I'm working on a X-plotter like widget that plots incomming data live.
I already searched for an solution to realize a scrolling along the x-axis if the widget has to much values and so they don't fit.
I had the folling approaches to realize it:
derive from a widget that supports scrolling and child widgets and add my own widget while making it bigger and bigger during the live updates: -> Which parent do I need to use and how do I avoid to draw all the stuff that is currently not visible?
modify my widget in a way that it supports the scrollbars itself -> but how?
draw/handle my own scrollbars -> worstcase :(
I really searched the web for suggestions or examples, but there is nothing about how to "construct" custom controls in a good way (beyond drawing something) esp. in the case of interaction...
Sorry but I'm a newbie at GTK in general :/
Most widgets in Gtk do not have scrollbars.
If you want to scroll the entire widget, you have to implement the GtkScrollable interface. Then, you add the widget to a GtkScrolledWindow. The scrolled window has the scrollbars, those GtkScrollbars are linked with GtkAdjustments which are passed to your custom widget through the GtkScrollable interface set_vadjustment and set_hadjustment.
If you just want to add a scrollbar and control its behaviour yourself, then you need to somehow add a GtkScrollbar in your widget, which means you will need to make it a container too.
The GtkScrollable approach is the following, first you implement vadjustment and hadjustment setters and getters, then when the GtkAdjustments are set, you set its lower and upper limits and the page size(how much of the widget is visible at once). After that, you connect their value-changed signal so you can refresh your widget when the scrollbars are dragged. A GtkScrollable doesn't get to check the scrollbars, only the adjustments that will be bound to the scrollbars. When drawing the widget you get the adjustments' value property in order to determine how much the scrollbars have shifted in the horizontal and vertical axes.
Related
How would I go about making a overlay widget with qt?
I've considered using a QPaintEvent or a QGraphicsScene, but I want to be able to add widgets and for the widget to not occupy space in a layout, causing other widgets to shift when the popup appears.
I believe the best solution is to parent the so called overlay widget to the window or even have the overlay widget be in its own window.
The first solution might be easier to do, but the overlay widget is bound to the inside of the window.
If you go with the second solution, you will have to play with the windows flags to make it borderless.
In both cases, you may have to use the raise() function to make sure your overlay widget is on top.
Discussing "using a QPaintEvent or a QGraphicsScene" is off-topic. How you draw the widget does not impact how the widget will interact with the widget stack.
If you want an example, you can take a look at the code of QCompleter which does something similar. In particular look for QCompleter::setPopup() and QCompleterPrivate::showPopup().
I'm new at GTK. I'm using Glade to make an interface and just want to insert objects (like buttons and others) into a container.
I've choosen GtkFixed so that all elements can be freely located and sized.
The problem is that when i drag a button for example, the button apparently gets it size from the parent (in this case the container) and takes a square shape.
Here's an image
I want the button to take the standard size, just like a rectangule or something. What i'm i doing wrong? I've checked some options in the container but can't figure out the way.
Thanks.
You have to remove the tick from Height request and Width request (I don't know the equivalent names in your language).
Besides, you should be aware that GtkFixed is difficult to use when the window can be resized. GtkBox is often easier.
I want to make a whole column of various widgets scrollable in a Tkinter GUI, like so:
Tkinter can only attach scrollbars to certain widgets, of which, frames are not included. Making a scollable column is a common practice in interfaces, and there should be a simple solution, but so far, all I have been able to find is this hacky example of a scrollable frame, using a canvas widget. A similar hacky solution was used in a similar stack overflow question.
Is there a commonly accepted way in Tkinter to make a column, or a group of widgets, that is scrollable?
The solution using the canvas is the commonly accepted way to solve this problem. It's really not all that hacky, and the end result can be indistinguishable from having a native scrolling container widget.
If you're making a single column, another option is to use a text widget, and use the widget's ability to embed other widgets. Insert a widget, then insert a newline, insert another widget, etc. You then get the scrolling ability for free. The only thing you need to worry about is configuring the width of the embedded windows, which isn't too hard to do.
I'm working on a PyQt program where I want to be able to have some objects, say shapes, in a 'toolbar' of sorts. I would like the user to be able to click and drag an instance of one of these shapes from the toolbar to a main canvas (a QGraphicsView).
For the toolbar I was thinking of using a QListView which I could populate using a QAbstractListModel. However, I'm not sure how I can make the QListView hold only the icons of the shapes that I want... and second of all, how I can make the object icons draggable onto my main canvas. Any ideas?
If this question contained some specific code examples with an existing direction, I could comment more specifically, but here is just some general points:
Your QListView data does not need to specifically relate to the drag and drop issue, so you can populate it however you want: QListWidget, QListView + model, ../
The important aspect is setting up drag methods on your QListX widget to set up an appropriate QMimeData in the QDrag. This is the important part that transfers the data to the drop site. You can have it send an image, or some reference to some data, for which the receiver can make use of.
Set up a drop event on the graphics view to receive and check the mime type. Lets say you are just sending an image. You can receive it and add a pixmap item to your scene. Or maybe you are sending some internal reference like an id to a dictionary. It can be looked up and the data can be added to the scene in the form you want.
Refer to the general Qt Drag and Drop docs. They are pretty much what you want.
How can I auto scroll for the scroll area? For example, when there is a new update instead of the view of the scroll area staying the same, I want to go down with the new text. Think of it as in a CMD console, when you type a command it autoscroll with the output.
I was just going to respond to the other answer, but I just didn't know the best way to phrase it in the space allotted.
QScrollArea's are very useful widgets to use when designing custom PyQt widgets - I use them often. Things like rollout widgets, card widgets, anything where you could be displaying multiple sub-widgets with the need for scrolling can be a very useful utility. I don't agree with the idea that a QScrollArea isn't much use on its own.
The QTextEdit answer solves the problem the developer was facing - but only because it so happens the question is really about that. If you're trying to scroll a text edit, go with that answer.
However, if you are searching for an answer to the actual question and come across this thread, then the way to scroll down a QScrollArea is by actually modifying the scrollbar's value.
area = QScrollArea(parent)
vbar = area.verticalScrollBar()
vbar.setValue(vbar.maximum())
If you want to scroll to particular areas or anything (like implementing the ensureCursorVisible) then you want to take the location on the area's widget that you want to scroll to, figure out the percentage of the height of it, and apply that value to the vertical scrollbar. (Pseudocode)
Use QTextEdit.moveCursor to set the location you want to scroll to, and then use QTextEdit.ensureCursorVisible to scroll to it:
textedit.moveCursor(QtGui.QTextCursor.End)
textedit.ensureCursorVisible()