How to implement text selection?

Question

My question is not language based or OS based. I assume that every system offers some kind of TextOut (text, x, y) method. I am looking for some recommendations or articles on how I should implement the selection of the displayed text. Could not find information about this.

The only thing that comes to my mind is this:

When a user clicks on a point on a text canvas, I know the coordinates of that point. I need to calculate exactly where it will be in my text buffer. Therefore, I go from the beginning of the buffer, and I apply a style (if any) to each character (or block of text). After that, I know that after this style the letter gave a size. I add its width and height to the previously calculated X, Y coordinates. Thus, I move the buffer until the calculated position reaches the point that the user clicked on. After I reached a point within a certain offset, I have a starting point for selection.

This is the main idea. I do not know if this is good, I would like to know how this is done for real, for example, in Firefox. I know that I can browse the sources, and if I have no choice, I will do it. But first I try to find an article about this ...

Answer 1

The choice of text is inherently specific to the control that contains it, and means that it saves that text.

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Answer 2

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