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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
use api::BorderRadius;
use api::units::*;
use euclid::{Point2D, Rect, Box2D, Size2D, Vector2D, point2, point3};
use euclid::{default, Transform2D, Transform3D, Scale, approxeq::ApproxEq};
use malloc_size_of::{MallocShallowSizeOf, MallocSizeOf, MallocSizeOfOps};
use plane_split::{Clipper, Polygon};
use std::{i32, f32, fmt, ptr};
use std::borrow::Cow;
use std::num::NonZeroUsize;
use std::os::raw::c_void;
use std::sync::Arc;
use std::mem::replace;
// Matches the definition of SK_ScalarNearlyZero in Skia.
const NEARLY_ZERO: f32 = 1.0 / 4096.0;
/// A typesafe helper that separates new value construction from
/// vector growing, allowing LLVM to ideally construct the element in place.
pub struct Allocation<'a, T: 'a> {
vec: &'a mut Vec<T>,
index: usize,
}
impl<'a, T> Allocation<'a, T> {
// writing is safe because alloc() ensured enough capacity
// and `Allocation` holds a mutable borrow to prevent anyone else
// from breaking this invariant.
#[inline(always)]
pub fn init(self, value: T) -> usize {
unsafe {
ptr::write(self.vec.as_mut_ptr().add(self.index), value);
self.vec.set_len(self.index + 1);
}
self.index
}
}
/// An entry into a vector, similar to `std::collections::hash_map::Entry`.
pub enum VecEntry<'a, T: 'a> {
Vacant(Allocation<'a, T>),
Occupied(&'a mut T),
}
impl<'a, T> VecEntry<'a, T> {
#[inline(always)]
pub fn set(self, value: T) {
match self {
VecEntry::Vacant(alloc) => { alloc.init(value); }
VecEntry::Occupied(slot) => { *slot = value; }
}
}
}
pub trait VecHelper<T> {
/// Growns the vector by a single entry, returning the allocation.
fn alloc(&mut self) -> Allocation<T>;
/// Either returns an existing elemenet, or grows the vector by one.
/// Doesn't expect indices to be higher than the current length.
fn entry(&mut self, index: usize) -> VecEntry<T>;
/// Equivalent to `mem::replace(&mut vec, Vec::new())`
fn take(&mut self) -> Self;
/// Functionally equivalent to `mem::replace(&mut vec, Vec::new())` but tries
/// to keep the allocation in the caller if it is empty or replace it with a
/// pre-allocated vector.
fn take_and_preallocate(&mut self) -> Self;
}
impl<T> VecHelper<T> for Vec<T> {
fn alloc(&mut self) -> Allocation<T> {
let index = self.len();
if self.capacity() == index {
self.reserve(1);
}
Allocation {
vec: self,
index,
}
}
fn entry(&mut self, index: usize) -> VecEntry<T> {
if index < self.len() {
VecEntry::Occupied(unsafe {
self.get_unchecked_mut(index)
})
} else {
assert_eq!(index, self.len());
VecEntry::Vacant(self.alloc())
}
}
fn take(&mut self) -> Self {
replace(self, Vec::new())
}
fn take_and_preallocate(&mut self) -> Self {
let len = self.len();
if len == 0 {
self.clear();
return Vec::new();
}
replace(self, Vec::with_capacity(len + 8))
}
}
// Represents an optimized transform where there is only
// a scale and translation (which are guaranteed to maintain
// an axis align rectangle under transformation). The
// scaling is applied first, followed by the translation.
// TODO(gw): We should try and incorporate F <-> T units here,
// but it's a bit tricky to do that now with the
// way the current spatial tree works.
#[repr(C)]
#[derive(Debug, Clone, Copy, MallocSizeOf, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct ScaleOffset {
pub scale: euclid::Vector2D<f32, euclid::UnknownUnit>,
pub offset: euclid::Vector2D<f32, euclid::UnknownUnit>,
}
impl ScaleOffset {
pub fn new(sx: f32, sy: f32, tx: f32, ty: f32) -> Self {
ScaleOffset {
scale: Vector2D::new(sx, sy),
offset: Vector2D::new(tx, ty),
}
}
pub fn identity() -> Self {
ScaleOffset {
scale: Vector2D::new(1.0, 1.0),
offset: Vector2D::zero(),
}
}
// Construct a ScaleOffset from a transform. Returns
// None if the matrix is not a pure scale / translation.
pub fn from_transform<F, T>(
m: &Transform3D<f32, F, T>,
) -> Option<ScaleOffset> {
// To check that we have a pure scale / translation:
// Every field must match an identity matrix, except:
// - Any value present in tx,ty
// - Any value present in sx,sy
if m.m12.abs() > NEARLY_ZERO ||
m.m13.abs() > NEARLY_ZERO ||
m.m14.abs() > NEARLY_ZERO ||
m.m21.abs() > NEARLY_ZERO ||
m.m23.abs() > NEARLY_ZERO ||
m.m24.abs() > NEARLY_ZERO ||
m.m31.abs() > NEARLY_ZERO ||
m.m32.abs() > NEARLY_ZERO ||
(m.m33 - 1.0).abs() > NEARLY_ZERO ||
m.m34.abs() > NEARLY_ZERO ||
m.m43.abs() > NEARLY_ZERO ||
(m.m44 - 1.0).abs() > NEARLY_ZERO {
return None;
}
Some(ScaleOffset {
scale: Vector2D::new(m.m11, m.m22),
offset: Vector2D::new(m.m41, m.m42),
})
}
pub fn from_offset(offset: default::Vector2D<f32>) -> Self {
ScaleOffset {
scale: Vector2D::new(1.0, 1.0),
offset,
}
}
pub fn from_scale(scale: default::Vector2D<f32>) -> Self {
ScaleOffset {
scale,
offset: Vector2D::new(0.0, 0.0),
}
}
pub fn inverse(&self) -> Self {
// If either of the scale factors is 0, inverse also has scale 0
// TODO(gw): Consider making this return Option<Self> in future
// so that callers can detect and handle when inverse
// fails here.
if self.scale.x.approx_eq(&0.0) || self.scale.y.approx_eq(&0.0) {
return ScaleOffset::new(0.0, 0.0, 0.0, 0.0);
}
ScaleOffset {
scale: Vector2D::new(
1.0 / self.scale.x,
1.0 / self.scale.y,
),
offset: Vector2D::new(
-self.offset.x / self.scale.x,
-self.offset.y / self.scale.y,
),
}
}
pub fn offset(&self, offset: default::Vector2D<f32>) -> Self {
self.accumulate(
&ScaleOffset {
scale: Vector2D::new(1.0, 1.0),
offset,
}
)
}
pub fn scale(&self, scale: f32) -> Self {
self.accumulate(
&ScaleOffset {
scale: Vector2D::new(scale, scale),
offset: Vector2D::zero(),
}
)
}
/// Produce a ScaleOffset that includes both self and other.
