Save/LoadLastRunWindowBounds: also save DpiWindowSizeFactor / restore…

… size with DPI handling
pthom · Jul 5, 2024 · 6027062 · 6027062
1 parent 004a648
commit 6027062
Show file tree

Hide file tree

Showing 4 changed files with 92 additions and 3 deletions.
diff --git a/src/hello_imgui/internal/backend_impls/abstract_runner.cpp b/src/hello_imgui/internal/backend_impls/abstract_runner.cpp
@@ -159,6 +159,39 @@ void AbstractRunner::PrepareWindowGeometry()
     params.appWindowParams.windowGeometry.size = windowBounds.size;
 }
 
+
+// If needed, change the size to match the current DPI versus the DPI when the size was saved
+// (we want the window to "look" as big as it was when saved, even if the DPI has changed,
+//  or if we are on a different monitor / computer / OS)
+void AbstractRunner::AdjustWindowBoundsAfterCreation_IfDpiChangedBetweenRuns()
+{
+    bool reloadLastSize = params.appWindowParams.restorePreviousGeometry &&
+                          HelloImGuiIniSettings::LoadLastRunWindowBounds(IniSettingsLocation(params)).has_value();
+    if (!reloadLastSize)
+        return;
+
+    std::optional<float> lastRunDpiWindowSizeFactorOpt = HelloImGuiIniSettings::LoadLastRunDpiWindowSizeFactor(IniSettingsLocation(params));
+    if (!lastRunDpiWindowSizeFactorOpt.has_value())
+        return;
+
+    float lastRunDpiWindowSizeFactor = lastRunDpiWindowSizeFactorOpt.value();
+    float currentDpiWindowSizeFactor = params.dpiAwareParams.dpiWindowSizeFactor;
+    float ratio = currentDpiWindowSizeFactor / lastRunDpiWindowSizeFactor;
+    bool isSane = ratio > 0.25f && ratio < 4.f;
+    if (isSane && ratio != 1.f)
+    {
+        auto bounds = mBackendWindowHelper->GetWindowBounds(mWindow);
+        bounds.size = {(int)((float)bounds.size[0] * ratio),
+                       (int)((float)bounds.size[1] * ratio)};
+        bounds.position = {
+            (int)((float)bounds.position[0] * ratio),
+            (int)((float)bounds.position[1] * ratio)
+        };
+        mBackendWindowHelper->SetWindowBounds(mWindow, bounds);
+    }
+}
+
+
 bool AbstractRunner::WantAutoSize()
 {
 #ifdef __EMSCRIPTEN__
@@ -717,6 +750,7 @@ void AbstractRunner::Setup()
             //printf("Window resized by code\n");
         }
     };
+
     Impl_CreateWindow(fnRenderCallbackDuringResize);
 
     #ifdef HELLOIMGUI_HAS_OPENGL
@@ -729,7 +763,11 @@ void AbstractRunner::Setup()
 
     Impl_SetWindowIcon();
 
+    // The order is important: first read the DPI aware params
     SetupDpiAwareParams();
+    // Then adjust window size if needed
+    AdjustWindowBoundsAfterCreation_IfDpiChangedBetweenRuns();
+
 
     // This should be done before Impl_LinkPlatformAndRenderBackends()
     // because, in the case of glfw ImGui_ImplGlfw_InstallCallbacks

diff --git a/src/hello_imgui/internal/backend_impls/abstract_runner.h b/src/hello_imgui/internal/backend_impls/abstract_runner.h
@@ -90,6 +90,7 @@ class AbstractRunner
     void SetupDpiAwareParams();
     bool CheckDpiAwareParamsChanges();
     void PrepareWindowGeometry();
+    void AdjustWindowBoundsAfterCreation_IfDpiChangedBetweenRuns();
     void HandleDpiOnSecondFrame();
     void MakeWindowSizeRelativeTo96Ppi_IfRequired();
     bool ShallSizeWindowRelativeTo96Ppi();

diff --git a/src/hello_imgui/internal/hello_imgui_ini_settings.cpp b/src/hello_imgui/internal/hello_imgui_ini_settings.cpp
@@ -173,11 +173,13 @@ namespace HelloImGui
 
         void SaveLastRunWindowBounds(const std::string& iniPartsFilename, const ScreenBounds& windowBounds)
         {
+            auto& dpiAwareParams = HelloImGui::GetRunnerParams()->dpiAwareParams;
             IniParts iniParts = IniParts::LoadFromFile(iniPartsFilename);
 
             ini::IniFile iniFile;
             iniFile["AppWindow"]["WindowPosition"] = IntPairToString(windowBounds.position);
             iniFile["AppWindow"]["WindowSize"] = IntPairToString(windowBounds.size);
+            iniFile["AppWindow"]["DpiWindowSizeFactor"] = dpiAwareParams.dpiWindowSizeFactor;
             std::string iniContent = iniFile.encode();
 
             iniParts.SetIniPart("AppWindow", iniContent);
@@ -191,7 +193,6 @@ namespace HelloImGui
             if (!iniParts.HasIniPart("AppWindow"))
                 return std::nullopt;
 
