GTK3 applications can be styled and themed with CSS. How can I force GTK to use solely the CSS shipped with my application, instead of combining / cascading it with the theme installed on the user's system?
Why would one want to do that? In theory, CSS would be a great rules-based styling system, where you just add one screen full judiciously chosen rules to define the looks of your application consistently. Unfortunately, in practice, people tend to add hundreds of brain-dead, repetitious definitions into their stylesheets, thereby counterfeiting the very nature of cascading.
The actual problem is that my application shall get the typical, subdued dark-grey look of a media handling application, irrespective of the global theme installed on the user's system. From reading the GTK documentation and the GTKmm tutorial, I came up with the following code to read my own CSS stylesheet:
auto screen = Gdk::Screen::get_default();
auto css_provider = Gtk::CssProvider::create();
try {
css_provider->load_from_path(lib::resolveModulePath (stylesheetName, resourceSerachPath));
} catch(Glib::Error const& failure) {
WARN(gui, "Failure while loading stylesheet '%s': %s", cStr(stylesheetName), cStr(failure.what()));
}
Gtk::StyleContext::add_provider_for_screen(screen, css_provider, GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
Technically this works perfect. However -- now I am forced to work "against" the CSS rules present on the user's system. If I start with setting a suitable border colour in the default rule and a dark grey background and suitable text colour in a rule for GtkWindow, plus some rule for text entry fields, I get the desired look on some parts, but whenever the user's system theme adds a specific definition for some specific widget or widget combination, thereby repeating explicitly the colours instead of inheriting them from a generic rule, I need to add yet another specific rule into my application style sheet to fix that specific case. That is, the possibly ill-guided structure of the installed system theme forces my application stylesheet into the same ill-guided bad practice and have hundreds of single-case definitions repeating the same values over and over.
Questions
How can I tell GTK to use only my stylesheet for my application?
Is there any viable alternative, which is not so radical, yet still allows me to use CSS the way it was intended to be used (minimal set of rules + cascading)?
You can use the reset.css file from the GTK demos to unset all existing rules.
A less radical alternative might be to just ignore user themes other than the default. Presumably if a user has a theme built with bad CSS practices, they nonetheless like that theme. So why shouldn't they be able to view your application with their preferred theme?
as pointed out by #ptomato, you can install a CSS to effectively override any pre-existing other rules on the system. However, this also shows a way towards a less radical solution: just cancel out the problematic parts of the pre-installed theme.
How does it work?
We add catch-all rules to the CSS, i.e. rules which somehow select any possible element, or at least a complete subtree. This is achieved by using a wildcard * in the selector. And since we install our stylesheet with a higher priority (typically GTK_STYLE_PROVIDER_PRIORITY_APPLICATION), these rules will "stamp over" every specific rule which happens to be present with lower priority.
we can use the value unset to clear out a setting
we can use the value inherit to force the property to be derived from the parent widget's setting of this property.
Especially for the given problem to get "grey-subdued media application" look within a environment with a "light" theme, we can use
* {
color: inherit;
background-color: inherit;
}
...to cancel out only the problematic part of the pre-existing "light" theme, which is the background and colour setting. We can then set our own values once at a central point, and they will be inherited as expected.
We can even expand on that idea and treat further problematic settings within a given scope, by using the wildcard below a CSS contextual selector. And a key trick to get that right is to use the GTK+ inspector on your running application and investigate the actual settings to find the lowest possible point still to "grab" the problematic setting. (To activate the GTK+ inspector run your application with GTK_DEBUG=interactive path/to/my/app )
Related
I want to be able to create an simple internal theming system for my program (by internal I mean I don't need to be able to load custom themes from user system... all themes will be embedded inside the program itself.)
I can think of some ways:
simply put all color inside the main stylesheet of the program, every time the colors need to change, retrieve main stylesheet, parse and change the colors, and then reapply it again (or have multiple stylesheet with different colors, and apply them when its needed).
