windows: Fix title bar height when maximized (zed-industries#9449)

screenshots and description incoming ## title bar when window is maximized | before | after | | --- | --- | | ![image](https://github.com/zed-industries/zed/assets/1284289/075a943d-54db-4b71-9fa0-15f823255182) | ![image](https://github.com/zed-industries/zed/assets/1284289/39a1d381-fcfd-4651-aab4-231a8ec3bd99) | ## ~~caption buttons at 200%~~ ~~buttons are now properly responsive at different scales~~ ~~closes zed-industries#9438~~ ~~proper scale factor handling in follow up PR (possibly zed-industries#9440)~~ <details> <summary>out of date image</summary> ![scale-factor](https://github.com/zed-industries/zed/assets/1284289/299d37b8-0d2e-4f2e-81db-2fff6fc59a62) </details> should be fixed by zed-industries#9456 Release Notes: - N/A
pjlast · pjlast · Mar 21, 2024 · Mar 21, 2024 · Mar 22, 2024 · Mar 19, 2024
commit 60f24dd6fd534a7ffe0552e6a8735ab7525e0677
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/gpui/src/platform/windows/window.rs b/crates/gpui/src/platform/windows/window.rs
@@ -134,33 134,37 @@ impl WindowsWindowInner {
  return false;
  }
 
- fn get_titlebar_rect(&self) -> anyhow::Result<RECT> {
- let top_and_bottom_borders = 2;
- let scale_factor = self.scale_factor.get();
- let theme = unsafe { OpenThemeData(self.hwnd, w!("WINDOW")) };
- let title_bar_size = unsafe {
- GetThemePartSize(
- theme,
- HDC::default(),
- WP_CAPTION.0,
- CS_ACTIVE.0,
- None,
- TS_TRUE,
- )
- }?;
- unsafe { CloseThemeData(theme) }?;
-
- let mut height =
- (title_bar_size.cy as f32 * scale_factor).round() as i32 top_and_bottom_borders;
  pub(crate) fn title_bar_padding(&self) -> Pixels {
  // using USER_DEFAULT_SCREEN_DPI because GPUI handles the scale with the scale factor
  let padding = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, USER_DEFAULT_SCREEN_DPI) };
  px(padding as f32)
  }
 
  pub(crate) fn title_bar_top_offset(&self) -> Pixels {
  if self.is_maximized() {
- let dpi = unsafe { GetDpiForWindow(self.hwnd) };
- height = unsafe { (GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) * 2) as i32 };
  self.title_bar_padding() * 2
  } else {
  px(0.)
  }
  }
 
  pub(crate) fn title_bar_height(&self) -> Pixels {
  // todo(windows) this is hard set to match the ui title bar
  // in the future the ui title bar component will report the size
  px(32.) self.title_bar_top_offset()
  }
 
  pub(crate) fn caption_button_width(&self) -> Pixels {
  // todo(windows) this is hard set to match the ui title bar
  // in the future the ui title bar component will report the size
  px(36.)
  }
 
  fn get_titlebar_rect(&self) -> anyhow::Result<RECT> {
  let height = self.title_bar_height();
  let mut rect = RECT::default();
  unsafe { GetClientRect(self.hwnd, &mut rect) }?;
- rect.bottom = rect.top height;
  rect.bottom = rect.top ((height.0 as f32 * self.scale_factor.get()).round() as i32);
  Ok(rect)
  }
 
@@ -923,7 927,8 @@ impl WindowsWindowInner {
  let titlebar_rect = self.get_titlebar_rect();
  if let Ok(titlebar_rect) = titlebar_rect {
  if cursor_point.y < titlebar_rect.bottom {
- let caption_btn_width = unsafe { GetSystemMetricsForDpi(SM_CXSIZE, dpi) };
  let caption_btn_width =
  (self.caption_button_width().0 * self.scale_factor.get()) as i32;
  if cursor_point.x >= titlebar_rect.right - caption_btn_width {
  return LRESULT(HTCLOSE as _);
  } else if cursor_point.x >= titlebar_rect.right - caption_btn_width * 2 {

diff --git a/crates/ui/Cargo.toml b/crates/ui/Cargo.toml
@@ -23,6 23,9 @@ story = { workspace = true, optional = true }
 strum = { version = "0.25.0", features = ["derive"] }
 theme.workspace = true
 
