Integrating Qt Quick components in Ministro

BogDan bog_dan_ro at yahoo.com
Thu Feb 2 14:19:59 UTC 2012 


Hi,

    Excuse me if I'm wrong, but why we don't do the same technique as Nokia did with qml components for desktop ? They are using the application current QStyle plugin to paint all qml controls ! Is there any reason not to do the same thing ?

Cheers,
BogDan.

> 
>
>There is the possibility of encapsulating widgets in QGraphicItem (as QGraphicWidget), thus allowing them to be used in QML.
>
>I don't know how these QGraphicWidget's handle QStyle, though....
>
>- Chris -
>
>
>On Thu, Feb 2, 2012 at 14:28, BogDan <bog_dan_ro at yahoo.com> wrote:
>
>
>>
>>Hi,
>>
>>
>>Yes ! BorderImage seems to be exactly the same thing with NinePatch, thanks for the tip !
>>
>>
>>   Anyway, as I said before I'd like to have a QStyle plugin which paints the classic widget also the qml ones, because it seems classic widgets are sill use by a lot of people !
>>
>>
>>Cheers,
>>
>>BogDan.
>>
>>
>>
>>----- Original Message -----
>>> From: Kate Alhola <kate.alhola at gmail.com>
>>
>>> Sent: Wednesday, February 1, 2012 10:59 PM
>>> Subject: Re: Integrating Qt Quick components in Ministro
>>>
>>
>>> Some quick look comments:
>>>
>>> On Wed, Feb 1, 2012 at 9:20 PM, BogDan <bog_dan_ro at yahoo.com> wrote:
>>>>  Hello everyone,
>>>>
>>>>    I have good news on this topic, I manage to check (a little bit)
>>> Android's source code and to extract, the exact, android's look and
>>> style informations for a few widgets (buttonStyle, editTextStyle,
>>> radioButtonStyle, checkboxStyle, etc.) and store them into a .json file (check
>>> the attachment). Because qt 4.x doesn't come with json support, IMHO we have
>>> two options:
>>>>    1 - to use this [1] qt json implementation.
>>>>    2 - or to backport Qt 5.x json implementation (my favorite option,
>>> because it seems more complex and complete than the first one).
>>>>
>>>>    I need more time to finish the extraction class (which will be part of
>>> the next Ministro release), so, if someone wants to step in and begin the Qt
>>> implementation it will be very appreciated !
>>>>
>>>>    To understand how android paints the widgets you have to check a simple
>>> widget how it's painted. So let's check Button class [2], which extends
>>> TextView class [3] which extends the View class [4].
>>>>
>>>>  How it works:
>>>>    - Button class only pass to its super class (TextView)  the style
>>> attribute (com.android.internal.R.attr.buttonStyle)
>>>>    - TextView class pass the same information to its super class (View) then
>>> in its constructor (check "public TextView(Context context, AttributeSet
>>> attrs, int defStyle)" ) extracts text informations
>>> (e.g.TextAppearance_textColor,TextAppearance_textSize, TextAppearance_typeface,
>>> etc.) which are used to draw the text (check onDraw (...)).
>>>>    - View class in its constructor (check "public View(Context context,
>>> AttributeSet attrs, int defStyle)") extracts a few informations e.g.
>>> View_background, View_paddingLeft, etc. which are used to paint the basic parts
>>> of the widget (e.g. the background).
>>>>
>>>>    If you check the json file, you'll see that there are more than one
>>> .png files used to paint the background, one for every view state (enabled,
>>> disabled, pressed, etc.). Android split every .png file into nine pieces (it
>>> uses nine patch technique [5], [6]) which are used to seamlessly resize the
>>> widget. AFAIK there is no support for such a thing into Qt, so IMHO this is the
>>> first thing which must be implemented.
>>>>
>>>
>>> The nime patch looks exactly same than Qt BorderImage (
>>> http://developer.qt.nokia.com/doc/qt-4.8/qml-borderimage.html )
>>>
>>>
>>> Also, system that uses different images for different states is
>>> exactly same that is used on components
>>> meegotouch-button-background-pressed.png
>>> meegotouch-button-background.png
>>> meegotouch-button-background-selected.png
>>> ....
>>> and this for all combinations, inverted, disabled ...
>>>
>>> The problem then comes more than could we do some mapping of Android
>>> and MeeGotouch states like
>>> meegotouch-button-background -> buttonStyle_View-background_Enabled.png
>>>
>>> MeeGocomponents uses mthemedaemon plugin that fetch images, so, if we
>>> could make just mapping names
>>> and json query, we could in theory get theme engine.
>>>
>>> Symbian components uses svg images , meegocomponents borderimages .
>>> There is very little
>>> difference in component API's. Least what I have used, porting on apps
>>> were mostly changing import statements
>>> and change of some colors.
>>>
>>> Kate
>>>
>>>>  This weekend I hope to have enough time to create a wiki page which will
>>> describe the content of the json file.
>>>>
>>>>  Cheers,
>>>>  BogDan.
>>>>
>>>>
>>>>  [1] https://github.com/ereilin/qt-json
>>>>  [2]
>>> http://www.java2s.com/Open-Source/Android/android-core/platform-frameworks-base/android/widget/Button.java.htm
>>>>  [3]
>>> http://www.java2s.com/Open-Source/Android/android-core/platform-frameworks-base/android/widget/TextView.java.htm