Create a top widget that only hold the colors for each widget, and then a child widget that hold other stylesheet for other styling, and all the UI as child of this widget... in this way we need to only change the first stylesheet.
... (not sure about other ways, but I'm sure there is some... maybe using QStyle or something..?)
I'm not sure what is the best way to achieve what I'm after, that will be best at both performance and the code itself...
I know the first way will be heavy in performance side, to each time change the whole stylesheet and rerender the whole program. (I think at least)
the second option though, I'm not sure how it will work, I mean its any better then the first one?!
or there is any other better methods..?
you should create a .qss file and add it in your .qrc like you add your icons.
then write all your stylesheet there. you can have multiple Style.qss files and these files are your themes and whenever you change it your theme will change.
add your Style.qss File in your Resources(.qrc)
write these codes in main.cpp
Load the application style
QFile styleFile(":/style.qss");
styleFile.open(QFile::ReadOnly);
Apply the loaded stylesheet
QString style(styleFile.readAll());
a.setStyleSheet(style);
For more information :
https://github.com/GTRONICK/QSS
https://github.com/ColinDuquesnoy/QDarkStyleSheet
How can I personalize a list within ServiceNow?
I mean, I have this list:
But I think its very confusing to see the position on the right side.. How can I center it?
Like CSS customization or JS or something like that.. where can I find the customization form?
You can customise the position of the field content by using Field Styles.
If you mean customising the position of the field header, I have had a play around with doing this and I seem to have got it working.
If you inspect the HTML of the column header you want to target (the th tag), you'll see that there's an attribute on it called glide_type which contains in it the type of column. You can use this to create a CSS rule to target only headers of a particular type.
For example, I have a field of type decimal, and the th tag has the following attribute:glide_type="decimal". So to target that element, I could create a CSS rule like the below:
th.text-align-left.list_header_cell[glide_type="decimal"] {
text-align: right;
}
The hacky part is including that CSS so that it applies throughout the SN interface. You can use a UI Script to run some JavaScript which includes the Style Sheet. So if you put the above CSS inside a new Style Sheet (navigate to Content Management > Design > Style Sheets), and copy that new Style Sheet's Sys ID, you can create a UI Script with the below in it to include that Style Sheet on all pages:
link = document.createElement("link");
link.href = "STYLE_SHEET_SYS_ID_GOES_HERE.cssdbx?";
link.type = "text/css";
link.rel = "stylesheet";
link.media = "screen,print";
document.getElementsByTagName("head")[0].appendChild(link);
After doing that, you'll see that the Style Sheet is getting loaded on all pages, and if you've written your CSS right then you should find that the column header is now right-aligned!
As #Kirk said, performing this kind of customisation will mean that it's hard for ServiceNow Customer Support to assist if there's something you've customised getting in the way of their troubleshooting. Take this into account if you decide to implement something like this, and also thoroughly test this on a non-production instance.
In addition to the above, this solution may break in future releases as ServiceNow may decide to change the way that lists work and thus the CSS selector may no longer target the right/any element.
Hope this helps!
Dylan
It's not suggested to customize any sort of CSS or JS with that, we were told that is voids your support for that section if you do so.
You could just add a few more display fields if you really desire to remove the extra white-space.
For a complete description of that (which you may know how to do):
Click the Gear icon
Then select some relevant fields from the Available section, and click the Right arrow to add them.
I'm making a game GUI API. It is coming along very nicely except for one aspect. I want themes similar to how GTK works. The way I want it to work is that every GUI element will have a default Windows9X-like way of drawing themselves. If it is found that a theme is set for that type of widget, it will be drawn with those bitmaps.
My original concept was to create a Theme class which would have getters and setters for the bitmaps.
for example:
themeManager.setButtonHover(Bitmap *bitmap);
The problem with this, is that it is not flexable if I want to create new types of Widgets. I may eventually want to create a superButton which would use a different theme than a button. This is the flaw with that concept. The concept I'm thinking of going with is that each widget type has static methods to set the theme for itself and the constructor uses that.