 [target.'cfg(windows)'.dependencies]
 windows.workspace = true
 
 [features]
 default = []
 stories = ["dep:itertools", "dep:story"]
diff --git a/crates/ui/src/components/title_bar/title_bar.rs b/crates/ui/src/components/title_bar/title_bar.rs
@@ -10,12 10,40 @@ pub struct TitleBar {
  content: Stateful<Div>,
  children: SmallVec<[AnyElement; 2]>,
 }
 #[cfg(not(target_os = "windows"))]
 fn title_bar_top_padding(_cx: &WindowContext) -> Pixels {
  px(0.)
 }
 
 #[cfg(target_os = "windows")]
 fn title_bar_top_padding(cx: &WindowContext) -> Pixels {
  use windows::Win32::UI::{
  HiDpi::GetSystemMetricsForDpi,
  WindowsAndMessaging::{SM_CXPADDEDBORDER, USER_DEFAULT_SCREEN_DPI},
  };
 
  // this top padding is not dependent on the title bar style and is instead a quirk of maximized windows on Windows
  // https://devblogs.microsoft.com/oldnewthing/20150304-00/?p=44543
  let padding = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, USER_DEFAULT_SCREEN_DPI) };
  if cx.is_maximized() {
  px((padding * 2) as f32)
  } else {
  px(0.)
  }
 }
 
 impl TitleBar {
  #[cfg(not(target_os = "windows"))]
  pub fn height(cx: &mut WindowContext) -> Pixels {
  (1.75 * cx.rem_size()).max(px(32.))
  }
 
  #[cfg(target_os = "windows")]
  pub fn height(_cx: &mut WindowContext) -> Pixels {
  // todo(windows) instead of hard coded size report the actual size to the Windows platform API
  px(32.)
  }
 
  pub fn new(id: impl Into<ElementId>) -> Self {
  Self {
  platform_style: PlatformStyle::platform(),
@@ -29,16 57,6 @@ impl TitleBar {
  self.platform_style = style;
  self
  }
-
- fn top_padding(&self, cx: &WindowContext) -> Pixels {
- if self.platform_style == PlatformStyle::Windows && cx.is_maximized() {
- // todo(windows): get padding from win32 api, need HWND from window context somehow
- // should be GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) * 2
- px(8.)
- } else {
- px(0.)
- }
- }
 }
 
 impl InteractiveElement for TitleBar {
@@ -58,13 76,11 @@ impl ParentElement for TitleBar {
 impl RenderOnce for TitleBar {
  fn render(self, cx: &mut WindowContext) -> impl IntoElement {
  let height = Self::height(cx);
- let top_padding = self.top_padding(cx);
-
  h_flex()
  .id("titlebar")
  .w_full()
- .pt(top_padding)
- .h(height)
  .pt(title_bar_top_padding(cx))
  .h(height title_bar_top_padding(cx))
  .map(|this| {
  if cx.is_fullscreen() {
  this.pl_2()
@@ -88,9 104,7 @@ impl RenderOnce for TitleBar {
  .children(self.children),
  )
  .when(self.platform_style == PlatformStyle::Windows, |title_bar| {
- let button_height = Self::height(cx) - top_padding;
-
- title_bar.child(WindowsWindowControls::new(button_height))
  title_bar.child(WindowsWindowControls::new(height))
  })
  }
 }
diff --git a/crates/ui/src/components/title_bar/windows_window_controls.rs b/crates/ui/src/components/title_bar/windows_window_controls.rs
@@ -98,9 98,11 @@ impl WindowsCaptionButton {
 
 impl RenderOnce for WindowsCaptionButton {
  fn render(self, _cx: &mut WindowContext) -> impl IntoElement {
- // todo(windows): get padding from win32 api, need HWND from window context somehow
- // should be GetSystemMetricsForDpi(SM_CXSIZE, dpi)
- let width = px(36.0);
  // todo(windows) report this width to the Windows platform API
  // NOTE: this is intentionally hard coded. An option to use the 'native' size
  // could be added when the width is reported to the Windows platform API
  // as this could change between future Windows versions.
  let width = px(36.);
 
  h_flex()
  .id(self.id)