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[skrifa] tthint tests batch 1 #847

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Mar 22, 2024
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[skrifa] tthint tests batch 1 #847

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86e8804
[skrifa] tthint tests batch 1
dfrg Mar 19, 2024
7c03942
Merge branch 'main' into tt-hint-tests1
dfrg Mar 20, 2024
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122 changes: 121 additions & 1 deletion skrifa/src/outline/glyf/hint/engine/data.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -144,7 +144,8 @@ impl<'a> Engine<'a> {

#[cfg(test)]
mod tests {
use super::super::MockEngine;
use super::super::{super::zone::ZonePointer, math, Engine, MockEngine};
use raw::types::F26Dot6;

#[test]
fn measure_ppem_and_point_size() {
Expand All @@ -157,4 +158,123 @@ mod tests {
engine.op_mps().unwrap();
assert_eq!(engine.value_stack.pop().unwrap(), ppem * 64);
}

#[test]
fn gc() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
set_test_vectors(&mut engine);
// current point projected coord
let point = engine.graphics.zones[1].point_mut(1).unwrap();
point.x = F26Dot6::from_bits(132);
point.y = F26Dot6::from_bits(-256);
engine.value_stack.push(1).unwrap();
engine.op_gc(0).unwrap();
assert_eq!(engine.value_stack.pop().unwrap(), 4);
// original point projected coord
let point = engine.graphics.zones[1].original_mut(1).unwrap();
point.x = F26Dot6::from_bits(-64);
point.y = F26Dot6::from_bits(521);
engine.value_stack.push(1).unwrap();
engine.op_gc(1).unwrap();
assert_eq!(engine.value_stack.pop().unwrap(), 176);
}

#[test]
fn scfs() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
set_test_vectors(&mut engine);
// This instruction is a nop in backward compatibility mode
// and before IUP.
engine.graphics.backward_compatibility = false;
engine.graphics.did_iup_x = true;
engine.graphics.did_iup_y = true;
// use the twilight zone to test the optional code path
engine.graphics.zp2 = ZonePointer::Twilight;
let point = engine.graphics.zones[0].point_mut(1).unwrap();
point.x = F26Dot6::from_bits(132);
point.y = F26Dot6::from_bits(-256);
// assert we're not currently the same
assert_ne!(
engine.graphics.zones[0].point(1).unwrap(),
engine.graphics.zones[0].original(1).unwrap()
);
// push point number
engine.value_stack.push(1).unwrap();
// push value to match
engine.value_stack.push(42).unwrap();
// set coordinate from stack!
engine.op_scfs().unwrap();
let point = engine.graphics.zones[0].point(1).unwrap();
assert_eq!(point.x.to_bits(), 166);
assert_eq!(point.y.to_bits(), -239);
// ensure that we set original = point
assert_eq!(point, engine.graphics.zones[0].original(1).unwrap());
}

#[test]
fn md_scaled() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
set_test_vectors(&mut engine);
// first path, measure in grid fitted outline
let zone = engine.graphics.zone_mut(ZonePointer::Glyph);
let point1 = zone.point_mut(1).unwrap();
point1.x = F26Dot6::from_bits(132);
point1.y = F26Dot6::from_bits(-256);
let point2 = zone.point_mut(3).unwrap();
point2.x = F26Dot6::from_bits(-64);
point2.y = F26Dot6::from_bits(100);
// now measure
engine.value_stack.push(1).unwrap();
engine.value_stack.push(3).unwrap();
engine.op_md(1).unwrap();
assert_eq!(engine.value_stack.pop().unwrap(), 16);
}

#[test]
fn md_unscaled() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
set_test_vectors(&mut engine);
// second path, measure in original unscaled outline.
// unscaled points are set in mock engine but we need a scale
engine.graphics.scale = 375912;
engine.value_stack.push(1).unwrap();
engine.value_stack.push(3).unwrap();
engine.op_md(0).unwrap();
assert_eq!(engine.value_stack.pop().unwrap(), 11);
}

