Struct CanvasRenderer

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pub struct CanvasRenderer { /* private fields */ }

Expand description

A wrapper around CanvasRenderingContext2d providing convenience drawing methods and camera management for the game engine.

Implementations§

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impl CanvasRenderer

Implements static font and color utility methods for CanvasRenderer.

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pub fn font<F>(size: f64, family: F) -> String
where F: AsRef<str>,

Builds a CSS font string from font size and family.

§Arguments

f64 - The font size in pixels.
F: AsRef<str> - The font family name.

§Returns

String - The CSS font string (e.g., "16px sans-serif").

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pub fn default_font() -> String

Creates a default font string using the default font size and family.

§Returns

String - The default CSS font string.

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pub fn enable_smoothing_on(context: &CanvasRenderingContext2d)

Enables high-quality anti-aliasing on an arbitrary canvas 2D context.

Applies the High rendering quality preset via apply_quality, which sets imageSmoothingEnabled, imageSmoothingQuality = "high", and textRendering = "geometricPrecision" on the given context.

Use this static helper when you manage your own CanvasRenderingContext2d and don’t hold a CanvasRenderer instance. For instances, call renderer.enable_smoothing() instead.

§Arguments

&CanvasRenderingContext2d - The canvas context to configure.

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pub fn detect_dpr() -> f64

Detects the host device pixel ratio (HiDPI scale factor) via reflection.

Reads window.devicePixelRatio using Reflect::get because the web-sys Window features currently in use do not expose a native getter for this property. Falls back to RENDERER_DEFAULT_DEVICE_PIXEL_RATIO (1.0) when the value is missing, not a finite number, or below 1.0.

§Returns

f64 - The detected device pixel ratio (clamped to >= 1.0).

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impl CanvasRenderer

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pub fn from_selector<S>( canvas_selector: S, viewport_width: f64, viewport_height: f64, ) -> Option<CanvasRenderer>
where S: AsRef<str>,

Creates a new renderer from a canvas element selector and viewport dimensions.

§Arguments

&str - The CSS selector for the canvas element.
f64 - The viewport width.
f64 - The viewport height.

§Returns

Option<CanvasRenderer> - The renderer, or None if the canvas was not found.

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pub fn enable_smoothing(&self)

Enables high-quality anti-aliasing on the canvas context by setting imageSmoothingEnabled to true and imageSmoothingQuality to "high".

Applies the active quality preset via the shared apply_quality helper so that all smoothing-related settings are kept in sync.

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pub fn clear(&self)

Clears the entire canvas viewport.

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pub fn clear_color<C>(&self, color: C)
where C: AsRef<str>,

Clears the canvas and fills it with the given CSS color string.

§Arguments

C: AsRef<str> - The CSS color string (e.g., "#000000").

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pub fn save(&self)

Saves the current canvas state (transform, styles) onto the state stack.

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pub fn restore(&self)

Restores the most recently saved canvas state.

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pub fn replay(&self, list: &DrawList)

Replays a recorded DrawList onto this renderer’s canvas.

Convenience wrapper around replay_context using this renderer’s context.

§Arguments

&DrawList - The recorded commands to replay.

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pub fn replay_context(context: &CanvasRenderingContext2d, list: &DrawList)

Replays a recorded DrawList onto an arbitrary canvas 2D context in a single batched pass.

Consecutive same-style shapes are merged into one path (one begin_path plus one fill/stroke per style run), fill/stroke colors and line widths are only re-applied when they change, and sprites are drawn with a single set_transform rather than a save/restore pair. This collapses the per-shape canvas state churn of immediate-mode drawing.

The canvas transform and global alpha are reset to identity / 1.0 when replay finishes, so callers can sandwich the call between save()/apply_camera() and restore() without leaking state.

§Arguments

&CanvasRenderingContext2d - The target canvas 2D context.
&DrawList - The recorded commands to replay.

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pub fn apply_camera(&self)

Applies the camera transform to the canvas context.

Translates to the screen center, applies zoom and rotation, then offsets by the negative camera position.

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pub fn set_fill_color<C>(&self, color: C)
where C: AsRef<str>,

Sets the fill color for subsequent fill operations.

§Arguments

C: AsRef<str> - The CSS color string.

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pub fn set_stroke_color<C>(&self, color: C)
where C: AsRef<str>,

Sets the stroke color for subsequent stroke operations.

§Arguments

C: AsRef<str> - The CSS color string.

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pub fn set_line_width(&self, width: f64)

Sets the line width for subsequent stroke operations.

