feat(view): implement LIMITS command

Closes #478

src/scene/limits.rs

@@ -0,0 +1,173 @@
+use super::*;
+
+impl Scene {
+    fn model_limits(&self) -> Option<(glam::DVec2, glam::DVec2)> {
+        let min = self.document.header.model_space_limits_min;
+        let max = self.document.header.model_space_limits_max;
+        Self::valid_limits(
+            glam::DVec2::new(min.x, min.y),
+            glam::DVec2::new(max.x, max.y),
+        )
+    }
+
+    fn paper_layout_limits(&self) -> Option<(glam::DVec2, glam::DVec2)> {
+        self.document.objects.values().find_map(|object| {
+            let ObjectType::Layout(layout) = object else {
+                return None;
+            };
+            (layout.name == self.current_layout).then(|| {
+                Self::valid_limits(
+                    glam::DVec2::new(layout.min_limits.0, layout.min_limits.1),
+                    glam::DVec2::new(layout.max_limits.0, layout.max_limits.1),
+                )
+            })?
+        })
+    }
+
+    fn valid_limits(min: glam::DVec2, max: glam::DVec2) -> Option<(glam::DVec2, glam::DVec2)> {
+        const SANE_LIMIT: f64 = 1.0e16;
+        (min.is_finite()
+            && max.is_finite()
+            && min.x < max.x
+            && min.y < max.y
+            && min.abs().max_element() < SANE_LIMIT
+            && max.abs().max_element() < SANE_LIMIT)
+            .then_some((min, max))
+    }
+
+    /// The active input space is model space on the Model tab and while editing
+    /// through a floating paper-space viewport (MSPACE).
+    pub fn input_uses_model_space(&self) -> bool {
+        self.current_layout == "Model" || self.active_viewport.is_some()
+    }
+
+    /// LIMITS rectangle for the active point-input space.
+    pub fn current_drawing_limits(&self) -> Option<(glam::DVec2, glam::DVec2)> {
+        if self.input_uses_model_space() {
+            self.model_limits()
+        } else {
+            self.paper_layout_limits().or_else(|| {
+                let min = self.document.header.paper_space_limits_min;
+                let max = self.document.header.paper_space_limits_max;
+                Self::valid_limits(
+                    glam::DVec2::new(min.x, min.y),
+                    glam::DVec2::new(max.x, max.y),
+                )
+            })
+        }
+    }
+
+    /// LIMITS rectangle belonging to a rendered grid viewport. Floating
+    /// viewports display model space; the sheet viewport displays paper space.
+    pub fn grid_limits_for_viewport(&self, viewport: Handle) -> Option<(glam::DVec2, glam::DVec2)> {
+        if self.current_layout == "Model" {
+            return self.model_limits();
+        }
+        let sheet = self.current_layout_sheet_viewport_handle();
+        if viewport.is_valid() && viewport != sheet {
+            self.model_limits()
+        } else {
+            self.paper_layout_limits()
+        }
+    }
+
+    pub fn drawing_limit_check_enabled(&self) -> bool {
+        if self.input_uses_model_space() {
+            self.document.header.limit_check
+        } else {
+            self.document.header.paper_space_limit_check
+        }
+    }
+
+    pub fn point_inside_drawing_limits(&self, point: glam::DVec3) -> bool {
+        let Some((min, max)) = self.current_drawing_limits() else {
+            return true;
+        };
+        point.x >= min.x && point.x <= max.x && point.y >= min.y && point.y <= max.y
+    }
+
+    pub fn set_drawing_limit_check(&mut self, enabled: bool) {
+        if self.input_uses_model_space() {
+            self.document.header.limit_check = enabled;
+        } else {
+            self.document.header.paper_space_limit_check = enabled;
+        }
+    }
+
+    pub fn set_current_drawing_limits(&mut self, min: glam::DVec2, max: glam::DVec2) {
+        if self.input_uses_model_space() {
+            self.document.header.model_space_limits_min =
+                acadrust::types::Vector2::new(min.x, min.y);
+            self.document.header.model_space_limits_max =
+                acadrust::types::Vector2::new(max.x, max.y);
+        } else {
+            self.document.header.paper_space_limits_min =
+                acadrust::types::Vector2::new(min.x, min.y);
+            self.document.header.paper_space_limits_max =
+                acadrust::types::Vector2::new(max.x, max.y);
+        }
+
+        // Keep the current Layout object synchronized with the header values.
+        // DWG stores per-layout limits here as well as the current-space header.
+        for object in self.document.objects.values_mut() {
+            if let ObjectType::Layout(layout) = object {
+                if layout.name == self.current_layout {
+                    layout.min_limits = (min.x, min.y);
+                    layout.max_limits = (max.x, max.y);
+                    break;
+                }
+            }
+        }
+    }
+
+    /// ZOOM All frames the configured drawing limits. Object-only framing
+    /// remains the responsibility of ZOOM Extents.
+    pub fn fit_all_with_limits(&mut self) {
+        let Some((limit_min, limit_max)) = self.current_drawing_limits() else {
+            self.fit_all();
+            return;
+        };
+
+        let min = glam::Vec3::new(limit_min.x as f32, limit_min.y as f32, 0.0);
+        let max = glam::Vec3::new(limit_max.x as f32, limit_max.y as f32, 0.0);
+
+        // MSPACE owns a camera encoded on the active viewport entity.
+        if let Some(viewport_handle) = self.active_viewport {
+            let (width, height, locked) = match self.document.get_entity(viewport_handle) {
+                Some(EntityType::Viewport(viewport)) => {
+                    (viewport.width, viewport.height, viewport.status.locked)
+                }
+                _ => return,
+            };
+            if locked {
+                return;
+            }
+            let aspect = (width / height.max(1e-9)) as f32;
+            let mut camera = match self.viewport_edit_frame(self.selection.borrow().vp_size) {
+                Some((camera, _)) => camera,
+                None => return,
+            };
+            camera.fit_to_bounds(min, max, aspect.max(0.01));
+            if let Some(EntityType::Viewport(viewport)) =
+                self.document.get_entity_mut(viewport_handle)
+            {
+                viewport.view_target.x = camera.target.x;
+                viewport.view_target.y = camera.target.y;
+                viewport.view_target.z = camera.target.z;
+                viewport.view_center.x = 0.0;
+                viewport.view_center.y = 0.0;
+                viewport.view_height = camera.ortho_size() as f64 * 2.0;
+                if viewport.view_height > 1e-9 {
+                    viewport.custom_scale = viewport.height / viewport.view_height;
+                }
+            }
+            self.camera_generation += 1;
+            return;
+        }
+
+        self.camera
+            .borrow_mut()
+            .fit_to_bounds(min, max, self.last_render_aspect.get().max(0.01));
+        self.camera_generation += 1;
+    }
+}

src/scene/mod.rs

@@ -20,6 +20,7 @@ mod camera_ops;
 mod entity;
 mod group_layer;
 mod layout;
+mod limits;
 mod modify;
 mod mspace;
 mod page_setup;