#[test]
fn md_twilight() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
set_test_vectors(&mut engine);
// final path, measure in original outline, in twilight zone
engine.graphics.zp0 = ZonePointer::Twilight;
engine.graphics.zp1 = ZonePointer::Twilight;
// set some points
let zone = engine.graphics.zone_mut(ZonePointer::Twilight);
let point1 = zone.original_mut(1).unwrap();
point1.x = F26Dot6::from_bits(132);
point1.y = F26Dot6::from_bits(-256);
let point2 = zone.original_mut(3).unwrap();
point2.x = F26Dot6::from_bits(-64);
point2.y = F26Dot6::from_bits(100);
// now measure
engine.value_stack.push(1).unwrap();
engine.value_stack.push(3).unwrap();
engine.op_md(0).unwrap();
assert_eq!(engine.value_stack.pop().unwrap(), 16);
}

fn set_test_vectors(engine: &mut Engine) {
let v = math::normalize14(100, 50);
engine.graphics.proj_vector = v;
engine.graphics.dual_proj_vector = v;
engine.graphics.freedom_vector = v;
engine.graphics.update_projection_state();
}
}
208 changes: 190 additions & 18 deletions skrifa/src/outline/glyf/hint/engine/misc.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,69 +22,53 @@ impl<'a> Engine<'a> {
/// See <https://learn.microsoft.com/en-us/typography/opentype/spec/tt_instructions#get-information>
/// and <https://gitlab.freedesktop.org/freetype/freetype/-/blob/57617782464411201ce7bbc93b086c1b4d7d84a5/src/truetype/ttinterp.c#L6689>
pub(super) fn op_getinfo(&mut self) -> OpResult {
use getinfo::*;
let selector = self.value_stack.pop()?;
let mut result = 0;
// Interpreter version (selector bit: 0, result bits: 0-7)
const VERSION_SELECTOR_BIT: i32 = 1 << 0;
if (selector & VERSION_SELECTOR_BIT) != 0 {
result = 42;
result = 40;
}
// Glyph rotated (selector bit: 1, result bit: 8)
const GLYPH_ROTATED_SELECTOR_BIT: i32 = 1 << 1;
if (selector & GLYPH_ROTATED_SELECTOR_BIT) != 0 && self.graphics.is_rotated {
const GLYPH_ROTATED_RESULT_BIT: i32 = 1 << 8;
result |= GLYPH_ROTATED_RESULT_BIT;
}
// Glyph stretched (selector bit: 2, result bit: 9)
const GLYPH_STRETCHED_SELECTOR_BIT: i32 = 1 << 2;
if (selector & GLYPH_STRETCHED_SELECTOR_BIT) != 0 && self.graphics.is_stretched {
const GLYPH_STRETCHED_RESULT_BIT: i32 = 1 << 9;
result |= GLYPH_STRETCHED_RESULT_BIT;
}
// Font variations (selector bit: 3, result bit: 10)
const FONT_VARIATIONS_SELECTOR_BIT: i32 = 1 << 3;
if (selector & FONT_VARIATIONS_SELECTOR_BIT) != 0 && self.axis_count != 0 {
const FONT_VARIATIONS_RESULT_BIT: i32 = 1 << 10;
result |= FONT_VARIATIONS_RESULT_BIT;
}
// The following only apply for smooth hinting.
if self.graphics.mode.is_smooth() {
// Subpixel hinting [cleartype enabled] (selector bit: 6, result bit: 13)
// (always enabled)
const SUBPIXEL_HINTING_SELECTOR_BIT: i32 = 1 << 6;
if (selector & SUBPIXEL_HINTING_SELECTOR_BIT) != 0 {
const SUBPIXEL_HINTING_RESULT_BIT: i32 = 1 << 13;
result |= SUBPIXEL_HINTING_RESULT_BIT;
}
// Vertical LCD subpixels? (selector bit: 8, result bit: 15)
const VERTICAL_LCD_SELECTOR_BIT: i32 = 1 << 8;
if (selector & VERTICAL_LCD_SELECTOR_BIT) != 0 && self.graphics.mode.is_vertical_lcd() {
const VERTICAL_LCD_RESULT_BIT: i32 = 1 << 15;
result |= VERTICAL_LCD_RESULT_BIT;
}
// Subpixel positioned? (selector bit: 10, result bit: 17)
// (always enabled)
const SUBPIXEL_POSITIONED_SELECTOR_BIT: i32 = 1 << 10;
if (selector & SUBPIXEL_POSITIONED_SELECTOR_BIT) != 0 {
const SUBPIXEL_POSITIONED_RESULT_BIT: i32 = 1 << 17;
result |= SUBPIXEL_POSITIONED_RESULT_BIT;
}
// Symmetrical smoothing (selector bit: 11, result bit: 18)
// Note: FreeType always enables this but we deviate when our own
// preserve linear metrics flag is enabled.
const SYMMETRICAL_SMOOTHING_SELECTOR_BIT: i32 = 1 << 11;
if (selector & SYMMETRICAL_SMOOTHING_SELECTOR_BIT) != 0
&& !self.graphics.mode.preserve_linear_metrics()
{
const SYMMETRICAL_SMOOTHING_RESULT_BIT: i32 = 1 << 18;
result |= SYMMETRICAL_SMOOTHING_RESULT_BIT;
}
// ClearType hinting and grayscale rendering (selector bit: 12, result bit: 19)
const GRAYSCALE_CLEARTYPE_SELECTOR_BIT: i32 = 1 << 12;
if (selector & GRAYSCALE_CLEARTYPE_SELECTOR_BIT) != 0
&& self.graphics.mode.is_grayscale_cleartype()
{
const GRAYSCALE_CLEARTYPE_RESULT_BIT: i32 = 1 << 19;
result |= GRAYSCALE_CLEARTYPE_RESULT_BIT;
}
}
Expand Down Expand Up @@ -145,3 +129,191 @@ impl<'a> Engine<'a> {
}
}
}

