Refactor: put each shape into its own file (#5564)

Much easier to navigate the code

crates/epaint/src/shapes/rect_shape.rs

@@ -0,0 +1,125 @@
+use crate::*;
+
+/// How to paint a rectangle.
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+pub struct RectShape {
+    pub rect: Rect,
+
+    /// How rounded the corners are. Use `Rounding::ZERO` for no rounding.
+    pub rounding: Rounding,
+
+    /// How to fill the rectangle.
+    pub fill: Color32,
+
+    /// The thickness and color of the outline.
+    ///
+    /// The stroke extends _outside_ the edge of [`Self::rect`],
+    /// i.e. using [`crate::StrokeKind::Outside`].
+    ///
+    /// This means the [`Self::visual_bounding_rect`] is `rect.size() + 2.0 * stroke.width`.
+    pub stroke: Stroke,
+
+    /// If larger than zero, the edges of the rectangle
+    /// (for both fill and stroke) will be blurred.
+    ///
+    /// This can be used to produce shadows and glow effects.
+    ///
+    /// The blur is currently implemented using a simple linear blur in sRGBA gamma space.
+    pub blur_width: f32,
+
+    /// If the rect should be filled with a texture, which one?
+    ///
+    /// The texture is multiplied with [`Self::fill`].
+    pub fill_texture_id: TextureId,
+
+    /// What UV coordinates to use for the texture?
+    ///
+    /// To display a texture, set [`Self::fill_texture_id`],
+    /// and set this to `Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0))`.
+    ///
+    /// Use [`Rect::ZERO`] to turn off texturing.
+    pub uv: Rect,
+}
+
+impl RectShape {
+    /// The stroke extends _outside_ the [`Rect`].
+    #[inline]
+    pub fn new(
+        rect: Rect,
+        rounding: impl Into<Rounding>,
+        fill_color: impl Into<Color32>,
+        stroke: impl Into<Stroke>,
+    ) -> Self {
+        Self {
+            rect,
+            rounding: rounding.into(),
+            fill: fill_color.into(),
+            stroke: stroke.into(),
+            blur_width: 0.0,
+            fill_texture_id: Default::default(),
+            uv: Rect::ZERO,
+        }
+    }
+
+    #[inline]
+    pub fn filled(
+        rect: Rect,
+        rounding: impl Into<Rounding>,
+        fill_color: impl Into<Color32>,
+    ) -> Self {
+        Self {
+            rect,
+            rounding: rounding.into(),
+            fill: fill_color.into(),
+            stroke: Default::default(),
+            blur_width: 0.0,
+            fill_texture_id: Default::default(),
+            uv: Rect::ZERO,
+        }
+    }
+
+    /// The stroke extends _outside_ the [`Rect`].
+    #[inline]
+    pub fn stroke(rect: Rect, rounding: impl Into<Rounding>, stroke: impl Into<Stroke>) -> Self {
+        Self {
+            rect,
+            rounding: rounding.into(),
+            fill: Default::default(),
+            stroke: stroke.into(),
+            blur_width: 0.0,
+            fill_texture_id: Default::default(),
+            uv: Rect::ZERO,
+        }
+    }
+
+    /// If larger than zero, the edges of the rectangle
+    /// (for both fill and stroke) will be blurred.
+    ///
+    /// This can be used to produce shadows and glow effects.
+    ///
+    /// The blur is currently implemented using a simple linear blur in `sRGBA` gamma space.
+    #[inline]
+    pub fn with_blur_width(mut self, blur_width: f32) -> Self {
+        self.blur_width = blur_width;
+        self
+    }
+
+    /// The visual bounding rectangle (includes stroke width)
+    #[inline]
+    pub fn visual_bounding_rect(&self) -> Rect {
+        if self.fill == Color32::TRANSPARENT && self.stroke.is_empty() {
+            Rect::NOTHING
+        } else {
+            let Stroke { width, .. } = self.stroke; // Make sure we remember to update this if we change `stroke` to `PathStroke`
+            self.rect.expand(width + self.blur_width / 2.0)
+        }
+    }
+}
+
+impl From<RectShape> for Shape {
+    #[inline(always)]
+    fn from(shape: RectShape) -> Self {
+        Self::Rect(shape)
+    }
+}