/// The 'self' ScaleOffset is applied after other.
/// This is equivalent to `Transform3D::pre_transform`.
pub fn accumulate(&self, other: &ScaleOffset) -> Self {
ScaleOffset {
scale: Vector2D::new(
self.scale.x * other.scale.x,
self.scale.y * other.scale.y,
),
offset: Vector2D::new(
self.offset.x + self.scale.x * other.offset.x,
self.offset.y + self.scale.y * other.offset.y,
),
}
}
pub fn map_rect<F, T>(&self, rect: &Box2D<f32, F>) -> Box2D<f32, T> {
// TODO(gw): The logic below can return an unexpected result if the supplied
// rect is invalid (has size < 0). Since Gecko currently supplied
// invalid rects in some cases, adding a max(0) here ensures that
// mapping an invalid rect retains the property that rect.is_empty()
// will return true (the mapped rect output will have size 0 instead
// of a negative size). In future we could catch / assert / fix
// these invalid rects earlier, and assert here instead.
let w = rect.width().max(0.0);
let h = rect.height().max(0.0);
let mut x0 = rect.min.x * self.scale.x + self.offset.x;
let mut y0 = rect.min.y * self.scale.y + self.offset.y;
let mut sx = w * self.scale.x;
let mut sy = h * self.scale.y;
// Handle negative scale. Previously, branchless float math was used to find the
// min / max vertices and size. However, that sequence of operations was producind
// additional floating point accuracy on android emulator builds, causing one test
// to fail an assert. Instead, we retain the same math as previously, and adjust
// the origin / size if required.
if self.scale.x < 0.0 {
x0 += sx;
sx = -sx;
}
if self.scale.y < 0.0 {
y0 += sy;
sy = -sy;
}
Box2D::from_origin_and_size(
Point2D::new(x0, y0),
Size2D::new(sx, sy),
)
}
pub fn unmap_rect<F, T>(&self, rect: &Box2D<f32, F>) -> Box2D<f32, T> {
// TODO(gw): The logic below can return an unexpected result if the supplied
// rect is invalid (has size < 0). Since Gecko currently supplied
// invalid rects in some cases, adding a max(0) here ensures that
// mapping an invalid rect retains the property that rect.is_empty()
// will return true (the mapped rect output will have size 0 instead
// of a negative size). In future we could catch / assert / fix
// these invalid rects earlier, and assert here instead.
let w = rect.width().max(0.0);
let h = rect.height().max(0.0);
let mut x0 = (rect.min.x - self.offset.x) / self.scale.x;
let mut y0 = (rect.min.y - self.offset.y) / self.scale.y;
let mut sx = w / self.scale.x;
let mut sy = h / self.scale.y;
// Handle negative scale. Previously, branchless float math was used to find the
// min / max vertices and size. However, that sequence of operations was producind
// additional floating point accuracy on android emulator builds, causing one test
// to fail an assert. Instead, we retain the same math as previously, and adjust
// the origin / size if required.
if self.scale.x < 0.0 {
x0 += sx;
sx = -sx;
}
if self.scale.y < 0.0 {
y0 += sy;
sy = -sy;
}
Box2D::from_origin_and_size(
Point2D::new(x0, y0),
Size2D::new(sx, sy),
)
}
pub fn map_vector<F, T>(&self, vector: &Vector2D<f32, F>) -> Vector2D<f32, T> {
Vector2D::new(
vector.x * self.scale.x,
vector.y * self.scale.y,
)
}
pub fn unmap_vector<F, T>(&self, vector: &Vector2D<f32, F>) -> Vector2D<f32, T> {
Vector2D::new(
vector.x / self.scale.x,
vector.y / self.scale.y,
)
}
pub fn map_point<F, T>(&self, point: &Point2D<f32, F>) -> Point2D<f32, T> {
Point2D::new(
point.x * self.scale.x + self.offset.x,
point.y * self.scale.y + self.offset.y,
)
}
pub fn unmap_point<F, T>(&self, point: &Point2D<f32, F>) -> Point2D<f32, T> {
Point2D::new(
(point.x - self.offset.x) / self.scale.x,
(point.y - self.offset.y) / self.scale.y,
)
}
pub fn to_transform<F, T>(&self) -> Transform3D<f32, F, T> {
Transform3D::new(
self.scale.x,
0.0,
0.0,
0.0,
0.0,
self.scale.y,
0.0,
0.0,
0.0,
0.0,
1.0,
0.0,
self.offset.x,
self.offset.y,
0.0,
1.0,
)
}
}
// TODO: Implement these in euclid!
pub trait MatrixHelpers<Src, Dst> {
/// A port of the preserves2dAxisAlignment function in Skia.
/// Defined in the SkMatrix44 class.
fn preserves_2d_axis_alignment(&self) -> bool;
fn has_perspective_component(&self) -> bool;
fn has_2d_inverse(&self) -> bool;
/// Check if the matrix post-scaling on either the X or Y axes could cause geometry
/// transformed by this matrix to have scaling exceeding the supplied limit.
fn exceeds_2d_scale(&self, limit: f64) -> bool;
fn inverse_project(&self, target: &Point2D<f32, Dst>) -> Option<Point2D<f32, Src>>;
fn inverse_rect_footprint(&self, rect: &Box2D<f32, Dst>) -> Option<Box2D<f32, Src>>;
fn transform_kind(&self) -> TransformedRectKind;
fn is_simple_translation(&self) -> bool;
fn is_simple_2d_translation(&self) -> bool;
fn is_2d_scale_translation(&self) -> bool;
/// Return the determinant of the 2D part of the matrix.
fn determinant_2d(&self) -> f32;
/// Turn Z transformation into identity. This is useful when crossing "flat"
/// transform styled stacking contexts upon traversing the coordinate systems.
