Text object

Design a Text object that allows you to set its size, color, and value. Its most important feature is to retrieve the text width and height so that developers can check whether they fit in a given region. For example, the feature allows you to check whether the text could fit inside a box of a given height and width.

A possible solution would be to create an image object, drawtext on it, then retrieve the objects resulting width and height as described [here](https://stackoverflow.com/questions/24190327/getting-the-dimensions-of-a-rendered-text-in-cimg-library). The suggested code is shown below for reference:

```cpp
CImg imgtext;
unsigned char color = 1;
imgtext.draw_text(0,0,"Hello guys !",&color,0,1,23); // Draw with font height 23.
// Now, imgtext.width() and imgtext.height() gives you the dimensions you want.
```

从链接的 CImg draw_text 示例开始，确定 Text 对象应如何提供 size、color、value 以及渲染后的尺寸。完成的标准是开发者可以设置这些属性，并获取 width 和 height，以检查文本是否适合指定区域。

由索引模型根据 Issue 内容生成。