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//! Mask generator.
use super::geometry::{Origin, Placement, Transform, Vector};
use super::path_data::{apply, PathData};
use super::scratch::Scratch;
use super::style::{Fill, Style};
use crate::lib::Vec;
use core::cell::RefCell;
/// The desired output image format for rendering.
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum Format {
/// 8-bit alpha mask.
Alpha,
/// 32-bit RGBA subpixel mask with 1/3 pixel offsets for the red and
/// blue channels.
Subpixel,
/// 32-bit RGBA subpixel mask with custom offsets.
CustomSubpixel([f32; 3]),
}
impl Format {
/// Creates a format for BGRA subpixel rendering.
pub fn subpixel_bgra() -> Self {
Self::CustomSubpixel([0.3, 0., -0.3])
}
/// Returns the necessary buffer size to hold an image of the specified
/// width and height with this format.
pub fn buffer_size(self, width: u32, height: u32) -> usize {
(width
* height
* match self {
Self::Alpha => 1,
_ => 4,
}) as usize
}
}
impl Default for Format {
fn default() -> Self {
Self::Alpha
}
}
/// Builder for configuring and rendering a mask.
pub struct Mask<'a, 's, D> {
data: D,
style: Style<'a>,
transform: Option<Transform>,
format: Format,
origin: Origin,
offset: Vector,
render_offset: Vector,
width: u32,
height: u32,
explicit_size: bool,
has_size: bool,
bounds_offset: Vector,
scratch: RefCell<Option<&'s mut Scratch>>,
}
impl<'a, 's, D> Mask<'a, 's, D>
where
D: PathData,
{
/// Creates a new mask builder for the specified path data.
pub fn new(data: D) -> Self {
Self {
data,
style: Style::Fill(Fill::NonZero),
transform: None,
format: Format::Alpha,
origin: Origin::TopLeft,
offset: Vector::ZERO,
render_offset: Vector::ZERO,
width: 0,
height: 0,
explicit_size: false,
has_size: false,
bounds_offset: Vector::ZERO,
scratch: RefCell::new(None),
}
}
/// Creates a new mask builder for the specified path data and scratch memory.
pub fn with_scratch(data: D, scratch: &'s mut Scratch) -> Self {
Self {
data,
style: Style::Fill(Fill::NonZero),
transform: None,
format: Format::Alpha,
origin: Origin::TopLeft,
offset: Vector::ZERO,
render_offset: Vector::ZERO,
width: 0,
height: 0,
explicit_size: false,
has_size: false,
bounds_offset: Vector::ZERO,
scratch: RefCell::new(Some(scratch)),
}
}
/// Sets the style of the path. The default is a non-zero fill.
pub fn style(&mut self, style: impl Into<Style<'a>>) -> &mut Self {
self.style = style.into();
self
}
/// Sets the transformation matrix of the path.
pub fn transform(&mut self, transform: Option<Transform>) -> &mut Self {
self.transform = transform;
self
}
/// Sets the desired format of the mask. The default value is an 8-bit
/// alpha format.
pub fn format(&mut self, format: Format) -> &mut Self {
self.format = format;
self
}
/// Sets the origin that defines the coordinate system for the mask.
pub fn origin(&mut self, origin: Origin) -> &mut Self {
self.origin = origin;
self
}
/// Sets the offset for the path.
pub fn offset(&mut self, offset: impl Into<Vector>) -> &mut Self {
self.offset = offset.into();
self
}
/// Sets an explicit size for the mask. If left unspecified, the size will
/// be computed from the bounding box of the path after applying any
/// relevant style, offset and transform.
pub fn size(&mut self, width: u32, height: u32) -> &mut Self {
self.width = width;
self.height = height;
self.explicit_size = true;
self.has_size = true;
self
}
/// Sets an additional rendering offset for the mask. This offset does not
/// affect bounds or size computations and is only applied during
/// rendering.
pub fn render_offset(&mut self, offset: impl Into<Vector>) -> &mut Self {
self.render_offset = offset.into();
self
}
/// Invokes a closure with the format, width and height of the mask provided
/// as arguments. This is primarily useful for preparing a target buffer without
/// interrupting the call chain.
pub fn inspect(&mut self, mut f: impl FnMut(Format, u32, u32)) -> &mut Self {
self.ensure_size();
f(self.format, self.width, self.height);
self
}
/// Renders the mask into a byte buffer. If specified, the pitch describes
/// the number of bytes between subsequent rows of the target buffer. This
/// is primarily useful for rendering into tiled images such as texture
/// atlases. If left unspecified, the buffer is assumed to be linear and
/// tightly packed.
pub fn render_into(&self, buffer: &mut [u8], pitch: Option<usize>) -> Placement {
let (offset, placement) = self.placement();
let pitch = match pitch {
Some(pitch) => pitch,
_ => {
placement.width as usize
* match self.format {
Format::Alpha => 1,
_ => 4,
}
}
};
render(self, offset, &placement, buffer, pitch);
placement
}
/// Renders the mask to a newly allocated buffer.