/// Constants for the GETINFO instruction. Extracted here
/// to enable access from tests.
mod getinfo {
// Interpreter version (selector bit: 0, result bits: 0-7)
pub const VERSION_SELECTOR_BIT: i32 = 1 << 0;

// Glyph rotated (selector bit: 1, result bit: 8)
pub const GLYPH_ROTATED_SELECTOR_BIT: i32 = 1 << 1;
pub const GLYPH_ROTATED_RESULT_BIT: i32 = 1 << 8;

// Glyph stretched (selector bit: 2, result bit: 9)
pub const GLYPH_STRETCHED_SELECTOR_BIT: i32 = 1 << 2;
pub const GLYPH_STRETCHED_RESULT_BIT: i32 = 1 << 9;

// Font variations (selector bit: 3, result bit: 10)
pub const FONT_VARIATIONS_SELECTOR_BIT: i32 = 1 << 3;
pub const FONT_VARIATIONS_RESULT_BIT: i32 = 1 << 10;

// Subpixel hinting [cleartype enabled] (selector bit: 6, result bit: 13)
// (always enabled)
pub const SUBPIXEL_HINTING_SELECTOR_BIT: i32 = 1 << 6;
pub const SUBPIXEL_HINTING_RESULT_BIT: i32 = 1 << 13;

// Vertical LCD subpixels? (selector bit: 8, result bit: 15)
pub const VERTICAL_LCD_SELECTOR_BIT: i32 = 1 << 8;
pub const VERTICAL_LCD_RESULT_BIT: i32 = 1 << 15;

// Subpixel positioned? (selector bit: 10, result bit: 17)
// (always enabled)
pub const SUBPIXEL_POSITIONED_SELECTOR_BIT: i32 = 1 << 10;
pub const SUBPIXEL_POSITIONED_RESULT_BIT: i32 = 1 << 17;

// Symmetrical smoothing (selector bit: 11, result bit: 18)
// Note: FreeType always enables this but we deviate when our own
// preserve linear metrics flag is enabled.
pub const SYMMETRICAL_SMOOTHING_SELECTOR_BIT: i32 = 1 << 11;
pub const SYMMETRICAL_SMOOTHING_RESULT_BIT: i32 = 1 << 18;

// ClearType hinting and grayscale rendering (selector bit: 12, result bit: 19)
pub const GRAYSCALE_CLEARTYPE_SELECTOR_BIT: i32 = 1 << 12;
pub const GRAYSCALE_CLEARTYPE_RESULT_BIT: i32 = 1 << 19;
}

#[cfg(test)]
mod tests {
use super::super::{
super::{super::super::LcdLayout, HintingMode},
Engine, HintErrorKind, MockEngine,
};
use raw::types::F2Dot14;
use read_fonts::tables::glyf::bytecode::Opcode;

