T-Panel: Fixed fullsize-helptex being cut off

Author: ohlidalp

source/main/gui/panels/GUI_VehicleInfoTPanel.cpp

@@ -220,13 +220,15 @@ void VehicleInfoTPanel::DrawVehicleCommandsUI(RoR::GfxActor* actorx)
         ImGui::SetCursorPosX(MIN_PANEL_WIDTH - (ImGui::CalcTextSize(_LC("VehicleDescription", "Full size")).x + 25.f));
         ImGui::Checkbox(_LC("VehicleDescription", "Full size"), &m_helptext_fullsize);
 
-        ImTextureID im_tex = reinterpret_cast<ImTextureID>(actorx->GetHelpTex()->getHandle());
         if (m_helptext_fullsize)
         {
-            ImGui::Image(im_tex, ImVec2(HELP_TEXTURE_WIDTH, HELP_TEXTURE_HEIGHT));
+            m_helptext_fullsize_screenpos = ImGui::GetCursorScreenPos();
+            ImGui::Dummy(ImVec2(MIN_PANEL_WIDTH, HELP_TEXTURE_HEIGHT));
+            this->DrawVehicleHelpTextureFullsize(actorx);
         }
         else
         {
+            ImTextureID im_tex = reinterpret_cast<ImTextureID>(actorx->GetHelpTex()->getHandle());
             ImGui::Image(im_tex, ImVec2(MIN_PANEL_WIDTH, HELP_TEXTURE_HEIGHT));
         }
     }
@@ -802,6 +804,26 @@ void VehicleInfoTPanel::DrawVehicleCommandHighlights(RoR::GfxActor* actorx)
     }
 }
 
+void VehicleInfoTPanel::DrawVehicleHelpTextureFullsize(RoR::GfxActor* actorx)
+{
+    // In order to draw the image on top of the T-panel, the window must be focusable, 
+    // so we can't simply use `GetImDummyFullscreenWindow()`
+    // ===============================================================================
+
+    int window_flags = ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoScrollbar
+        | ImGuiWindowFlags_NoSavedSettings ;
+    ImGui::SetNextWindowPos(m_helptext_fullsize_screenpos - ImGui::GetStyle().WindowPadding);
+    ImGui::SetNextWindowSize(ImVec2(HELP_TEXTURE_WIDTH, HELP_TEXTURE_HEIGHT) + ImGui::GetStyle().WindowPadding);
+    ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(0, 0, 0, 0)); // Fully transparent background!
+    ImGui::Begin("T-Panel help tex fullsize", NULL, window_flags);
+    ImDrawList* drawlist = ImGui::GetWindowDrawList();
+    ImTextureID im_tex = reinterpret_cast<ImTextureID>(actorx->GetHelpTex()->getHandle());
+    drawlist->AddImage(im_tex, m_helptext_fullsize_screenpos,
+        m_helptext_fullsize_screenpos + ImVec2(HELP_TEXTURE_WIDTH, HELP_TEXTURE_HEIGHT));
+    ImGui::End();
+    ImGui::PopStyleColor(1); // WindowBg
+}
+
 bool DrawSingleButtonRow(bool active, const Ogre::TexturePtr& icon, const char* name, RoR::events ev, bool* btn_active = nullptr)
 {
     if (active)

source/main/gui/panels/GUI_VehicleInfoTPanel.h

@@ -61,6 +61,7 @@ class VehicleInfoTPanel
     /// @{
     void DrawVehicleCommandsUI(RoR::GfxActor* actorx);
     void DrawVehicleCommandHighlights(RoR::GfxActor* actorx);
+    void DrawVehicleHelpTextureFullsize(RoR::GfxActor* actorx);
 
     CommandkeyID_t m_active_commandkey = COMMANDKEYID_INVALID;
     CommandkeyID_t m_hovered_commandkey = COMMANDKEYID_INVALID;
@@ -70,6 +71,7 @@ class VehicleInfoTPanel
     float m_cmdbeam_highlight_thickness = 15.f;
     ImVec4 m_command_hovered_text_color = ImVec4(0.1f, 0.1f, 0.1f, 1.f);
     bool m_helptext_fullsize = false;
+    ImVec2 m_helptext_fullsize_screenpos; //!< The image is drawn into separate window
     /// @}
 
     /// @name 'Vehicle stats' tab