fn flatten_z_output(&mut self);
fn cast_unit<NewSrc, NewDst>(&self) -> Transform3D<f32, NewSrc, NewDst>;
}
impl<Src, Dst> MatrixHelpers<Src, Dst> for Transform3D<f32, Src, Dst> {
fn preserves_2d_axis_alignment(&self) -> bool {
if self.m14 != 0.0 || self.m24 != 0.0 {
return false;
}
let mut col0 = 0;
let mut col1 = 0;
let mut row0 = 0;
let mut row1 = 0;
if self.m11.abs() > NEARLY_ZERO {
col0 += 1;
row0 += 1;
}
if self.m12.abs() > NEARLY_ZERO {
col1 += 1;
row0 += 1;
}
if self.m21.abs() > NEARLY_ZERO {
col0 += 1;
row1 += 1;
}
if self.m22.abs() > NEARLY_ZERO {
col1 += 1;
row1 += 1;
}
col0 < 2 && col1 < 2 && row0 < 2 && row1 < 2
}
fn has_perspective_component(&self) -> bool {
self.m14.abs() > NEARLY_ZERO ||
self.m24.abs() > NEARLY_ZERO ||
self.m34.abs() > NEARLY_ZERO ||
(self.m44 - 1.0).abs() > NEARLY_ZERO
}
fn has_2d_inverse(&self) -> bool {
self.determinant_2d() != 0.0
}
fn exceeds_2d_scale(&self, limit: f64) -> bool {
let limit2 = (limit * limit) as f32;
self.m11 * self.m11 + self.m12 * self.m12 > limit2 ||
self.m21 * self.m21 + self.m22 * self.m22 > limit2
}
/// Find out a point in `Src` that would be projected into the `target`.
fn inverse_project(&self, target: &Point2D<f32, Dst>) -> Option<Point2D<f32, Src>> {
// form the linear equation for the hyperplane intersection
let m = Transform2D::<f32, Src, Dst>::new(
self.m11 - target.x * self.m14, self.m12 - target.y * self.m14,
self.m21 - target.x * self.m24, self.m22 - target.y * self.m24,
self.m41 - target.x * self.m44, self.m42 - target.y * self.m44,
);
let inv = m.inverse()?;
// we found the point, now check if it maps to the positive hemisphere
if inv.m31 * self.m14 + inv.m32 * self.m24 + self.m44 > 0.0 {
Some(Point2D::new(inv.m31, inv.m32))
} else {
None
}
}
fn inverse_rect_footprint(&self, rect: &Box2D<f32, Dst>) -> Option<Box2D<f32, Src>> {
Some(Box2D::from_points(&[
self.inverse_project(&rect.top_left())?,
self.inverse_project(&rect.top_right())?,
self.inverse_project(&rect.bottom_left())?,
self.inverse_project(&rect.bottom_right())?,
]))
}
fn transform_kind(&self) -> TransformedRectKind {
if self.preserves_2d_axis_alignment() {
TransformedRectKind::AxisAligned
} else {
TransformedRectKind::Complex
}
}
fn is_simple_translation(&self) -> bool {
if (self.m11 - 1.0).abs() > NEARLY_ZERO ||
(self.m22 - 1.0).abs() > NEARLY_ZERO ||
(self.m33 - 1.0).abs() > NEARLY_ZERO ||
(self.m44 - 1.0).abs() > NEARLY_ZERO {
return false;
}
self.m12.abs() < NEARLY_ZERO && self.m13.abs() < NEARLY_ZERO &&
self.m14.abs() < NEARLY_ZERO && self.m21.abs() < NEARLY_ZERO &&
self.m23.abs() < NEARLY_ZERO && self.m24.abs() < NEARLY_ZERO &&
self.m31.abs() < NEARLY_ZERO && self.m32.abs() < NEARLY_ZERO &&
self.m34.abs() < NEARLY_ZERO
}
fn is_simple_2d_translation(&self) -> bool {
if !self.is_simple_translation() {
return false;
}
self.m43.abs() < NEARLY_ZERO
}
/* is this...
* X 0 0 0
* 0 Y 0 0
* 0 0 1 0
* a b 0 1
*/
fn is_2d_scale_translation(&self) -> bool {
(self.m33 - 1.0).abs() < NEARLY_ZERO &&
(self.m44 - 1.0).abs() < NEARLY_ZERO &&
self.m12.abs() < NEARLY_ZERO && self.m13.abs() < NEARLY_ZERO && self.m14.abs() < NEARLY_ZERO &&
self.m21.abs() < NEARLY_ZERO && self.m23.abs() < NEARLY_ZERO && self.m24.abs() < NEARLY_ZERO &&
self.m31.abs() < NEARLY_ZERO && self.m32.abs() < NEARLY_ZERO && self.m34.abs() < NEARLY_ZERO &&
self.m43.abs() < NEARLY_ZERO
}
fn determinant_2d(&self) -> f32 {
self.m11 * self.m22 - self.m12 * self.m21
}
fn flatten_z_output(&mut self) {
self.m13 = 0.0;
self.m23 = 0.0;
self.m33 = 1.0;
self.m43 = 0.0;
//Note: we used to zero out m3? as well, see "reftests/flatten-all-flat.yaml" test
}
fn cast_unit<NewSrc, NewDst>(&self) -> Transform3D<f32, NewSrc, NewDst> {
Transform3D::new(
self.m11, self.m12, self.m13, self.m14,
self.m21, self.m22, self.m23, self.m24,
self.m31, self.m32, self.m33, self.m34,
self.m41, self.m42, self.m43, self.m44,
)
}
}
pub trait PointHelpers<U>
where
Self: Sized,
{
fn snap(&self) -> Self;
}
impl<U> PointHelpers<U> for Point2D<f32, U> {
fn snap(&self) -> Self {
Point2D::new(
(self.x + 0.5).floor(),
(self.y + 0.5).floor(),
)
}
}
pub trait RectHelpers<U>
where
Self: Sized,
{
fn from_floats(x0: f32, y0: f32, x1: f32, y1: f32) -> Self;
fn snap(&self) -> Self;
}
impl<U> RectHelpers<U> for Rect<f32, U> {
fn from_floats(x0: f32, y0: f32, x1: f32, y1: f32) -> Self {
Rect::new(
Point2D::new(x0, y0),
Size2D::new(x1 - x0, y1 - y0),
)
}
fn snap(&self) -> Self {
let origin = Point2D::new(
(self.origin.x + 0.5).floor(),
(self.origin.y + 0.5).floor(),
);
Rect::new(
origin,
Size2D::new(
(self.origin.x + self.size.width + 0.5).floor() - origin.x,
(self.origin.y + self.size.height + 0.5).floor() - origin.y,
),
)
}
}
impl<U> RectHelpers<U> for Box2D<f32, U> {
fn from_floats(x0: f32, y0: f32, x1: f32, y1: f32) -> Self {
Box2D {
min: Point2D::new(x0, y0),
max: Point2D::new(x1, y1),
}
}
fn snap(&self) -> Self {
self.round()
}
}
pub fn lerp(a: f32, b: f32, t: f32) -> f32 {
(b - a) * t + a
}
#[repr(u32)]
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum TransformedRectKind {
AxisAligned = 0,
Complex = 1,
}
#[inline(always)]
pub fn pack_as_float(value: u32) -> f32 {
value as f32 + 0.5
}
#[inline]
fn extract_inner_rect_impl<U>(
rect: &Box2D<f32, U>,
radii: &BorderRadius,
k: f32,
) -> Option<Box2D<f32, U>> {
// `k` defines how much border is taken into account
// We enforce the offsets to be rounded to pixel boundaries
// by `ceil`-ing and `floor`-ing them
let xl = (k * radii.top_left.width.max(radii.bottom_left.width)).ceil();
let xr = (rect.width() - k * radii.top_right.width.max(radii.bottom_right.width)).floor();
let yt = (k * radii.top_left.height.max(radii.top_right.height)).ceil();
let yb =
(rect.height() - k * radii.bottom_left.height.max(radii.bottom_right.height)).floor();
if xl <= xr && yt <= yb {
Some(Box2D::from_origin_and_size(
Point2D::new(rect.min.x + xl, rect.min.y + yt),
Size2D::new(xr - xl, yb - yt),
))
} else {
None
}
}
/// Return an aligned rectangle that is inside the clip region and doesn't intersect
/// any of the bounding rectangles of the rounded corners.
