Remove duplicated setup code from Context examples

Author: ElectrifyPro

cairo/src/context.rs

@@ -60,14 +60,33 @@ impl fmt::Debug for RectangleList {
 /// ```
 /// use cairo::{Context, Format, ImageSurface};
 ///
-/// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-/// let ctx = Context::new(&surface).unwrap();
+/// fn main() -> Result<(), cairo::Error> {
+///     let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+///     let ctx = Context::new(&surface)?;
 ///
-/// // paint the background black
-/// ctx.set_source_rgb(0.0, 0.0, 0.0);
-/// ctx.paint();
+///     // paint the background black
+///     ctx.set_source_rgb(0.0, 0.0, 0.0);
+///     ctx.paint();
 ///
-/// // etc.
+///     // etc., other drawing operations
+///     Ok(())
+/// }
+/// ```
+///
+/// Each example in the documentation below can be used with the above setup. To view the images
+/// generated by the examples, you can render the surface to a file. For example, to render the
+/// surface to a PNG file (requires the `png` feature to be enabled), you can use the following
+/// code after drawing on the surface:
+///
+/// ```
+/// # fn main() -> Result<(), cairo::Error> {
+/// # use cairo::{Context, Format, ImageSurface};
+/// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+/// # let ctx = Context::new(&surface)?;
+/// let mut file = std::fs::File::create("example.png")?;
+/// surface.write_to_png(&mut file)?;
+/// # Ok(())
+/// # }
 /// ```
 ///
 /// [`ImageSurface`]: crate::ImageSurface
@@ -205,11 +224,9 @@ impl Context {
     ///
     /// ```
     /// # fn main() -> Result<(), cairo::Error> {
-    /// use cairo::{Context, Format, ImageSurface};
-    ///
-    /// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-    /// let ctx = Context::new(&surface).unwrap();
-    ///
+    /// # use cairo::{Context, Format, ImageSurface};
+    /// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+    /// # let ctx = Context::new(&surface)?;
     /// // set source to red
     /// ctx.set_source_rgb(1.0, 0.0, 0.0);
     ///
@@ -349,11 +366,9 @@ impl Context {
     ///
     /// ```
     /// # fn main() -> Result<(), cairo::Error> {
-    /// use cairo::{Context, Format, ImageSurface};
-    ///
-    /// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-    /// let ctx = Context::new(&surface).unwrap();
-    ///
+    /// # use cairo::{Context, Format, ImageSurface};
+    /// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+    /// # let ctx = Context::new(&surface)?;
     /// // paint the background black
     /// ctx.paint()?;
     ///
@@ -381,11 +396,9 @@ impl Context {
     ///
     /// ```
     /// # fn main() -> Result<(), cairo::Error> {
-    /// use cairo::{Context, Format, ImageSurface};
-    ///
-    /// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-    /// let ctx = Context::new(&surface).unwrap();
-    ///
+    /// # use cairo::{Context, Format, ImageSurface};
+    /// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+    /// # let ctx = Context::new(&surface)?;
     /// // paint the background black
     /// ctx.paint()?;
     ///
@@ -419,12 +432,10 @@ impl Context {
     ///
     /// ```
     /// # fn main() -> Result<(), cairo::Error> {
-    /// use cairo::{Context, Format, ImageSurface, RadialGradient};
-    ///
-    /// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-    /// let ctx = Context::new(&surface).unwrap();
-    ///
-    /// // creates a radial gradient from red to blue
+    /// # use cairo::{Context, Format, ImageSurface};
+    /// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+    /// # let ctx = Context::new(&surface)?;
+    /// // create a radial gradient from red to blue
     ///
     /// // gradient will begin at (50, 50) with radius 0
     /// // ends at (50, 50) with radius 50
@@ -436,7 +447,7 @@ impl Context {
     /// // second color stop: at offset=1, draw with blue=(0, 0, 1)
     /// pattern.add_color_stop_rgb(1.0, 0.0, 0.0, 1.0);
     ///
-    /// // paints the canvas with the gradient
+    /// // paint the canvas with the gradient
     /// ctx.set_source(&pattern)?;
     /// ctx.paint()?;
     /// # Ok(())
@@ -1086,11 +1097,9 @@ impl Context {
     ///
     /// ```
     /// # fn main() -> Result<(), cairo::Error> {
-    /// use cairo::{Context, Format, ImageSurface};
-    ///
-    /// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-    /// let ctx = Context::new(&surface).unwrap();
-    ///
+    /// # use cairo::{Context, Format, ImageSurface};
+    /// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+    /// # let ctx = Context::new(&surface)?;
     /// // paint the background black
     /// ctx.paint()?;
     ///
@@ -1159,11 +1168,9 @@ impl Context {
     ///
     /// ```
     /// # fn main() -> Result<(), cairo::Error> {
-    /// use cairo::{Context, Format, ImageSurface};
-    ///
-    /// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-    /// let ctx = Context::new(&surface).unwrap();
-    ///
+    /// # use cairo::{Context, Format, ImageSurface};
+    /// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+    /// # let ctx = Context::new(&surface)?;
     /// // paint the background black
     /// ctx.paint()?;
     ///

cairo/src/paths.rs

@@ -19,11 +19,9 @@ use crate::{ffi, PathDataType};
 ///
 /// ```
 /// # fn main() -> Result<(), cairo::Error> {
-/// use cairo::{Context, Format, ImageSurface};
-///
-/// let surface = ImageSurface::create(Format::ARgb32, 100, 100).unwrap();
-/// let ctx = Context::new(&surface).unwrap();
-///
+/// # use cairo::{Context, Format, ImageSurface};
+/// # let surface = ImageSurface::create(Format::ARgb32, 100, 100)?;
+/// # let ctx = Context::new(&surface)?;
 /// // paint the background black
 /// ctx.paint()?;
 ///