Implement outline view mode (#401)

* Created wasm binding to action's of the radio buttons which control the view mode
Added entry to DocumentMessage Enum

* draw in wireframe mode by changing parameters on each shape
added functions/changed behavior to do as above
not working yet
   - newly added shapes should be drawn in wireframe
   - setting fill to "none" on a path does not only draw an outline
      - maybe the stroke width is 0?

* Wire frame view mostly functional for ellipses
   - Need to implement for all shapes
   - BUG: shapes don't immediatley update upon changing view-mode

* Fixed: active document now updates after view mode swap

* The Pros:
   - wire frame mode effects all shapes correctly

The Cons:
   - wire frame mode effects everything, including things that maybe shouldn't be, like select boxes and pen lines

* wire frame view no longer effects overlay layers

* Fixed: While in wireframe view the pen tool will draw regular thickness lines.

* some commenting

* Fixed potential bug:
   In layer/file system with a Folder layer with a sub-layer that is also
   a Folder cache_dirty must be set in order for all shapes to update properly

* refactored code to use ViewMode enum names throughout

* Changed: All wireframe lines are blank
cargo fmt

* Wireframe thickness doesn't change as a result of zooming
   - Added DocumentMessage::ReRenderDocument, which marks layers as dirty and renders with the updated render-string
   - All "zoom" messages in the movement_handler send a re-render message
   - while in wireframe view, the "render-transform" of all shapes includes the root layer transform

Added getter/setter methods for graphene::Document::view_mode

* cargo fmt

* wireframe now has proper thickness after "Zoom Canvas to Fit all" action

* Refactored
   - Changed FrontendMessage::UpdateCanvas to RenderDocument message to allow for lazy evaluation
   - Created DocumentOperation::SetViewMode to be more consistent with existing code
   - removed log statement
   - Added constants for empty fill and thin-black stroke

* cargo fmt

* Removed ReRenderDocument message

* cargo fmt

* Fixes as suggested by TrueDoctor

* clean up merge
cargo fmt

* Refactor:
   moved view_mode to DocumentMessageHandler

* Polishing

* changed those two comments

* Remove unknown todo comment

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

graphene/src/layers/style/mod.rs

@@ -1,15 +1,29 @@
 use crate::color::Color;
+use crate::consts::{LAYER_OUTLINE_STROKE_COLOR, LAYER_OUTLINE_STROKE_WIDTH};
 use serde::{Deserialize, Serialize};
+
 const OPACITY_PRECISION: usize = 3;
 
 fn format_opacity(name: &str, opacity: f32) -> String {
-	if (opacity - 1.).abs() > 10f32.powi(-(OPACITY_PRECISION as i32)) {
+	if (opacity - 1.).abs() > 10_f32.powi(-(OPACITY_PRECISION as i32)) {
 		format!(r#" {}-opacity="{:.precision$}""#, name, opacity, precision = OPACITY_PRECISION)
 	} else {
 		String::new()
 	}
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Deserialize, Serialize)]
+pub enum ViewMode {
+	Normal,
+	Outline,
+	Pixels,
+}
+impl Default for ViewMode {
+	fn default() -> Self {
+		ViewMode::Normal
+	}
+}
+
 #[repr(C)]
 #[derive(Debug, Clone, Copy, PartialEq, Default, Serialize, Deserialize)]
 pub struct Fill {
@@ -22,7 +36,7 @@ impl Fill {
 	pub fn color(&self) -> Option<Color> {
 		self.color
 	}
-	pub fn none() -> Self {
+	pub const fn none() -> Self {
 		Self { color: None }
 	}
 	pub fn render(&self) -> String {
@@ -41,7 +55,7 @@ pub struct Stroke {
 }
 
 impl Stroke {
-	pub fn new(color: Color, width: f32) -> Self {
+	pub const fn new(color: Color, width: f32) -> Self {
 		Self { color, width }
 	}
 	pub fn color(&self) -> Color {
@@ -83,17 +97,18 @@ impl PathStyle {
 	pub fn clear_stroke(&mut self) {
 		self.stroke = None;
 	}
-	pub fn render(&self) -> String {
-		format!(
-			"{}{}",
-			match self.fill {
-				Some(fill) => fill.render(),
-				None => String::new(),
-			},
-			match self.stroke {
-				Some(stroke) => stroke.render(),
-				None => String::new(),
-			},
-		)
+
+	pub fn render(&self, view_mode: ViewMode) -> String {
+		let fill_attribute = match (view_mode, self.fill) {
+			(ViewMode::Outline, _) => Fill::none().render(),
+			(_, Some(fill)) => fill.render(),
+			(_, None) => String::new(),
+		};
+		let stroke_attribute = match (view_mode, self.stroke) {
+			(ViewMode::Outline, _) => Stroke::new(LAYER_OUTLINE_STROKE_COLOR, LAYER_OUTLINE_STROKE_WIDTH).render(),
+			(_, Some(stroke)) => stroke.render(),
+			(_, None) => String::new(),
+		};
+		format!("{}{}", fill_attribute, stroke_attribute)
 	}
 }