🎉 Improve performace for zoom and pan with wasm render

frontend/src/app/render_wasm/api.cljs

@@ -11,6 +11,7 @@
    [app.common.uuid :as uuid]
    [app.config :as cf]
    [app.render-wasm.helpers :as h]
+   [app.util.functions :as fns]
    [promesa.core :as p]))
 
 (defonce internal-frame-id nil)
@@ -119,15 +120,17 @@
   ;; https://rust-skia.github.io/doc/skia_safe/enum.BlendMode.html
   (h/call internal-module "_set_shape_blend_mode" (translate-blend-mode blend-mode)))
 
+(def debounce_render (fns/debounce render 100))
+
 (defn set-view
   [zoom vbox]
-  (h/call internal-module "_set_view" zoom (- (:x vbox)) (- (:y vbox)))
-  (request-render))
+  (h/call internal-module "_set_view" zoom (- (:x vbox)) (- (:y vbox)) (:width vbox) (:height vbox))
+  (h/call internal-module "_navigate")
+  (debounce_render))
 
 (defn set-objects
   [objects]
   (let [shapes        (into [] (vals objects))
-
         total-shapes  (count shapes)]
     (loop [index 0]
       (when (< index total-shapes)

render-wasm/src/main.rs

@@ -3,6 +3,7 @@ pub mod shapes;
 pub mod state;
 pub mod utils;
 pub mod view;
+pub mod images;
 
 use skia_safe as skia;
 
@@ -46,7 +47,13 @@ pub unsafe extern "C" fn resize_surface(width: i32, height: i32) {
 #[no_mangle]
 pub unsafe extern "C" fn render() {
     let state = unsafe { STATE.as_mut() }.expect("got an invalid state pointer");
-    state.draw_all_shapes(state.view.zoom, state.view.x, state.view.y);
+    state.draw_all_shapes();
+}
+
+#[no_mangle]
+    pub unsafe extern "C" fn navigate() {
+    let state = unsafe { STATE.as_mut() }.expect("got an invalid state pointer");
+    state.navigate();
 }
 
 #[no_mangle]
@@ -56,11 +63,13 @@ pub extern "C" fn reset_canvas() {
 }
 
 #[no_mangle]
-pub extern "C" fn set_view(zoom: f32, x: f32, y: f32) {
+pub extern "C" fn set_view(zoom: f32, x: f32, y: f32, width: f32, height: f32) {
     let state = unsafe { STATE.as_mut() }.expect("got an invalid state pointer");
+    state.view.zoom = zoom;
     state.view.x = x;
     state.view.y = y;
-    state.view.zoom = zoom;
+    state.view.width = width;
+    state.view.height = height;
 }
 
 #[no_mangle]

render-wasm/src/render.rs

@@ -4,6 +4,8 @@ use std::collections::HashMap;
 use uuid::Uuid;
 
 use crate::shapes::Shape;
+use crate::view::View;
+use crate::images::Image;
 
 struct GpuState {
     pub context: DirectContext,
@@ -48,10 +50,16 @@ impl GpuState {
     }
 }
 
+pub(crate) struct CachedSurfaceImage {
+  pub image: Image,
+  pub view: View,
+}
+
 pub(crate) struct RenderState {
     gpu_state: GpuState,
     pub final_surface: skia::Surface,
     pub drawing_surface: skia::Surface,
+    pub cached_surface_image: Option<CachedSurfaceImage>,
 }
 
 impl RenderState {
@@ -67,6 +75,7 @@ impl RenderState {
             gpu_state,
             final_surface,
             drawing_surface,
+            cached_surface_image: None,
         }
     }
 
@@ -154,20 +163,59 @@ impl RenderState {
             .clear(skia::Color::TRANSPARENT);
     }
 
-    pub fn draw_all_shapes(
+    pub fn navigate(
         &mut self,
-        zoom: f32,
-        pan_x: f32,
-        pan_y: f32,
+        view: &View,
         shapes: &HashMap<Uuid, Shape>,
     ) {
         self.reset_canvas();
 
-        self.scale(zoom, zoom);
-        self.translate(pan_x, pan_y);
+        if let Some(cached_surface_image) = &self.cached_surface_image {
+            // If we are drawing something bigger than the visible let's do a redraw
+            if (view.x > cached_surface_image.view.x) ||
+                (-view.x + view.width > -cached_surface_image.view.x + cached_surface_image.view.width) ||
+                (view.y > cached_surface_image.view.y) ||
+                (-view.y + view.height > -cached_surface_image.view.y + cached_surface_image.view.height) {         
+                self.draw_all_shapes(view, shapes);
+            }
+            else {
 
+                let image = &cached_surface_image.image;
+                let paint = skia::Paint::default();
+                self.final_surface.canvas().save();
+                self.drawing_surface.canvas().save();
+
+                let navigate_zoom = view.zoom / cached_surface_image.view.zoom;          
+                let navigate_x =  cached_surface_image.view.zoom * (view.x - cached_surface_image.view.x);
+                let navigate_y =  cached_surface_image.view.zoom * (view.y - cached_surface_image.view.y);
+
+                self.final_surface.canvas().scale((navigate_zoom, navigate_zoom));
+                self.final_surface.canvas().translate((navigate_x, navigate_y));
+                self.final_surface.canvas().draw_image(image.clone(), (0, 0), Some(&paint));
+
+                self.final_surface.canvas().restore();
+                self.drawing_surface.canvas().restore();
+            }
+        }
+
+        self.flush();
+    }
+
+    pub fn draw_all_shapes(
+        &mut self,
+        view: &View,
+        shapes: &HashMap<Uuid, Shape>,
+    ) {
+        self.reset_canvas();
+        self.scale(view.zoom, view.zoom);
+        self.translate(view.x, view.y);
         self.render_shape_tree(Uuid::nil(), shapes);
 
+        self.cached_surface_image = Some(CachedSurfaceImage {
+            image: self.final_surface.image_snapshot(),
+            view: view.clone(),
+        });
+
         self.flush();
     }
 

render-wasm/src/state.rs

@@ -29,6 +29,8 @@ impl<'a> State<'a> {
                 x: 0.,
                 y: 0.,
                 zoom: 1.,
+                width: 0.,
+                height: 0.,
             }
         }
     }
@@ -37,9 +39,14 @@ impl<'a> State<'a> {
         &mut self.render_state
     }
 
-    pub fn draw_all_shapes(&mut self, zoom: f32, pan_x: f32, pan_y: f32) {
+    pub fn navigate(&mut self) {
         self.render_state
-            .draw_all_shapes(zoom, pan_x, pan_y, &self.shapes);
+            .navigate(&self.view, &self.shapes);
+    }
+
+    pub fn draw_all_shapes(&mut self) {
+        self.render_state
+            .draw_all_shapes(&self.view, &self.shapes);
     }
 
     pub fn use_shape(&'a mut self, id: Uuid) {

render-wasm/src/view.rs

@@ -1,6 +1,9 @@
+#[derive(Debug, Clone, Copy)]
 pub(crate) struct View
 {
   pub x: f32,
   pub y: f32,
   pub zoom: f32,
+  pub width: f32,
+  pub height: f32,
 }