Corrects padding

dessin/src/contrib/padding.rs

@@ -4,13 +4,30 @@ use std::ops::{Deref, DerefMut};
 
 #[derive(Debug, Clone, PartialEq, Shape)]
 pub struct Padding<T> {
+    #[shape(into)]
     pub shape: T,
 
     pub padding_left: f32,
     pub padding_right: f32,
     pub padding_top: f32,
     pub padding_bottom: f32,
 }
+
+impl<T> Default for Padding<T>
+where
+    T: Default,
+{
+    fn default() -> Self {
+        Padding {
+            shape: T::default(),
+            padding_left: 0.,
+            padding_right: 0.,
+            padding_top: 0.,
+            padding_bottom: 0.,
+        }
+    }
+}
+
 impl<T> Padding<T> {
     /// Wrap a [`Shape`] with Padding
     #[inline]
@@ -141,3 +158,74 @@ impl<T: ShapeOp> ShapeOp for Padding<T> {
         self.shape.global_transform(parent_transform)
     }
 }
+
+// creates 2 tests to check that the code works
+#[cfg(test)]
+mod tests {
+    use crate::prelude::*;
+
+    #[test]
+    fn similar_op_1() {
+        let rectangle_1 = dessin2!(Rectangle!(width = 3., height = 2., translate = [1., 0.]));
+
+        let base_1 = dessin2!(Padding<Style<Rectangle>>(
+            shape = rectangle_1,
+            padding_left = 1.5,
+            padding_right = 1.,
+            padding_top = 0.8,
+            padding_bottom = 1.,
+        ));
+
+        let rectangle_2 = dessin2!(Rectangle!(scale = [5.5, 3.8], translate = [0.75, -0.1]));
+
+        let base_2 = dessin2!(Padding<Style<Rectangle>>(
+            shape = rectangle_2,
+            padding_left = 0.,
+            padding_right = 0.,
+            padding_top = 0.,
+            padding_bottom = 0.,
+        ));
+
+        let base_1 = Shape::from(base_1);
+        let base_2 = Shape::from(base_2);
+
+        assert_eq!(
+            base_1.local_bounding_box().straigthen(),
+            base_2.local_bounding_box().straigthen()
+        );
+    }
+
+    #[test]
+    fn similar_op_2() {
+        let test_1 = dessin2!([
+            Circle!(radius = 1., translate = [0.5, 0.]),
+            Rectangle!(width = 1., height = 0.4, translate = [2., 0.])
+        ]);
+
+        let base_1 = dessin2!(Padding<Shape>(
+            shape = test_1,
+            padding_left = 1.5,
+            padding_right = 1.,
+            padding_top = 0.8,
+            padding_bottom = 1.,
+        ));
+
+        let rectangle = dessin2!(Rectangle!(scale = [5.5, 3.8], translate = [0.75, -0.1]));
+
+        let base_2 = dessin2!(Padding<Style<Rectangle>>(
+            shape = rectangle,
+            padding_left = 0.,
+            padding_right = 0.,
+            padding_top = 0.,
+            padding_bottom = 0.,
+        ));
+
+        let base_1 = Shape::from(base_1);
+        let base_2 = Shape::from(base_2);
+
+        assert_eq!(
+            base_1.local_bounding_box().straigthen(),
+            base_2.local_bounding_box().straigthen()
+        );
+    }
+}

examples/Cargo.toml

@@ -126,3 +126,7 @@ path = "./line_with_macro.rs"
 [[example]]
 name = "line_without_macro"
 path = "./line_without_macro.rs"
+
+[[example]]
+name = "purple_padding"
+path = "./purple_padding.rs"

examples/purple_padding.rs

@@ -0,0 +1,52 @@
+use dessin::prelude::*;
+use project_root::get_project_root;
+use std::fs;
+
+fn main() {
+    let rectangle_1 = dessin2!(Rectangle!(
+        width = 3.,
+        height = 2.,
+        translate = [1., 0.],
+        fill = rgb(255, 0, 0)
+    ));
+
+    let base = dessin2!(Padding<Shape>( // here, we can replace 'Shape' with 'Rectangle' but in case we want to use the
+                                                        // Padding to a multiple geometric form, using Shape become a must
+        shape = rectangle_1.clone(),
+        padding_left = 1.5,
+        padding_right = 1.,
+        padding_top = 0.8,
+        padding_bottom = 1.,
+
+    ));
+
+    let rectangle_2 = dessin2!(Rectangle!(
+        width = 5.5,
+        height = 3.8,
+        stroke = Stroke::Full {
+            color: rgb(0, 150, 0),
+            width: 0.1
+        },
+        translate = [0.75, -0.1]
+    ));
+
+    let base = Shape::from(base);
+    let rectangle_1 = Shape::from(rectangle_1);
+    let rectangle_2 = Shape::from(rectangle_2);
+
+    // creates a group
+    let mut group = Group::default();
+
+    group.shapes = vec![];
+
+    group.shapes.push(base);
+    group.shapes.push(rectangle_1);
+    group.shapes.push(rectangle_2);
+
+    // prints in svg version
+    fs::write(
+        get_project_root().unwrap().join("examples/out/padding.svg"),
+        dessin_svg::to_string(&Shape::Group(group)).unwrap(),
+    )
+    .unwrap();
+}