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// Copyright 2006 The Android Open Source Project
// Copyright 2020 Yevhenii Reizner
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
mod gradient;
mod linear_gradient;
mod pattern;
mod radial_gradient;
use tiny_skia_path::{NormalizedF32, Scalar};
pub use gradient::GradientStop;
pub use linear_gradient::LinearGradient;
pub use pattern::{FilterQuality, Pattern, PixmapPaint};
pub use radial_gradient::RadialGradient;
use crate::{Color, Transform};
use crate::pipeline::RasterPipelineBuilder;
/// A shader spreading mode.
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum SpreadMode {
/// Replicate the edge color if the shader draws outside of its
/// original bounds.
Pad,
/// Repeat the shader's image horizontally and vertically, alternating
/// mirror images so that adjacent images always seam.
Reflect,
/// Repeat the shader's image horizontally and vertically.
Repeat,
}
impl Default for SpreadMode {
fn default() -> Self {
SpreadMode::Pad
}
}
/// A shader specifies the source color(s) for what is being drawn.
///
/// If a paint has no shader, then the paint's color is used. If the paint has a
/// shader, then the shader's color(s) are use instead, but they are
/// modulated by the paint's alpha. This makes it easy to create a shader
/// once (e.g. bitmap tiling or gradient) and then change its transparency
/// without having to modify the original shader. Only the paint's alpha needs
/// to be modified.
#[derive(Clone, PartialEq, Debug)]
pub enum Shader<'a> {
/// A solid color shader.
SolidColor(Color),
/// A linear gradient shader.
LinearGradient(LinearGradient),
/// A radial gradient shader.
RadialGradient(RadialGradient),
/// A pattern shader.
Pattern(Pattern<'a>),
}
impl<'a> Shader<'a> {
/// Checks if the shader is guaranteed to produce only opaque colors.
pub fn is_opaque(&self) -> bool {
match self {
Shader::SolidColor(ref c) => c.is_opaque(),
Shader::LinearGradient(ref g) => g.is_opaque(),
Shader::RadialGradient(_) => false,
Shader::Pattern(_) => false,
}
}
// Unlike Skia, we do not have is_constant, because we don't have Color shaders.
/// If this returns false, then we draw nothing (do not fall back to shader context)
#[must_use]
pub(crate) fn push_stages(&self, p: &mut RasterPipelineBuilder) -> bool {
match self {
Shader::SolidColor(color) => {
p.push_uniform_color(color.premultiply());
true
}
Shader::LinearGradient(ref g) => g.push_stages(p),
Shader::RadialGradient(ref g) => g.push_stages(p),
Shader::Pattern(ref patt) => patt.push_stages(p),
}
}
/// Transforms the shader.
pub fn transform(&mut self, ts: Transform) {
match self {
Shader::SolidColor(_) => {}
Shader::LinearGradient(g) => {
g.base.transform = g.base.transform.post_concat(ts);
}
Shader::RadialGradient(g) => {
g.base.transform = g.base.transform.post_concat(ts);
}
Shader::Pattern(p) => {
p.transform = p.transform.post_concat(ts);
}
}
}
/// Shifts shader's opacity.
///
/// `opacity` will be clamped to the 0..=1 range.
///
/// This is roughly the same as Skia's `SkPaint::setAlpha`.
///
/// Unlike Skia, we do not support global alpha/opacity, which is in Skia
/// is set via the alpha channel of the `SkPaint::fColor4f`.
/// Instead, you can shift the opacity of the shader to whatever value you need.
///
/// - For `SolidColor` this function will multiply `color.alpha` by `opacity`.
/// - For gradients this function will multiply all colors by `opacity`.
/// - For `Pattern` this function will multiply `Patter::opacity` by `opacity`.
pub fn apply_opacity(&mut self, opacity: f32) {
match self {
Shader::SolidColor(ref mut c) => {
c.apply_opacity(opacity);
}
Shader::LinearGradient(g) => {
g.base.apply_opacity(opacity);
}
Shader::RadialGradient(g) => {
g.base.apply_opacity(opacity);
}
Shader::Pattern(ref mut p) => {
p.opacity = NormalizedF32::new(p.opacity.get() * opacity.bound(0.0, 1.0)).unwrap();
}
}
}
}