Delete erases logical clusters, whereas backspace erases logical characters.
We don't see any discrepancy in how ICU/Openoffice does deletion (not yet anyway). Regards Rajeev J Sebastian On Thu, Jul 21, 2011 at 11:57 AM, [email protected] <[email protected]> wrote: > > > On 21 July 2011 11:27, Harshula <[email protected]> wrote: >> >> Hi Shriramana, >> >> On Thu, 2011-07-21 at 09:27 +0530, Shriramana Sharma wrote: >> > On 07/21/2011 09:04 AM, Pravin Satpute wrote: >> >> > > 1) In pango we have faced problem of backspace due to decomposition. >> > > i.e. U+0958 was getting decomposed into U+0915 and U+093C, so for >> > > entered character was required 2 backspaces to delete. >> > >> > That doesn't sound right. The backspace should erase the last character >> > that was input. Rendering engines should only take care of rendering >> > whatever sequence of characters has been input and not change the >> > sequence of characters right? >> >> That's a bit simplistic. When a smart input method engine (IME) is >> activated, it can make sure that a backspace erases only the part of the >> glyph that the last keystroke inserted. e.g. It takes four keystrokes to >> generate කෝ (Sinhala syllable) with a particular IM. Another IM requires >> only two keystrokes. Each of these IMs controls how the backspace key >> operates and only deletes the part of the glyph inserted by the last >> keystroke. >> >> However, when the smart IME is deactivated, backspace then becomes >> someone else's responsibility. Here we see behaviour differences. e.g. >> For කෝ , Pango/gedit deletes in decomposed form (press backspace 4 >> times) and ICU/OpenOffice deletes in composed form (press backspace 2 >> times). >> >> Perhaps, there should be a separate discussion on which behaviour should >> be the default? >> >> Also, IIRC, Pango had a separate module that handled the cursor >> movement. I remember having to modify it for Sinhala. >> > > Looks like we are going off topic little bit so changed subject line, but i > would like to ask one thing > is there any standard define for Backspace and Delete keys behaviour? I > think Unicode has given this but i have not find it yet > anyone knows anything? > > Regards, > Pravin S > > _______________________________________________ > HarfBuzz mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/harfbuzz > > _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