pub fn extract_inner_rect_safe<U>(
rect: &Box2D<f32, U>,
radii: &BorderRadius,
) -> Option<Box2D<f32, U>> {
// value of `k==1.0` is used for extraction of the corner rectangles
// see `SEGMENT_CORNER_*` in `clip_shared.glsl`
extract_inner_rect_impl(rect, radii, 1.0)
}
#[cfg(test)]
use euclid::vec3;
#[cfg(test)]
pub mod test {
use super::*;
use euclid::default::{Point2D, Size2D, Transform3D};
use euclid::{Angle, approxeq::ApproxEq};
use std::f32::consts::PI;
use crate::clip::{is_left_of_line, polygon_contains_point};
use crate::prim_store::PolygonKey;
use api::FillRule;
#[test]
fn inverse_project() {
let m0 = Transform3D::identity();
let p0 = Point2D::new(1.0, 2.0);
// an identical transform doesn't need any inverse projection
assert_eq!(m0.inverse_project(&p0), Some(p0));
let m1 = Transform3D::rotation(0.0, 1.0, 0.0, Angle::radians(-PI / 3.0));
// rotation by 60 degrees would imply scaling of X component by a factor of 2
assert_eq!(m1.inverse_project(&p0), Some(Point2D::new(2.0, 2.0)));
}
#[test]
fn inverse_project_footprint() {
let m = Transform3D::new(
0.477499992, 0.135000005, -1.0, 0.000624999986,
-0.642787635, 0.766044438, 0.0, 0.0,
0.766044438, 0.642787635, 0.0, 0.0,
1137.10986, 113.71286, 402.0, 0.748749971,
);
let r = Box2D::from_size(Size2D::new(804.0, 804.0));
{
let points = &[
r.top_left(),
r.top_right(),
r.bottom_left(),
r.bottom_right(),
];
let mi = m.inverse().unwrap();
// In this section, we do the forward and backward transformation
// to confirm that its bijective.
// We also do the inverse projection path, and confirm it functions the same way.
info!("Points:");
for p in points {
let pp = m.transform_point2d_homogeneous(*p);
let p3 = pp.to_point3d().unwrap();
let pi = mi.transform_point3d_homogeneous(p3);
let px = pi.to_point2d().unwrap();
let py = m.inverse_project(&pp.to_point2d().unwrap()).unwrap();
info!("\t{:?} -> {:?} -> {:?} -> ({:?} -> {:?}, {:?})", p, pp, p3, pi, px, py);
assert!(px.approx_eq_eps(p, &Point2D::new(0.001, 0.001)));
assert!(py.approx_eq_eps(p, &Point2D::new(0.001, 0.001)));
}
}
// project
let rp = project_rect(&m, &r, &Box2D::from_size(Size2D::new(1000.0, 1000.0))).unwrap();
info!("Projected {:?}", rp);
// one of the points ends up in the negative hemisphere
assert_eq!(m.inverse_project(&rp.min), None);
// inverse
if let Some(ri) = m.inverse_rect_footprint(&rp) {
// inverse footprint should be larger, since it doesn't know the original Z
assert!(ri.contains_box(&r), "Inverse {:?}", ri);
}
}
fn validate_convert(xref: &LayoutTransform) {
let so = ScaleOffset::from_transform(xref).unwrap();
let xf = so.to_transform();
assert!(xref.approx_eq(&xf));
}
#[test]
fn negative_scale_map_unmap() {
let xref = LayoutTransform::scale(1.0, -1.0, 1.0)
.pre_translate(LayoutVector3D::new(124.0, 38.0, 0.0));
let so = ScaleOffset::from_transform(&xref).unwrap();
let local_rect = Box2D {
min: LayoutPoint::new(50.0, -100.0),
max: LayoutPoint::new(250.0, 300.0),
};
let mapped_rect = so.map_rect::<LayoutPixel, DevicePixel>(&local_rect);
let xf_rect = project_rect(
&xref,
&local_rect,
&LayoutRect::max_rect(),
).unwrap();
assert!(mapped_rect.min.x.approx_eq(&xf_rect.min.x));
assert!(mapped_rect.min.y.approx_eq(&xf_rect.min.y));
assert!(mapped_rect.max.x.approx_eq(&xf_rect.max.x));
assert!(mapped_rect.max.y.approx_eq(&xf_rect.max.y));
let unmapped_rect = so.unmap_rect::<DevicePixel, LayoutPixel>(&mapped_rect);
assert!(unmapped_rect.min.x.approx_eq(&local_rect.min.x));
assert!(unmapped_rect.min.y.approx_eq(&local_rect.min.y));
assert!(unmapped_rect.max.x.approx_eq(&local_rect.max.x));
assert!(unmapped_rect.max.y.approx_eq(&local_rect.max.y));
}
#[test]
fn scale_offset_convert() {
let xref = LayoutTransform::translation(130.0, 200.0, 0.0);
validate_convert(&xref);
let xref = LayoutTransform::scale(13.0, 8.0, 1.0);
validate_convert(&xref);
let xref = LayoutTransform::scale(0.5, 0.5, 1.0)
.pre_translate(LayoutVector3D::new(124.0, 38.0, 0.0));
validate_convert(&xref);
let xref = LayoutTransform::scale(30.0, 11.0, 1.0)
.then_translate(vec3(50.0, 240.0, 0.0));
validate_convert(&xref);
}
fn validate_inverse(xref: &LayoutTransform) {
let s0 = ScaleOffset::from_transform(xref).unwrap();
let s1 = s0.inverse().accumulate(&s0);
assert!((s1.scale.x - 1.0).abs() < NEARLY_ZERO &&
(s1.scale.y - 1.0).abs() < NEARLY_ZERO &&
s1.offset.x.abs() < NEARLY_ZERO &&
s1.offset.y.abs() < NEARLY_ZERO,
"{:?}",
s1);
}
#[test]
fn scale_offset_inverse() {
let xref = LayoutTransform::translation(130.0, 200.0, 0.0);
validate_inverse(&xref);
let xref = LayoutTransform::scale(13.0, 8.0, 1.0);
validate_inverse(&xref);
let xref = LayoutTransform::translation(124.0, 38.0, 0.0).
