Messages

1

Graphics / Re: overlaying text onto graphics

« on: August 14, 2014, 05:15:22 pm »

Thank you for the replies.

I currently use the Intel IPP library for my image processing. It has routines for alpha blending one image on top of another image. I have that all implemented and working in my code--I can overlay a smaller camera feed on top of a larger background camera feed. I am not currently using SFML so none of my current code uses SFML for any rendering.

I did not realize that text is render in the GPU. My application is a headless multi-Xeon server app and currently does not have a graphics card installed in it. In my code development, I only use the motherboard graphics to display the System Monitor so I can monitor the thread usage. (I have considered adding a dedicated GPU for image processing if the Xeons run out of cycles--but for now I still have plenty of unused cycles because the Xeons are all multi-core).

Laurent, you are correct in that the alpha blending code is not SFML as I explained above.  Currently my need is for a text rendering library. You have stated my intent more clearly than I did in that the need is to be able to render text directly to memory. The SFML API is so nicely designed that I was attracted to it and was wondering if it would fit my needs.

Thanks again for all your counsel and help.

-Andres

2

Graphics / overlaying text onto graphics

« on: August 14, 2014, 08:12:46 am »

While I was searching for some text libraries for linux I came upon SFML and it really looks nice. This appears to have one of the cleanest and nicest OO/C++ APIs that I have ever seen.  Very nice indeed.

I am currently developing a video application that uses several camera feeds. My code directly deals with the raw video data usually in RGB 24 bit format.  I need to be able to overlay text on top of the video. I have the overlay part working in that I have picture-in-picture working and now I want to add alpha blended text overlays on top of the video.

What I am looking for is a way to generate the rendered text in a raw buffer so I can overlay it on top of my video and I am wondering if this API will work for me.  However, it appears that this API is so well designed that I do not see how I can access the raw buffer pointers of the sf::Font and sf::Text classes.  I need to be able to render the dynamic text (which it appears SFML will do very nicely) and then have access to a pointer to the internal buffer of the rendered text so I can alpha blend the rendered text buffer onto my video buffer.  I have all of the alpha blending working--all I need is the text rendering part.

Can this be easily done with the SFML libs?

Thanks,
-Andres