From 10fca0e8b1ec42785678f8d2d9a018917b0a620f Mon Sep 17 00:00:00 2001
From: Soph <236479497+LunarInvasion@users.noreply.github.com>
Date: Thu, 20 Nov 2025 04:30:44 +0000
Subject: [PATCH] Examples: DPI awareness on Win32 OpenGL
---
backends/imgui_impl_win32.cpp | 8 ++--
.../example_win32_opengl3.vcxproj | 38 ++++++++++++++++---
examples/example_win32_opengl3/main.cpp | 4 +-
3 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/backends/imgui_impl_win32.cpp b/backends/imgui_impl_win32.cpp
index dc7e66f02..df29090b0 100644
--- a/backends/imgui_impl_win32.cpp
+++ b/backends/imgui_impl_win32.cpp
@@ -858,17 +858,17 @@ DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
#endif
typedef HRESULT(WINAPI* PFN_SetProcessDpiAwareness)(PROCESS_DPI_AWARENESS); // Shcore.lib + dll, Windows 8.1+
typedef HRESULT(WINAPI* PFN_GetDpiForMonitor)(HMONITOR, MONITOR_DPI_TYPE, UINT*, UINT*); // Shcore.lib + dll, Windows 8.1+
-typedef DPI_AWARENESS_CONTEXT(WINAPI* PFN_SetThreadDpiAwarenessContext)(DPI_AWARENESS_CONTEXT); // User32.lib + dll, Windows 10 v1607+ (Creators Update)
-
+typedef BOOL(WINAPI* PFN_SetProcessDpiAwarenessContext)(DPI_AWARENESS_CONTEXT); // User32.lib + dll, Windows 10 v1607+ (Creators Update)
// Helper function to enable DPI awareness without setting up a manifest
void ImGui_ImplWin32_EnableDpiAwareness()
{
if (_IsWindows10OrGreater())
{
static HINSTANCE user32_dll = ::LoadLibraryA("user32.dll"); // Reference counted per-process
- if (PFN_SetThreadDpiAwarenessContext SetThreadDpiAwarenessContextFn = (PFN_SetThreadDpiAwarenessContext)::GetProcAddress(user32_dll, "SetThreadDpiAwarenessContext"))
+ if (PFN_SetProcessDpiAwarenessContext SetProcessDpiAwarenessContext = (PFN_SetProcessDpiAwarenessContext)::GetProcAddress(user32_dll, "SetProcessDpiAwarenessContext"))
{
- SetThreadDpiAwarenessContextFn(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
+ // https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setprocessdpiawarenesscontext
+ SetProcessDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
return;
}
}
diff --git a/examples/example_win32_opengl3/example_win32_opengl3.vcxproj b/examples/example_win32_opengl3/example_win32_opengl3.vcxproj
index 98fc38fd3..711ad9bff 100644
--- a/examples/example_win32_opengl3/example_win32_opengl3.vcxproj
+++ b/examples/example_win32_opengl3/example_win32_opengl3.vcxproj
@@ -21,34 +21,34 @@
{C624E5FF-D4FE-4D35-9164-B8A91864F98E}
example_win32_opengl2
- 8.1
+ 10.0
Application
true
Unicode
- v140
+ v143
Application
true
Unicode
- v140
+ v143
Application
false
true
Unicode
- v140
+ v143
Application
false
true
Unicode
- v140
+ v143
@@ -69,18 +69,22 @@
$(ProjectDir)$(Configuration)\
$(ProjectDir)$(Configuration)\
+ true
$(ProjectDir)$(Configuration)\
$(ProjectDir)$(Configuration)\
+ true
$(ProjectDir)$(Configuration)\
$(ProjectDir)$(Configuration)\
+ true
$(ProjectDir)$(Configuration)\
$(ProjectDir)$(Configuration)\
+ true
@@ -95,6 +99,9 @@
opengl32.lib;%(AdditionalDependencies)
Console
+
+ PerMonitorHighDPIAware
+
@@ -109,6 +116,9 @@
opengl32.lib;%(AdditionalDependencies)
Console
+
+ PerMonitorHighDPIAware
+
@@ -128,6 +138,15 @@
opengl32.lib;%(AdditionalDependencies)
Console
+
+ PerMonitorHighDPIAware
+
+
+
+
+
+
+
@@ -147,6 +166,15 @@
opengl32.lib;%(AdditionalDependencies)
Console
+
+ PerMonitorHighDPIAware
+
+
+
+
+
+
+
diff --git a/examples/example_win32_opengl3/main.cpp b/examples/example_win32_opengl3/main.cpp
index 9ad74d61f..169e56437 100644
--- a/examples/example_win32_opengl3/main.cpp
+++ b/examples/example_win32_opengl3/main.cpp
@@ -30,14 +30,14 @@ static int g_Height;
// Forward declarations of helper functions
bool CreateDeviceWGL(HWND hWnd, WGL_WindowData* data);
void CleanupDeviceWGL(HWND hWnd, WGL_WindowData* data);
-void ResetDeviceWGL();
LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
// Main code
int main(int, char**)
{
// Make process DPI aware and obtain main monitor scale
- //ImGui_ImplWin32_EnableDpiAwareness(); // FIXME: This somehow doesn't work in the Win32+OpenGL example. Why?
+ // https://learn.microsoft.com/en-us/windows/win32/hidpi/setting-the-default-dpi-awareness-for-a-process
+ // ImGui_ImplWin32_EnableDpiAwareness(); // This is already set in the manifest so the call will fail, but leaving it for completeness.
float main_scale = ImGui_ImplWin32_GetDpiScaleForMonitor(::MonitorFromPoint(POINT{ 0, 0 }, MONITOR_DEFAULTTOPRIMARY));
// Create application window