then_scale(0.5, 0.5, 1.0);
validate_inverse(&xref);
let xref = LayoutTransform::scale(30.0, 11.0, 1.0)
.then_translate(vec3(50.0, 240.0, 0.0));
validate_inverse(&xref);
}
fn validate_accumulate(x0: &LayoutTransform, x1: &LayoutTransform) {
let x = x1.then(&x0);
let s0 = ScaleOffset::from_transform(x0).unwrap();
let s1 = ScaleOffset::from_transform(x1).unwrap();
let s = s0.accumulate(&s1).to_transform();
assert!(x.approx_eq(&s), "{:?}\n{:?}", x, s);
}
#[test]
fn scale_offset_accumulate() {
let x0 = LayoutTransform::translation(130.0, 200.0, 0.0);
let x1 = LayoutTransform::scale(7.0, 3.0, 1.0);
validate_accumulate(&x0, &x1);
}
#[test]
fn scale_offset_invalid_scale() {
let s0 = ScaleOffset::new(0.0, 1.0, 10.0, 20.0);
let i0 = s0.inverse();
assert_eq!(i0, ScaleOffset::new(0.0, 0.0, 0.0, 0.0));
let s1 = ScaleOffset::new(1.0, 0.0, 10.0, 20.0);
let i1 = s1.inverse();
assert_eq!(i1, ScaleOffset::new(0.0, 0.0, 0.0, 0.0));
}
#[test]
fn polygon_clip_is_left_of_point() {
// Define points of a line through (1, -3) and (-2, 6) to test against.
// If the triplet consisting of these two points and the test point
// form a counter-clockwise triangle, then the test point is on the
// left. The easiest way to visualize this is with an "ascending"
// line from low-Y to high-Y.
let p0_x = 1.0;
let p0_y = -3.0;
let p1_x = -2.0;
let p1_y = 6.0;
// Test some points to the left of the line.
assert!(is_left_of_line(-9.0, 0.0, p0_x, p0_y, p1_x, p1_y) > 0.0);
assert!(is_left_of_line(-1.0, 1.0, p0_x, p0_y, p1_x, p1_y) > 0.0);
assert!(is_left_of_line(1.0, -4.0, p0_x, p0_y, p1_x, p1_y) > 0.0);
// Test some points on the line.
assert!(is_left_of_line(-3.0, 9.0, p0_x, p0_y, p1_x, p1_y) == 0.0);
assert!(is_left_of_line(0.0, 0.0, p0_x, p0_y, p1_x, p1_y) == 0.0);
assert!(is_left_of_line(100.0, -300.0, p0_x, p0_y, p1_x, p1_y) == 0.0);
// Test some points to the right of the line.
assert!(is_left_of_line(0.0, 1.0, p0_x, p0_y, p1_x, p1_y) < 0.0);
assert!(is_left_of_line(-4.0, 13.0, p0_x, p0_y, p1_x, p1_y) < 0.0);
assert!(is_left_of_line(5.0, -12.0, p0_x, p0_y, p1_x, p1_y) < 0.0);
}
#[test]
fn polygon_clip_contains_point() {
// We define the points of a self-overlapping polygon, which we will
// use to create polygons with different windings and fill rules.
let p0 = LayoutPoint::new(4.0, 4.0);
let p1 = LayoutPoint::new(6.0, 4.0);
let p2 = LayoutPoint::new(4.0, 7.0);
let p3 = LayoutPoint::new(2.0, 1.0);
let p4 = LayoutPoint::new(8.0, 1.0);
let p5 = LayoutPoint::new(6.0, 7.0);
let poly_clockwise_nonzero = PolygonKey::new(
&[p5, p4, p3, p2, p1, p0].to_vec(), FillRule::Nonzero
);
let poly_clockwise_evenodd = PolygonKey::new(
&[p5, p4, p3, p2, p1, p0].to_vec(), FillRule::Evenodd
);
let poly_counter_clockwise_nonzero = PolygonKey::new(
&[p0, p1, p2, p3, p4, p5].to_vec(), FillRule::Nonzero
);
let poly_counter_clockwise_evenodd = PolygonKey::new(
&[p0, p1, p2, p3, p4, p5].to_vec(), FillRule::Evenodd
);
// We define a rect that provides a bounding clip area of
// the polygon.
let rect = LayoutRect::from_size(LayoutSize::new(10.0, 10.0));
// And we'll test three points of interest.
let p_inside_once = LayoutPoint::new(5.0, 3.0);
let p_inside_twice = LayoutPoint::new(5.0, 5.0);
let p_outside = LayoutPoint::new(9.0, 9.0);
// We should get the same results for both clockwise and
// counter-clockwise polygons.
// For nonzero polygons, the inside twice point is considered inside.
for poly_nonzero in vec![poly_clockwise_nonzero, poly_counter_clockwise_nonzero].iter() {
assert_eq!(polygon_contains_point(&p_inside_once, &rect, &poly_nonzero), true);
assert_eq!(polygon_contains_point(&p_inside_twice, &rect, &poly_nonzero), true);
assert_eq!(polygon_contains_point(&p_outside, &rect, &poly_nonzero), false);
}
// For evenodd polygons, the inside twice point is considered outside.
for poly_evenodd in vec![poly_clockwise_evenodd, poly_counter_clockwise_evenodd].iter() {
assert_eq!(polygon_contains_point(&p_inside_once, &rect, &poly_evenodd), true);
assert_eq!(polygon_contains_point(&p_inside_twice, &rect, &poly_evenodd), false);
assert_eq!(polygon_contains_point(&p_outside, &rect, &poly_evenodd), false);
}
}
}
pub trait MaxRect {
fn max_rect() -> Self;
}
impl MaxRect for DeviceIntRect {
fn max_rect() -> Self {
DeviceIntRect::from_origin_and_size(
DeviceIntPoint::new(i32::MIN / 2, i32::MIN / 2),
DeviceIntSize::new(i32::MAX, i32::MAX),
)
}
}
impl<U> MaxRect for Rect<f32, U> {
fn max_rect() -> Self {
// Having an unlimited bounding box is fine up until we try
// to cast it to `i32`, where we get `-2147483648` for any
// values larger than or equal to 2^31.
