adds global world and screen scaling

RobertBrewitz · RobertBrewitz · commit f817af91b230 · 2025-06-12T20:16:30.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -17,6 +17,9 @@ This release supports Bevy version 0.16 and has an [MSRV][] of 1.87.
 
 ### Added
 
+- Adds `VelloScreenScale` resource to control the scale of screen space rendering.
+- Adds `VelloWorldScale` resource to control the scale of world space rendering.
+- Adds `NoVelloScale` component to disable scaling for specific entities.
 - Adds `VelloScreenSpace` component.
 - Adds `VelloScreenSpace` to `bevy_vello::prelude`.
 - Adds `calculate_text_content_size` system that calculates the content size of `VelloTextSection` if it has a `ContentSize` component.
diff --git a/src/integrations/lottie/render.rs b/src/integrations/lottie/render.rs
@@ -16,7 +16,7 @@ use super::{
 use crate::{
     SkipEncoding, VelloScreenSpace,
     render::{
-        VelloEntityCountData, VelloView,
+        NoVelloScale, VelloEntityCountData, VelloScreenScale, VelloView, VelloWorldScale,
         prepare::{PrepareRenderInstance, PreparedAffine, PreparedTransform},
     },
 };
@@ -31,6 +31,7 @@ pub struct ExtractedLottieAsset {
     pub theme: Option<Theme>,
     pub playhead: f64,
     pub screen_space: Option<VelloScreenSpace>,
+    pub no_scaling: Option<NoVelloScale>,
 }
 
 pub fn extract_lottie_assets(
@@ -52,6 +53,7 @@ pub fn extract_lottie_assets(
                 &ViewVisibility,
                 &InheritedVisibility,
                 Option<&VelloScreenSpace>,
+                Option<&NoVelloScale>,
             ),
             Without<SkipEncoding>,
         >,
@@ -76,6 +78,7 @@ pub fn extract_lottie_assets(
         view_visibility,
         inherited_visibility,
         screen_space,
+        no_scaling,
     ) in query_vectors.iter()
     {
         // Skip if visibility conditions are not met
@@ -102,6 +105,7 @@ pub fn extract_lottie_assets(
                     alpha: asset.alpha,
                     ui_node: ui_node.cloned(),
                     screen_space: screen_space.cloned(),
+                    no_scaling: no_scaling.cloned(),
                 })
                 .insert(TemporaryRenderEntity);
             n_lotties += 1;
@@ -115,13 +119,21 @@ pub fn prepare_asset_affines(
     mut commands: Commands,
     views: Query<(&ExtractedCamera, &ExtractedView), With<Camera2d>>,
     mut render_entities: Query<(Entity, &ExtractedLottieAsset)>,
+    world_scale: Res<VelloWorldScale>,
+    screen_scale: Res<VelloScreenScale>,
 ) {
     for (camera, view) in views.iter() {
         let viewport_size: UVec2 = camera.physical_viewport_size.unwrap();
         for (entity, render_entity) in render_entities.iter_mut() {
             // Prepare render data needed for the subsequent render system
             let final_transform = render_entity.final_transform();
-            let affine = render_entity.scene_affine(view, *final_transform, viewport_size);
+            let affine = render_entity.scene_affine(
+                view,
+                *final_transform,
+                viewport_size,
+                world_scale.0,
+                screen_scale.0,
+            );
 
             commands.entity(entity).insert((affine, final_transform));
         }
@@ -142,12 +154,19 @@ impl PrepareRenderInstance for ExtractedLottieAsset {
         view: &ExtractedView,
         world_transform: GlobalTransform,
         viewport_size: UVec2,
+        world_scale: f32,
+        screen_scale: f32,
     ) -> PreparedAffine {
         let local_center_matrix = self.asset.local_transform_center.compute_matrix().inverse();
 
         let raw_transform = if let Some(node) = self.ui_node {
             let mut model_matrix = world_transform.compute_matrix();
 
+            if self.no_scaling.is_none() {
+                model_matrix.x_axis.x *= screen_scale;
+                model_matrix.y_axis.y *= screen_scale;
+            }
+
             let asset_size = Vec2::new(self.asset.width, self.asset.height);
 
