Set color to a single point in Cairo

[Luis via Digitalmars-d-learn]

On Sunday, 20 December 2015 at 01:17:50 UTC, Basile B. wrote:
> On Saturday, 19 December 2015 at 14:16:23 UTC, TheDGuy wrote:
>> is it possible to set the color of a single pixel with Cairo?
>
> Not like you would do with a classic canvas (2d grid), because 
> colors are applied with `cairo_fill()` and `cairo_stroke()` on 
> a particular path.
>
> but you can define a path that represents a single pixel and 
> fill it:
>
> ```
> cairo_rectangle (cr, x, y, 1, 1); // 1 pix rectangle
> cairo_set_source_rgba (cr, 0, 0, 0, 1); // color
> cairo_fill (cr); // fill the rectangle with source rgba
>
> ```
>
> However cairo is node made to be used like this. The workflow 
> is usually more based on stacked layers (1 layer = 1 path) with 
> different filling, different transparency.

I did something similar here : 
https://github.com/Zardoz89/DEDCPU-16/blob/master/src/lem1802_fontview.d#L287

I need to clean these code...