//
// Note: clamping to i32::MIN and i32::MAX is not a solution,
// with explanation left as an exercise for the reader.
const MAX_COORD: f32 = 1.0e9;
Rect::new(
Point2D::new(-MAX_COORD, -MAX_COORD),
Size2D::new(2.0 * MAX_COORD, 2.0 * MAX_COORD),
)
}
}
impl<U> MaxRect for Box2D<f32, U> {
fn max_rect() -> Self {
// Having an unlimited bounding box is fine up until we try
// to cast it to `i32`, where we get `-2147483648` for any
// values larger than or equal to 2^31.
//
// Note: clamping to i32::MIN and i32::MAX is not a solution,
// with explanation left as an exercise for the reader.
const MAX_COORD: f32 = 1.0e9;
Box2D::new(
Point2D::new(-MAX_COORD, -MAX_COORD),
Point2D::new(MAX_COORD, MAX_COORD),
)
}
}
/// An enum that tries to avoid expensive transformation matrix calculations
/// when possible when dealing with non-perspective axis-aligned transformations.
#[derive(Debug, MallocSizeOf)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum FastTransform<Src, Dst> {
/// A simple offset, which can be used without doing any matrix math.
Offset(Vector2D<f32, Src>),
/// A 2D transformation with an inverse.
Transform {
transform: Transform3D<f32, Src, Dst>,
inverse: Option<Transform3D<f32, Dst, Src>>,
is_2d: bool,
},
}
impl<Src, Dst> Clone for FastTransform<Src, Dst> {
fn clone(&self) -> Self {
*self
}
}
impl<Src, Dst> Copy for FastTransform<Src, Dst> { }
impl<Src, Dst> FastTransform<Src, Dst> {
pub fn identity() -> Self {
FastTransform::Offset(Vector2D::zero())
}
pub fn with_vector(offset: Vector2D<f32, Src>) -> Self {
FastTransform::Offset(offset)
}
pub fn with_scale_offset(scale_offset: ScaleOffset) -> Self {
if scale_offset.scale == Vector2D::new(1.0, 1.0) {
FastTransform::Offset(Vector2D::from_untyped(scale_offset.offset))
} else {
FastTransform::Transform {
transform: scale_offset.to_transform(),
inverse: Some(scale_offset.inverse().to_transform()),
is_2d: true,
}
}
}
#[inline(always)]
pub fn with_transform(transform: Transform3D<f32, Src, Dst>) -> Self {
if transform.is_simple_2d_translation() {
return FastTransform::Offset(Vector2D::new(transform.m41, transform.m42));
}
let inverse = transform.inverse();
let is_2d = transform.is_2d();
FastTransform::Transform { transform, inverse, is_2d}
}
pub fn to_transform(&self) -> Cow<Transform3D<f32, Src, Dst>> {
match *self {
FastTransform::Offset(offset) => Cow::Owned(
Transform3D::translation(offset.x, offset.y, 0.0)
),
FastTransform::Transform { ref transform, .. } => Cow::Borrowed(transform),
}
}
/// Return true if this is an identity transform
#[allow(unused)]
pub fn is_identity(&self)-> bool {
match *self {
FastTransform::Offset(offset) => {
offset == Vector2D::zero()
}
FastTransform::Transform { ref transform, .. } => {
*transform == Transform3D::identity()
}
}
}
pub fn then<NewDst>(&self, other: &FastTransform<Dst, NewDst>) -> FastTransform<Src, NewDst> {
match *self {
FastTransform::Offset(offset) => match *other {
FastTransform::Offset(other_offset) => {
FastTransform::Offset(offset + other_offset * Scale::<_, _, Src>::new(1.0))
}
FastTransform::Transform { transform: ref other_transform, .. } => {
FastTransform::with_transform(
other_transform
.with_source::<Src>()
.pre_translate(offset.to_3d())
)
}
}
FastTransform::Transform { ref transform, ref inverse, is_2d } => match *other {
FastTransform::Offset(other_offset) => {
FastTransform::with_transform(
transform
.then_translate(other_offset.to_3d())
.with_destination::<NewDst>()
)
}
FastTransform::Transform { transform: ref other_transform, inverse: ref other_inverse, is_2d: other_is_2d } => {
FastTransform::Transform {
transform: transform.then(other_transform),
inverse: inverse.as_ref().and_then(|self_inv|
other_inverse.as_ref().map(|other_inv| other_inv.then(self_inv))
),
is_2d: is_2d & other_is_2d,
}
}
}
}
}
pub fn pre_transform<NewSrc>(
&self,
other: &FastTransform<NewSrc, Src>
) -> FastTransform<NewSrc, Dst> {
other.then(self)
}
pub fn pre_translate(&self, other_offset: Vector2D<f32, Src>) -> Self {
match *self {
FastTransform::Offset(offset) =>
FastTransform::Offset(offset + other_offset),
FastTransform::Transform { transform, .. } =>
FastTransform::with_transform(transform.pre_translate(other_offset.to_3d()))
}
}
pub fn then_translate(&self, other_offset: Vector2D<f32, Dst>) -> Self {
match *self {
FastTransform::Offset(offset) => {
FastTransform::Offset(offset + other_offset * Scale::<_, _, Src>::new(1.0))
}
FastTransform::Transform { ref transform, .. } => {
let transform = transform.then_translate(other_offset.to_3d());
FastTransform::with_transform(transform)
}
}
}
#[inline(always)]
pub fn is_backface_visible(&self) -> bool {
match *self {
FastTransform::Offset(..) => false,
FastTransform::Transform { inverse: None, .. } => false,
//TODO: fix this properly by taking "det|M33| * det|M34| > 0"
FastTransform::Transform { inverse: Some(ref inverse), .. } => inverse.m33 < 0.0,
}
}
#[inline(always)]
pub fn transform_point2d(&self, point: Point2D<f32, Src>) -> Option<Point2D<f32, Dst>> {
match *self {
FastTransform::Offset(offset) => {
let new_point = point + offset;
Some(Point2D::from_untyped(new_point.to_untyped()))
}
FastTransform::Transform { ref transform, .. } => transform.transform_point2d(point),
}
}
#[inline(always)]
pub fn project_point2d(&self, point: Point2D<f32, Src>) -> Option<Point2D<f32, Dst>> {
match* self {
FastTransform::Offset(..) => self.transform_point2d(point),
FastTransform::Transform{ref transform, ..} => {
// Find a value for z that will transform to 0.