-
             auto iniPartContent = iniParts.GetIniPart("AppWindow");
             ini::IniFile iniFile;
             try
@@ -206,16 +207,26 @@ namespace HelloImGui
             ScreenBounds screenBounds;
             bool failed = false;
 
+            if (iniFile.find("AppWindow") == iniFile.end())
+                return std::nullopt;
+            auto & appWindowSection = iniFile["AppWindow"];
+
+            // Read Window Position
             {
-                auto strValue = iniFile["AppWindow"]["WindowPosition"].as<std::string>();
+                if (appWindowSection.find("WindowPosition") == appWindowSection.end())
+                    return std::nullopt;
+                auto strValue = appWindowSection["WindowPosition"].as<std::string>();
                 auto intPair = StringToIntPair(strValue);
                 if (intPair[0] >= 0)
                     screenBounds.position = intPair;
                 else
                     failed = true;
             }
+            // Read Window Size
             {
-                auto strValue = iniFile["AppWindow"]["WindowSize"].as<std::string>();
+                if (appWindowSection.find("WindowSize") == appWindowSection.end())
+                    return std::nullopt;
+                auto strValue = appWindowSection["WindowSize"].as<std::string>();
                 auto intPair = StringToIntPair(strValue);
                 if (intPair[0] >= 0)
                     screenBounds.size = intPair;
@@ -230,6 +241,44 @@ namespace HelloImGui
 
         }
 
+        std::optional<float> LoadLastRunDpiWindowSizeFactor(const std::string& iniPartsFilename)
+        {
+            IniParts iniParts = IniParts::LoadFromFile(iniPartsFilename);
+
+            if (!iniParts.HasIniPart("AppWindow"))
+                return std::nullopt;
+
+            auto iniPartContent = iniParts.GetIniPart("AppWindow");
+            ini::IniFile iniFile;
+            try
+            {
+                iniFile.decode(iniPartContent);
+            }
+            catch (const std::exception &)
+            {
+                return std::nullopt;
+            }
+
+            ScreenBounds screenBounds;
+            bool failed = false;
+
+            if (iniFile.find("AppWindow") == iniFile.end())
+                return std::nullopt;
+            auto &appWindowSection = iniFile["AppWindow"];
+
+            if (appWindowSection.find("DpiWindowSizeFactor") != appWindowSection.end())
+            {
+                float dpiWindowSizeFactor_WhenSaved =
+                    iniFile["AppWindow"]["DpiWindowSizeFactor"].as<float>();
+                bool isDpiSane = (dpiWindowSizeFactor_WhenSaved >= 0.1f) &&
+                                 (dpiWindowSizeFactor_WhenSaved <= 10.f);
+                if (isDpiSane)
+                    return dpiWindowSizeFactor_WhenSaved;
+            }
+            return std::nullopt;
+        }
+
+
         void LoadImGuiSettings(const std::string& iniPartsFilename, const std::string& layoutName)
         {
             std::string iniPartName = "ImGui_" + details::SanitizeIniNameOrCategory(layoutName);

diff --git a/src/hello_imgui/internal/hello_imgui_ini_settings.h b/src/hello_imgui/internal/hello_imgui_ini_settings.h
@@ -61,6 +61,7 @@ namespace HelloImGui
         //
         void SaveLastRunWindowBounds(const std::string& iniPartsFilename, const ScreenBounds& windowBounds);
         std::optional<ScreenBounds> LoadLastRunWindowBounds(const std::string& iniPartsFilename);
+        std::optional<float> LoadLastRunDpiWindowSizeFactor(const std::string& iniPartsFilename);
         void SaveHelloImGuiMiscSettings(const std::string& iniPartsFilename, const RunnerParams& runnerParams);
         void LoadHelloImGuiMiscSettings(const std::string& iniPartsFilename, RunnerParams* inOutRunnerParams);