From c3361139d74ba0f774abc6f9baddb16b2c257548 Mon Sep 17 00:00:00 2001
From: Phillip Tennen <phillip@axleos.com>
Date: Wed, 7 Feb 2024 15:14:42 +0000
Subject: [PATCH] [TTF] Flip glyph coordinate system by ascent, not by
 em-square-units

---
 rust_programs/ttf_renderer/src/glyphs.rs |  8 ++++----
 rust_programs/ttf_renderer/src/lib.rs    | 13 ++++++++-----
 rust_programs/ttf_renderer/src/parser.rs |  2 +-
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/rust_programs/ttf_renderer/src/glyphs.rs b/rust_programs/ttf_renderer/src/glyphs.rs
index 3f2831cd5..915449276 100644
--- a/rust_programs/ttf_renderer/src/glyphs.rs
+++ b/rust_programs/ttf_renderer/src/glyphs.rs
@@ -1,4 +1,4 @@
-use crate::metrics::{GlyphRenderMetrics, LongHorMetric, VerticalMetrics};
+use crate::metrics::{FontGlobalLayoutMetrics, GlyphRenderMetrics, LongHorMetric, VerticalMetrics};
 use crate::parse_utils::{BigEndianValue, FromFontBufInPlace, TransmuteFontBufInPlace};
 use crate::parser::FontParser;
 use crate::println;
@@ -401,7 +401,7 @@ pub(crate) fn parse_glyph(
     parser: &FontParser,
     glyph_index: usize,
     all_glyphs_bounding_box: &Rect,
-    units_per_em: usize,
+    font_layout_metrics: &FontGlobalLayoutMetrics,
 ) -> GlyphRenderDescription {
     let glyph_header = parser.table_headers.get("glyf").unwrap();
     let (glyph_local_offset, glyph_data_length) = get_glyph_offset_and_length(parser, glyph_index);
@@ -469,7 +469,7 @@ pub(crate) fn parse_glyph(
         flag_count_to_parse -= 1;
     }
 
-    // Parse X coordinates
+    // Parse coordinates
     let x_values =
         interpret_values_via_flags(parser, &mut cursor, &all_flags, CoordinateComponentType::X);
     let y_values =
@@ -478,7 +478,7 @@ pub(crate) fn parse_glyph(
         .iter()
         .zip(y_values.iter())
         // Flip the Y axis of every point to match our coordinate system
-        .map(|(&x, &y)| PointF64::new(x as _, (units_per_em as isize - y) as _))
+        .map(|(&x, &y)| PointF64::new(x as _, (font_layout_metrics.ascent - y) as _))
         .collect();
 
     // Split the total collection of points into polygons, using the last-point-indexes that
diff --git a/rust_programs/ttf_renderer/src/lib.rs b/rust_programs/ttf_renderer/src/lib.rs
index fa5d3e67a..47f803cb9 100644
--- a/rust_programs/ttf_renderer/src/lib.rs
+++ b/rust_programs/ttf_renderer/src/lib.rs
@@ -1,4 +1,4 @@
-#![cfg_attr(target_os = "axle", no_std)]
+#![cfg_attr(any(target_os = "axle", feature = "no_std"), no_std)]
 #![feature(core_intrinsics)]
 #![feature(slice_ptr_get)]
 #![feature(format_args_nl)]
@@ -17,9 +17,11 @@ mod render_context;
 
 pub use crate::glyphs::{GlyphRenderDescription, GlyphRenderInstructions};
 pub use crate::metrics::GlyphMetrics;
-pub use crate::render::{render_antialiased_glyph_onto, render_char_onto, render_glyph_onto};
+pub use crate::render::{
+    render_antialiased_glyph_onto, render_char_onto, render_glyph_onto, rendered_string_size,
+};
 pub use crate::render_context::FontRenderContext;
-use agx_definitions::Rect;
+use agx_definitions::{Rect, Size};
 use alloc::collections::BTreeMap;
 use alloc::string::{String, ToString};
 use alloc::vec::Vec;
@@ -27,9 +29,10 @@ use core::fmt::{Display, Formatter};
 use parser::FontParser;
 
 use crate::hints::FunctionDefinition;
-#[cfg(target_os = "axle")]
+use crate::metrics::FontGlobalLayoutMetrics;
+#[cfg(any(target_os = "axle", feature = "no_std"))]
 pub(crate) use axle_rt::{print, println};
-#[cfg(not(target_os = "axle"))]
+#[cfg(not(any(target_os = "axle", feature = "no_std")))]
 pub(crate) use std::{print, println};
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
diff --git a/rust_programs/ttf_renderer/src/parser.rs b/rust_programs/ttf_renderer/src/parser.rs
index 5a692483a..fb4d9f173 100644
--- a/rust_programs/ttf_renderer/src/parser.rs
+++ b/rust_programs/ttf_renderer/src/parser.rs
@@ -354,7 +354,7 @@ impl<'a> FontParser<'a> {
         let mut all_glyphs = vec![];
         let mut codepoints_to_glyph_indexes = BTreeMap::new();
         for i in 0..max_profile.num_glyphs {
-            let parsed_glyph = parse_glyph(self, i, &glyph_bounding_box, head.units_per_em as _);
+            let parsed_glyph = parse_glyph(self, i, &glyph_bounding_box, &horizontal_glyph_metrics);
             all_glyphs.push(parsed_glyph);
 
             match glyph_indexes_to_codepoints.get(&i) {