// The transformed value of z is computed as:
// z' = point.x * self.m13 + point.y * self.m23 + z * self.m33 + self.m43
// Solving for z when z' = 0 gives us:
let z = -(point.x * transform.m13 + point.y * transform.m23 + transform.m43) / transform.m33;
transform.transform_point3d(point3(point.x, point.y, z)).map(| p3 | point2(p3.x, p3.y))
}
}
}
#[inline(always)]
pub fn inverse(&self) -> Option<FastTransform<Dst, Src>> {
match *self {
FastTransform::Offset(offset) =>
Some(FastTransform::Offset(Vector2D::new(-offset.x, -offset.y))),
FastTransform::Transform { transform, inverse: Some(inverse), is_2d, } =>
Some(FastTransform::Transform {
transform: inverse,
inverse: Some(transform),
is_2d
}),
FastTransform::Transform { inverse: None, .. } => None,
}
}
}
impl<Src, Dst> From<Transform3D<f32, Src, Dst>> for FastTransform<Src, Dst> {
fn from(transform: Transform3D<f32, Src, Dst>) -> Self {
FastTransform::with_transform(transform)
}
}
impl<Src, Dst> From<Vector2D<f32, Src>> for FastTransform<Src, Dst> {
fn from(vector: Vector2D<f32, Src>) -> Self {
FastTransform::with_vector(vector)
}
}
pub type LayoutFastTransform = FastTransform<LayoutPixel, LayoutPixel>;
pub type LayoutToWorldFastTransform = FastTransform<LayoutPixel, WorldPixel>;
pub fn project_rect<F, T>(
transform: &Transform3D<f32, F, T>,
rect: &Box2D<f32, F>,
bounds: &Box2D<f32, T>,
) -> Option<Box2D<f32, T>>
where F: fmt::Debug
{
let homogens = [
transform.transform_point2d_homogeneous(rect.top_left()),
transform.transform_point2d_homogeneous(rect.top_right()),
transform.transform_point2d_homogeneous(rect.bottom_left()),
transform.transform_point2d_homogeneous(rect.bottom_right()),
];
// Note: we only do the full frustum collision when the polygon approaches the camera plane.
// Otherwise, it will be clamped to the screen bounds anyway.
if homogens.iter().any(|h| h.w <= 0.0 || h.w.is_nan()) {
let mut clipper = Clipper::new();
let polygon = Polygon::from_rect(rect.to_rect().cast().cast_unit(), 1);
let planes = match Clipper::<usize>::frustum_planes(
&transform.cast_unit().cast(),
Some(bounds.to_rect().cast_unit().to_f64()),
) {
Ok(planes) => planes,
Err(..) => return None,
};
for plane in planes {
clipper.add(plane);
}
let results = clipper.clip(polygon);
if results.is_empty() {
return None
}
Some(Box2D::from_points(results
.into_iter()
// filter out parts behind the view plane
.flat_map(|poly| &poly.points)
.map(|p| {
let mut homo = transform.transform_point2d_homogeneous(p.to_2d().to_f32().cast_unit());
homo.w = homo.w.max(0.00000001); // avoid infinite values
homo.to_point2d().unwrap()
})
))
} else {
// we just checked for all the points to be in positive hemisphere, so `unwrap` is valid
Some(Box2D::from_points(&[
homogens[0].to_point2d().unwrap(),
homogens[1].to_point2d().unwrap(),
homogens[2].to_point2d().unwrap(),
homogens[3].to_point2d().unwrap(),
]))
}
}
/// Run the first callback over all elements in the array. If the callback returns true,
/// the element is removed from the array and moved to a second callback.
///
/// This is a simple implementation waiting for Vec::drain_filter to be stable.
/// When that happens, code like:
///
/// let filter = |op| {
/// match *op {
/// Enum::Foo | Enum::Bar => true,
/// Enum::Baz => false,
/// }
/// };
/// drain_filter(
/// &mut ops,
/// filter,
/// |op| {
/// match op {
/// Enum::Foo => { foo(); }
/// Enum::Bar => { bar(); }
/// Enum::Baz => { unreachable!(); }
/// }
/// },
/// );
///
/// Can be rewritten as:
///
/// let filter = |op| {
/// match *op {
/// Enum::Foo | Enum::Bar => true,
/// Enum::Baz => false,
/// }
/// };
/// for op in ops.drain_filter(filter) {
/// match op {
/// Enum::Foo => { foo(); }
/// Enum::Bar => { bar(); }
/// Enum::Baz => { unreachable!(); }
/// }
/// }
///
pub fn drain_filter<T, Filter, Action>(
vec: &mut Vec<T>,
mut filter: Filter,
mut action: Action,
)
where
Filter: FnMut(&mut T) -> bool,
Action: FnMut(T)
{
let mut i = 0;
while i != vec.len() {
if filter(&mut vec[i]) {
action(vec.remove(i));
} else {
i += 1;
}
}
}
#[derive(Debug)]
pub struct Recycler {
pub num_allocations: usize,
}
impl Recycler {
/// Maximum extra capacity that a recycled vector is allowed to have. If the actual capacity
/// is larger, we re-allocate the vector storage with lower capacity.
const MAX_EXTRA_CAPACITY_PERCENT: usize = 200;
/// Minimum extra capacity to keep when re-allocating the vector storage.
const MIN_EXTRA_CAPACITY_PERCENT: usize = 20;
/// Minimum sensible vector length to consider for re-allocation.
const MIN_VECTOR_LENGTH: usize = 16;
pub fn new() -> Self {
Recycler {
num_allocations: 0,
}
}
/// Clear a vector for re-use, while retaining the backing memory buffer. May shrink the buffer
/// if it's currently much larger than was actually used.
pub fn recycle_vec<T>(&mut self, vec: &mut Vec<T>) {
let extra_capacity = (vec.capacity() - vec.len()) * 100 / vec.len().max(Self::MIN_VECTOR_LENGTH);
if extra_capacity > Self::MAX_EXTRA_CAPACITY_PERCENT {
// Reduce capacity of the buffer if it is a lot larger than it needs to be. This prevents
// a frame with exceptionally large allocations to cause subsequent frames to retain
// more memory than they need.
//TODO: use `shrink_to` when it's stable
*vec = Vec::with_capacity(vec.len() + vec.len() * Self::MIN_EXTRA_CAPACITY_PERCENT / 100);
self.num_allocations += 1;
} else {
vec.clear();
}
}
}
/// Record the size of a data structure to preallocate a similar size
/// at the next frame and avoid growing it too many time.
#[derive(Copy, Clone, Debug)]
pub struct Preallocator {
size: usize,
}
impl Preallocator {
pub fn new(initial_size: usize) -> Self {
Preallocator {
size: initial_size,
}
}
/// Record the size of a vector to preallocate it the next frame.
pub fn record_vec<T>(&mut self, vec: &Vec<T>) {
let len = vec.len();
if len > self.size {
self.size = len;
} else {
self.size = (self.size + len) / 2;
}
}
/// The size that we'll preallocate the vector with.
pub fn preallocation_size(&self) -> usize {
// Round up to multiple of 16 to avoid small tiny
// variations causing reallocations.
(self.size + 15) & !15
}
/// Preallocate vector storage.
