A Bump in the Road

Today I thought I'd add in the special keystrokes to the editview. There are three groups of them: a set that interact with the Find dialog (^f, ^g, etc), and these I'm deferring until I actually work on the Find panel; a bookmark set, (ctl-1 to 9 to jump to a bookmark, ctl-alt-1 to 9 to set one); and ctl-plus/minus to zoom. All of these were implemented and working in version 1, using the keyPressEvent() method to trap the keys.

So I messed around and tidied up the constants that define the various groups of keys as sets, so the keyPressEvent can very quickly determine if a key is one it handles, or not: if the_key in zoom_set and so on.

With the brush cleared, I copied over the keyPressEvent code from V1 and recoded it (smarter and tighter) for V2 and ran a test, and oops something is not working.

Specifically, it is no longer possible to set bookmark 2 by pressing ctl-alt-2. On a mac, that's command-option-2, which Qt delivers as the Qt.ALT_MODIFIER plus Qt.CTL_MODIFIER and the key of Qt.KEY_2.

Or rather, it used to do that. I fired up PPQT version 1 just to make sure. Yup, could set a bookmark using cmd-opt-2. But not in the new version. Put in debug printout. The key event delivered the same modifier values, ctl+alt, but the key value was... 0x2122, the ™ key? And cmd-alt-3 gave me Qt.KEY_STERLING, 0xA3. And cmd-alt-1 is a dead key.

Pondering ensued. OK, these are the glyphs that you see, if you open the Mac Keyboard viewer widget and depress the Option key. So under Qt5, the keyboard event processor is delivering the OS's logical key, but under Qt4 in the same machine at the same time it delivers the physical key.

Oh dear.

I spent several hours searching stackoverflow and the qt-project forums and bug database but nothing seemed relevant. I posted a query in the Qt forum. But I have little hope. It looks very much as if I'll have to change they key choices for bookmarks, and make them platform-dependent. In Windows and Linux they can continue to be ctl[-alt]-1 to 9, but in Mac OS this will change. The only reliable special key modifiers are control (Command) and meta (the Control key!).

In V1 it was great that I could document just once at the top of the docs, that in Mac, "ctl means cmd" and "alt means option". And that was consistent throughout. Now it won't be because the Option key is effectively dead for my purposes. I'll have to tell the mac user, "when I say control I mean command, but when I say alt, I mean control." Won't that be nice? Plus, I'll have to have code that looks at the platform and redefines the key sets for Mac at startup. Very disappointing.