better names

src/durandal/image.rs

@@ -30,13 +30,13 @@ pub fn rgb8_to_rgb16(r: u8, g: u8, b: u8) -> Color16
 }
 
 /// Writes a PPM file from an image.
-pub fn write_ppm<T: Image>(out: &mut impl io::Write, im: &T) -> ResultS<()>
+pub fn write_ppm(out: &mut impl io::Write, im: &impl Image) -> ResultS<()>
 {
    write!(out, "P3\n{} {}\n{}\n", im.w(), im.h(), u16::max_value())?;
 
    for y in 0..im.h() {
       for x in 0..im.w() {
-         let cr = im.cr_at(x, y);
+         let cr = im.index(x, y);
          write!(out, "{} {} {} ", cr.r(), cr.g(), cr.b())?;
       }
 
@@ -52,12 +52,12 @@ pub trait Image
 
    fn w(&self) -> usize;
    fn h(&self) -> usize;
-   fn cr_at(&self, x: usize, y: usize) -> &Self::Output;
+   fn index(&self, x: usize, y: usize) -> &Self::Output;
 
-   fn cr_get(&self, x: usize, y: usize) -> Option<&Self::Output>
+   fn get(&self, x: usize, y: usize) -> Option<&Self::Output>
    {
       if x < self.w() && y < self.h() {
-         Some(self.cr_at(x, y))
+         Some(&self.index(x, y))
       } else {
          None
       }
@@ -72,6 +72,16 @@ pub trait Color
    fn a(&self) -> u16;
 }
 
+impl<T: Color> std::ops::Index<(usize, usize)> for Image<Output = T>
+{
+   type Output = T;
+
+   fn index(&self, (x, y): (usize, usize)) -> &Self::Output
+   {
+      <Self as Image>::index(self, x, y)
+   }
+}
+
 impl Image16
 {
    /// Creates a new Image16.
@@ -88,7 +98,7 @@ impl Image for Image16
    fn w(&self) -> usize {self.w}
    fn h(&self) -> usize {self.h}
 
-   fn cr_at(&self, x: usize, y: usize) -> &Self::Output
+   fn index(&self, x: usize, y: usize) -> &Self::Output
    {
       &self.cr[x + y * self.w]
    }
@@ -110,7 +120,7 @@ impl Image for Image8
    fn w(&self) -> usize {self.w}
    fn h(&self) -> usize {self.h}
 
-   fn cr_at(&self, x: usize, y: usize) -> &Self::Output
+   fn index(&self, x: usize, y: usize) -> &Self::Output
    {
       &self.cr[x + y * self.w]
    }

src/marathon/shp.rs

@@ -262,7 +262,7 @@ impl Image for ImageShp<'_>
    fn w(&self) -> usize {self.w}
    fn h(&self) -> usize {self.h}
 
-   fn cr_at(&self, x: usize, y: usize) -> &Self::Output
+   fn index(&self, x: usize, y: usize) -> &Self::Output
    {
       static TRANSLUCENT_COLOR: ColorShp = ColorShp::Translucent;