             // Make the screen space vector instance sized to fill the
@@ -161,7 +180,13 @@ impl PrepareRenderInstance for ExtractedLottieAsset {
             local_center_matrix.w_axis.y *= -1.0;
             model_matrix * local_center_matrix
         } else if self.screen_space.is_some() {
-            let model_matrix = world_transform.compute_matrix();
+            let mut model_matrix = world_transform.compute_matrix();
+
+            if self.no_scaling.is_none() {
+                model_matrix.x_axis.x *= screen_scale;
+                model_matrix.y_axis.y *= screen_scale;
+            }
+
             let mut local_center_matrix = local_center_matrix;
             local_center_matrix.w_axis.y *= -1.0;
             model_matrix * local_center_matrix
@@ -180,6 +205,11 @@ impl PrepareRenderInstance for ExtractedLottieAsset {
             let mut model_matrix = world_transform.compute_matrix() * local_matrix;
             model_matrix.w_axis.y *= -1.0;
 
+            if self.no_scaling.is_none() {
+                model_matrix.x_axis.x *= world_scale;
+                model_matrix.y_axis.y *= world_scale;
+            }
+
             let (projection_mat, view_mat) = {
                 let mut view_mat = view.world_from_view.compute_matrix();
                 view_mat.w_axis.y *= -1.0;
diff --git a/src/integrations/svg/render.rs b/src/integrations/svg/render.rs
@@ -17,7 +17,7 @@ use crate::{
     VelloScreenSpace,
     prelude::*,
     render::{
-        VelloEntityCountData,
+        NoVelloScale, VelloEntityCountData, VelloScreenScale, VelloWorldScale,
         prepare::{PrepareRenderInstance, PreparedAffine, PreparedTransform},
     },
 };
@@ -30,6 +30,7 @@ pub struct ExtractedVelloSvg {
     pub ui_node: Option<ComputedNode>,
     pub alpha: f32,
     pub screen_space: Option<VelloScreenSpace>,
+    pub no_scaling: Option<NoVelloScale>,
 }
 
 pub fn extract_svg_assets(
@@ -49,6 +50,7 @@ pub fn extract_svg_assets(
                 &ViewVisibility,
                 &InheritedVisibility,
                 Option<&VelloScreenSpace>,
+                Option<&NoVelloScale>,
             ),
             Without<SkipEncoding>,
         >,
@@ -71,6 +73,7 @@ pub fn extract_svg_assets(
         view_visibility,
         inherited_visibility,
         screen_space,
+        no_scaling,
     ) in query_vectors.iter()
     {
         // Skip if visibility conditions are not met
@@ -95,6 +98,7 @@ pub fn extract_svg_assets(
                     ui_node: ui_node.cloned(),
                     alpha: asset.alpha,
                     screen_space: screen_space.cloned(),
+                    no_scaling: no_scaling.cloned(),
                 })
                 .insert(TemporaryRenderEntity);
             n_svgs += 1;
@@ -108,13 +112,21 @@ pub fn prepare_asset_affines(
     mut commands: Commands,
     views: Query<(&ExtractedCamera, &ExtractedView), With<Camera2d>>,
     mut render_entities: Query<(Entity, &ExtractedVelloSvg)>,
+    world_scale: Res<VelloWorldScale>,
+    screen_scale: Res<VelloScreenScale>,
 ) {
     for (camera, view) in views.iter() {
         let viewport_size: UVec2 = camera.physical_viewport_size.unwrap();
         for (entity, render_entity) in render_entities.iter_mut() {
             // Prepare render data needed for the subsequent render system
             let final_transform = render_entity.final_transform();
-            let affine = render_entity.scene_affine(view, *final_transform, viewport_size);
+            let affine = render_entity.scene_affine(
+                view,
+                *final_transform,
+                viewport_size,
+                world_scale.0,
+                screen_scale.0,
+            );
             commands.entity(entity).insert((affine, final_transform));
         }
     }
@@ -134,6 +146,8 @@ impl PrepareRenderInstance for ExtractedVelloSvg {
         view: &ExtractedView,
         world_transform: GlobalTransform,
         viewport_size: UVec2,
+        world_scale: f32,
+        screen_scale: f32,
     ) -> PreparedAffine {
         let local_center_matrix = self.asset.local_transform_center.compute_matrix().inverse();
 
