new cairo backend! for now only tested on X11 on Linux

also includes a couple small changes everywhere

Cargo.toml

@@ -16,6 +16,7 @@ raw-window-handle = "0.4.3"
 [workspace]
 members = [
     "abletk-macros",
+    "abletk-cairo",
     "abletk-common",
     "abletk-direct2d",
 ]

abletk-cairo/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "abletk-cairo"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+raw-window-handle = "0.4.3"
+cairo-sys-rs = { version = "0.15.1", features = ["xlib"] }
+x11 = "2.19.1"

abletk-cairo/src/brush.rs

@@ -0,0 +1,11 @@
+/*
+ * Copyright (C) 2022 Umut İnan Erdoğan <umutinanerdogan@pm.me>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+pub enum Brush {
+    Solid(f64, f64, f64, f64),
+}

abletk-cairo/src/lib.rs

@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2022 Umut İnan Erdoğan <umutinanerdogan@pm.me>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+pub mod brush;
+
+use std::{mem, ffi::CString};
+use brush::Brush;
+use cairo_sys::*;
+use raw_window_handle::XlibHandle;
+use x11::xlib::{XDefaultScreen, XDefaultVisual, XGetGeometry};
+
+pub struct Renderer {
+    handle: XlibHandle,
+    surface: *mut cairo_surface_t,
+    ctx: *mut cairo_t,
+}
+
+impl Renderer {
+    pub fn new(handle: XlibHandle) -> Self {
+        println!("{:#?}", handle);
+        let (width, height) = unsafe {
+            let mut root = mem::zeroed();
+            let mut x = mem::zeroed();
+            let mut y = mem::zeroed();
+            let mut width = mem::zeroed();
+            let mut height = mem::zeroed();
+            let mut border_width = mem::zeroed();
+            let mut depth = mem::zeroed();
+            assert_ne!(XGetGeometry(
+                handle.display as _,
+                handle.window.try_into().unwrap(),
+                &mut root,
+                &mut x,
+                &mut y,
+                &mut width,
+                &mut height,
+                &mut border_width,
+                &mut depth,
+            ), 0);
+            (width.try_into().unwrap(), height.try_into().unwrap())
+        };
+
+        let surface = unsafe {
+            cairo_xlib_surface_create(handle.display as _,
+                handle.window,
+                XDefaultVisual(handle.display as _, XDefaultScreen(handle.display as _)),
+                width,
+                height
+            )
+        };
+
+        let ctx = unsafe {
+            cairo_create(surface)
+        };
+
+        Self {
+            handle,
+            surface,
+            ctx,
+        }
+    }
+
+    pub fn begin_draw(&mut self) {
+        unsafe {
+            // fixme
+            let font = CString::new("Georgia").unwrap();
+            cairo_select_font_face(
+                self.ctx,
+                font.as_ptr(),
+                FONT_SLANT_NORMAL,
+                FONT_WEIGHT_NORMAL,
+            );
+            cairo_set_font_size(self.ctx, 20.0);
+            cairo_set_line_width(self.ctx, 1.0)
+        }
+    }
+
+    pub fn clear<C: Into<(f64, f64, f64, f64)>>(&self, color: C) {
+        let (r, g, b, a) = color.into();
+        unsafe {
+            cairo_save(self.ctx);
+            cairo_set_source_rgba(self.ctx, r, g, b, a);
+            cairo_set_operator(self.ctx, OPERATOR_SOURCE);
+            cairo_paint(self.ctx);
+            cairo_restore(self.ctx)
+        }
+    }
+
+    pub fn draw_rect<R: Into<(f64, f64, f64, f64)>>(&self, rect: R) {
+        let (x, y, width, height) = rect.into();
+        unsafe {
+            cairo_rectangle(self.ctx, x, y, width, height);
+            cairo_stroke(self.ctx)
+        }
+    }
+
+    pub fn draw_text<R>(&self, text: &str, layout_rect: R)
+    where
+        R: Into<(f64, f64, f64, f64)>
+    {
+        let (x, y, _, _) = layout_rect.into();
+        let font_extents = self.font_extents();
+        let text_extents = self.text_extents(text);
+        let text = CString::new(text).unwrap();
+        unsafe {
+            cairo_move_to(
+                self.ctx,
+                x - text_extents.x_bearing,
+                y
+                    + font_extents.height
+                    + font_extents.descent
+                    + text_extents.y_bearing,
+            );
+            cairo_show_text(self.ctx, text.as_ptr())
+        }
+    }
+
+    pub fn end_draw(&self) {
+        unsafe {
+            cairo_surface_flush(self.surface)
+        }
+    }
+
+    pub fn fill_rect<R: Into<(f64, f64, f64, f64)>>(&self, rect: R) {
+        let (x, y, width, height) = rect.into();
+        unsafe {
+            cairo_rectangle(self.ctx, x, y, width, height);
+            cairo_fill(self.ctx)
+        }
+    }
+
+    // fixme: this and abletk-direct2d's get_text_size have small differences
+    pub fn get_text_size(&self, text: &str) -> (u32, u32) {
+        let text_extents = self.text_extents(text);
+        let font_extents = self.font_extents();
+        let result = (
+            text_extents.x_advance as u32,
+            (font_extents.ascent + font_extents.descent) as u32,
+        );
+        result
+    }
+
+    pub fn resized(&mut self, width: u32, height: u32) {
+        unsafe {
+            cairo_xlib_surface_set_size(
+                self.surface,
+                width.try_into().unwrap(),
+                height.try_into().unwrap(),
+            )
+        }
+    }
+
+    pub fn set_brush<B: Into<Brush>>(&mut self, brush: B) {
+        let brush = brush.into();
+        match brush {
+            Brush::Solid(r, g, b, a) => unsafe {
+                cairo_set_source_rgba(self.ctx, r, g, b, a)
+            },
+        }
+    }
+
+    pub fn size(&self) -> (u32, u32) {
+        unsafe {
+            let mut root = mem::zeroed();
+            let mut x = mem::zeroed();
+            let mut y = mem::zeroed();
+            let mut width = mem::zeroed();
+            let mut height = mem::zeroed();
+            let mut border_width = mem::zeroed();
+            let mut depth = mem::zeroed();
+            assert_ne!(XGetGeometry(
+                self.handle.display as _,
+                self.handle.window.try_into().unwrap(),
+                &mut root,
+                &mut x,
+                &mut y,
+                &mut width,
+                &mut height,
+                &mut border_width,
+                &mut depth,
+            ), 0);
+            (width, height)
+        }
+    }
+
+    fn text_extents(&self, text: &str) -> TextExtents {
+        unsafe {
+            let mut extents = mem::zeroed();
+            let text = CString::new(text).unwrap();
+            cairo_text_extents(
+                self.ctx,
+                text.as_ptr() as _,
+                &mut extents,
+            );
+            extents
+        }
+    }
+
+    fn font_extents(&self) -> FontExtents {
+        unsafe {
+            let mut extents = mem::zeroed();
+            cairo_font_extents(self.ctx, &mut extents);
+            extents
+        }
+    }
+}

