I was playing around with the examples buttons.ml, checkbuttons.ml, and radiobuttons.ml in the lambda-term library, and I noticed that all of the "dynamic" examples (i.e. involving events, resizing the terminal, etc.) were in black and white, while all of the color examples were "static" (i.e. no events).
Is there any way to have colored widgets, that is, to associate a widget with a color?
For example, is there any way to color the buttons of buttons.ml different colors without hardcoding based on location?
It is possible, but not with the base widget provided in lambda-term.
It's not particularly complicated, it's simply historical. I suggest you either:
Patch the lambda-term widget to have color properties
Copy the code of the widget you want, and tweak them internally, for instance to add colors.
Related
I'm working on some Qt GUI application with shiny glossy design.
I have a list view customized with my QItemDeleagte subclass. I draw items in paint virtual method. Selected items need to be drawn with glow effect on the border. Normal items must be without glow effect
That's RectangularGlow QML Type which is exactly what I need my view items border to look like. Unfortunately the app was written in Qt 4.7 and there is no way to port the app and all its dependencies to Qt 5.
QGraphicsDropShadowEffect is not sutable since shadow gradient has one direction and an offset. QLinearGradient doesn't help too or I don't know how to use it.
I consider drawing some kind of border image.
Is there any proper and elegant way to implement this using gradients or graphics effects?
EDIT:
As cmannett85 pointed out QGraphicsDropShadowEffect seems to be ok. However graphics effect may be installed on a whole paintdevice and for view item i cant just draw only selected item border rectangle with glow effect and leave other elements in a normal state. Instead all drawing on a list view affected
EDIT2:
I found a solution in an answer for another question. So I think this question may be closed
I was just wondering, is there any way at all to control the drop-shadow effect around an active QMainWindow? Here is a picture:
I would like to be able to control the color of that shadow, and possibly even change the size of it, too. Is there any way to do this? I am adding CSS as a tag because i'm pretty sure this might require using their skinning system.
Within my GUI (C++, GTKMM 3), i have a text field that is providing some status information. i'd like to change the background color of this field (along with the text, which i can easily do), based upon the status.
there's not a lot out there on how to do this with GTKMM 3.X. i know i need to use the CssProvider class, and have found some examples on how to load one into the program. but the examples show how to set the properties one time.
but what i haven't figured out is how i can use the CSS properties to change the color of the background, based upon a state (not a state as in 'hover' or anything like that. i want to be able to swap the background from red to green whenever i please). if the CSS is written in terms of using the name of the widget, or the type of widget, how do you handle a changing state with the widget to change its properties?
if anyone has any clues, or knows of any examples, i could really use some help. the purpose of this is to give the user some immediate feedback at a glance. in a rush, they won't have to read the status of the box (or from a distance). the color will allow them to gauge what is going on at a glance.
Adding code
this is what i have tried so far (condensed):
std::string style_sheet = ".red_bg {background: #FF0000; color: #000000; } ";
style_sheet += ".green_bg {background: #33FF33; color: #000000; }";
Glib::RefPtr<Gtk::StyleContext> stylecontext = my_text_field->get_style_context();
Glib::RefPtr<Gtk::CssProvider> cssprov = Gtk::CssProvider::create();
cssprov->load_from_data(style_sheet);
stylecontext->add_provider(cssprov, GTK_STYLE_PROVIDER_PRIORITY_USER);
stylecontext->add_class("red_bg");
stylecontext->context_save();
so that works. when the program fires up, i get a text entry with a red background.
but later on, if i do the following, nothing happens:
Glib::RefPtr<Gtk::StyleContext>stylecontext = my_text_field->get_style_context();
stylecontext->remove_class("red_bg");
stylecontext->context_save(); // probably not necessary
stylecontext->add_class("green_bg");
stylecontext->context_save();
at that point, the background stays red. no transition from red to green. i've seen suggestions to use the override_background_color function in the GtkWidget object, but that doesn't work. that only changes the color that is used when you highlight the text in the widget. i'd still like to see it done the CSS way.
You could do away with the CSS and just use override_background_color, a standard GTK widget method:
override_background_color (StateFlags state, RGBA color)
Sets the background color to use for a widget.
All other style values are left untouched.
Note:
This API is mostly meant as a quick way for applications to change a widget appearance. If you are developing a widgets library and intend this change to be themeable, it is better done by setting meaningful CSS classes and regions in your widget/container implementation through add_class and add_region.
This way, your widget library can install a CssProvider with the STYLE_PROVIDER_PRIORITY_FALLBACK priority in order to provide a default styling for those widgets that need so, and this theming may fully overridden by the user's theme.
Note:
Note that for complex widgets this may bring in undesired results (such as uniform background color everywhere), in these cases it is better to fully style such widgets through a CssProvider with the STYLE_PROVIDER_PRIORITY_APPLICATION priority.
Parameters:
StateFlags state the state for which to set the background color
RGBA color the color to assign, or null to undo the effect of previous calls to override_background_color
I want to create a slider which contain a different slider handle and i want to paint it according to slider handle position in the slider.
You could use QProxyStyle to ovrride drawComplexControl method - you will have to draw entire control on your own, as there is no separate flags in QStyle::ControlElement for parts of QSlider.
maybe you should look at this: http://doc.qt.io/qt-4.8/stylesheet-examples.html#customizing-qslider
If I understand you correctly, you want a slider that changes not only its position but also its appearance as you slide, right? For example, a mix of QDial and QSlider, ie. a slider with a turning knob.
If so, you will need to subclass either QSlider or QAbstractSlider (or QDial) and do the painting in your own paintEvent(). Note, however, that you will loose all style-awareness unless you care about that yourself (and that is an interesting topic in itself, see http://doc.qt.io/qt-4.8/style-reference.html for more info).
The Qt demos and examples, or the QSlider/QDial source code itself may serve as examples on how to overload a paintEvent().
I've got a QWidget that contains several QLineEdits. When I tell the parent QWidget to change its background color
dynamically, I'd like the children (i.e. QLineEdits) to inherit this modification.
Is there an easy (read: one function call) to do this?
If nothing pops up, I think I'll just loop through the children of the QWidget, but when doing this properly I expect to end up with a recursive function with a lot of overhead, that's why I'm asking.
EDITs in Bold face.
Generally speaking you don't need to worry about "overhead" in dialogs. Unless you're doing some sort of massive draw operation, UI applications simply don't need a lot of optimizations. Digging down to all children and changing their background is a relatively fast operation compared to the Qt system itself actually doing the change.
That said, I'd assume there is a way to get what you want but I don't know what it is. My bet is that it will do exactly what you would anyway.
How are you going about telling it to "change color" btw? Qt doesn't seem to have operations to do that. You can assign a background role or change the pallete. As to the latter:
http://doc.qt.nokia.com/4.7/qwidget.html#palette-prop
If you set the background color using a style sheet assigned to that widget and don't specify any selectors in the CSS, all child widgets will inherit any properties that apply to them.
I found it useful to use a selector that allowed me to target specific widgets for a certain style.
QWidget[objectName|="special_color"]
{
color: rgb(255, 255, 255);
}
If I used this in a style sheet assigned to a container widget, it would apply the specified color to any child widgets whose name started with "special_color" like "special_colorEditBox1" no matter how they are nested or contained.