71 lines
2.0 KiB
Rust
71 lines
2.0 KiB
Rust
use super::{Color32, Margin, Rect, RectShape, Rounding, Vec2};
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/// The color and fuzziness of a fuzzy shape.
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///
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/// Can be used for a rectangular shadow with a soft penumbra.
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///
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/// Very similar to a box-shadow in CSS.
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#[derive(Clone, Copy, Debug, Default, PartialEq)]
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#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
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pub struct Shadow {
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/// Move the shadow by this much.
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///
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/// For instance, a value of `[1.0, 2.0]` will move the shadow 1 point to the right and 2 points down,
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/// causing a drop-shadow effect.
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pub offset: Vec2,
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/// The width of the blur, i.e. the width of the fuzzy penumbra.
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///
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/// A value of 0.0 means a sharp shadow.
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pub blur: f32,
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/// Expand the shadow in all directions by this much.
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pub spread: f32,
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/// Color of the opaque center of the shadow.
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pub color: Color32,
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}
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impl Shadow {
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/// No shadow at all.
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pub const NONE: Self = Self {
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offset: Vec2::ZERO,
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blur: 0.0,
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spread: 0.0,
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color: Color32::TRANSPARENT,
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};
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/// The argument is the rectangle of the shadow caster.
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pub fn as_shape(&self, rect: Rect, rounding: impl Into<Rounding>) -> RectShape {
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// tessellator.clip_rect = clip_rect; // TODO(emilk): culling
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let Self {
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offset,
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blur,
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spread,
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color,
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} = *self;
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let rect = rect.translate(offset).expand(spread);
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let rounding = rounding.into() + Rounding::same(spread.abs());
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RectShape::filled(rect, rounding, color).with_blur_width(blur)
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}
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/// How much larger than the parent rect are we in each direction?
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pub fn margin(&self) -> Margin {
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let Self {
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offset,
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blur,
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spread,
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color: _,
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} = *self;
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Margin {
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left: spread + 0.5 * blur - offset.x,
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right: spread + 0.5 * blur + offset.x,
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top: spread + 0.5 * blur - offset.y,
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bottom: spread + 0.5 * blur + offset.y,
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}
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}
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}
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