Are there better ways of doing this that I'm not thinking of? Since it is an API, I want to avoid reading text files, so reading the theme from a text document is not an option.
Thanks
May be template the superButton on a policy and then have a default policy which does the default and the user has the option of providing a different policy? The policy could then define the attributes of the button (such as the hover image etc.) - does what I describe make sense?
I have been away from C++ for a couple of years now doing AS3/Flex work. I have gotten used to being able to create a component and place it in design mode with very little fuss and I am struggling to get my head around the C++ Builder way of doing the same thing.
I have written many components for C++ Builder in the past, but none of them have been visual. What I would like to do now is create a component for customer search and another for order processing because I want to be able to create a new instance of these on the fly. What I don't want to do is have to place each of the components like the dbgrid and search fields manually in code. I would like to do this (as well as set their properties) in design mode.
How do I go about this? I have browsed the source for other Delphi components and I notice they have dfm files which seems to be what I need. How do I do this in C++ Builder? The only option I see is to add a new form if I want a dfm, but this isn't what I want as my components will be based on TPanel.
Is there a way to do this or do I have to resort to doing it all in code with no visual reference?
Pursuing the DFM idea I did a test this morning where I created a component based on TPanel and added a new form to it which I create and parent in the constructor of the component. In design mode I set the form border to none and placed a grid on it. This all looks OK until I place the component in my application, at that point it looks like a panel with a standard looking form in it and the grid is missing. If I run the app the panel shows as expected, borderless and with a grid. The DFM appears to be ignored in design mode for some reason.
If you know a better way to do this than using components then please give me some pointers.
Any help and advice will be appreciated beyond words
You might want to have a look at frames (look for "Frame objects"). They are "subforms" you can design visually and then place on forms.
Just as an FYI item, you can also drop the panel on a form, put any other controls on it, position them, set captions, etc..
Now, click the panel to select it, and use Component->Create Component Template from the IDE's main menu. This creates a unit you can install as a component which will add the panel and it's sub-controls (as a single component) to the IDE's component palette.
Of course, you can then modify the source for that new component like any other component source.
I'v done a tree view in xsl using a javascript function
I want to change the icons depending on the status (+ for to open , - for to close)
This questions is as clear as thick molasses in a pool of mud. (Will try to answer, though.)
I assume you mean XML stylesheets with xsl. If you meant Excel, it should have been xls. But let's assume you mean stylesheets and you're using it to generate a webpage which contains a treeview. In this treeview there are icons indicating if the node is expanded or not. If expanded, display +, else display -. Am I right, here?
Now, it depends on how you've implemented this treeview in your stylesheet. The most practical way would be to just send the tree data fully expanded to the page and let the Javascript handle this client-side. In that case, all you need to know is how to expand and collapse nodes in Javascript with the additional icon change.
Another possible implementation would be when expanding and collapsing is done serverside, thus you'd only send the visible data. In that case you can also just tell the page which icon to use and there would be no need for any javascript. The icon would just be a link back to the server, updating the data through a new requests which builds a new webpage.
A third option would be the WEB 2.0 solution, where you just send the list as a collapsed treeview and every time the user clicks an icon, a AJAX event gets triggered, collecing the additional node data and changing the icon of the treenode.
These are three very different techniques and they're not always the best solution. The first solution is a problem when dealing with lots of data in your tree. It needs to load it all. The second option will generate a lot more traffic with the server but handles better with large amounts of data because you only display the open node. The third option is a bit of a mixture between the first two options. You don't need all data from the beginning and you're not recreating the webpage over and over again. But it's also more complex to code.
Now, I wonder which of these options you use. Once we know this, we can help you. (Edit your question to provide this information and perhaps even add the JavaScript tag to it.)
To be honest, xsl is only used to change the shape of an XML document and it knows nothing about treeviews or whatever. So I don't see any link between xsl and treeviews. It's just that you use xsl to transform your data into something that some Javascript library can process as a treeview. Which Javascript library is this?