§Arguments

f64 - The line width in pixels.

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pub fn set_global_alpha(&self, alpha: f64)

Sets the global alpha (opacity) for all subsequent drawing operations.

§Arguments

f64 - The alpha value in the range 0.0 to 1.0.

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pub fn fill_rect(&self, position: Vector2D, width: f64, height: f64)

Fills a rectangle at the given world-space position and dimensions.

§Arguments

Vector2D - The top-left position in world space.
f64 - The width.
f64 - The height.

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pub fn stroke_rect(&self, position: Vector2D, width: f64, height: f64)

Strokes the outline of a rectangle at the given world-space position and dimensions.

§Arguments

Vector2D - The top-left position in world space.
f64 - The width.
f64 - The height.

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pub fn fill_circle(&self, center: Vector2D, radius: f64)

Fills a circle at the given world-space center with the specified radius.

§Arguments

Vector2D - The center in world space.
f64 - The radius.

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pub fn stroke_circle(&self, center: Vector2D, radius: f64)

Strokes the outline of a circle at the given world-space center.

§Arguments

Vector2D - The center in world space.
f64 - The radius.

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pub fn draw_line(&self, start: Vector2D, end: Vector2D)

Draws a line segment between two world-space points.

§Arguments

Vector2D - The start point.
Vector2D - The end point.

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pub fn fill_text<T>(&self, text: T, position: Vector2D)
where T: AsRef<str>,

Fills text at the given world-space position.

§Arguments

T: AsRef<str> - The text to draw.
Vector2D - The position in world space.

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pub fn set_font<F>(&self, font: F)
where F: AsRef<str>,

Sets the font for subsequent text rendering.

§Arguments

F: AsRef<str> - The CSS font string (e.g., "16px sans-serif").

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pub fn draw_image( &self, image: &HtmlImageElement, position: Vector2D, width: f64, height: f64, )

Draws an image element at the given world-space position and dimensions.

§Arguments

&HtmlImageElement - The image element to draw.
Vector2D - The top-left position in world space.
f64 - The destination width.
f64 - The destination height.

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pub fn draw_image_rect( &self, image: &HtmlImageElement, source: Rect, dest_position: Vector2D, dest_width: f64, dest_height: f64, )

Draws a sub-region of an image element at the given world-space position.

§Arguments

&HtmlImageElement - The image element to draw.
Rect - The source rectangle within the image.
Vector2D - The destination top-left position in world space.
f64 - The destination width.
f64 - The destination height.

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impl CanvasRenderer

Implements blend mode, shadow, and gradient rendering methods for CanvasRenderer.

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pub fn set_blend_mode(&self, mode: BlendMode)

Sets the blend mode for compositing subsequent draw operations.

§Arguments

BlendMode - The blend mode to apply.

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pub fn set_shadow(&self, config: &ShadowConfig)

Applies a shadow configuration for subsequent draw operations.

§Arguments

&ShadowConfig - The shadow configuration to apply.

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pub fn clear_shadow(&self)

Clears any previously applied shadow, disabling shadow rendering.

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pub fn set_linear_gradient_fill(&self, gradient: &LinearGradient)

Applies a linear gradient as the fill style for subsequent operations.

§Arguments

&LinearGradient - The linear gradient to use as fill style.

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pub fn set_radial_gradient_fill(&self, gradient: &RadialGradient)

Applies a radial gradient as the fill style for subsequent operations.

§Arguments

&RadialGradient - The radial gradient to use as fill style.

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pub fn set_linear_gradient_stroke(&self, gradient: &LinearGradient)

Applies a linear gradient as the stroke style for subsequent operations.

§Arguments

&LinearGradient - The linear gradient to use as stroke style.

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pub fn set_radial_gradient_stroke(&self, gradient: &RadialGradient)

Applies a radial gradient as the stroke style for subsequent operations.

§Arguments

&RadialGradient - The radial gradient to use as stroke style.

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pub fn new( context: CanvasRenderingContext2d, camera: Camera2D, quality: RenderQuality, ) -> Self

Trait Implementations§

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impl Clone for CanvasRenderer

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fn clone(&self) -> CanvasRenderer

Returns a duplicate of the value. Read more

1.0.0 (const: unstable) · Source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

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impl RenderBackend for CanvasRenderer

Implements the RenderBackend trait for CanvasRenderer, providing a backend-agnostic rendering interface.

Each method forwards to the inherent CanvasRenderer method of the same name, so the per-call documentation lives on the trait definition in engine::renderer::trait — the inherent method is the source of truth, this impl is the trait bridge.

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