Fix crashes related to 0-scale shapes (#777)

* Fix crashes when dragging the bounding box/transform cage of a 0-scale shape.

* Fix crashes when dragging the pivot point of a 0-scale shape

* Fix rotation computation on DAffine2 when scale.x is 0, avoids Nan display

* remove remaining log::info that I introduced in earlier commit

* Fix crash when updating the scale of a transform that was already 0.

* Fix NumberInput behaviour when the requested value changed is does not happen.

* Fix rotation computation when Scale X and Scale Y are both 0. Display 0. This also fixes crashes when modifying the rotation in such case

editor/src/messages/portfolio/document/properties_panel/utility_functions.rs

@@ -964,7 +964,12 @@ impl DAffine2Utils for DAffine2 {
 	}
 
 	fn update_scale_x(self, new_width: f64) -> Self {
-		self * DAffine2::from_scale((new_width / self.scale_x(), 1.).into())
+		let scale_x = self.scale_x();
+		if scale_x != 0. {
+			self * DAffine2::from_scale((new_width / scale_x, 1.).into())
+		} else {
+			self
+		}
 	}
 
 	fn scale_y(&self) -> f64 {
@@ -972,7 +977,12 @@ impl DAffine2Utils for DAffine2 {
 	}
 
 	fn update_scale_y(self, new_height: f64) -> Self {
-		self * DAffine2::from_scale((1., new_height / self.scale_y()).into())
+		let scale_y = self.scale_y();
+		if scale_y != 0. {
+			self * DAffine2::from_scale((1., new_height / scale_y).into())
+		} else {
+			self
+		}
 	}
 
 	fn x(&self) -> f64 {
@@ -994,9 +1004,19 @@ impl DAffine2Utils for DAffine2 {
 	}
 
 	fn rotation(&self) -> f64 {
-		let cos = self.matrix2.col(0).x / self.scale_x();
-		let sin = self.matrix2.col(0).y / self.scale_x();
-		sin.atan2(cos)
+		if self.scale_x() != 0. {
+			let cos = self.matrix2.col(0).x / self.scale_x();
+			let sin = self.matrix2.col(0).y / self.scale_x();
+			sin.atan2(cos)
+		} else if self.scale_y() != 0. {
+			let sin = -self.matrix2.col(1).x / self.scale_y();
+			let cos = self.matrix2.col(1).y / self.scale_y();
+			sin.atan2(cos)
+		} else {
+			// Rotation information does not exists anymore in the matrix
+			// return 0 for user experience.
+			0.
+		}
 	}
 
 	fn update_rotation(self, new_rotation: f64) -> Self {

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

@@ -158,9 +158,12 @@ impl Pivot {
 		for layer_path in document.selected_visible_layers() {
 			if let Ok(layer) = document.graphene_document.layer(layer_path) {
 				let transform = Self::get_layer_pivot_transform(layer_path, layer, document, font_cache);
-				let pivot = transform.inverse().transform_point2(position).into();
-				let layer_path = layer_path.to_owned();
-				responses.push_back(Operation::SetPivot { layer_path, pivot }.into());
+				let pivot = transform.inverse().transform_point2(position);
+				// Only update the pivot when computed position is finite. Infinite can happen when scale is 0.
+				if pivot.is_finite() {
+					let layer_path = layer_path.to_owned();
+					responses.push_back(Operation::SetPivot { layer_path, pivot: pivot.into() }.into());
+				}
 			}
 		}
 	}

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

@@ -130,7 +130,13 @@ impl SelectedEdges {
 
 	/// Calculates the required scaling to resize the bounding box
 	pub fn bounds_to_scale_transform(&self, position: DVec2, size: DVec2) -> (DAffine2, DVec2) {
-		let enlargement_factor = size / (self.bounds[1] - self.bounds[0]);
+		let mut enlargement_factor = size / (self.bounds[1] - self.bounds[0]);
+		if enlargement_factor.x.is_nan() {
+			enlargement_factor.x = 0.;
+		}
+		if enlargement_factor.y.is_nan() {
+			enlargement_factor.y = 0.;
+		}
 		let mut pivot = (self.bounds[0] * enlargement_factor - position) / (enlargement_factor - DVec2::splat(1.));
 		if pivot.x.is_nan() {
 			pivot.x = 0.;

frontend/src/components/widgets/inputs/NumberInput.vue

@@ -183,9 +183,10 @@ export default defineComponent({
 			if (typeof this.min === "number" && !Number.isNaN(this.min) && cleaned !== undefined) cleaned = Math.max(cleaned, this.min);
 			if (typeof this.max === "number" && !Number.isNaN(this.max) && cleaned !== undefined) cleaned = Math.min(cleaned, this.max);
 
-			if (newValue !== undefined) this.$emit("update:value", cleaned);
+			// Required as the call to update:value can, not change the value
+			this.text = this.displayText(this.value);
 
-			this.text = this.displayText(cleaned);
+			if (newValue !== undefined) this.$emit("update:value", cleaned);
 		},
 		displayText(value: number | undefined): string {
 			if (value === undefined) return "-";