>>>>  [4]
>>> http://www.java2s.com/Open-Source/Android/android-core/platform-frameworks-base/android/view/View.java.htm
>>>>  [5] http://developer.android.com/reference/android/graphics/NinePatch.html
>>>>
>>>>  [6]
>>> http://developer.android.com/guide/topics/graphics/2d-graphics.html#nine-patch
>>>>
>>>>
>>>>>
>>>>>  Hi,
>>>>>
>>>>>     Yes, sadly we have to get our hands  very dirty.
>>>>>     First step is to identify all Qt components then we have to find
>>>>>  Android's corresponding components, then we must extract the style
>>> &
>>>>>  look information to a central location (IMHO Ministro should do this
>>> job), then
>>>>>  any application which starts will peek this infos from that location
>>> and use
>>>>>  them to paint all controls.
>>>>>     Second step is to check how Android paints the controls, here the
>>> things will
>>>>>  become dirty, we have to check
>>>>>  "frameworks/base/core/java/android/widget/TextView.java" from
>>> Android
>>>>>  source code and it seems we have to use a lot of private data, I hope
>>> the
>>>>>  Android versions are not so different.
>>>>>    Third step is to change Ministro in order to extract all the infos we
>>> need to
>>>>>  paint our controls.
>>>>>     Fourth step is to create a QStyle plugin (which will be used by QML
>>> as well)
>>>>>  which loads the data extracted by Ministro and use it to paint the
>>> controls. If
>>>>>  the extract procedure is very fast (less than 10ms), I doubt it will be
>>> that
>>>>>  fast :),  we can skip the third step and extract the data directly in 
>>> QStyle.
>>>>>     Fifth step, if everything works, we must get drunk !
>>>>>
>>>>>
>>>>>  Cheers,
>>>>>  BogDan.
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>  While I don't agree on "almost all applications have the
>>> same
>>>>>  look" (as far as I can see, the only fully common UI element is
>>> the
>>>>>  menu/toolbar combo), I respect your choice.
>>>>>>
>>>>>>  The first step would be to define what is the "Android
>>> style". Is
>>>>>  there some Google guidelines you plan to follow?
>>>>>>
>>>>>>  Regards
>>>>>>  - Chris -
>>>>>>
>>>>>>
>>>>>>  On Tue, Jan 3, 2012 at 17:45, BogDan <bog_dan_ro at yahoo.com>
>>> wrote:
>>>>>>
>>>>>>  Hi,
>>>>>>>
>>>>>>>
>>>>>>>    I think none of your examples are good to follow :) The
>>> reason why
>>>>>  meego doesn't use QtStyle to draw the widgets is because meego
>>> doesn't
>>>>>  have a "native" style. Symbian is even worst, open any two
>>>>>  applications on symbian and you'll see that none of them have the
>>> same look
>>>>>  & style :) On Android is a different story, almost all applications
>>> have the
>>>>>  same look & style, so if we want to have a first class citizen
>>> port, all Qt
>>>>>  applications *MUST* look the same as any android application. I'm
>>> choosing
>>>>>  to make QStyle plugin because this way all Qt applications will benefit
>>> from it,
>>>>>  either they are made using old-fashion widgets or QML components.
>>>>>>>  For me a good android style is a top priority, I don't
>>> believe
>>>>>  I'll have enough time to finish it till beta 1 but who knows ...:)
>>> maybe if
>>>>>  other people will join me we can split the work and we can have this
>>> feature in
>>>>>  time for beta1.
>>>>>>>
>>>>>>>
>>>>>>>  Cheers,
>>>>>>>  BogDan.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>>  and please note that the Qt quick components (either
>>> symbian or
>>>>>  meego) don't use Qt widget styles. All the components are drawn in
>>> qml so
>>>>>  the componenets would unfortunately not benefit from your work on a
>>> widget
>>>>>  style.
>>>>>>>>>  - Chris -
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>  On Thu, Dec 22, 2011 at 21:53, BogDan
>>> <bog_dan_ro at yahoo.com>
>>>>>  wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>>  Hi Chris,
>>>>>>>>>
>>>>>>>>>  Please accept my apologize for the slow reply.
>>>>>>>>>  I think before we'll integrate the components into
>>> Ministro,
>>>>>  we must do a few things:
>>>>>>>>>   - the components MUST use Android's style, next
>>> year
>>>>>  I'm planning to create a style plugin for
>>>>>>>>>
>>>>>>>>>  widgets which should be used by Qt Quick Components for
>>> Android.
>>>>>>>>>   - wait until Nokia finishes to define the API for Qt
>>> Quick
>>>>>  components [1]. We can't afford to break the API after we release
>>> it :)
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>  Cheers,
>>>>>>>>>  BogDan.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>  [1]
>>> https://bugreports.qt.nokia.com/browse/QTCOMPONENTS-200
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>  Hi guys,
>>>>>>>>>>
>>>>>>>>>>  What would the steps be to integrate the Qt quick
>>> components
>>>>>  for Android to Ministro as a package?
>>>>>>>>>>
>>>>>>>>>>  - Chris -
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>  _______________________________________________
>>>>>  Necessitas-devel mailing list
>>>>>  Necessitas-devel at kde.org
>>>>>  https://mail.kde.org/mailman/listinfo/necessitas-devel
>>>>>
>>>
>>
>
>
>

More information about the Necessitas-devel mailing list