OpenGL GLFW not correctly recognising window resize - c++

Question

I have some graph that I need to resize concurrently when the window is also resized, however as of now, it changes the axis size's perfectly when resizing but when I let go of the resize (stop clicking on the corner of a window) the application's graph limits revert back to something entirely incorrect.
Here is a MRE displaying the issue:
#include <GL/glew.h>
#ifndef GLFW_INCLUDE_NONE
#define GLFW_INCLUDE_NONE // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
#endif // GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>
#include "ImGui/imgui.h"
#include "ImGui/implot.h"
#include "ImGui/implot_internal.h"
#include "ImGui/imgui_impl_glfw.h"
#include "ImGui/imgui_impl_opengl3.h"
#include <iostream>
static bool changedWinSize = false;
static int winWidth = 1280;
static int winHeight = 720;
static void MainLoop(GLFWwindow* window)
{
// Start the Dear ImGui frame
ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplGlfw_NewFrame();
ImGui::NewFrame();
ImGui::SetNextWindowSize({ (float)winWidth, (float)winHeight });
ImGui::SetNextWindowPos({ 0, 0 });
ImGui::Begin("Window", (bool*)0, ImGuiWindowFlags_NoBringToFrontOnFocus | ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize);
static bool fitPlot = false;
if (fitPlot) {
fitPlot = false;
ImPlot::SetNextPlotLimits(-10, 80, -3, 20, ImGuiCond_Always);
}
ImPlotStyle& style = ImPlot::GetStyle();
style.PlotDefaultSize.y = ImGui::GetWindowSize().y / 2 - 45 + (style.PlotDefaultSize.y = ImGui::GetWindowSize().y / 3 - 30) / 2 - 60;
style.PlotDefaultSize.x = ImGui::GetWindowSize().x - 150;
if (ImPlot::BeginPlot("Sim", "Range (m)", "Height (m)", { 0, 0 }, ImPlotFlags_NoLegend | ImPlotFlags_Equal)) {
if (ImPlot::BeginItem("Sim"))
{
if (ImPlot::FitThisFrame() || changedWinSize) {
fitPlot = true;
}
}
ImPlot::EndPlot();
}
ImGui::End();
changedWinSize = false;
// Rendering
ImGui::Render();
glClearColor(0.45f, 0.55f, 0.60f, 1.00f);
glClear(GL_COLOR_BUFFER_BIT);
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
glfwSwapBuffers(window);
}
static void window_size_callback(GLFWwindow* window, int width, int height)
{
changedWinSize = true;
winWidth = width;
winHeight = height;
MainLoop(window);
}
int main(int argc, char* argv[])
{
const char* glslVersion = "#version 460";
glfwInit();
// Create window with graphics context
GLFWwindow* window = glfwCreateWindow(1280, 720, "Program", NULL, NULL);
glfwMakeContextCurrent(window);
glfwSwapInterval(0); // vsync
//Initialize GLEW + ImGui
glewInit();
// Setup Dear ImGui context
IMGUI_CHECKVERSION();
ImGui::CreateContext();
ImPlot::CreateContext();
// Setup Dear ImGui style
ImGui::StyleColorsLight();
// Setup Platform/Renderer backends
ImGui_ImplGlfw_InitForOpenGL(window, true);
ImGui_ImplOpenGL3_Init(glslVersion);
glfwSetWindowSizeCallback(window, window_size_callback);
while (!glfwWindowShouldClose(window))
{
//Events
glfwPollEvents();
MainLoop(window);
}
ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplGlfw_Shutdown();
ImPlot::DestroyContext();
ImGui::DestroyContext();
glfwDestroyWindow(window);
glfwTerminate();
return 0;
}
From this example, the plot x-axis labels begin at -5 and go to 75. When you try to resize the window (shorten the width) after a pixel or so shrinking the window, the plot lables display -10 and 80, which is exactly what I want. This correct size only occurs when resizing the window and not letting go. It is only when you let go of the window that it reverts back to the incorrect side. I can't figure out where in my code it goes wrong.
ImPlot::FitThisFrame() returns true when double clicking on the plot, however what is weird is that the plot fits correctly if winChangedSize is true, entering that if statement, but when i double click to enter it it doesn't fit the plot correctly?