From cbbc46215fe0a0ad8a50e991ec442890b8eadc0a Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Sun, 2 Aug 2020 21:17:42 +0200
Subject: =?UTF-8?q?Layout=20elements=20and=20pure=20rust=20rendering=20?=
 =?UTF-8?q?=F0=9F=A5=8F?=
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---
 src/layout/elements.rs | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 src/layout/elements.rs

(limited to 'src/layout/elements.rs')

diff --git a/src/layout/elements.rs b/src/layout/elements.rs
new file mode 100644
index 00000000..e524e1fd
--- /dev/null
+++ b/src/layout/elements.rs
@@ -0,0 +1,84 @@
+//! The elements layouts are composed of.
+
+use std::fmt::{self, Debug, Formatter};
+
+use ttf_parser::GlyphId;
+use fontdock::FaceId;
+use crate::geom::Size;
+
+/// A sequence of positioned layout elements.
+#[derive(Debug, Clone, PartialEq)]
+pub struct LayoutElements(pub Vec<(Size, LayoutElement)>);
+
+impl LayoutElements {
+    /// Create an empty sequence.
+    pub fn new() -> Self {
+        LayoutElements(vec![])
+    }
+
+    /// Add an element at a position.
+    pub fn push(&mut self, pos: Size, element: LayoutElement) {
+        self.0.push((pos, element));
+    }
+
+    /// Add a sequence of elements offset by an `offset`.
+    pub fn extend_offset(&mut self, offset: Size, more: Self) {
+        for (subpos, element) in more.0 {
+            self.0.push((subpos + offset, element));
+        }
+    }
+}
+
+impl Default for LayoutElements {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// A layouting action, which is the basic building block layouts are composed
+/// of.
+#[derive(Debug, Clone, PartialEq)]
+pub enum LayoutElement {
+    /// Shaped text.
+    Text(Shaped),
+}
+
+/// A shaped run of text.
+#[derive(Clone, PartialEq)]
+pub struct Shaped {
+    pub text: String,
+    pub face: FaceId,
+    pub glyphs: Vec<GlyphId>,
+    pub offsets: Vec<f64>,
+    pub size: f64,
+}
+
+impl Shaped {
+    /// Create an empty shape run.
+    pub fn new(face: FaceId, size: f64) -> Shaped {
+        Shaped {
+            text: String::new(),
+            face,
+            glyphs: vec![],
+            offsets: vec![],
+            size,
+        }
+    }
+
+    /// Encode the glyph ids into a big-endian byte buffer.
+    pub fn encode_glyphs(&self) -> Vec<u8> {
+        const BYTES_PER_GLYPH: usize = 2;
+        let mut bytes = Vec::with_capacity(BYTES_PER_GLYPH * self.glyphs.len());
+        for g in &self.glyphs {
+            bytes.push((g.0 >> 8) as u8);
+            bytes.push((g.0 & 0xff) as u8);
+        }
+        bytes
+    }
+}
+
+impl Debug for Shaped {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "Shaped({})", self.text)
+    }
+}
-- 
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