///
/// The preallocated amount depends on the length recorded in the last
/// record_vec call.
pub fn preallocate_vec<T>(&self, vec: &mut Vec<T>) {
let len = vec.len();
let cap = self.preallocation_size();
if len < cap {
vec.reserve(cap - len);
}
}
}
impl Default for Preallocator {
fn default() -> Self {
Self::new(0)
}
}
/// Arc wrapper to support measurement via MallocSizeOf.
///
/// Memory reporting for Arcs is tricky because of the risk of double-counting.
/// One way to measure them is to keep a table of pointers that have already been
/// traversed. The other way is to use knowledge of the program structure to
/// identify which Arc instances should be measured and which should be skipped to
/// avoid double-counting.
///
/// This struct implements the second approach. It identifies the "main" pointer
/// to the Arc-ed resource, and measures the buffer as if it were an owned pointer.
/// The programmer should ensure that there is at most one PrimaryArc for a given
/// underlying ArcInner.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub struct PrimaryArc<T>(pub Arc<T>);
impl<T> ::std::ops::Deref for PrimaryArc<T> {
type Target = Arc<T>;
#[inline]
fn deref(&self) -> &Arc<T> {
&self.0
}
}
impl<T> MallocShallowSizeOf for PrimaryArc<T> {
fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
unsafe {
// This is a bit sketchy, but std::sync::Arc doesn't expose the
// base pointer.
let raw_arc_ptr: *const Arc<T> = &self.0;
let raw_ptr_ptr: *const *const c_void = raw_arc_ptr as _;
let raw_ptr = *raw_ptr_ptr;
(ops.size_of_op)(raw_ptr)
}
}
}
impl<T: MallocSizeOf> MallocSizeOf for PrimaryArc<T> {
fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
self.shallow_size_of(ops) + (**self).size_of(ops)
}
}
/// Computes the scale factors of this matrix; that is,
/// the amounts each basis vector is scaled by.
///
/// This code comes from gecko gfx/2d/Matrix.h with the following
/// modifications:
///
/// * Removed `xMajor` parameter.
/// * All arithmetics is done with double precision.
pub fn scale_factors<Src, Dst>(
mat: &Transform3D<f32, Src, Dst>
) -> (f32, f32) {
let m11 = mat.m11 as f64;
let m12 = mat.m12 as f64;
// Determinant is just of the 2D component.
let det = m11 * mat.m22 as f64 - m12 * mat.m21 as f64;
if det == 0.0 {
return (0.0, 0.0);
}
// ignore mirroring
let det = det.abs();
let major = (m11 * m11 + m12 * m12).sqrt();
let minor = if major != 0.0 { det / major } else { 0.0 };
(major as f32, minor as f32)
}
#[test]
fn scale_factors_large() {
let mat = Transform3D::<f32, (), ()>::new(
1.6534229920333123e27, 3.673100922561787e27, 0.0, 0.0,
-3.673100922561787e27, 1.6534229920333123e27, 0.0, 0.0,
0.0, 0.0, 1.0, 0.0,
-828140552192.0, -1771307401216.0, 0.0, 1.0,
);
let (major, minor) = scale_factors(&mat);
assert!(major.is_normal() && minor.is_normal());
}
/// Clamp scaling factor to a power of two.
///
/// This code comes from gecko gfx/thebes/gfxUtils.cpp with the following
/// modification:
///
/// * logs are taken in base 2 instead of base e.
pub fn clamp_to_scale_factor(val: f32, round_down: bool) -> f32 {
// Arbitary scale factor limitation. We can increase this
// for better scaling performance at the cost of worse
// quality.
const SCALE_RESOLUTION: f32 = 2.0;
// Negative scaling is just a flip and irrelevant to
// our resolution calculation.
let val = val.abs();
let (val, inverse) = if val < 1.0 {
(1.0 / val, true)
} else {
(val, false)
};
let power = val.log2() / SCALE_RESOLUTION.log2();
// If power is within 1e-5 of an integer, round to nearest to
// prevent floating point errors, otherwise round up to the
// next integer value.
let power = if (power - power.round()).abs() < 1e-5 {
power.round()
} else if inverse != round_down {
// Use floor when we are either inverted or rounding down, but
// not both.
power.floor()
} else {
// Otherwise, ceil when we are not inverted and not rounding
// down, or we are inverted and rounding down.
power.ceil()
};
let scale = SCALE_RESOLUTION.powf(power);
if inverse {
1.0 / scale
} else {
scale
}
}
/// Rounds a value up to the nearest multiple of mul
pub fn round_up_to_multiple(val: usize, mul: NonZeroUsize) -> usize {
match val % mul.get() {
0 => val,
rem => val - rem + mul.get(),
}
}
#[macro_export]
macro_rules! c_str {
($lit:expr) => {
unsafe {
std::ffi::CStr::from_ptr(concat!($lit, "\0").as_ptr()
as *const std::os::raw::c_char)
}
}
}
/// This is inspired by the `weak-table` crate.
/// It holds a Vec of weak pointers that are garbage collected as the Vec
pub struct WeakTable {
inner: Vec<std::sync::Weak<Vec<u8>>>
}
impl WeakTable {
pub fn new() -> WeakTable {
WeakTable { inner: Vec::new() }
}
pub fn insert(&mut self, x: std::sync::Weak<Vec<u8>>) {
if self.inner.len() == self.inner.capacity() {
self.remove_expired();
// We want to make sure that we change capacity()
// even if remove_expired() removes some entries
// so that we don't repeatedly hit remove_expired()
if self.inner.len() * 3 < self.inner.capacity() {
// We use a different multiple for shrinking then
// expanding so that we we don't accidentally
// oscilate.
self.inner.shrink_to_fit();
} else {
// Otherwise double our size
self.inner.reserve(self.inner.len())
}
}
self.inner.push(x);
}
fn remove_expired(&mut self) {
self.inner.retain(|x| x.strong_count() > 0)
}
pub fn iter(&self) -> impl Iterator<Item = Arc<Vec<u8>>> + '_ {
self.inner.iter().filter_map(|x| x.upgrade())
}
}
#[test]
fn weak_table() {
let mut tbl = WeakTable::new();
let mut things = Vec::new();
let target_count = 50;
for _ in 0..target_count {
things.push(Arc::new(vec![4]));
}
for i in &things {
tbl.insert(Arc::downgrade(i))
}
assert_eq!(tbl.inner.len(), target_count);
drop(things);
assert_eq!(tbl.iter().count(), 0);
// make sure that we shrink the table if it gets too big
// by adding a bunch of dead items
for _ in 0..target_count*2 {
tbl.insert(Arc::downgrade(&Arc::new(vec![5])))
}
assert!(tbl.inner.capacity() <= 4);
}