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c530504a04
This makes `epaint::Shadow` more like CSS's box-shadow, adding `offset` and replacing `extrusion` with `blur` and `spread`. * Closes https://github.com/emilk/egui/pull/3047 The offsets make for nice drop-shadow effects. Old shadows: <img width="1447" alt="old-shadows" src="https://github.com/emilk/egui/assets/1148717/8a30f7b9-fb9d-49ea-9a2f-9367a60c448a"> New shadows: <img width="1447" alt="new-shadows-full" src="https://github.com/emilk/egui/assets/1148717/28cc9c1e-b0de-4c5b-a705-22e52c556584">
89 lines
2.6 KiB
Rust
89 lines
2.6 KiB
Rust
use super::*;
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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 effet.
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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 no blur.
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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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pub fn tessellate(&self, rect: Rect, rounding: impl Into<Rounding>) -> Mesh {
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// tessellator.clip_rect = clip_rect; // TODO(emilk): culling
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use crate::tessellator::*;
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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);
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let rounding_expansion = spread.abs() + 0.5 * blur;
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let rounding = rounding.into() + Rounding::from(rounding_expansion);
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let rect = RectShape::filled(rect.expand(spread), rounding, color);
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let pixels_per_point = 1.0; // doesn't matter here
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let font_tex_size = [1; 2]; // unused since we are not tessellating text.
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let mut tessellator = Tessellator::new(
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pixels_per_point,
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TessellationOptions {
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feathering: true,
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feathering_size_in_pixels: blur * pixels_per_point,
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..Default::default()
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},
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font_tex_size,
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vec![],
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);
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let mut mesh = Mesh::default();
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tessellator.tessellate_rect(&rect, &mut mesh);
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mesh
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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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