src: use core instead of std in some places, aiming for no_std compat

src/geometry.rs

@@ -1,7 +1,7 @@
-use std::fmt::{Debug, Formatter};
-use std::ops::{Mul, Sub, Add};
+use core::fmt::{Debug, Formatter};
+use core::ops::{Mul, Sub, Add};
 use num::{One, pow, integer::Roots};
-use std::cmp::{min, max};
+use core::cmp::{min, max};
 
 pub trait CoordinateOp: PartialOrd + PartialEq + Sub + Clone + Mul + Copy + One + Add + Eq + Debug where
 Self: Sub<Output=Self> {
@@ -21,7 +21,7 @@ pub struct Coordinates<S: CoordinateSpace> {
 }
 
 impl<S: CoordinateSpace> Debug for Coordinates<S> where S::Data: Debug {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
         f.debug_tuple("@")
             .field(&self.x)
             .field(&self.y)

src/lib8/interpolate.rs

@@ -1,5 +1,5 @@
 use num::PrimInt;
-use std::ops::BitOr;
+use core::ops::BitOr;
 
 use rgb::Rgb;
 

src/mappings.rs

@@ -2,8 +2,8 @@ use crate::geometry::*;
 
 use crate::lib8::interpolate::scale8;
 
-use std::cmp::{max, min};
-use std::fmt::{Formatter, Debug};
+use core::cmp::{max, min};
+use core::fmt::{Formatter, Debug};
 
 pub trait CoordinateView<'a>: Debug {
     type Space: CoordinateSpace;
@@ -216,7 +216,7 @@ pub struct StrideView<'a> {
 }
 
 impl<'a> Debug for StrideView<'a> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
         f.debug_struct("StrideView")
         .field("range", &self.range)
         .field("step", &self.step_size)
@@ -247,8 +247,8 @@ impl<'a> StrideView<'a> {
             (map.size.width(), map.size.height())
         );
         let step_size = VirtualCoordinates::new(
-            u8::MAX / std::cmp::max(1, range.width()),
-            u8::MAX / std::cmp::max(1, range.height())
+            u8::MAX / core::cmp::max(1, range.width()),
+            u8::MAX / core::cmp::max(1, range.height())
             //scale8(255, std::cmp::max(1, range.bottom_right.x - range.top_left.x)),
             //scale8(255, std::cmp::max(1, range.bottom_right.y - range.top_left.y))
         );

src/platform/smart_leds_lib.rs

@@ -6,7 +6,7 @@ use crate::power::brightness_for_mw;
 use crate::geometry::*;
 use crate::mappings::*;
 
-use std::fmt::Debug;
+use core::fmt::Debug;
 
 struct StrideSampler<'a, P: Pixbuf> {
     pixbuf: &'a mut P,
@@ -26,7 +26,7 @@ impl<'a, P: Pixbuf> PixelView for StrideSampler<'a, P> {
 }
 
 impl<P: Pixbuf, T: FastWrite> Debug for StrideOutput<P, T> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         f.debug_struct("StrideOutput").finish()
     }
 }

src/render.rs

@@ -7,7 +7,7 @@ use crate::power::AsMilliwatts;
 use crate::task::Task;
 use crate::time::Periodically;
 use running_average::RealTimeRunningAverage;
-use std::fmt::Debug;
+use core::fmt::Debug;
 
 pub trait HardwarePixel: Send + Sync + Copy + AsMilliwatts + Default + From<Rgb<u8>> + Fract8Ops {}
 impl<T> HardwarePixel for T where T: Send + Sync + Copy + AsMilliwatts + Default + From<Rgb<u8>> + Fract8Ops {}

src/task.rs

@@ -1,6 +1,6 @@
-use std::fmt;
+use core::fmt;
 
-pub trait Task: std::fmt::Debug {
+pub trait Task: core::fmt::Debug {
     fn tick(&mut self) {}
     fn start(&mut self) {}
     fn stop(&mut self) {}