How to make a Widget slide view with Qt4? - animation

I currently display several widgets (quite large ones, almost screen-wide) on a QStackedLayout, let's call these widgets "pages". Switching from a page to another is done with buttons below (previous, index, next).
I would like pages to slide while switching, as if they were placed on a larger-than-screen row, moving left or right depending on what the user wants.
For this I thought the QScrollArea would be OK, but I can add only one widget to it and I cannot index sub-items to move accordingly nor can I force a per-item-scroll (I don't want the sliding movement to stop between two pages.)
Another option is the QListView or other derivate from QAbstractItemView, but I can't find how to pass a widget as a QListItemModel or other reimplemented QAbstractItemModel. Roles for data are quite limited, and none seem to allow QWidgets.
How can I proceed to achieve this?

It seems using a QScrollArea and scroll programmatically using the inherited scrollContentsBy() would do the trick. The viewport then would be an elongated widget, sliding left or right so one section could be seen at a time.

Related

Implementing a "fisheye" view with a ListBox

I am new to Windows Phone Programming. In my application, I Have a listbox which lists the phone contacts. Currently it is listed as a regular list with equal size for list items in the UI.I am looking to modify the front end like this :
I dont want to have different sizes /back ground color for each list items rather a fixed UI and let the lists scroll through it and the list item in the view, at any time, should be displayed as in the picture.
I dont expect any codes as answers but any examples are welcome too, just want to know using what feature this kind of functionality is possible so that i can do my reading!
Thanks,
Deepak
It would be difficult to modify an existing control (ListBox for example) to act like this, so your best bet would probably be an ItemsControl with its RenderTransform set as a TranslateTransform.
If you place a Rectangle (with Fill="Transparent") over the ItemsControl, you can attach handlers to the ManipulationStarted, ManipulationDelta, and ManipulationCompleted events to control the "scrolling" by setting the TranslateTransform's Y offset.
To resize the items in the list there are two options: a custom panel or manual setting.
Custom Panel
You could create a custom Panel implementation that will appropriately resize its Children based on a property you would create to represent the scroll position. Set the ItemsControl to use your panel, and either through binding or attaching a handler to the panel's Loaded event and keeping a pointer to the panel, update the aforementioned property from inside the ManipulationDelta handler.
Manual Setting
From inside of the ManipulationDelta handler, you can also calculate the various heights of the boxes and use MyItemsControl.ItemContainerGenerator.ContainerFromIndex to get the visual for each item and set its height.
I would suggest putting this all inside of a custom UserControl.
You may have issues with clipping using the TranslateTransform but hopefully this will get you started. Unfortunately, this looks like a rather difficult control to try making as your first windows phone project!
So Finally I did manage to find a way to do it.
First approach was as #Murkaeus suggested, Using UserControl and ManipulationDelta event handler. However for some reason the manipulationDelta event was triggered only for 2 finger gestures (Zoom, Pinch..etc), I have no clue why. And after some trying I had to give up on this.
The next approach was using Listbox itself. The source of the Listbox was set as the List( of Models objects) that I create after reading the contact information from phone. The height and color of the listbox item was bound to a property in my model named "scaleLevel" and was accordingly converted by implementing IValueConvertors to give predefined color and height values for different scale levels.
I created an attached property for the scrollviewer vertical offset like mentioned [here] (http://www.scottlogic.co.uk/blog/colin/2010/07/exposing-and-binding-to-a-silverlight-scrollviewer%E2%80%99s-scrollbars/)!
This event is triggered on change of the vertical offset and every time there is a scroll, I find out which listbox item to be enlarged and which reduced based current vertical offset.
Once I have this information, I change the property ("scaleLevel") of the affected items in the List (of Model) (which is bound to listbox height and color). This change is updated in UI using the INotifyPropertyChanged Event.
I have no idea if this the best way of doing it , but it works well and there is no considerable in updating the UI despite the processing involved.
I would like to hear your opinion about the implementation and any other solution which you feel will work better.

Drawing on an image which is inside a QScrollArea?

