Arabic was written by hand for a very long time after printing reached the lands where it was used, and the delay was neither accidental nor simply a failure to adopt a technique. Movable type suits a script whose letters have one shape each. Arabic letters have up to four, they join, and the joins are not mechanical: a well written line adjusts the length of a connecting stroke, stacks certain combinations, and treats the ligature of lam and alif as a single mark. Reducing that to a case of sorts meant either a very large font or an ugly page, and early European attempts at Arabic type produced both.
Printing in Arabic characters began in Europe in the sixteenth century, largely for the use of scholars and of Christian missions, and presses working in Arabic operated in the Ottoman lands from the eighteenth century. Copying by hand continued alongside them, and for Quranic manuscripts the manuscript remained the norm long after other books were printed, because copying was itself an act with religious weight and because the accuracy of the text was guaranteed by a trained scribe rather than by a compositor. Lithography offered a compromise that several traditions preferred: the page was written out by a calligrapher and then reproduced photographically, so the hand survived the multiplication. Much of the printing of Persian and Urdu was done this way, and nastaliq in particular resisted type entirely.
Digital typesetting returned to the problem and solved it differently, by having software choose the form of each letter from its neighbours at the moment of display. That is why an Arabic string stored as a sequence of abstract letters renders as connected writing, and why an isolated letter in a table is a citation form rather than a picture of how it appears in use.