fix tests

Author: 0b01

README.md

@@ -16,8 +16,8 @@
   <img src="https://codecov.io/gh/38/plotters/branch/master/graph/badge.svg" />
 </a>
 
-Plotters is drawing library designed for rendering figures, plots, and charts, in pure rust. Plotters supports various types of back-ends, 
-including bitmap, vector graph, piston window, GTK/Cairo and WebAssembly. 
+Plotters is drawing library designed for rendering figures, plots, and charts, in pure rust. Plotters supports various types of back-ends,
+including bitmap, vector graph, piston window, GTK/Cairo and WebAssembly.
 
 - A new Plotters Developer's Guide is working in progress. The preview version is available at [here](https://plotters-rs.github.io/book).
 - To try Plotters with interactive Jupyter notebook, or view [here](https://plotters-rs.github.io/plotters-doc-data/evcxr-jupyter-integration.html) for the static HTML version.
@@ -147,7 +147,7 @@ And the following code draws a quadratic function. `src/main.rs`,
 ```rust
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/0.png", (640, 480)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/0.png", (640, 480)).into_drawing_area();
     root.fill(&WHITE)?;
     let mut chart = ChartBuilder::on(&root)
         .caption("y=x^2", ("sans-serif", 50).into_font())
@@ -225,7 +225,7 @@ figure
 *This tutorial is now working in progress and isn't complete*
 
 Thanks to the evcxr, now we have an interactive tutorial for Plotters!
-To use the interactive notebook, you must have Jupyter and evcxr installed on your computer. 
+To use the interactive notebook, you must have Jupyter and evcxr installed on your computer.
 Follow the instruction on [this page](https://github.com/google/evcxr/tree/master/evcxr_jupyter) below to install it.
 
 After that, you should be able to start your Jupyter server locally and load the tutorial!
@@ -249,23 +249,23 @@ But Rust is one of the best languages fits the need.
 Plotting in Rust can be as easy as most of the high-level programming languages. The Rust based plotting library
 can be very easy to use.
 
-* **Fast** If you need rendering a figure with trillions of data points, 
-Rust is a good choice. Rust's performance allows you to combine data processing step 
+* **Fast** If you need rendering a figure with trillions of data points,
+Rust is a good choice. Rust's performance allows you to combine data processing step
 and rendering step into a single application. When plotting in high-level programming languages,
-e.g. Javascript or Python, data points must be down-sampled before feeding into the plotting 
-program because of the performance considerations. Rust is fast enough to do the data processing and visualization 
-within a single program. You can also integrate the 
+e.g. Javascript or Python, data points must be down-sampled before feeding into the plotting
+program because of the performance considerations. Rust is fast enough to do the data processing and visualization
+within a single program. You can also integrate the
 figure rendering code into your application handling a huge amount of data and visualize it in real-time.
 
-* **WebAssembly Support** Rust is one of few the language with the best WASM support. Plotting in Rust could be 
+* **WebAssembly Support** Rust is one of few the language with the best WASM support. Plotting in Rust could be
 very useful for visualization on a web page and would have a huge performance improvement comparing to Javascript.
 
 ## Plotting on HTML5 canvas with WASM Backend
 
-Plotters currently supports backend that uses the HTML5 canvas. To use the WASM support, you can simply use 
+Plotters currently supports backend that uses the HTML5 canvas. To use the WASM support, you can simply use
 `CanvasBackend` instead of other backend and all other API remains the same!
 
-There's a small demo for Plotters + WASM under `examples/wasm-demo` directory of this repo. 
+There's a small demo for Plotters + WASM under `examples/wasm-demo` directory of this repo.
 To play with the deployed version, follow this [link](https://plumberserver.com/plotters-wasm-demo/index.html).
 
 
@@ -288,7 +288,7 @@ Plotters can use different drawing back-ends, including SVG, BitMap, and even re
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     // Create a 800*600 bitmap and start drawing
-    let mut backend = BitMapBackend::new("plotters-doc-data/1.png", (300, 200));
+    let mut backend = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/1.png", (300, 200));
     // And if we want SVG backend
     // let backend = SVGBackend::new("output.svg", (800, 600));
     backend.draw_rect((50, 50), (200, 150), &RED, true)?;
@@ -309,7 +309,7 @@ Besides that, the drawing area also allows the customized coordinate system, by
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root_drawing_area =
-        BitMapBackend::new("plotters-doc-data/2.png", (300, 200)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/2.png", (300, 200)).into_drawing_area();
     // And we can split the drawing area into 3x3 grid
     let child_drawing_areas = root_drawing_area.split_evenly((3, 3));
     // Then we fill the drawing area with different color
@@ -335,7 +335,7 @@ To learn more about the element system, please read the [element module document
 ```rust
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/3.png", (300, 200)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/3.png", (300, 200)).into_drawing_area();
     root.fill(&WHITE)?;
     // Draw an circle on the drawing area
     root.draw(&Circle::new(
@@ -352,7 +352,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 ### Composable Elements
 
