I am somewhat confused by the buttons across the top of all of the windows ("Welcome!", "The Choice", "Partitions", etc). I imagine much of their functionality is dictated by Gambas but they seem to violate some of the principles of user interface design. In particular, the outlining of the button for the currently active window. A button is outlined to signify that it is the Default action to be taken if RETURN is pressed, not to indicate the current "tab" in a set of windows. Since the result of clicking on the outlined button in the current setup would be to redisplay the same screen (presumably), it is therefore effectively just a Cancel operation. If the Default operation of a screen is Cancel, all of the HIGs with which I am familiar recommend that no button be outlined.
The WelcomeThis looks great and seems very intuitive. My only criticism is the above mentioned issue with the outlined "Welcome!" button. For this screen, it would seem safe to make the "Start" button the Default action and therefore it should be outlined.
The ChoiceAlmost perfect aside from the Default action. In this case, I would propose there be no Default action as all three of the options are equally valid.
Partitions ToolI personally dislike the "You have been WARNED!" attached to the "Full disk" blurb. It is unnecessary, seems patronizing, and serves as something of a distraction -- the user has just been presented with the suggestion that having multiple disks affects his decision and should be permitted a chance to absorb that concept.
I am presuming that the buttons "GParted", "cfdisk", and "Preset strategies" will fork the process off to another window where those specifications are made. If this is the case then those buttons should have ellipses after the text to indicate this ("GParted...", "cfdisk...", and "Preset strategies..."). I realize that ellipses detract from the "beauty" of the interface but they are something of a standard "hint" for buttons which bring up a dialog for further input.
Personally, I think that any external utilities should be hidden from the user (except for "Advanced" installs) and "wrapper" user interfaces consistent with the rest of the GUI install written. I realize that this is extra work but I felt it should be mentioned as the ideal.
PackagesLooks good aside from the previously mentioned issues of specifying (or not) a Default action and adding ellipses (in this case, to the "By groups" and "Manual" buttons).
ConfigureThis window looks good. My only concern would be about "Other configurations": to be symmetrical with "Boot manager", there should be a grouping of buttons for "Config 1", another grouping for "Config 2", et cetera (unless I am misinterpreting those other configurations).
Go for it! For this window, I assume the install is already in progress and the message "Ready to install" should be updated to say "Installation in progress" or somesuch. If the screen capture is actually showing the program waiting for user input (i.e., actually "ready to install") then there should be a 'proceed' button (or somesuch) underneath the "Ready to install" label.
ToolsLooks good. Even the lack of ellipses could be justified as they might lead to confusion. I would only restate my distaste for the "You have been WARNED!" admonition.
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I don't mean to sound overly negative; I actually think it is a phenomenally good interface design. I also imagine I have misinterpreted what is being presented in some cases and that in others, your designs are so preliminary as to have not yet address some of the aspects I mentioned.
My main point of contention would be the outlining of the header buttons along the top. Hopefully there will be some other way provided by Gambas to signify the "active page"; outlining of a button is already taken. (I don't think a "tabbed" approach would be desirable here, either. Tabs tend to place things on an equal footing whereas your buttons have a "sequence" associated with them.)
