From f161ab8e57b0149b368f892f11c83d953c55dd5a Mon Sep 17 00:00:00 2001
From: Utsav Oza <utsavoza96@gmail.com>
Date: Sat, 23 May 2020 22:03:04 +0530
Subject: [PATCH] Basic implementation of canvas.fillText

---
 components/canvas/canvas_data.rs    | 36 +++++++++++++++++++++++++----
 components/canvas/raqote_backend.rs | 29 +++++++++++++++++++++++
 2 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/components/canvas/canvas_data.rs b/components/canvas/canvas_data.rs
index c3e02b674638..a3616f7e3dac 100644
--- a/components/canvas/canvas_data.rs
+++ b/components/canvas/canvas_data.rs
@@ -264,6 +264,15 @@ pub trait GenericDrawTarget {
         operator: CompositionOp,
     );
     fn fill(&mut self, path: &Path, pattern: Pattern, draw_options: &DrawOptions);
+    fn fill_text(
+        &mut self,
+        text: String,
+        x: f64,
+        y: f64,
+        max_width: Option<f64>,
+        pattern: Pattern,
+        draw_options: &DrawOptions,
+    );
     fn fill_rect(&mut self, rect: &Rect<f32>, pattern: Pattern, draw_options: Option<&DrawOptions>);
     fn get_format(&self) -> SurfaceFormat;
     fn get_size(&self) -> Size2D<i32>;
@@ -456,10 +465,29 @@ impl<'a> CanvasData<'a> {
         }
     }
 
-    pub fn fill_text(&self, text: String, x: f64, y: f64, max_width: Option<f64>) {
-        error!(
-            "Unimplemented canvas2d.fillText. Values received: {}, {}, {}, {:?}.",
-            text, x, y, max_width
+    pub fn fill_text(&mut self, text: String, x: f64, y: f64, max_width: Option<f64>) {
+        // 1. If maxWidth was provided but is less than or equal to zero or equal to NaN,
+        //    then return an empty array.
+        if max_width.map_or(false, |max_width| max_width <= 0.) {
+            return;
+        }
+
+        // 2. Replace all ASCII whitespace in text with U+0020 SPACE characters.
+        let text = text
+            .chars()
+            .map(|c| match c {
+                ' ' | '\t' | '\n' | '\r' | '\x0C' => '\x20',
+                _ => c,
+            })
+            .collect();
+
+        self.draw_target.fill_text(
+            text,
+            x,
+            y,
+            max_width,
+            self.state.fill_style.clone(),
+            &self.state.draw_options,
         );
     }
 
diff --git a/components/canvas/raqote_backend.rs b/components/canvas/raqote_backend.rs
index 72eae8b40c8a..c732d686472c 100644
--- a/components/canvas/raqote_backend.rs
+++ b/components/canvas/raqote_backend.rs
@@ -13,6 +13,9 @@ use canvas_traits::canvas::*;
 use cssparser::RGBA;
 use euclid::default::{Point2D, Rect, Size2D, Transform2D, Vector2D};
 use euclid::Angle;
+use font_kit::family_name::FamilyName;
+use font_kit::properties::Properties;
+use font_kit::source::SystemSource;
 use lyon_geom::Arc;
 use raqote::PathOp;
 use std::marker::PhantomData;
@@ -513,6 +516,32 @@ impl GenericDrawTarget for raqote::DrawTarget {
             ),
         }
     }
+
+    fn fill_text(
+        &mut self,
+        text: String,
+        x: f64,
+        y: f64,
+        max_width: Option<f64>,
+        pattern: canvas_data::Pattern,
+        draw_options: &DrawOptions,
+    ) {
+        let font = SystemSource::new()
+            .select_best_match(&[FamilyName::SansSerif], &Properties::new())
+            .unwrap()
+            .load()
+            .unwrap();
+
+        self.draw_text(
+            &font,
+            24.,
+            &text,
+            Point2D::new(x as f32, y as f32),
+            &pattern.source(),
+            draw_options.as_raqote(),
+        );
+    }
+
     fn fill_rect(
         &mut self,
         rect: &Rect<f32>,