 Besides the built-in elements, elements can be composed into a logic group we called composed elements.
-When composing new elements, the upper-left corner is given in the target coordinate, and a new pixel-based 
+When composing new elements, the upper-left corner is given in the target coordinate, and a new pixel-based
 coordinate which has the upper-left corner defined as `(0,0)` is used for further element composition purpose.
 
 For example, we can have an element which includes a dot and its coordinate.
@@ -361,7 +361,7 @@ For example, we can have an element which includes a dot and its coordinate.
 use plotters::prelude::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/4.png", (640, 480)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/4.png", (640, 480)).into_drawing_area();
 
     root.fill(&RGBColor(240, 200, 200))?;
 
@@ -400,7 +400,7 @@ of the chart context object.
 ```rust
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/5.png", (640, 480)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/5.png", (640, 480)).into_drawing_area();
     root.fill(&WHITE);
     let root = root.margin(10, 10, 10, 10);
     // After this point, we should be able to draw construct a chart context
@@ -475,7 +475,7 @@ This behavior can also be turned off by setting `default_features = false`.
 
 ### List of Features
 
-This is the full list of features that is defined by `Plotters` crate. Use `default_features = false` to disable those default enabled features, and then you should be able to cherry-pick what features you want to include into `Plotters` crate. 
+This is the full list of features that is defined by `Plotters` crate. Use `default_features = false` to disable those default enabled features, and then you should be able to cherry-pick what features you want to include into `Plotters` crate.
 
 | Name    |  Description | Additional Dependency |Default?|
 |---------|--------------|--------|------------|
@@ -495,12 +495,12 @@ This is the full list of features that is defined by `Plotters` crate. Use `defa
 
 	The WASM example requires using `wasm32` target to build. Using `cargo build` is likely to use the default target
 	which in most of the case is any of the x86 target. Thus you need add `--target=wasm32-unknown-unknown` in the cargo
-	parameter list  to build it. 
+	parameter list  to build it.
 
 * How to draw text/circle/point/rectangle/... on the top of chart ?
-	
-	As you may realized, Plotters is a drawing library rather than a traditional data plotting library, 
+
+	As you may realized, Plotters is a drawing library rather than a traditional data plotting library,
 	you have the freedom to draw anything you want on the drawing area.
-	Use `DrawingArea::draw` to draw any element on the drawing area. 
+	Use `DrawingArea::draw` to draw any element on the drawing area.
 
 

doc-template/examples/chart.rs

@@ -1,6 +1,6 @@
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/5.png", (640, 480)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/5.png", (640, 480)).into_drawing_area();
     root.fill(&WHITE);
     let root = root.margin(10, 10, 10, 10);
     // After this point, we should be able to draw construct a chart context

doc-template/examples/composable_elements.rs

@@ -1,7 +1,7 @@
 use plotters::prelude::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/4.png", (640, 480)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/4.png", (640, 480)).into_drawing_area();
 
     root.fill(&RGBColor(240, 200, 200))?;
 

doc-template/examples/drawing_area.rs

@@ -1,7 +1,7 @@
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root_drawing_area =
-        BitMapBackend::new("plotters-doc-data/2.png", (300, 200)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/2.png", (300, 200)).into_drawing_area();
     // And we can split the drawing area into 3x3 grid
     let child_drawing_areas = root_drawing_area.split_evenly((3, 3));
     // Then we fill the drawing area with different color