#[test]
fn getinfo() {
use super::getinfo::*;
let mut mock = MockEngine::new();
let mut engine = mock.engine();
// version
engine.getinfo_test(VERSION_SELECTOR_BIT, 40);
// not rotated
engine.getinfo_test(GLYPH_ROTATED_SELECTOR_BIT, 0);
// rotated
engine.graphics.is_rotated = true;
engine.getinfo_test(GLYPH_ROTATED_SELECTOR_BIT, GLYPH_ROTATED_RESULT_BIT);
// not stretched
engine.getinfo_test(GLYPH_STRETCHED_SELECTOR_BIT, 0);
// stretched
engine.graphics.is_stretched = true;
engine.getinfo_test(GLYPH_STRETCHED_SELECTOR_BIT, GLYPH_STRETCHED_RESULT_BIT);
// stretched and rotated
engine.getinfo_test(
GLYPH_ROTATED_SELECTOR_BIT | GLYPH_STRETCHED_SELECTOR_BIT,
GLYPH_ROTATED_RESULT_BIT | GLYPH_STRETCHED_RESULT_BIT,
);
// not variable
engine.getinfo_test(FONT_VARIATIONS_SELECTOR_BIT, 0);
// variable
engine.axis_count = 1;
engine.getinfo_test(FONT_VARIATIONS_SELECTOR_BIT, FONT_VARIATIONS_RESULT_BIT);
// in strong hinting mode, the following selectors are always disabled
engine.graphics.mode = HintingMode::Strong;
for selector in [
SUBPIXEL_HINTING_SELECTOR_BIT,
VERTICAL_LCD_SELECTOR_BIT,
SUBPIXEL_POSITIONED_SELECTOR_BIT,
SYMMETRICAL_SMOOTHING_SELECTOR_BIT,
GRAYSCALE_CLEARTYPE_SELECTOR_BIT,
] {
engine.getinfo_test(selector, 0);
}
// set back to smooth mode
engine.graphics.mode = HintingMode::default();
for (selector, result) in [
// default smooth mode is grayscale cleartype
(
GRAYSCALE_CLEARTYPE_SELECTOR_BIT,
GRAYSCALE_CLEARTYPE_RESULT_BIT,
),
// always enabled in smooth mode
(SUBPIXEL_HINTING_SELECTOR_BIT, SUBPIXEL_HINTING_RESULT_BIT),
(
SUBPIXEL_POSITIONED_SELECTOR_BIT,
SUBPIXEL_POSITIONED_RESULT_BIT,
),
] {
engine.getinfo_test(selector, result);
}
// vertical lcd
engine.graphics.mode = HintingMode::Smooth {
lcd_subpixel: Some(LcdLayout::Vertical),
preserve_linear_metrics: true,
};
engine.getinfo_test(VERTICAL_LCD_SELECTOR_BIT, VERTICAL_LCD_RESULT_BIT);
// symmetical smoothing is disabled when preserving linear metrics
engine.getinfo_test(SYMMETRICAL_SMOOTHING_SELECTOR_BIT, 0);
// grayscale cleartype is disabled when lcd_subpixel is not None
engine.getinfo_test(GRAYSCALE_CLEARTYPE_SELECTOR_BIT, 0);
// reset to default to disable preserve linear metrics
engine.graphics.mode = HintingMode::default();
// now symmetrical smoothing is enabled
engine.getinfo_test(
SYMMETRICAL_SMOOTHING_SELECTOR_BIT,
SYMMETRICAL_SMOOTHING_RESULT_BIT,
);
}

#[test]
fn getvariation() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
// no variations should trigger unknown opcode
assert!(matches!(
engine.op_getvariation(),
Err(HintErrorKind::UnhandledOpcode(Opcode::GETVARIATION))
));
// set the axis count to a non-zero value to enable variations
engine.axis_count = 2;
// and creates some coords
let coords = [
F2Dot14::from_f32(-1.0),
F2Dot14::from_f32(0.5),
F2Dot14::from_f32(1.0),
];
let coords_bits = coords.map(|x| x.to_bits() as i32);
// too few, pad with zeros
engine.coords = &coords[0..1];
engine.op_getvariation().unwrap();
assert_eq!(engine.value_stack.len(), 2);
assert_eq!(engine.value_stack.values(), &[coords_bits[0], 0]);
engine.value_stack.clear();
// too many, truncate
engine.coords = &coords[0..3];
engine.op_getvariation().unwrap();
assert_eq!(engine.value_stack.len(), 2);
assert_eq!(engine.value_stack.values(), &coords_bits[0..2]);
engine.value_stack.clear();
// just right
engine.coords = &coords[0..2];
engine.op_getvariation().unwrap();
assert_eq!(engine.value_stack.len(), 2);
assert_eq!(engine.value_stack.values(), &coords_bits[0..2]);
}

#[test]
fn getdata() {
let mut mock = MockEngine::new();
let mut engine = mock.engine();
// no variations should trigger unknown opcode
assert!(matches!(
engine.op_getdata(),
Err(HintErrorKind::UnhandledOpcode(Opcode::GETDATA))
));
// set the axis count to a non-zero value to enable variations
engine.axis_count = 1;
engine.op_getdata().unwrap();
// :shrug:
assert_eq!(engine.value_stack.pop().unwrap(), 17);
}

impl<'a> Engine<'a> {
fn getinfo_test(&mut self, selector: i32, expected: i32) {
self.value_stack.push(selector).unwrap();
self.op_getinfo().unwrap();
assert_eq!(self.value_stack.pop().unwrap(), expected);
}
}
}
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