DPI for everyone (#548)

src/platform/linux/x11/util/geometry.rs

@@ -1,6 +1,7 @@
 use std::cmp;
 
 use super::*;
+use {LogicalPosition, LogicalSize};
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Rect {
@@ -78,6 +79,24 @@ impl FrameExtents {
     pub fn from_border(border: c_ulong) -> Self {
         Self::new(border, border, border, border)
     }
+
+    pub fn as_logical(&self, factor: f64) -> LogicalFrameExtents {
+        let logicalize = |value: c_ulong| value as f64 / factor;
+        LogicalFrameExtents {
+            left: logicalize(self.left),
+            right: logicalize(self.right),
+            top: logicalize(self.top),
+            bottom: logicalize(self.bottom),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct LogicalFrameExtents {
+    pub left: f64,
+    pub right: f64,
+    pub top: f64,
+    pub bottom: f64,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -103,6 +122,16 @@ impl FrameExtentsHeuristic {
         }
     }
 
+    pub fn inner_pos_to_outer_logical(&self, mut logical: LogicalPosition, factor: f64) -> LogicalPosition {
+        use self::FrameExtentsHeuristicPath::*;
+        if self.heuristic_path != UnsupportedBordered {
+            let frame_extents = self.frame_extents.as_logical(factor);
+            logical.x -= frame_extents.left;
+            logical.y -= frame_extents.top;
+        }
+        logical
+    }
+
     pub fn inner_size_to_outer(&self, width: u32, height: u32) -> (u32, u32) {
         (
             width.saturating_add(
@@ -113,6 +142,13 @@ impl FrameExtentsHeuristic {
             ),
         )
     }
+
+    pub fn inner_size_to_outer_logical(&self, mut logical: LogicalSize, factor: f64) -> LogicalSize {
+        let frame_extents = self.frame_extents.as_logical(factor);
+        logical.width += frame_extents.left + frame_extents.right;
+        logical.height += frame_extents.top + frame_extents.bottom;
+        logical
+    }
 }
 
