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fix(windows): dpi getter leaks HDC handles #15614

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Merged
Legend-Master merged 1 commit into from
Jun 30, 2026
Merged

fix(windows): dpi getter leaks HDC handles #15614

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5 changes: 5 additions & 0 deletions .changes/fix-dpi-leak-hdc.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
---
tauri-runtime-wry: patch:bug
---

Fix getting the DPI internally leaks `HDC` handles on Windows. This also improves the resizing speed on undecorated windows
12 changes: 7 additions & 5 deletions crates/tauri-runtime-wry/src/util.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -68,10 +68,6 @@ mod imp {

#[allow(non_snake_case)]
pub unsafe fn hwnd_dpi(hwnd: HWND) -> u32 {
let hdc = GetDC(Some(hwnd));
if hdc.is_invalid() {
return USER_DEFAULT_SCREEN_DPI;
}
if let Some(GetDpiForWindow) = *GET_DPI_FOR_WINDOW {
// We are on Windows 10 Anniversary Update (1607) or later.
match GetDpiForWindow(hwnd) {
Expand All @@ -95,9 +91,15 @@ mod imp {
} else {
// We are on Vista or later.
if IsProcessDPIAware().as_bool() {
let hdc = GetDC(Some(hwnd));
if hdc.is_invalid() {
return USER_DEFAULT_SCREEN_DPI;
}
// If the process is DPI aware, then scaling must be handled by the application using
// this DPI value.
GetDeviceCaps(Some(hdc), LOGPIXELSX) as u32
let dpi = GetDeviceCaps(Some(hdc), LOGPIXELSX) as u32;
ReleaseDC(Some(hwnd), hdc);
dpi
} else {
// If the process is DPI unaware, then scaling is performed by the OS; we thus return
// 96 (scale factor 1.0) to prevent the window from being re-scaled by both the
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