abletk-common/Cargo.toml

@@ -11,3 +11,7 @@ raw-window-handle = "0.4.3"
 [target.'cfg(windows)'.dependencies]
 abletk-direct2d = { path = "../abletk-direct2d" }
 windows = { version = "0.36.1", features = ["Win32_Graphics_Direct2D_Common"] }
+
+[target.'cfg(target_os = "linux")'.dependencies]
+abletk-cairo = { path = "../abletk-cairo" }
+

abletk-common/src/brush.rs

@@ -9,6 +9,9 @@
 #[cfg(windows)]
 use abletk_direct2d::brush::Brush as RawBrush;
 
+#[cfg(target_os = "linux")]
+use abletk_cairo::brush::Brush as RawBrush;
+
 use crate::color::Color;
 
 #[derive(Copy, Clone, Debug)]
@@ -16,6 +19,7 @@ pub enum Brush {
     Solid(Color),
 }
 
+#[cfg(windows)]
 impl From<Brush> for RawBrush {
     fn from(brush: Brush) -> Self {
         match brush {
@@ -23,3 +27,17 @@ impl From<Brush> for RawBrush {
         }
     }
 }
+
+#[cfg(target_os = "linux")]
+impl From<Brush> for RawBrush {
+    fn from(brush: Brush) -> Self {
+        match brush {
+            Brush::Solid(color) => RawBrush::Solid(
+                color.0.into(),
+                color.1.into(),
+                color.2.into(),
+                color.3.into(),
+            ),
+        }
+    }
+}

abletk-common/src/color.rs

@@ -22,6 +22,12 @@ impl Color {
     }
 }
 
+impl From<Color> for (f64, f64, f64, f64) {
+    fn from(color: Color) -> Self {
+        (color.0.into(), color.1.into(), color.2.into(), color.3.into())
+    }
+}
+
 #[cfg(windows)]
 impl From<Color> for D2D1_COLOR_F {
     fn from(color: Color) -> Self {

abletk-common/src/lib.rs

@@ -18,6 +18,9 @@ use rect::Rect;
 #[cfg(windows)]
 use abletk_direct2d as backend;
 
