Add quick measure overlays with Alt pressed (#1894)

* Measure with alt

* Code review

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/messages/tool/common_functionality/measure.rs

@@ -0,0 +1,36 @@
+use crate::messages::portfolio::document::overlays::utility_types::{self, OverlayContext};
+use crate::messages::tool::tool_messages::tool_prelude::*;
+
+use graphene_std::renderer::Rect;
+
+pub fn overlay(selected_bounds: Rect, hovered_bounds: Rect, transform: DAffine2, document_to_viewport: DAffine2, overlay_context: &mut OverlayContext) {
+	let transform_to_document = document_to_viewport.inverse() * transform;
+	if selected_bounds.intersects(hovered_bounds) {
+		// TODO: I'm not sure what to do here?
+		return;
+	}
+
+	// Always do horizontal then vertical from the selected
+	let turn_x = selected_bounds.center().x.clamp(hovered_bounds.min().x, hovered_bounds.max().x);
+	let turn_y = hovered_bounds.center().y.clamp(selected_bounds.min().y, selected_bounds.max().y);
+
+	let selected_x = turn_x.clamp(selected_bounds.min().x, selected_bounds.max().x);
+	let hovered_y = turn_y.clamp(hovered_bounds.min().y, hovered_bounds.max().y);
+
+	if turn_x != selected_x {
+		let min_viewport = transform.transform_point2(DVec2::new(turn_x.min(selected_x), turn_y));
+		let max_viewport = transform.transform_point2(DVec2::new(turn_x.max(selected_x), turn_y));
+		overlay_context.line(min_viewport, max_viewport);
+		let length = format!("{:.2}", transform_to_document.transform_vector2(DVec2::X * (turn_x - selected_x)).length());
+		let direction = -(min_viewport - max_viewport).normalize_or_zero();
+		overlay_context.angle_text(&length, (min_viewport + max_viewport) / 2., direction, 5., utility_types::Pivot::TopCentreX);
+	}
+	if turn_y != hovered_y {
+		let min_viewport = transform.transform_point2(DVec2::new(turn_x, turn_y.min(hovered_y)));
+		let max_viewport = transform.transform_point2(DVec2::new(turn_x, turn_y.max(hovered_y)));
+		overlay_context.line(min_viewport, max_viewport);
+		let length = format!("{:.2}", transform_to_document.transform_vector2(DVec2::Y * (turn_y - hovered_y)).length());
+		let direction = (min_viewport - max_viewport).normalize_or_zero().perp();
+		overlay_context.angle_text(&length, (min_viewport + max_viewport) / 2., direction, 5., utility_types::Pivot::LeftCentreY);
+	}
+}

editor/src/messages/tool/common_functionality/mod.rs

@@ -1,6 +1,7 @@
 pub mod auto_panning;
 pub mod color_selector;
 pub mod graph_modification_utils;
+pub mod measure;
 pub mod pivot;
 pub mod resize;
 pub mod shape_editor;