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This article mainly introduces the rust graphics drawing library valora has what characteristics, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let Xiaobian with you to understand.

Valora feature valora includes rng (Random Number Generator) to reproduce graphics of any resolution without changing composition scale. Using type-safe color can ensure color printing consistency and make full use of hardware resources to make full use of Rust features, which greatly reduces the debugging workload.

Let's refer to the tutorials on the valora website to experience the rendering function.

Development environment Windows 10cargo version: cargo 1.45.0-nightly (9fcb8c1d2 2020-05-25) rustc-- version: rustc 1.45.0-nightly (56daaf669 2020-06-03)

Use the command to install after initializing a new rust project

Cargo install cargo-edit & & cargo add valora

Note: because some of the packages in valora's dependencies use the beta version, you need to use the rustc nightly version to install smoothly. If you use the rustc stable version, you will get an error.

Switch from stable to nightly version

Rustup default nightly experience valora drawing function

Next, let's experience the drawing function through the example of the Introduction section of the valora home page.

The original code is as follows:

Use valora::prelude::*

Fn main ()-> Result {run_fn (Options::from_args (), | _ gpu, world, _ rng | {Ok (move | ctx: Context, canvas: & mut Canvas | {canvas.set_color (LinSrgb::new (1,1.1,1.)); canvas.paint (Filled (ctx.world))

Let max_radius = world.width / 3; let radius = ctx.time.as_secs_f32 (). Cos (). Abs () * max_radius

Canvas.set_color (LinSrgb::new (1.,0.,0.)); canvas.paint (Filled (Ellipse::circle (world.center (), radius));})})

Next, we experience the playability of valora drawing by modifying some parameters in the original code.

First of all, we are going to start with the background color and circular color in the example. As for the relative details of the example code, such as ctx, _ gpu and other key parts, you do not need to understand them in depth at this stage.

The color definition LinSrgb used by valora is the uniform rgb. Generally speaking, the value range of rgb is 0 ~ 255. the normalization is 0 ~ 1. It is worth noting that floating-point numbers are used for assignment (1, 0, 0.). Generally speaking, floating-point numbers are commonly used in the category of graphics.

With these concepts, we can find an online color picker to choose the background color and round color we want.

After a period of picker

The background color is rgb (153,204,255), which is similar to sky blue. The color of the circle is similar to an orange rgb (255,153,51)

So let's paste the selected color into the code and do a uniform division.

/ / color of background canvas.set_color (LinSrgb::new (153.Compact 255.204.Universe 255.255.Universe 255.255.))

/ / color of circle canvas.set_color (LinSrgb::new (255.Univer 255.153.Universe 255.51.Unix 255.))

In the original code, the circle is just scaled in the middle position by scale, which is a bit dazed.

Combined with a little bit of background knowledge of writing code, generally speaking, visual libraries with drawing functions use a two-dimensional or three-dimensional vector as position parameters, rotation with a 3X3 matrix and other routines.

Combined with a little knowledge of linear algebra, the outer layer of a vector multiplied by a fixed coefficient should still be a vector.

So let's just copy and paste the above code responsible for deformation next to the location matrix and do a multiplication to change the scale of the center of the circle, such as x and y.

In this way, the visual error similar to the visual error of shooting a bouncing ball downward by a high-altitude camera can be realized, copy and paste and walk (mainly lazy).

Canvas.paint (Filled (Ellipse::circle (world.center () * ctx.time.as_secs_f32 (). Cos (). Abs (), radius)

After modification, run it to see the effect, and it's all right.

Thank you for reading this article carefully. I hope the article "what are the characteristics of valora under rust" shared by the editor will be helpful to you. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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