doc-template/examples/drawing_backends.rs

@@ -1,7 +1,7 @@
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     // Create a 800*600 bitmap and start drawing
-    let mut backend = BitMapBackend::new("plotters-doc-data/1.png", (300, 200));
+    let mut backend = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/1.png", (300, 200));
     // And if we want SVG backend
     // let backend = SVGBackend::new("output.svg", (800, 600));
     backend.draw_rect((50, 50), (200, 150), &RED, true)?;

doc-template/examples/elements.rs

@@ -1,6 +1,6 @@
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/3.png", (300, 200)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/3.png", (300, 200)).into_drawing_area();
     root.fill(&WHITE)?;
     // Draw an circle on the drawing area
     root.draw(&Circle::new(

doc-template/examples/quick_start.rs

@@ -1,6 +1,6 @@
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/0.png", (640, 480)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/0.png", (640, 480)).into_drawing_area();
     root.fill(&WHITE)?;
     let mut chart = ChartBuilder::on(&root)
         .caption("y=x^2", ("sans-serif", 50).into_font())

examples/animation.rs

@@ -18,7 +18,7 @@ fn snowflake_iter(points: &[(f64, f64)]) -> Vec<(f64, f64)> {
 }
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::gif("plotters-doc-data/animation.gif", (800, 600), 1_000)?
+    let root = BitMapBackend::<image::Rgb<u8>>::gif("plotters-doc-data/animation.gif", (800, 600), 1_000)?
         .into_drawing_area();
 
     for i in 0..8 {

examples/area-chart.rs

@@ -17,7 +17,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     };
 
     let root =
-        BitMapBackend::new("plotters-doc-data/area-chart.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/area-chart.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/blit-bitmap.rs

@@ -7,7 +7,7 @@ use std::io::BufReader;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/blit-bitmap.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/blit-bitmap.png", (1024, 768)).into_drawing_area();
     root.fill(&WHITE)?;
 
     let mut chart = ChartBuilder::on(&root)

examples/chart.rs

@@ -2,7 +2,7 @@ use plotters::prelude::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root_area =
-        BitMapBackend::new("plotters-doc-data/sample.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/sample.png", (1024, 768)).into_drawing_area();
 
     root_area.fill(&WHITE)?;
 

examples/console.rs

@@ -175,7 +175,7 @@ where
 
 fn main() -> Result<(), Box<dyn Error>> {
     draw_chart(TextDrawingBackend(vec![PixelState::Empty; 5000]).into_drawing_area())?;
-    let b = BitMapBackend::new("plotters-doc-data/console-example.png", (1024, 768))
+    let b = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/console-example.png", (1024, 768))
         .into_drawing_area();
     b.fill(&WHITE)?;
     draw_chart(b)?;

examples/errorbar.rs

@@ -12,7 +12,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let down_sampled = down_sample(&data[..]);
 
     let root =
-        BitMapBackend::new("plotters-doc-data/errorbar.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/errorbar.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/histogram.rs

@@ -1,7 +1,7 @@
 use plotters::prelude::*;
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/histogram.png", (640, 480)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/histogram.png", (640, 480)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/mandelbrot.rs

@@ -3,7 +3,7 @@ use std::ops::Range;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/mandelbrot.png", (800, 600)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/mandelbrot.png", (800, 600)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/matshow.rs

@@ -1,7 +1,7 @@
 use plotters::prelude::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let root = BitMapBackend::new("plotters-doc-data/matshow.png", (1024, 768)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/matshow.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/normal-dist.rs

