renderer: Remove the str slice from text_size()

Instead, hide access to the string behind a RenderString trait.

The objective in the future is to cache the layout, which means that we need to query the text and other properties only if the cache is dirty.

Author: tronical

internal/backends/qt/qt_window.rs

@@ -2091,13 +2091,12 @@ impl WindowAdapterInternal for QtWindow {
 impl i_slint_core::renderer::RendererSealed for QtWindow {
     fn text_size(
         &self,
-        text_item: Pin<&dyn i_slint_core::item_rendering::HasFont>,
+        text_item: Pin<&dyn i_slint_core::item_rendering::RenderString>,
         item_rc: &ItemRc,
-        text: &str,
         max_width: Option<LogicalLength>,
         text_wrap: TextWrap,
     ) -> LogicalSize {
-        sharedparley::text_size(self, text_item, item_rc, text, max_width, text_wrap)
+        sharedparley::text_size(self, text_item, item_rc, max_width, text_wrap)
     }
 
     fn char_size(

internal/backends/testing/testing_backend.rs

@@ -163,13 +163,12 @@ impl WindowAdapter for TestingWindow {
 impl RendererSealed for TestingWindow {
     fn text_size(
         &self,
-        _text_item: Pin<&dyn i_slint_core::item_rendering::HasFont>,
+        text_item: Pin<&dyn i_slint_core::item_rendering::RenderString>,
         _item_rc: &i_slint_core::item_tree::ItemRc,
-        text: &str,
         _max_width: Option<LogicalLength>,
         _text_wrap: TextWrap,
     ) -> LogicalSize {
-        LogicalSize::new(text.len() as f32 * 10., 10.)
+        LogicalSize::new(text_item.text().len() as f32 * 10., 10.)
     }
 
     fn char_size(

internal/core/item_rendering.rs

@@ -292,11 +292,16 @@ pub trait HasFont {
     fn font_request(self: Pin<&Self>, self_rc: &crate::items::ItemRc) -> FontRequest;
 }
 
+/// Trait for an item that represents an string towards the renderer
+#[allow(missing_docs)]
+pub trait RenderString: HasFont {
+    fn text(self: Pin<&Self>) -> SharedString;
+}
+
 /// Trait for an item that represents an Text towards the renderer
 #[allow(missing_docs)]
-pub trait RenderText: HasFont {
+pub trait RenderText: RenderString {
     fn target_size(self: Pin<&Self>) -> LogicalSize;
-    fn text(self: Pin<&Self>) -> SharedString;
     fn color(self: Pin<&Self>) -> Brush;
     fn alignment(self: Pin<&Self>) -> (TextHorizontalAlignment, TextVerticalAlignment);
     fn wrap(self: Pin<&Self>) -> TextWrap;
@@ -319,15 +324,17 @@ impl HasFont for (SharedString, Brush) {
     }
 }
 
+impl RenderString for (SharedString, Brush) {
+    fn text(self: Pin<&Self>) -> SharedString {
+        self.0.clone()
+    }
+}
+
 impl RenderText for (SharedString, Brush) {
     fn target_size(self: Pin<&Self>) -> LogicalSize {
         LogicalSize::default()
     }
 
-    fn text(self: Pin<&Self>) -> SharedString {
-        self.0.clone()
-    }
-
     fn color(self: Pin<&Self>) -> Brush {
         self.1.clone()
     }

internal/core/items/text.rs

@@ -18,7 +18,7 @@ use crate::input::{
     key_codes, FocusEvent, FocusEventResult, FocusReason, InputEventFilterResult, InputEventResult,
     KeyEvent, KeyboardModifiers, MouseEvent, StandardShortcut, TextShortcut,
 };
-use crate::item_rendering::{CachedRenderingData, HasFont, ItemRenderer, RenderText};
+use crate::item_rendering::{CachedRenderingData, HasFont, ItemRenderer, RenderString, RenderText};
 use crate::layout::{LayoutInfo, Orientation};
 use crate::lengths::{LogicalLength, LogicalPoint, LogicalRect, LogicalSize};
 use crate::platform::Clipboard;
@@ -168,15 +168,17 @@ impl HasFont for ComplexText {
     }
 }
 
+impl RenderString for ComplexText {
+    fn text(self: Pin<&Self>) -> SharedString {
+        self.text()
+    }
+}
+
 impl RenderText for ComplexText {
     fn target_size(self: Pin<&Self>) -> LogicalSize {
         LogicalSize::from_lengths(self.width(), self.height())
     }
 