@@ -149,11 +163,22 @@ impl PrepareRenderInstance for ExtractedVelloSvg {
             model_matrix.x_axis.x *= scale_factor;
             model_matrix.y_axis.y *= scale_factor;
 
+            if self.no_scaling.is_none() {
+                model_matrix.x_axis.x *= screen_scale;
+                model_matrix.y_axis.y *= screen_scale;
+            }
+
             let mut local_center_matrix = local_center_matrix;
             local_center_matrix.w_axis.y *= -1.0;
             model_matrix * local_center_matrix
         } else if self.screen_space.is_some() {
-            let model_matrix = world_transform.compute_matrix();
+            let mut model_matrix = world_transform.compute_matrix();
+
+            if self.no_scaling.is_none() {
+                model_matrix.x_axis.x *= screen_scale;
+                model_matrix.y_axis.y *= screen_scale;
+            }
+
             let mut local_center_matrix = local_center_matrix;
             local_center_matrix.w_axis.y *= -1.0;
             model_matrix * local_center_matrix
@@ -172,6 +197,11 @@ impl PrepareRenderInstance for ExtractedVelloSvg {
             let mut model_matrix = world_transform.compute_matrix() * local_matrix;
             model_matrix.w_axis.y *= -1.0;
 
+            if self.no_scaling.is_none() {
+                model_matrix.x_axis.x *= world_scale;
+                model_matrix.y_axis.y *= world_scale;
+            }
+
             let (projection_mat, view_mat) = {
                 let mut view_mat = view.world_from_view.compute_matrix();
                 view_mat.w_axis.y *= -1.0;
diff --git a/src/integrations/text/render.rs b/src/integrations/text/render.rs
@@ -12,7 +12,10 @@ use vello::kurbo::Affine;
 use super::{VelloFont, VelloTextAnchor, VelloTextSection};
 use crate::{
     VelloScreenSpace,
-    render::{SkipEncoding, VelloEntityCountData, VelloView, prepare::PreparedAffine},
+    render::{
+        NoVelloScale, SkipEncoding, VelloEntityCountData, VelloScreenScale, VelloView,
+        VelloWorldScale, prepare::PreparedAffine,
+    },
 };
 
 #[derive(Component, Clone)]
@@ -22,6 +25,7 @@ pub struct ExtractedVelloText {
     pub transform: GlobalTransform,
     pub ui_node: Option<ComputedNode>,
     pub screen_space: Option<VelloScreenSpace>,
+    pub no_scaling: Option<NoVelloScale>,
 }
 
 pub fn extract_text(
@@ -41,6 +45,7 @@ pub fn extract_text(
                 Option<&RenderLayers>,
                 Option<&ComputedNode>,
                 Option<&VelloScreenSpace>,
+                Option<&NoVelloScale>,
             ),
             Without<SkipEncoding>,
         >,
@@ -63,6 +68,7 @@ pub fn extract_text(
         render_layers,
         ui_node,
         screen_space,
+        no_scaling,
     ) in query_scenes.iter()
     {
         // Skip if visibility conditions are not met
@@ -86,6 +92,7 @@ pub fn extract_text(
                     transform: *transform,
                     ui_node: ui_node.cloned(),
                     screen_space: screen_space.cloned(),
+                    no_scaling: no_scaling.cloned(),
                 })
                 .insert(TemporaryRenderEntity);
             n_texts += 1;
@@ -99,6 +106,8 @@ pub fn prepare_text_affines(
     mut commands: Commands,
     views: Query<(&ExtractedCamera, &ExtractedView), (With<Camera2d>, With<VelloView>)>,
     render_entities: Query<(Entity, &ExtractedVelloText)>,
+    world_scale: Res<VelloWorldScale>,
+    screen_scale: Res<VelloScreenScale>,
 ) {
     for (camera, view) in views.iter() {
         let size_pixels: UVec2 = camera.physical_viewport_size.unwrap();
@@ -118,8 +127,17 @@ pub fn prepare_text_affines(
 