pub fn render(&self) -> (Vec<u8>, Placement) {
let mut buf = Vec::new();
let (offset, placement) = self.placement();
buf.resize(
self.format.buffer_size(placement.width, placement.height),
0,
);
let pitch = placement.width as usize
* match self.format {
Format::Alpha => 1,
_ => 4,
};
render(self, offset, &placement, &mut buf, pitch);
(buf, placement)
}
fn ensure_size(&mut self) {
if self.has_size {
return;
}
let (offset, placement) = self.placement();
self.bounds_offset = offset;
self.width = placement.width;
self.height = placement.height;
self.explicit_size = false;
self.has_size = true;
}
fn placement(&self) -> (Vector, Placement) {
let mut placement = Placement {
left: 0,
top: 0,
width: self.width,
height: self.height,
};
let mut offset = self.offset;
if self.explicit_size {
return (offset, placement);
} else if !self.has_size {
let mut scratch = self.scratch.borrow_mut();
let mut bounds = if let Some(scratch) = scratch.as_mut() {
scratch.bounds(&self.data, self.style, self.transform)
} else {
super::bounds(&self.data, self.style, self.transform)
};
bounds.min = (bounds.min + self.offset).floor();
bounds.max = (bounds.max + self.offset).ceil();
offset = Vector::new(-bounds.min.x + 1., -bounds.min.y);
placement.width = bounds.width() as u32 + 2;
placement.height = bounds.height() as u32;
} else {
offset = self.bounds_offset;
}
placement.left = -offset.x as i32;
placement.top = if self.origin == Origin::BottomLeft {
(-offset.y).floor() + self.height as f32
} else {
-offset.y
} as i32;
(offset, placement)
}
}
pub fn render<'a, 'c, D>(
mask: &'a Mask<'a, 'c, D>,
offset: Vector,
placement: &Placement,
buf: &mut [u8],
pitch: usize,
) where
D: PathData,
{
let y_up = mask.origin == Origin::BottomLeft;
let (is_subpx, subpx) = match mask.format {
Format::Alpha => (false, [Vector::ZERO; 3]),
Format::Subpixel => (
true,
[Vector::new(-0.3, 0.), Vector::ZERO, Vector::new(0.3, 0.)],
),
Format::CustomSubpixel(subpx) => (
true,
[
Vector::new(subpx[0], 0.),
Vector::new(subpx[1], 0.),
Vector::new(subpx[2], 0.),
],
),
};
let fill = match mask.style {
Style::Fill(fill) => fill,
_ => Fill::NonZero,
};
let w = placement.width;
let h = placement.height;
let shift = offset + mask.render_offset;
let data = &mask.data;
let style = mask.style;
let transform = mask.transform;
let mut scratch = mask.scratch.borrow_mut();
use super::raster::{AdaptiveStorage, Rasterizer};
if let Some(scratch) = scratch.as_mut() {
let mut ras = Rasterizer::new(&mut scratch.render);
let inner = &mut scratch.inner;
if is_subpx {
ras.rasterize_write(
shift + subpx[0],
w,
h,
&mut |r| {
inner.apply(data.clone(), &style, transform, r);
},
fill,
pitch,
y_up,
&mut |row_offset, x, count, coverage| {
let buf = &mut buf[row_offset..];
let mut i = 0;
let mut j = x * 4;
while i < count {
buf[j] = coverage;
i += 1;
j += 4;
}
},
);
ras.rasterize_write(
shift + subpx[1],
w,
h,
&mut |r| {
inner.apply(data, &style, transform, r);
},
fill,
pitch,
y_up,
&mut |row_offset, x, count, coverage| {
let buf = &mut buf[row_offset..];
let mut i = 0;
let mut j = x * 4 + 1;
while i < count {
buf[j] = coverage;
i += 1;
j += 4;
}
},
);
ras.rasterize_write(
shift + subpx[2],
w,
h,
&mut |r| {
inner.apply(data, &style, transform, r);
},
fill,
pitch,
y_up,
&mut |row_offset, x, count, coverage| {
let buf = &mut buf[row_offset..];
let mut i = 0;
let mut j = x * 4 + 2;
while i < count {
buf[j] = coverage;
i += 1;
j += 4;
}
},
);
} else {
ras.rasterize(
shift,
w,
h,
&mut |r| {
inner.apply(data, &style, transform, r);
},
fill,
buf,
pitch,
y_up,
);
}
} else {
let mut storage = AdaptiveStorage::new();
let mut ras = Rasterizer::new(&mut storage);
if is_subpx {
ras.rasterize_write(
shift + subpx[0],
w,
h,
&mut |r| {
apply(data, style, transform, r);
},
fill,
pitch,
y_up,
&mut |row_offset, x, count, coverage| {
let buf = &mut buf[row_offset..];
let mut i = 0;
let mut j = x * 4;
while i < count {
buf[j] = coverage;
i += 1;
j += 4;
}
},
);
ras.rasterize_write(
shift + subpx[1],
w,
h,
&mut |r| {
apply(data, style, transform, r);
},
fill,
pitch,
y_up,
&mut |row_offset, x, count, coverage| {
let buf = &mut buf[row_offset..];
let mut i = 0;
let mut j = x * 4 + 1;
while i < count {
buf[j] = coverage;
i += 1;
j += 4;
}
},
);
ras.rasterize_write(
shift + subpx[2],
w,
h,
&mut |r| {
apply(data, style, transform, r);
},
fill,
pitch,
y_up,
&mut |row_offset, x, count, coverage| {
let buf = &mut buf[row_offset..];
let mut i = 0;
let mut j = x * 4 + 2;
while i < count {
buf[j] = coverage;
i += 1;
j += 4;
}
},
);
} else {
ras.rasterize(
shift,
w,
h,
&mut |r| {
apply(data, style, transform, r);
},
fill,
buf,
pitch,
y_up,
);
}
}
}