gdi+ - How do applications like Firefox calculate text height efficiently? -

I'm curious about what techniques fast applications (probably Safari is a better example), long page of text (e.g. For, chat logs or a big document).

Considering that there is a large amount of text with the height of the same row, it is already something that can be multiplied by the number of those lines, though, how it will know How many rows would one and be in a specific width?

What I can come up with is that they:

• Calculate the width of each character and submit it for quick addition
• Use this to calculate the width of the words,
• Add words and spaces to the spaces while comparing with blocks - the width of the small, adding lines according to the need.

It seems very fast, because there is an additional and comparable way, a faster way than measuring a string in GDI +. But I do not know that such a thing has been done, because credibility comes first, and AAAIK text rendering usually introduces Carning, and I do not know how easy or difficult this information is from GDI +.

Also, I also believed that Firefox calculates the size and position of each letter.