 impl XConnection {

src/platform/linux/x11/util/hint.rs

@@ -68,6 +68,99 @@ impl WindowType {
     }
 }
 
+pub struct NormalHints<'a> {
+    size_hints: XSmartPointer<'a, ffi::XSizeHints>,
+}
+
+impl<'a> NormalHints<'a> {
+    pub fn new(xconn: &'a XConnection) -> Self {
+        NormalHints { size_hints: xconn.alloc_size_hints() }
+    }
+
+    pub fn has_flag(&self, flag: c_long) -> bool {
+        has_flag(self.size_hints.flags, flag)
+    }
+
+    fn getter(&self, flag: c_long, field1: &c_int, field2: &c_int) -> Option<(u32, u32)> {
+        if self.has_flag(flag) {
+            Some((*field1 as _, *field2 as _))
+        } else {
+            None
+        }
+    }
+
+    pub fn get_size(&self) -> Option<(u32, u32)> {
+        self.getter(ffi::PSize, &self.size_hints.width, &self.size_hints.height)
+    }
+
+    // WARNING: This hint is obsolete
+    pub fn set_size(&mut self, size: Option<(u32, u32)>) {
+        if let Some((width, height)) = size {
+            self.size_hints.flags |= ffi::PSize;
+            self.size_hints.width = width as c_int;
+            self.size_hints.height = height as c_int;
+        } else {
+            self.size_hints.flags &= !ffi::PSize;
+        }
+    }
+
+    pub fn get_max_size(&self) -> Option<(u32, u32)> {
+        self.getter(ffi::PMaxSize, &self.size_hints.max_width, &self.size_hints.max_height)
+    }
+
+    pub fn set_max_size(&mut self, max_size: Option<(u32, u32)>) {
+        if let Some((max_width, max_height)) = max_size {
+            self.size_hints.flags |= ffi::PMaxSize;
+            self.size_hints.max_width = max_width as c_int;
+            self.size_hints.max_height = max_height as c_int;
+        } else {
+            self.size_hints.flags &= !ffi::PMaxSize;
+        }
+    }
+
+    pub fn get_min_size(&self) -> Option<(u32, u32)> {
+        self.getter(ffi::PMinSize, &self.size_hints.min_width, &self.size_hints.min_height)
+    }
+
+    pub fn set_min_size(&mut self, min_size: Option<(u32, u32)>) {
+        if let Some((min_width, min_height)) = min_size {
+            self.size_hints.flags |= ffi::PMinSize;
+            self.size_hints.min_width = min_width as c_int;
+            self.size_hints.min_height = min_height as c_int;
+        } else {
+            self.size_hints.flags &= !ffi::PMinSize;
+        }
+    }
+
+    pub fn get_resize_increments(&self) -> Option<(u32, u32)> {
+        self.getter(ffi::PResizeInc, &self.size_hints.width_inc, &self.size_hints.height_inc)
+    }
+
+    pub fn set_resize_increments(&mut self, resize_increments: Option<(u32, u32)>) {
+        if let Some((width_inc, height_inc)) = resize_increments {
+            self.size_hints.flags |= ffi::PResizeInc;
+            self.size_hints.width_inc = width_inc as c_int;
+            self.size_hints.height_inc = height_inc as c_int;
+        } else {
+            self.size_hints.flags &= !ffi::PResizeInc;
+        }
+    }
+
+    pub fn get_base_size(&self) -> Option<(u32, u32)> {
+        self.getter(ffi::PBaseSize, &self.size_hints.base_width, &self.size_hints.base_height)
+    }
+
+    pub fn set_base_size(&mut self, base_size: Option<(u32, u32)>) {
+        if let Some((base_width, base_height)) = base_size {
+            self.size_hints.flags |= ffi::PBaseSize;
+            self.size_hints.base_width = base_width as c_int;
+            self.size_hints.base_height = base_height as c_int;
+        } else {
+            self.size_hints.flags &= !ffi::PBaseSize;
+        }
+    }
+}
+
 impl XConnection {
     pub fn get_wm_hints(&self, window: ffi::Window) -> Result<XSmartPointer<ffi::XWMHints>, XError> {
         let wm_hints = unsafe { (self.xlib.XGetWMHints)(self.display, window) };
@@ -90,4 +183,29 @@ impl XConnection {
         }
         Flusher::new(self)
     }
+
+    pub fn get_normal_hints(&self, window: ffi::Window) -> Result<NormalHints, XError> {
+        let size_hints = self.alloc_size_hints();
+        let mut supplied_by_user: c_long = unsafe { mem::uninitialized() };
+        unsafe {
+            (self.xlib.XGetWMNormalHints)(
+                self.display,
+                window,
+                size_hints.ptr,
+                &mut supplied_by_user,
+            );
+        }
+        self.check_errors().map(|_| NormalHints { size_hints })
+    }
+
+    pub fn set_normal_hints(&self, window: ffi::Window, normal_hints: NormalHints) -> Flusher {
+        unsafe {
+            (self.xlib.XSetWMNormalHints)(
+                self.display,
+                window,
+                normal_hints.size_hints.ptr,
+            );
+        }
+        Flusher::new(self)
+    }
 }

src/platform/linux/x11/util/mod.rs

@@ -27,10 +27,16 @@ pub use self::wm::*;
 
 use std::mem;
 use std::ptr;
+use std::ops::BitAnd;
 use std::os::raw::*;
 
 use super::{ffi, XConnection, XError};
 
+pub fn reinterpret<'a, A, B>(a: &'a A) -> &'a B {
+    let b_ptr = a as *const _ as *const B;
+    unsafe { &*b_ptr }
+}
+
 pub fn maybe_change<T: PartialEq>(field: &mut Option<T>, value: T) -> bool {
     let wrapped = Some(value);
     if *field != wrapped {
@@ -41,6 +47,13 @@ pub fn maybe_change<T: PartialEq>(field: &mut Option<T>, value: T) -> bool {
     }
 }
 
+pub fn has_flag<T>(bitset: T, flag: T) -> bool
+where T:
+    Copy + PartialEq + BitAnd<T, Output = T>
+{
+    bitset & flag == flag
+}
+
 #[must_use = "This request was made asynchronously, and is still in the output buffer. You must explicitly choose to either `.flush()` (empty the output buffer, sending the request now) or `.queue()` (wait to send the request, allowing you to continue to add more requests without additional round-trips). For more information, see the documentation for `util::flush_requests`."]
 pub struct Flusher<'a> {
     xconn: &'a XConnection,

src/platform/linux/x11/util/randr.rs

@@ -1,21 +1,48 @@
 use std::{env, slice};
 use std::str::FromStr;
 
