImGuiStyle& style = ImGui::GetStyle();
+  style.Colors[ImGuiCol_WindowBg] = ImVec4(
+    this->BackdropColor[0], this->BackdropColor[1], this->BackdropColor[2], this->BackdropOpacity);
 
   ImGuiWindowFlags flags = ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoSavedSettings |
     ImGuiWindowFlags_NoFocusOnAppearing | ImGuiWindowFlags_NoNav | ImGuiWindowFlags_NoMove;
@@ -886,7 +892,9 @@ void vtkF3DImguiActor::RenderHDRIFileName()
 
     ::SetupNextWindow(
       ImVec2(viewport->GetWorkCenter().x - 0.5f * totalWidth + winOffsetX, margin), winSize);
-    ImGui::SetNextWindowBgAlpha(this->BackdropOpacity);
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.Colors[ImGuiCol_WindowBg] = ImVec4(this->BackdropColor[0], this->BackdropColor[1],
+      this->BackdropColor[2], this->BackdropOpacity);
 
     ImGuiWindowFlags flags = ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoSavedSettings |
       ImGuiWindowFlags_NoFocusOnAppearing | ImGuiWindowFlags_NoNav | ImGuiWindowFlags_NoMove;
@@ -985,7 +993,9 @@ void vtkF3DImguiActor::RenderCheatSheet()
   ::SetupNextWindow(ImVec2(margin, winTop),
     ImVec2(
       this->Pimpl->CheatSheetWidth, std::min(viewport->WorkSize.y - (2 * margin), textHeight)));
-  ImGui::SetNextWindowBgAlpha(this->BackdropOpacity);
+  ImGuiStyle& style = ImGui::GetStyle();
+  style.Colors[ImGuiCol_WindowBg] = ImVec4(
+    this->BackdropColor[0], this->BackdropColor[1], this->BackdropColor[2], this->BackdropOpacity);
 
   ImGuiWindowFlags flags = ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize |
     ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoSavedSettings |
@@ -1136,7 +1146,9 @@ void vtkF3DImguiActor::RenderFpsCounter()
     viewport->WorkSize.x - winSize.x - margin, viewport->WorkSize.y - winSize.y - margin);
 
   ::SetupNextWindow(position, winSize);
-  ImGui::SetNextWindowBgAlpha(this->BackdropOpacity);
+  ImGuiStyle& style = ImGui::GetStyle();
+  style.Colors[ImGuiCol_WindowBg] = ImVec4(
+    this->BackdropColor[0], this->BackdropColor[1], this->BackdropColor[2], this->BackdropOpacity);
 
   ImGuiWindowFlags flags = ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoSavedSettings |
     ImGuiWindowFlags_NoFocusOnAppearing | ImGuiWindowFlags_NoNav | ImGuiWindowFlags_NoMove;

vtkext/private/module/vtkF3DRenderer.cxx

@@ -1600,6 +1600,12 @@ void vtkF3DRenderer::SetDPIAware(bool enable)
   }
 }
 
+//----------------------------------------------------------------------------
+void vtkF3DRenderer::SetBackdropColor(const std::array<double, 3>& color)
+{
+  this->UIActor->SetBackdropColor(color);
+}
+
 //----------------------------------------------------------------------------
 void vtkF3DRenderer::SetBackdropOpacity(const double backdropOpacity)
 {

vtkext/private/module/vtkF3DRenderer.h

@@ -134,6 +134,11 @@ class vtkF3DRenderer : public vtkOpenGLRenderer
     const std::vector<double>& colorZAxis);
   ///@}
 
+  /**
+   * Set the backdrop color on the underlying UI Actor
+   */
+  void SetBackdropColor(const std::array<double, 3>& color);
+
   /**
    * Set the backdrop opacity
    * Should be called before ShowAxis

vtkext/private/module/vtkF3DUIActor.cxx

@@ -180,6 +180,16 @@ void vtkF3DUIActor::SetFontColor(const std::array<double, 3>& color)
   }
 }
 
+//----------------------------------------------------------------------------
+void vtkF3DUIActor::SetBackdropColor(const std::array<double, 3>& color)
+{
+  if (this->BackdropColor != color)
+  {
+    this->BackdropColor = color;
+    this->Initialized = false;
+  }
+}
+
 //----------------------------------------------------------------------------
 void vtkF3DUIActor::SetBackdropOpacity(const double backdropOpacity)
 {

vtkext/private/module/vtkF3DUIActor.h

@@ -8,13 +8,13 @@
 #ifndef vtkF3DUIActor_h
 #define vtkF3DUIActor_h
 
-#include <vtkProp.h>
-
+#include <F3DStyle.h>
 #include <array>
 #include <chrono>
 #include <cstdint>
 #include <deque>
 #include <map>
+#include <vtkProp.h>
 
 class vtkOpenGLRenderWindow;
 
@@ -198,6 +198,12 @@ class vtkF3DUIActor : public vtkProp
    */
   int RenderOverlay(vtkViewport* vp) override;
 
+  /**
+   * Set the backdrop color
+   * f3d_black by default
+   */
+  void SetBackdropColor(const std::array<double, 3>& color);
+
   /**
    * Set the backdrop opacity
    */
@@ -344,6 +350,7 @@ class vtkF3DUIActor : public vtkProp
    */
   std::array<double, 3> FontColor = { 1.0, 1.0, 1.0 };
 
+  std::array<double, 3> BackdropColor = { 0, 0, 0 };
   double BackdropOpacity = 0.9;
 
   bool NotificationVisible = false;