-    fn text(self: Pin<&Self>) -> SharedString {
-        self.text()
-    }
-
     fn color(self: Pin<&Self>) -> Brush {
         self.color()
     }
@@ -386,15 +388,17 @@ impl HasFont for MarkdownText {
     }
 }
 
+impl RenderString for MarkdownText {
+    fn text(self: Pin<&Self>) -> SharedString {
+        self.text()
+    }
+}
+
 impl RenderText for MarkdownText {
     fn target_size(self: Pin<&Self>) -> LogicalSize {
         LogicalSize::from_lengths(self.width(), self.height())
     }
 
-    fn text(self: Pin<&Self>) -> SharedString {
-        self.text()
-    }
-
     fn color(self: Pin<&Self>) -> Brush {
         self.color()
     }
@@ -561,15 +565,17 @@ impl HasFont for SimpleText {
     }
 }
 
+impl RenderString for SimpleText {
+    fn text(self: Pin<&Self>) -> SharedString {
+        self.text()
+    }
+}
+
 impl RenderText for SimpleText {
     fn target_size(self: Pin<&Self>) -> LogicalSize {
         LogicalSize::from_lengths(self.width(), self.height())
     }
 
-    fn text(self: Pin<&Self>) -> SharedString {
-        self.text()
-    }
-
     fn color(self: Pin<&Self>) -> Brush {
         self.color()
     }
@@ -618,15 +624,8 @@ fn text_layout_info(
     orientation: Orientation,
     width: Pin<&Property<LogicalLength>>,
 ) -> LayoutInfo {
-    let text_string = text.text();
     let implicit_size = |max_width, text_wrap| {
-        window_adapter.renderer().text_size(
-            text,
-            self_rc,
-            text_string.as_str(),
-            max_width,
-            text_wrap,
-        )
+        window_adapter.renderer().text_size(text, self_rc, max_width, text_wrap)
     };
 
     // Stretch uses `round_layout` to explicitly align the top left and bottom right of layout nodes
@@ -758,12 +757,8 @@ impl Item for TextInput {
         window_adapter: &Rc<dyn WindowAdapter>,
         self_rc: &ItemRc,
     ) -> LayoutInfo {
-        let text = self.text();
         let implicit_size = |max_width, text_wrap| {
-            if text.is_empty() {
-                return window_adapter.renderer().char_size(self, self_rc, '*');
-            }
-            window_adapter.renderer().text_size(self, self_rc, text.as_str(), max_width, text_wrap)
+            window_adapter.renderer().text_size(self, self_rc, max_width, text_wrap)
         };
 
         // Stretch uses `round_layout` to explicitly align the top left and bottom right of layout nodes
@@ -1272,6 +1267,12 @@ impl HasFont for TextInput {
     }
 }
 
+impl RenderString for TextInput {
+    fn text(self: Pin<&Self>) -> SharedString {
+        self.as_ref().text()
+    }
+}
+
 pub enum TextCursorDirection {
     Forward,
     Backward,

internal/core/renderer.rs

@@ -30,9 +30,8 @@ pub trait RendererSealed {
     /// using the wrapping type passed by `text_wrap`.
     fn text_size(
         &self,
-        text_item: Pin<&dyn crate::item_rendering::HasFont>,
+        text_item: Pin<&dyn crate::item_rendering::RenderString>,
         item_rc: &crate::item_tree::ItemRc,
-        text: &str,
         max_width: Option<LogicalLength>,
         text_wrap: TextWrap,
     ) -> LogicalSize;