+use validate_hidpi_factor;
 use super::*;
-use super::ffi::{
-    RROutput,
-    XRRCrtcInfo,
-    XRRMonitorInfo,
-    XRRScreenResources,
-};
+
+pub fn calc_dpi_factor(
+    (width_px, height_px): (u32, u32),
+    (width_mm, height_mm): (u64, u64),
+) -> f64 {
+    // Override DPI if `WINIT_HIDPI_FACTOR` variable is set
+    let dpi_override = env::var("WINIT_HIDPI_FACTOR")
+        .ok()
+        .and_then(|var| f64::from_str(&var).ok());
+    if let Some(dpi_override) = dpi_override {
+        if !validate_hidpi_factor(dpi_override) {
+            panic!(
+                "`WINIT_HIDPI_FACTOR` invalid; DPI factors must be normal floats greater than 0. Got `{}`",
+                dpi_override,
+            );
+        }
+        return dpi_override;
+    }
+
+    // See http://xpra.org/trac/ticket/728 for more information.
+    if width_mm == 0 || width_mm == 0 {
+        return 1.0;
+    }
+
+    let ppmm = (
+        (width_px as f64 * height_px as f64) / (width_mm as f64 * height_mm as f64)
+    ).sqrt();
+    // Quantize 1/12 step size
+    let dpi_factor = ((ppmm * (12.0 * 25.4 / 96.0)).round() / 12.0).max(1.0);
+    assert!(validate_hidpi_factor(dpi_factor));
+    dpi_factor
+}
 
 pub enum MonitorRepr {
-    Monitor(*mut XRRMonitorInfo),
-    Crtc(*mut XRRCrtcInfo),
+    Monitor(*mut ffi::XRRMonitorInfo),
+    Crtc(*mut ffi::XRRCrtcInfo),
 }
 
 impl MonitorRepr {
-    pub unsafe fn get_output(&self) -> RROutput {
+    pub unsafe fn get_output(&self) -> ffi::RROutput {
         match *self {
             // Same member names, but different locations within the struct...
             MonitorRepr::Monitor(monitor) => *((*monitor).outputs.offset(0)),
@@ -38,47 +65,20 @@ impl MonitorRepr {
     }
 }
 
-impl From<*mut XRRMonitorInfo> for MonitorRepr {
-    fn from(monitor: *mut XRRMonitorInfo) -> Self {
+impl From<*mut ffi::XRRMonitorInfo> for MonitorRepr {
+    fn from(monitor: *mut ffi::XRRMonitorInfo) -> Self {
         MonitorRepr::Monitor(monitor)
     }
 }
 
-impl From<*mut XRRCrtcInfo> for MonitorRepr {
-    fn from(crtc: *mut XRRCrtcInfo) -> Self {
+impl From<*mut ffi::XRRCrtcInfo> for MonitorRepr {
+    fn from(crtc: *mut ffi::XRRCrtcInfo) -> Self {
         MonitorRepr::Crtc(crtc)
     }
 }
 
-pub fn calc_dpi_factor(
-    (width_px, height_px): (u32, u32),
-    (width_mm, height_mm): (u64, u64),
-) -> f64 {
-    // Override DPI if `WINIT_HIDPI_FACTOR` variable is set
-    if let Ok(dpi_factor_str) = env::var("WINIT_HIDPI_FACTOR") {
-        if let Ok(dpi_factor) = f64::from_str(&dpi_factor_str) {
-            if dpi_factor <= 0. {
-                panic!("Expected `WINIT_HIDPI_FACTOR` to be bigger than 0, got '{}'", dpi_factor);
-            }
-
-            return dpi_factor;
-        }
-    }
-
-    // See http://xpra.org/trac/ticket/728 for more information
-    if width_mm == 0 || width_mm == 0 {
-        return 1.0;
-    }
-
-    let ppmm = (
-        (width_px as f64 * height_px as f64) / (width_mm as f64 * height_mm as f64)
-    ).sqrt();
-    // Quantize 1/12 step size
-    ((ppmm * (12.0 * 25.4 / 96.0)).round() / 12.0).max(1.0)
-}
-
 impl XConnection {
-    pub unsafe fn get_output_info(&self, resources: *mut XRRScreenResources, repr: &MonitorRepr) -> (String, f32) {
+    pub unsafe fn get_output_info(&self, resources: *mut ffi::XRRScreenResources, repr: &MonitorRepr) -> (String, f64) {
         let output_info = (self.xrandr.XRRGetOutputInfo)(
             self.display,
             resources,
@@ -92,7 +92,7 @@ impl XConnection {
         let hidpi_factor = calc_dpi_factor(
             repr.get_dimensions(),
             ((*output_info).mm_width as u64, (*output_info).mm_height as u64),
-        ) as f32;
+        );
         (self.xrandr.XRRFreeOutputInfo)(output_info);
         (name, hidpi_factor)
     }