Use new coordinate system in Magpie and text rendering

apps/magpie/src/gl.rs

@@ -1,5 +1,5 @@
-use canary::DrawCommand;
-use glium::{glutin, Display, Surface};
+use canary::{DrawCommand, Vec2, PX_PER_MM};
+use glium::Surface;
 
 #[derive(Copy, Clone)]
 pub struct Vertex {
@@ -9,11 +9,15 @@ pub struct Vertex {
 
 glium::implement_vertex!(Vertex, position normalize(false), color normalize(true));
 
-impl From<&canary::MeshVertex> for Vertex {
-    fn from(v: &canary::MeshVertex) -> Self {
+impl Vertex {
+    pub fn from_canary(size: Vec2, v: &canary::MeshVertex) -> Self {
+        // TODO do this in the vertex shader with a size uniform
         let (r, g, b, a) = v.color.to_rgba_unmultiplied();
         Self {
-            position: [v.position.x, v.position.y],
+            position: [
+                (v.position.x / size.x) * 2.0 - 1.0,
+                (v.position.y / size.y) * -2.0 + 1.0,
+            ],
             color: [r, g, b, a],
         }
     }
@@ -62,11 +66,22 @@ impl Graphics {
         let mut joined_vs: Vec<Vertex> = Vec::new();
         let mut joined_is = Vec::new();
 
+        let (width, height) = {
+            let size = self.display.gl_window().window().inner_size();
+            let (width, height) = (size.width as f32, size.height as f32);
+            (width * PX_PER_MM, height * PX_PER_MM)
+        };
+
+        let size = Vec2 {
+            x: width,
+            y: height,
+        };
+
         for command in commands.iter() {
             match command {
                 canary::DrawCommand::Mesh { vertices, indices } => {
                     let voff = joined_vs.len() as canary::MeshIndex;
-                    joined_vs.extend(vertices.iter().map(Vertex::from));
+                    joined_vs.extend(vertices.iter().map(|v| Vertex::from_canary(size, v)));
                     joined_is.extend(indices.iter().map(|i| i + voff));
                 }
                 _ => unimplemented!(),

scripts/music-player/src/lib.rs

@@ -28,8 +28,8 @@ impl PanelImpl for MusicPlayerPanel {
 
     fn draw(&mut self) {
         let layout = TextLayout::new(&self.display_font, "Hello world!");
-        let offset = Vec2 { x: 0.0, y: 0.0 };
-        let scale = 0.1;
+        let offset = Vec2 { x: 100.0, y: 100.0 };
+        let scale = 14.0;
         let color = Color::WHITE;
         self.panel.draw_text_layout(&layout, offset, scale, color);
     }

src/lib.rs

@@ -9,6 +9,9 @@ use std::sync::Arc;
 
 pub mod text;
 
+/// Proportion constant between pixels (at 96dpi) to millimeters (Canary's unit measurement).
+pub const PX_PER_MM: f32 = 25.4 / 96.0;
+
 /// Low-level script API callbacks.
 ///
 /// If you're a casual user of Canary the struct you're looking for is

src/text/glyph.rs

@@ -135,7 +135,7 @@ impl OutlineSink {
     }
 
     fn pf_vector_to_lyon(&mut self, v: &Vector2F) -> lyon::geom::Point<f32> {
-        let point = lyon::geom::Point::<f32>::new(v.x(), v.y()) / self.units_per_em;
+        let point = lyon::geom::Point::<f32>::new(v.x(), -v.y()) / self.units_per_em;
 
         // TODO clean this up with helper math methods?
         let bb = &mut self.bounding_box;
@@ -148,12 +148,12 @@ impl OutlineSink {
             bb.tr.x = point.x;
         }
 
-        if point.y < bb.bl.y {
-            bb.bl.y = point.y;
+        if point.y < bb.tr.y {
+            bb.tr.y = point.y;
         }
 
-        if point.y > bb.tr.y {
-            bb.tr.y = point.y;
+        if point.y > bb.bl.y {
+            bb.bl.y = point.y;
         }
 
         point

src/text/mod.rs

@@ -133,8 +133,8 @@ impl Font {
             ycur += position.vert_advance;
 
             let voff = vertices.len() as MeshIndex;
-            let xpos = xpos as f32 * pos_scale + offset.x;
-            let ypos = ypos as f32 * pos_scale + offset.y;
+            let xpos = offset.x + xpos as f32 * pos_scale;
+            let ypos = offset.y - ypos as f32 * pos_scale;
 
             for v in glyph.vertices.iter() {
                 let x = v.x * scale + xpos;