If I subclass QLabel and I add a QLabel directly to my QDialog, it works fine. If I add this label inside a ScrollArea, the thing I’m drawing doesn’t show unless I resize the dialog itself. Yes, weird.
I’ve setup compilable example code that indicates what the problem is. What I am trying to do is to select an area of an image with my mouse, by drawing a rectangle on the corresponding area. The images my program is designed to work with can be very large, and thus, I need to have a scroll area so as the dialog to stay at a logical dimension, and not to fill the entire screen (or even multiple workspaces, if we are talking about a linux machine with multiple desktops).
Everything works fine, except that the drawing (selection-rectangle) isn’t visible unless the dialog is resized – manually. I think I have to update something while drawing, but I’m not sure what. Well, here’s the example code: http://paste.ubuntu.com/1151553/
Another issues that I don’t know how to solve (and I want your suggestions there) are (1) when the user is selecting an area, how to set it to automatically scroll when the user actually selects an area by pushing against to a wall of the scroll area (I guess I am understandable here). (2) is there a way to let the user select a rectangle and then, when he left-clicks on a position with holding down the [Shift] button, the bottom right edge of his previous selection to actually go through the point he clicks at?
The documentation indicates that you have to set a Layout somehow somewhere, but I'm not sure how to do this to my occassion.
Thanks in advance for any help.
about problem (1):
just use of Event. i think mouse Enter Event or Leave Event is good for that.
and to do that i think you can use a hidden rectangular that fill the whole of the screen.
and over write the mouse leave Event for that rectangular and tell in that function , to scroll the page.

GTK# - Problem with components overlapping upon resize

I have a panel containing a form (elements such as labels and textboxes within a table) and 3 buttons (in an hbuttonbox) at the bottom-right. If I shorten the panel by dragging the bottom border upwards, the 3 buttons come with it, and lay on top of the other form components, causing messy graphics. I would like the panel to not resize smaller than the bottom edge of the last component within it. Due to employer restrictions, I am not able to show a screenshot of the GUI. I will try to make any clarifications that are asked.
This probably has something to do with some resizing or general size settings on the components, but there are so many options that I'm not sure where to start.
Any ideas for an easy fix to this without getting down into the complicated nest of components? If not, any ideas on where I should start messing with settings?
Thanks!
UPDATE:
Everything is contained in a VBox with 3 cells. Elements in cells (top to bottom): Table, ScrolledWindow, HButtonBox. The ScrolledWindow bottom edge also moves (resizes) with the bottom edge of the panel when resizing, until the panel bottom goes above the whole ScrolledWindow. Then the buttons keep moving up, staying in relation to the panel's bottom edge.
By "form" do you mean you are using a Gtk.Fixed to contain your table and buttonbox? Then that's probably what's going wrong - you should use vboxes and hboxes for your layout. These will resize properly. Fixed layouts are only for exceptional cases.
EDIT:
Other suggestions:
Perhaps the HButtonBox has pack type 'end' instead of 'start'?
You could try playing with the 'fill' and 'expand' packing properties of the VBox's children.
I ended up adding a Height Request to the container, just slightly longer than the part of the scrolled window. This now stops resizing to where the bottom buttons would overlap the components above it. The problem (before the fix) is shown below:

Which is better, some grids collapsed or some user controls?

I'm developing a Windows Phone 7 application that uses some Transient content.
To avoid to go back to that transient content I've decided to use a phew page with several grids on the same page.
When I have to show another "page" I set to collapsed current grid and then I set to visible desired grid.
I know this can be done using user control, but I'm not sure if using user controls can be slowest that using Grids. Any advice?
And another question is if I use grids, how can I use page transitions?
Another option for when you want to show transient content is to use a Popup control. This won't appear in the navigation stack, so when a user goes back (<-) they won't see this content.
However, Popup content isnt GPU accelerated, so you only want to display simple content, no animations etc...
If you want page transitions etc... then i think your only option is to use Pages. That way you can do the transitions and the back button works as expected.
It doesn't matter if you do this via user controls or grids - what matters speed wise is the complexity of your layout.
A user control may be better if you are doing this on a number of pages so you don't repeat yourself.
One way to do page transitions is to do it with stack panels. Have the second "hidden" stack panel way off to the right so it is off screen then animate it in.

Best animation to show addition/removal of list element

What is the best way to communicate visually that an element has been added to or removed from a list of items? (I'm going for usability, not gratuitous eye candy)
Slide the other items up or down to show the new item or hide the deleted item
Fade items in or out, but do not animate the other items
A combination of #1 and #2
No animation at all
Some other form of animation
I think a direct insertion with a progressive (and slow) change of background color would do the trick... I find it especially effective on SO itself.
Removing:
If you remove an item from a list, you can assume that this item is visible (because the user just selected it for removing), so just fade it out (maybe with a flashing effect).
Adding:
If an item is added to a list then scrolling isn't a good alternative because it isn't something that the user initiated directly. He maybe has to scroll back then. That would be a penetrating behaviour.
As an alternative just show a flashing information message next to the list, that the new item had been added.

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