             let raw_transform =
                 if render_entity.ui_node.is_some() || render_entity.screen_space.is_some() {
+                    if render_entity.no_scaling.is_none() {
+                        model_matrix.x_axis.x *= screen_scale.0;
+                        model_matrix.y_axis.y *= screen_scale.0;
+                    }
                     model_matrix
                 } else {
+                    if render_entity.no_scaling.is_none() {
+                        model_matrix.x_axis.x *= world_scale.0;
+                        model_matrix.y_axis.y *= world_scale.0;
+                    }
+
                     model_matrix.w_axis.y *= -1.0;
 
                     let (projection_mat, view_mat) = {
diff --git a/src/render/extract.rs b/src/render/extract.rs
@@ -6,8 +6,8 @@ use bevy::{
     },
 };
 
-use super::{VelloEntityCountData, VelloFrameProfileData};
-use crate::{VelloScreenSpace, prelude::*};
+use super::{NoVelloScale, VelloEntityCountData, VelloFrameProfileData};
+use crate::prelude::*;
 
 #[derive(SystemSet, Debug, Hash, PartialEq, Eq, Clone)]
 pub enum VelloExtractStep {
@@ -23,6 +23,7 @@ pub struct ExtractedVelloScene {
     pub transform: GlobalTransform,
     pub ui_node: Option<ComputedNode>,
     pub screen_space: Option<VelloScreenSpace>,
+    pub no_scaling: Option<NoVelloScale>,
 }
 
 pub fn extract_scenes(
@@ -41,6 +42,7 @@ pub fn extract_scenes(
                 Option<&ComputedNode>,
                 Option<&RenderLayers>,
                 Option<&VelloScreenSpace>,
+                Option<&NoVelloScale>,
             ),
             Without<SkipEncoding>,
         >,
@@ -61,6 +63,7 @@ pub fn extract_scenes(
         ui_node,
         render_layers,
         screen_space,
+        no_scaling,
     ) in query_scenes.iter()
     {
         // Skip if visibility conditions are not met
@@ -79,6 +82,7 @@ pub fn extract_scenes(
                     scene: scene.clone(),
                     ui_node: ui_node.cloned(),
                     screen_space: screen_space.cloned(),
+                    no_scaling: no_scaling.cloned(),
                 })
                 .insert(TemporaryRenderEntity);
             n_scenes += 1;
diff --git a/src/render/mod.rs b/src/render/mod.rs
@@ -35,6 +35,45 @@ pub const SSRT_SHADER_HANDLE: Handle<Shader> = weak_handle!("e7235b72-1181-4e18-
 #[derive(Component, Debug, Clone, Copy, ExtractComponent)]
 pub struct VelloView;
 
+/// A resource that holds the scale factor for Vello world coordinates.
+#[derive(Resource, Clone)]
+pub struct VelloWorldScale(pub f32);
+
+impl Default for VelloWorldScale {
+    fn default() -> Self {
+        Self(1.0)
+    }
+}
+
+impl ExtractResource for VelloWorldScale {
+    type Source = VelloWorldScale;
+
+    fn extract_resource(source: &Self::Source) -> Self {
+        source.clone()
+    }
+}
+
+/// A resource that holds the scale factor for Vello screen coordinates.
+#[derive(Resource, Clone)]
+pub struct VelloScreenScale(pub f32);
+
+impl Default for VelloScreenScale {
+    fn default() -> Self {
+        Self(1.0)
+    }
+}
+
+impl ExtractResource for VelloScreenScale {
+    type Source = VelloScreenScale;
+
+    fn extract_resource(source: &Self::Source) -> Self {
+        source.clone()
+    }
+}
+
+#[derive(Component, Debug, Clone)]
+pub struct NoVelloScale;
+
 /// A canvas material, with a shader that samples a texture with view-independent UV coordinates.
 #[derive(AsBindGroup, TypePath, Asset, Clone)]
 pub struct VelloCanvasMaterial {
diff --git a/src/render/plugin.rs b/src/render/plugin.rs
diff --git a/src/render/prepare.rs b/src/render/prepare.rs
