clean up implot context management, add some tests

Author: nmwsharp

src/polyscope.cpp

@@ -207,11 +207,13 @@ void pushContext(std::function<void()> callbackFunction, bool drawDefaultUI) {
 
   // Create a new context and push it on to the stack
   ImGuiContext* newContext = ImGui::CreateContext();
+  ImPlotContext* newPlotContext = ImPlot::CreateContext();
   ImGuiIO& oldIO = ImGui::GetIO(); // used to GLFW + OpenGL data to the new IO object
 #ifdef IMGUI_HAS_DOCK
   ImGuiPlatformIO& oldPlatformIO = ImGui::GetPlatformIO();
 #endif
   ImGui::SetCurrentContext(newContext);
+  ImPlot::SetCurrentContext(newPlotContext);
 #ifdef IMGUI_HAS_DOCK
   // Propagate GLFW window handle to new context
   ImGui::GetMainViewport()->PlatformHandle = oldPlatformIO.Viewports[0]->PlatformHandle;
@@ -221,8 +223,6 @@ void pushContext(std::function<void()> callbackFunction, bool drawDefaultUI) {
 
   render::engine->configureImGui();
 
-  // Implot context too
-  ImPlotContext* newPlotContext = ImPlot::CreateContext();
 
   contextStack.push_back(ContextEntry{newContext, newPlotContext, callbackFunction, drawDefaultUI});
 
@@ -264,6 +264,7 @@ void pushContext(std::function<void()> callbackFunction, bool drawDefaultUI) {
   // Workaround overzealous ImGui assertion before destroying any inner context
   // https://github.com/ocornut/imgui/pull/7175
   ImGui::SetCurrentContext(newContext);
+  ImPlot::SetCurrentContext(newPlotContext);
   ImGui::GetIO().BackendPlatformUserData = nullptr;
   ImGui::GetIO().BackendRendererUserData = nullptr;
 

src/render/opengl/gl_engine_glfw.cpp

@@ -199,6 +199,7 @@ void GLEngineGLFW::shutdownImGui() {
   ImGui_ImplOpenGL3_Shutdown();
   ImGui_ImplGlfw_Shutdown();
   ImGui::DestroyContext();
+  ImPlot::DestroyContext();
 }
 
 void GLEngineGLFW::ImGuiNewFrame() {

src/screenshot.cpp

@@ -50,15 +50,20 @@ std::vector<unsigned char> getRenderInBuffer(const ScreenshotOptions& options =
   // Create a new context and push it on to the stack
   ImGuiContext* oldContext;
   ImGuiContext* newContext;
+  ImPlotContext* oldPlotContext;
+  ImPlotContext* newPlotContext;
   if (options.includeUI) {
     // WARNING: code duplicated here and in pushContext()
     oldContext = ImGui::GetCurrentContext();
     newContext = ImGui::CreateContext();
+    oldPlotContext = ImPlot::GetCurrentContext();
+    newPlotContext = ImPlot::CreateContext();
     ImGuiIO& oldIO = ImGui::GetIO(); // used to GLFW + OpenGL data to the new IO object
 #ifdef IMGUI_HAS_DOCK
     ImGuiPlatformIO& oldPlatformIO = ImGui::GetPlatformIO();
 #endif
     ImGui::SetCurrentContext(newContext);
+    ImPlot::SetCurrentContext(newPlotContext);
 #ifdef IMGUI_HAS_DOCK
     // Propagate GLFW window handle to new context
     ImGui::GetMainViewport()->PlatformHandle = oldPlatformIO.Viewports[0]->PlatformHandle;
@@ -81,11 +86,15 @@ std::vector<unsigned char> getRenderInBuffer(const ScreenshotOptions& options =
     // Workaround overzealous ImGui assertion before destroying any inner context
     // https://github.com/ocornut/imgui/pull/7175
     ImGui::SetCurrentContext(newContext);
+    ImPlot::SetCurrentContext(newPlotContext);
     ImGui::GetIO().BackendPlatformUserData = nullptr;
     ImGui::GetIO().BackendRendererUserData = nullptr;
 
     ImGui::DestroyContext(newContext);
+    ImPlot::DestroyContext(newPlotContext);
+
     ImGui::SetCurrentContext(oldContext);
+    ImPlot::SetCurrentContext(oldPlotContext);
   }
 
 

test/src/basics_test.cpp

@@ -45,6 +45,7 @@ TEST_F(PolyscopeTest, FrameTickWithImgui) {
   polyscope::state::userCallback = nullptr;
 }
 
+
 // We should be able to nest calls to show() via the callback. ImGUI causes headaches here
 TEST_F(PolyscopeTest, NestedShow) {
 
@@ -148,6 +149,55 @@ TEST_F(PolyscopeTest, ScreenshotBuffer) {
   EXPECT_EQ(buff2.size(), polyscope::view::bufferWidth * polyscope::view::bufferHeight * 4);
 }
 
+TEST_F(PolyscopeTest, ImPlotBasic) {
+
+  std::vector<float> xvals = {0., 2., 4., 8.};
+
+  auto showCallback = [&]() { 
+    ImGui::Button("do something"); 
+    if(ImPlot::BeginPlot("test plot")) {
+      ImPlot::PlotLine("test line", &xvals.front(), xvals.size());
+      ImPlot::EndPlot();
+    }
+  };
+  polyscope::state::userCallback = showCallback;
+
+  polyscope::show(3);
+  
+  for (int i = 0; i < 3; i++) {
+    polyscope::frameTick();
+  }
+
+  polyscope::state::userCallback = nullptr;
+}
+
+
+TEST_F(PolyscopeTest, ImPlotScreenshot) {
+  // test this because there is some context logic duplicated there
+
+  std::vector<float> xvals = {0., 2., 4., 8.};
+
+  auto showCallback = [&]() { 
+    ImGui::Button("do something"); 
+    if(ImPlot::BeginPlot("test plot")) {
+      ImPlot::PlotLine("test line", &xvals.front(), xvals.size());
+      ImPlot::EndPlot();
+    }
+  };
+  polyscope::state::userCallback = showCallback;
+
+  polyscope::show(3);
+  
+  polyscope::ScreenshotOptions opts;
+  opts.includeUI = true;
+  opts.transparentBackground = false;
+  polyscope::screenshot(opts);
+  
+  polyscope::show(3);
+  
+  polyscope::state::userCallback = nullptr;
+}
+
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