+#[cfg(target_os = "linux")]
+use abletk_cairo as backend;
+
 pub struct Renderer {
     renderer: backend::Renderer,
     x: u32,
@@ -27,7 +30,10 @@ pub struct Renderer {
 impl Renderer {
     pub fn new(handle: RawWindowHandle) -> Self {
         let handle = match handle {
+            #[cfg(windows)]
             RawWindowHandle::Win32(handle) => handle,
+            #[cfg(target_os = "linux")]
+            RawWindowHandle::Xlib(handle) => handle,
             _ => todo!(),
         };
   
@@ -50,8 +56,8 @@ impl Renderer {
         self.renderer.draw_rect(Rect::new(
             self.x as f32,
             self.y as f32,
-            (self.x + width) as f32,
+            width as f32,
-            (self.y + height) as f32,
+            height as f32,
         ))
     }
 
@@ -78,8 +84,8 @@ impl Renderer {
         self.renderer.fill_rect(Rect::new(
             self.x as f32,
             self.y as f32,
-            (self.x + width) as f32,
+            width as f32,
-            (self.y + height) as f32,
+            height as f32,
         ))
     }
 
@@ -101,10 +107,10 @@ impl Renderer {
     }
 
     pub fn set_brush(&mut self, brush: Brush) {
-        self.renderer.set_brush(brush.into())
+        self.renderer.set_brush(brush)
     }
 
-    pub fn size(&self) -> (f32, f32) {
+    pub fn size(&self) -> (u32, u32) {
         self.renderer.size()
     }
 }

abletk-common/src/rect.rs

@@ -31,6 +31,12 @@ impl Rect {
     }
 }
 
+impl From<Rect> for (f64, f64, f64, f64) {
+    fn from(rect: Rect) -> Self {
+        (rect.x.into(), rect.y.into(), rect.width.into(), rect.height.into())
+    }
+}
+
 #[cfg(windows)]
 impl From<Rect> for RECT {
     fn from(rect: Rect) -> Self {

abletk-direct2d/src/lib.rs

@@ -65,9 +65,9 @@ impl Renderer {
         unsafe {
             self.target.as_ref().unwrap()
                 .DrawRectangle(
-                    &rect.into(),
+                    &xywh_to_ltrb_rect(rect.into()),
                     self.brush.as_ref().unwrap(),
-                    1.0,
+                    1.0, // fixme
                     &self.stroke_style)
         }
     }
@@ -97,7 +97,7 @@ impl Renderer {
         unsafe {
             self.target.as_ref().unwrap()
                 .FillRectangle(
-                    &rect.into(),
+                    &xywh_to_ltrb_rect(rect.into()),
                     self.brush.as_ref().unwrap())
         }
     }
@@ -128,15 +128,15 @@ impl Renderer {
         }
     }
     
-    pub fn set_brush(&mut self, brush: Brush) {
+    pub fn set_brush<B: Into<Brush>>(&mut self, brush: B) {
-        self.brush = Some(brush.to_brush(self.target.as_ref().unwrap()))
+        self.brush = Some(brush.into().to_brush(self.target.as_ref().unwrap()))
     }
     
-    pub fn size(&self) -> (f32, f32) {
+    pub fn size(&self) -> (u32, u32) {
         let size = unsafe {
             self.target.as_ref().unwrap().GetSize()
         };
-        (size.width, size.height)
+        (size.width as u32, size.height as u32)
     }
 
     fn setup_target(&mut self) {
@@ -229,3 +229,14 @@ fn create_text_format(factory: &IDWriteFactory, fonts: &IDWriteFontCollection)
         format
     }
 }
+
+/// D2D sometimes expects a rect to have LTRB (left, top, right, bottom) values
+/// but abletk-common uses XYWH (x, y, width, height) values.
+fn xywh_to_ltrb_rect(xywh: D2D_RECT_F) -> D2D_RECT_F {
+    D2D_RECT_F {
+        left: xywh.left,
+        top: xywh.top,
+        right: xywh.left + xywh.right,
+        bottom: xywh.top + xywh.bottom,
+    }
+}

src/main.rs

@@ -20,7 +20,7 @@ fn launch() -> _ {
                 .add(Column::new()
                     .add(Label::new("World!"))
                     .add(Label::new("AbleTK!")))
-                .add(Label::new("this is a label!")
+                .add(Label::new("this is a label! jjjjyyy")
                     .bg_color(rgb!(0xFF0000FF)))
                 .padding_left(10))
         .on_event(WindowEvent::Closed, |_, window| {