[librsvg: 16/31] ViewParams::with_units - Allow creating a ViewParams from another one

[Federico Mena Quintero <federico src gnome org>]

commit 0066fc1d1ac3a18df54a04b9888638da9e64e7b6
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Jun 2 18:32:59 2021 -0500

    ViewParams::with_units - Allow creating a ViewParams from another one
    
    Now that we don't push a coordinate system except in a single place,
    the rest of the code doesn't need the whole DrawingCtx just to get the
    ViewParams for a particular CoordUnits.

 src/drawing_ctx.rs  | 24 +++++++++++++++++++++---
 src/gradient.rs     |  6 +++---
 src/paint_server.rs |  8 ++++----
 src/pattern.rs      |  8 ++++----
 4 files changed, 32 insertions(+), 14 deletions(-)
---
diff --git a/src/drawing_ctx.rs b/src/drawing_ctx.rs
index c24f0f80..90162318 100644
--- a/src/drawing_ctx.rs
+++ b/src/drawing_ctx.rs
@@ -68,6 +68,22 @@ impl ViewParams {
             viewport_stack: None,
         }
     }
+
+    pub fn with_units(&self, units: CoordUnits) -> ViewParams {
+        match units {
+            CoordUnits::ObjectBoundingBox => ViewParams {
+                dpi: self.dpi,
+                vbox: ViewBox::from(Rect::from_size(1.0, 1.0)),
+                viewport_stack: None,
+            },
+
+            CoordUnits::UserSpaceOnUse => ViewParams {
+                dpi: self.dpi,
+                vbox: self.vbox,
+                viewport_stack: None,
+            },
+        }
+    }
 }
 
 impl Drop for ViewParams {
@@ -731,12 +747,14 @@ impl DrawingCtx {
 
                     let current_color = values.color().0;
 
+                    let params = temporary_draw_ctx.get_view_params();
+
                     let stroke_paint_source = Rc::new(
                         values
                             .stroke()
                             .0
                             .resolve(acquired_nodes, values.stroke_opacity().0, current_color)
-                            .to_user_space(&bbox, &temporary_draw_ctx, values),
+                            .to_user_space(&bbox, &params, values),
                     );
 
                     let fill_paint_source = Rc::new(
@@ -744,7 +762,7 @@ impl DrawingCtx {
                             .fill()
                             .0
                             .resolve(acquired_nodes, values.fill_opacity().0, current_color)
-                            .to_user_space(&bbox, &temporary_draw_ctx, values),
+                            .to_user_space(&bbox, &params, values),
                     );
 
                     // Filter functions (like "blend()", not the <filter> element) require
@@ -753,7 +771,7 @@ impl DrawingCtx {
                     // here and pass them down.
                     let user_space_params = NormalizeParams::new(
                         values,
-                        &temporary_draw_ctx.get_view_params_for_units(CoordUnits::UserSpaceOnUse),
+                        &params.with_units(CoordUnits::UserSpaceOnUse),
                     );
 
                     (
diff --git a/src/gradient.rs b/src/gradient.rs
index 6f5130b9..fa61796d 100644
--- a/src/gradient.rs
+++ b/src/gradient.rs
@@ -8,7 +8,7 @@ use markup5ever::{
 use crate::bbox::BoundingBox;
 use crate::coord_units::CoordUnits;
 use crate::document::{AcquiredNodes, NodeId, NodeStack};
-use crate::drawing_ctx::DrawingCtx;
+use crate::drawing_ctx::{DrawingCtx, ViewParams};
 use crate::element::{Draw, Element, ElementResult, SetAttributes};
 use crate::error::*;
 use crate::href::{is_href, set_href};
@@ -682,7 +682,7 @@ impl ResolvedGradient {
     pub fn to_user_space(
         &self,
         bbox: &BoundingBox,
-        draw_ctx: &DrawingCtx,
+        current_params: &ViewParams,
         values: &ComputedValues,
     ) -> Option<UserSpaceGradient> {
         let units = self.units.0;
@@ -692,7 +692,7 @@ impl ResolvedGradient {
             return None;
         };
 
