wip

Author: prokopyl

src/wrappers/win32/window.rs

@@ -3,6 +3,12 @@ mod handle;
 mod proc;
 mod window_class;
 
+#[cfg(feature = "opengl")]
+mod dc;
+
+#[cfg(feature = "opengl")]
+pub use dc::*;
+
 use data::WindowData;
 use dpi::PhysicalSize;
 pub use handle::HWnd;
@@ -16,7 +22,7 @@ use crate::wrappers::win32::h_instance::HInstance;
 use crate::wrappers::win32::style::WindowStyle;
 use crate::wrappers::win32::DpiAwarenessContext;
 use windows_sys::Win32::Foundation::{HWND, LPARAM, LRESULT, WPARAM};
-use windows_sys::Win32::UI::WindowsAndMessaging::CreateWindowExW;
+use windows_sys::Win32::UI::WindowsAndMessaging::{CreateWindowExW, CW_USEDEFAULT};
 
 pub trait WindowImpl: 'static {
     /// Called during the processing of the WM_CREATE message, but after this type was properly
@@ -82,3 +88,30 @@ pub fn create_window<W: WindowImpl>(
 
     Ok(hwnd)
 }
+
+pub fn with_dummy_window<T>(handler: impl FnOnce(HWnd) -> Result<T>) -> Result<T> {
+    let instance = HInstance::get_from_dll();
+    let window_class = RegisteredClass::register_new(instance, None)?;
+    let hwnd = unsafe {
+        CreateWindowExW(
+            0,
+            window_class.as_atom_ptr(),
+            null_mut(),
+            0,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            null_mut(),
+            null_mut(),
+            instance.as_raw(),
+            null_mut(),
+        )
+    };
+
+    if hwnd.is_null() {
+        return Err(Error::from_thread());
+    }
+
+    handler(hwnd)
+}

src/wrappers/win32/window/dc.rs

@@ -0,0 +1,26 @@
+use crate::wrappers::win32::window::HWnd;
+use std::ffi::c_void;
+use std::ptr::NonNull;
+use windows_core::{Error, Result};
+use windows_sys::Win32::Graphics::Gdi::{GetDC, ReleaseDC};
+
+pub struct DeviceContext {
+    window: HWnd,
+    inner: NonNull<c_void>,
+}
+
+impl DeviceContext {
+    pub(super) fn from_window(window: HWnd) -> Result<Self> {
+        let dc = unsafe { GetDC(window.as_raw()) };
+
+        let dc = NonNull::new(dc).ok_or_else(Error::from_thread)?;
+
+        Ok(Self { window, inner: dc })
+    }
+}
+
+impl Drop for DeviceContext {
+    fn drop(&mut self) {
+        unsafe { ReleaseDC(self.window.as_raw(), self.inner.as_ptr()) };
+    }
+}

src/wrappers/win32/window/window_class.rs

@@ -6,7 +6,7 @@ use std::sync::Arc;
 use windows_core::{Error, Result, HSTRING};
 use windows_sys::core::PCWSTR;
 use windows_sys::Win32::UI::WindowsAndMessaging::{
-    LoadCursorW, RegisterClassW, UnregisterClassW, CS_OWNDC, IDC_ARROW, WNDCLASSW, WNDPROC,
+    LoadCursorW, RegisterClassW, UnregisterClassW, IDC_ARROW, WNDCLASSW, WNDPROC,
 };
 
 #[derive(Clone)]
@@ -22,7 +22,7 @@ impl RegisteredClass {
             hInstance: instance.as_raw(),
             lpszClassName: class_name.as_ptr(),
 
-            style: CS_OWNDC, // TODO: this is very suspicious
+            style: 0,
             cbClsExtra: 0,
             cbWndExtra: 0,
             hIcon: null_mut(),                                      // Default icon