@@ -5,7 +5,7 @@ use rand_distr::{Distribution, Normal};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/normal-dist.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/normal-dist.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/normal-dist2.rs

@@ -16,7 +16,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     };
 
     let root =
-        BitMapBackend::new("plotters-doc-data/normal-dist2.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/normal-dist2.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/relative_size.rs

@@ -30,7 +30,7 @@ fn draw_chart<B: DrawingBackend>(root: &DrawingArea<B, Shift>) -> DrawResult<(),
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/relative_size.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/relative_size.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/sierpinski.rs

@@ -3,7 +3,7 @@ use plotters::prelude::*;
 
 pub fn sierpinski_carpet(
     depth: u32,
-    drawing_area: &DrawingArea<BitMapBackend, Shift>,
+    drawing_area: &DrawingArea<BitMapBackend<image::Rgb<u8>>, Shift>,
 ) -> Result<(), Box<dyn std::error::Error>> {
     if depth > 0 {
         let sub_areas = drawing_area.split_evenly((3, 3));
@@ -21,7 +21,7 @@ pub fn sierpinski_carpet(
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/sierpinski.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/sierpinski.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/slc-temp.rs

@@ -7,7 +7,7 @@ use std::error::Error;
 
 fn main() -> Result<(), Box<dyn Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/slc-temp.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/slc-temp.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/snowflake.rs

@@ -19,7 +19,7 @@ fn snowflake_iter(points: &[(f64, f64)]) -> Vec<(f64, f64)> {
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/snowflake.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/snowflake.png", (1024, 768)).into_drawing_area();
 
     root.fill(&WHITE)?;
 

examples/stock.rs

@@ -9,7 +9,7 @@ fn parse_time(t: &str) -> Date<Local> {
 }
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let data = get_data();
-    let root = BitMapBackend::new("plotters-doc-data/stock.png", (1024, 768)).into_drawing_area();
+    let root = BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/stock.png", (1024, 768)).into_drawing_area();
     root.fill(&WHITE)?;
 
     let (to_date, from_date) = (

examples/two-scales.rs

@@ -2,7 +2,7 @@ use plotters::prelude::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let root =
-        BitMapBackend::new("plotters-doc-data/twoscale.png", (1024, 768)).into_drawing_area();
+        BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/twoscale.png", (1024, 768)).into_drawing_area();
     root.fill(&WHITE)?;
 
     let mut chart = ChartBuilder::on(&root)

src/element/mod.rs

@@ -51,7 +51,7 @@
     }
 
     fn main() -> Result<(), Box<dyn std::error::Error>> {
-        let root = BitMapBackend::new(
+        let root = BitMapBackend::<image::Rgb<u8>>::new(
             "plotters-doc-data/element-0.png",
             (640, 480)
         ).into_drawing_area();
@@ -72,7 +72,7 @@
     ```rust
     use plotters::prelude::*;
     fn main() -> Result<(), Box<dyn std::error::Error>> {
-        let root = BitMapBackend::new(
+        let root = BitMapBackend::<image::Rgb<u8>>::new(
             "plotters-doc-data/element-1.png",
             (640, 480)
         ).into_drawing_area();
@@ -120,7 +120,7 @@
     }
     fn main() -> Result<(), Box<dyn std::error::Error>> {
         let root =
-            BitMapBackend::new("plotters-doc-data/element-3.png", (640, 480))
+            BitMapBackend::<image::Rgb<u8>>::new("plotters-doc-data/element-3.png", (640, 480))
             .into_drawing_area();
         root.fill(&WHITE)?;
         let mut chart = ChartBuilder::on(&root)