First of all, you need to specify data export format by adding a parametr to
You'll get an xml response that for each recognized character will contain an instance of
The XML you get is synthesised according to this schema.
Those "l", "t", "r", "b" params stand for left, top, right and bottom, they describe a rectangle of each character with top-left and bottom-right corner. I beleive that's exatly what you are looking for.
The element will contain the coordinates in page pixels - the same XML also contains a
where the image width and height are stored. So
Also it's worth mentioning explicitly that all coordinates are in pixels - they are completely resolution-agnostic. This is why whenever you try to highlight anything on an image you have to take zoom into account - the image will likely not be always displayed as is by your device software, but will be downscaled and so you have to map page coordinates onto your zoomed-out image coordinates and highlight appropriately.