TextEasyWriting can put texts on the image and save it.
it is not only the straight line, but also the shape of the diagonal and the circle.
And make outline text.

if share apps are on your phone such as mail, twitter, and facebook, the image that you've just made can be transmitted. The image is saved before transmitted.

How to
Please input by a keyboard or speech in the text box of the upper part.
Turn on the button of "Text on". And scrolling would be stopped.
Touch on the image in order to decide an initial point, slide your finger to the terminal.
Turn on the button of "Text off", When you want to let a screen scroll.
Font is selectable by default in Android.
Color is changeable by the value of the seek bar.
Turn on the button of "Outline on".
The hemming makes the symmetric color of the text color.
The straight line outputs texts from the initial point to the terminal direction.
Circle outputs texts to clockwise direction or the counterclockwise direction from the initial point.
A radius of circle is half distance of the terminal from the initial point.
You can input an image from the camera or a picture folder of the dafault.
The output is right under a picture folder. 
The file name consists of date and time. The extension is JPG.
Because the original image is only input, don't worry.
Large size input file causes out of memory. Sorry.