internal/core/software_renderer.rs

@@ -723,9 +723,8 @@ impl SoftwareRenderer {
 impl RendererSealed for SoftwareRenderer {
     fn text_size(
         &self,
-        text_item: Pin<&dyn crate::item_rendering::HasFont>,
+        text_item: Pin<&dyn crate::item_rendering::RenderString>,
         item_rc: &crate::item_tree::ItemRc,
-        text: &str,
         max_width: Option<LogicalLength>,
         text_wrap: TextWrap,
     ) -> LogicalSize {
@@ -738,13 +737,14 @@ impl RendererSealed for SoftwareRenderer {
         match (font, parley_disabled()) {
             #[cfg(feature = "software-renderer-systemfonts")]
             (fonts::Font::VectorFont(_), false) => {
-                sharedparley::text_size(self, text_item, item_rc, text, max_width, text_wrap)
+                sharedparley::text_size(self, text_item, item_rc, max_width, text_wrap)
             }
             #[cfg(feature = "software-renderer-systemfonts")]
             (fonts::Font::VectorFont(vf), true) => {
                 let layout = fonts::text_layout_for_font(&vf, &font_request, scale_factor);
+                let text = text_item.text();
                 let (longest_line_width, height) = layout.text_size(
-                    text,
+                    text.as_str(),
                     max_width.map(|max_width| (max_width.cast() * scale_factor).cast()),
                     text_wrap,
                 );
@@ -753,8 +753,9 @@ impl RendererSealed for SoftwareRenderer {
             }
             (fonts::Font::PixelFont(pf), _) => {
                 let layout = fonts::text_layout_for_font(&pf, &font_request, scale_factor);
+                let text = text_item.text();
                 let (longest_line_width, height) = layout.text_size(
-                    text,
+                    text.as_str(),
                     max_width.map(|max_width| (max_width.cast() * scale_factor).cast()),
                     text_wrap,
                 );
@@ -773,7 +774,7 @@ impl RendererSealed for SoftwareRenderer {
         let Some(scale_factor) = self.scale_factor() else {
             return LogicalSize::default();
         };
-        let font_request = FontRequest::new(text_item, item_rc);
+        let font_request = text_item.font_request(item_rc);
         let font = fonts::match_font(&font_request, scale_factor);
 
         match (font, parley_disabled()) {

internal/core/textlayout/sharedparley.rs

@@ -1358,18 +1358,18 @@ pub fn draw_text_input(
 
 pub fn text_size(
     renderer: &dyn RendererSealed,
-    text_item: Pin<&dyn crate::item_rendering::HasFont>,
+    text_item: Pin<&dyn crate::item_rendering::RenderString>,
     item_rc: &crate::item_tree::ItemRc,
-    text: &str,
     max_width: Option<LogicalLength>,
     text_wrap: TextWrap,
 ) -> LogicalSize {
     let Some(scale_factor) = renderer.scale_factor() else {
         return LogicalSize::default();
     };
     let font_request = text_item.font_request(item_rc);
+    let text = text_item.text();
     let layout = layout(
-        Text::PlainText(text),
+        Text::PlainText(text.as_str()),
         scale_factor,
         LayoutOptions {
             max_width,
@@ -1393,7 +1393,7 @@ pub fn char_size(
     item_rc: &crate::item_tree::ItemRc,
     ch: char,
 ) -> Option<LogicalSize> {
-    let font_request = FontRequest::new(text_item, item_rc);
+    let font_request = text_item.font_request(item_rc);
     let font = font_request.query_fontique()?;
 
     let char_map = font.charmap()?;

internal/renderers/femtovg/lib.rs

@@ -284,13 +284,12 @@ impl<B: GraphicsBackend> FemtoVGRenderer<B> {
 impl<B: GraphicsBackend> RendererSealed for FemtoVGRenderer<B> {
     fn text_size(
         &self,
-        text_item: Pin<&dyn i_slint_core::item_rendering::HasFont>,
+        text_item: Pin<&dyn i_slint_core::item_rendering::RenderString>,
         item_rc: &ItemRc,
-        text: &str,
         max_width: Option<LogicalLength>,
         text_wrap: TextWrap,
     ) -> LogicalSize {
-        sharedparley::text_size(self, text_item, item_rc, text, max_width, text_wrap)
+        sharedparley::text_size(self, text_item, item_rc, max_width, text_wrap)
     }
 
     fn char_size(

internal/renderers/skia/lib.rs

@@ -824,13 +824,12 @@ impl SkiaRenderer {
 impl i_slint_core::renderer::RendererSealed for SkiaRenderer {
     fn text_size(
         &self,
-        text_item: Pin<&dyn i_slint_core::item_rendering::HasFont>,
+        text_item: Pin<&dyn i_slint_core::item_rendering::RenderString>,
         item_rc: &ItemRc,
-        text: &str,
         max_width: Option<LogicalLength>,
         text_wrap: TextWrap,
     ) -> LogicalSize {
-        sharedparley::text_size(self, text_item, item_rc, text, max_width, text_wrap)
+        sharedparley::text_size(self, text_item, item_rc, max_width, text_wrap)
     }
 
     fn char_size(