Add dimension indicator without direct value editing

1 files changed, 123 insertions, 0 deletions

diff --git a/src/dimension_indicator.rs b/src/dimension_indicator.rs
new file mode 100644
index 0000000..a08d22c
--- /dev/null
+++ b/src/dimension_indicator.rs
@@ -0,0 +1,123 @@
+use crate::math::Vec2;
+use crate::transform::Transform;
+use raylib::drawing::RaylibDraw;
+use raylib::ffi::Color;
+
+pub struct DimensionIndicator {
+    /// The lines that are used to draw the Dimension Indicator. For a rectangle for instance these
+    /// would be two. One for width and one for height.
+    length_lines: Vec<(Vec2<f32>, Vec2<f32>)>,
+}
+
+impl DimensionIndicator {
+    pub fn new() -> Self {
+        Self {
+            length_lines: Vec::new(),
+        }
+    }
+
+    pub fn from_corner_points(corner_points: &Vec<Vec2<f32>>) -> Self {
+        let mut this = Self::new();
+        this.update_dimensions(corner_points);
+
+        this
+    }
+
+    /// Update the dimensions by analysing a given set of points and adjusting the internal
+    /// (measured) dimensions.
+    pub fn update_dimensions(&mut self, corner_points: &[Vec2<f32>]) {
+        if corner_points.len() < 2 {
+            warn!("Cannot discern dimensions when not at least two points are given. The dimensions were not updated.");
+            return;
+        }
+
+        // Discern the bounding box for the given corner points.
+        let mut min = corner_points[0];
+        let mut max = corner_points[0];
+        for point in corner_points.iter().skip(1) {
+            if point.x < min.x {
+                min.x = point.x;
+            }
+            if point.x > max.x {
+                max.x = point.x;
+            }
+
+            if point.y < min.y {
+                min.y = point.y;
+            }
+            if point.y > max.y {
+                max.y = point.y;
+            }
+        }
+
+        // For now, only use the width and height vectors.
+        // TODO: Change to a more sophisticated approach.
+        self.length_lines.clear();
+        // Horizontal dimensions, left to right.
+        self.length_lines
+            .push((Vec2::new(min.x, max.y), Vec2::new(max.x, max.y)));
+        // Vertical dimensions, bottom to top.
+        self.length_lines
+            .push((Vec2::new(max.x, max.y), Vec2::new(max.x, min.y)));
+    }
+
+    pub fn draw(&self, rld: &mut impl RaylibDraw, transform: &Transform) {
+        // Draw all the dimension lines.
+        for (start, end) in &self.length_lines {
+            // Don't draw anything if the length is zero.
+            if start == end {
+                continue;
+            }
+
+            /* Get the vector that is perpendicular and points right/down from the line, assuming
+             * the lines prefer left as start over right and bottom over top.
+             */
+            let line_normal = {
+                // Start with the direction of the line vector.
+                let dir = *start - *end;
+                // Calculate perpendicular vec and normalise.
+                dir.rotated_90_clockwise() / dir.len()
+            };
+
+            // To not have the line directly in the rect, move start and end outside a bit.
+            let start_px = transform.point_m_to_px(*start) + line_normal * 10.;
+            let end_px = transform.point_m_to_px(*end) + line_normal * 10.;
+
+            /* Draw the indicator line, with stubs at both ends. */
+            let line_colour = Color {
+                r: 200,
+                g: 200,
+                b: 200,
+                a: 255,
+            };
+            // First the two stubs.
+            rld.draw_line_ex(
+                start_px - line_normal * 5.,
+                start_px + line_normal * 5.,
+                2.,
+                line_colour,
+            );
+            rld.draw_line_ex(
+                end_px - line_normal * 5.,
+                end_px + line_normal * 5.,
+                2.,
+                line_colour,
+            );
+            // Then the actual indicator line.
+            rld.draw_line_ex(start_px, end_px, 2., line_colour);
+
+            /* Draw the indicator text showing how long this line is in meters.
+             * It should be placed in the middle of the line, but not into the line directly, so it
+             * will be moved out by the normal.
+             */
+            let text_pos = transform.point_m_to_px((*end + *start) / 2.) + line_normal * 20.;
+            rld.draw_text(
+                &format!("{}m", &(*end - *start).len()),
+                text_pos.x as i32,
+                text_pos.y as i32,
+                20,
+                line_colour,
+            );
+        }
+    }
+}