From 77c309f4cb43b4993d96879e7759588a14e02910 Mon Sep 17 00:00:00 2001
From: Vojtech Kral <vojtech@kral.hk>
Date: Fri, 22 Feb 2019 14:52:32 +0100
Subject: [PATCH] imgui: Fix assert in new_frame()

---
 src/slic3r/GUI/ImGuiWrapper.cpp | 14 ++++++++++++++
 src/slic3r/GUI/ImGuiWrapper.hpp |  1 +
 2 files changed, 15 insertions(+)

diff --git a/src/slic3r/GUI/ImGuiWrapper.cpp b/src/slic3r/GUI/ImGuiWrapper.cpp
index 0e437ef6d..61baf352b 100644
--- a/src/slic3r/GUI/ImGuiWrapper.cpp
+++ b/src/slic3r/GUI/ImGuiWrapper.cpp
@@ -101,6 +101,10 @@ void ImGuiWrapper::set_style_scaling(float scaling)
 
 bool ImGuiWrapper::update_mouse_data(wxMouseEvent& evt)
 {
+    if (! display_initialized()) {
+        return false;
+    }
+
     ImGuiIO& io = ImGui::GetIO();
     io.MousePos = ImVec2((float)evt.GetX(), (float)evt.GetY());
     io.MouseDown[0] = evt.LeftDown();
@@ -116,6 +120,10 @@ bool ImGuiWrapper::update_mouse_data(wxMouseEvent& evt)
 
 bool ImGuiWrapper::update_key_data(wxKeyEvent &evt)
 {
+    if (! display_initialized()) {
+        return false;
+    }
+
     ImGuiIO& io = ImGui::GetIO();
 
     if (evt.GetEventType() == wxEVT_CHAR) {
@@ -521,6 +529,12 @@ void ImGuiWrapper::render_draw_data(ImDrawData *draw_data)
     glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
 }
 
+bool ImGuiWrapper::display_initialized() const
+{
+    const ImGuiIO& io = ImGui::GetIO();
+    return io.DisplaySize.x >= 0.0f && io.DisplaySize.y >= 0.0f;
+}
+
 void ImGuiWrapper::destroy_device_objects()
 {
     destroy_fonts_texture();
diff --git a/src/slic3r/GUI/ImGuiWrapper.hpp b/src/slic3r/GUI/ImGuiWrapper.hpp
index e8755718b..2cadc773c 100644
--- a/src/slic3r/GUI/ImGuiWrapper.hpp
+++ b/src/slic3r/GUI/ImGuiWrapper.hpp
@@ -75,6 +75,7 @@ private:
     void init_input();
     void init_style();
     void render_draw_data(ImDrawData *draw_data);
+    bool display_initialized() const;
     void destroy_device_objects();
     void destroy_fonts_texture();