-        let view_params = draw_ctx.get_view_params_for_units(units);
+        let view_params = current_params.with_units(units);
         let params = NormalizeParams::new(values, &view_params);
 
         let transform = transform.pre_transform(&self.transform).invert()?;
diff --git a/src/paint_server.rs b/src/paint_server.rs
index 8ac01795..3fa6812d 100644
--- a/src/paint_server.rs
+++ b/src/paint_server.rs
@@ -4,7 +4,7 @@ use cssparser::Parser;
 
 use crate::bbox::BoundingBox;
 use crate::document::{AcquiredNodes, NodeId};
-use crate::drawing_ctx::DrawingCtx;
+use crate::drawing_ctx::{DrawingCtx, ViewParams};
 use crate::element::Element;
 use crate::error::{AcquireError, NodeIdError, ParseError, ValueErrorKind};
 use crate::gradient::{ResolvedGradient, UserSpaceGradient};
@@ -193,20 +193,20 @@ impl PaintSource {
     pub fn to_user_space(
         &self,
         bbox: &BoundingBox,
-        draw_ctx: &DrawingCtx,
+        current_params: &ViewParams,
         values: &ComputedValues,
     ) -> UserSpacePaintSource {
         match *self {
             PaintSource::None => UserSpacePaintSource::None,
             PaintSource::SolidColor(c) => UserSpacePaintSource::SolidColor(c),
 
-            PaintSource::Gradient(ref g, c) => match (g.to_user_space(bbox, draw_ctx, values), c) {
+            PaintSource::Gradient(ref g, c) => match (g.to_user_space(bbox, current_params, values), c) {
                 (Some(gradient), c) => UserSpacePaintSource::Gradient(gradient, c),
                 (None, Some(c)) => UserSpacePaintSource::SolidColor(c),
                 (None, None) => UserSpacePaintSource::None,
             },
 
-            PaintSource::Pattern(ref p, c) => match (p.to_user_space(bbox, draw_ctx, values), c) {
+            PaintSource::Pattern(ref p, c) => match (p.to_user_space(bbox, current_params, values), c) {
                 (Some(pattern), c) => UserSpacePaintSource::Pattern(pattern, c),
                 (None, Some(c)) => UserSpacePaintSource::SolidColor(c),
                 (None, None) => UserSpacePaintSource::None,
diff --git a/src/pattern.rs b/src/pattern.rs
index c33ba11d..63316a01 100644
--- a/src/pattern.rs
+++ b/src/pattern.rs
@@ -6,7 +6,7 @@ use crate::aspect_ratio::*;
 use crate::bbox::BoundingBox;
 use crate::coord_units::CoordUnits;
 use crate::document::{AcquiredNodes, NodeId, NodeStack};
-use crate::drawing_ctx::DrawingCtx;
+use crate::drawing_ctx::{DrawingCtx, ViewParams};
 use crate::element::{Draw, Element, ElementResult, SetAttributes};
 use crate::error::*;
 use crate::href::{is_href, set_href};
@@ -327,13 +327,13 @@ impl ResolvedPattern {
     pub fn to_user_space(
         &self,
         bbox: &BoundingBox,
-        draw_ctx: &DrawingCtx,
+        current_params: &ViewParams,
         values: &ComputedValues,
     ) -> Option<UserSpacePattern> {
         let node_with_children = self.node_with_children()?;
 
-        let params =
-            NormalizeParams::new(values, &draw_ctx.get_view_params_for_units(self.units.0));
+        let view_params = current_params.with_units(self.units.0);
+        let params = NormalizeParams::new(values, &view_params);
 
         let rect = self.get_rect(&params);
         let bbrect = bbox.rect.unwrap();