How can I trim a widget? - qt

I need to trim a QWidget. I need it to be sliced as if a mask were applied and part of it be invisible.
How can I do that?

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Overlay grid onto QFrame

So, I have a QFrame with its layout set as a QGridLayout.
Within this layout I have tiles in rows of 16 which represent something of a palette.
I want this grid of tiles to be separated by lines, like a grid should be. I can do this easily with the tiles' paintEvents.
However, the obvious problem is that between the tiles, the lines are doubled up. When I scale this up for other applications, the difference becomes even more noticeable.
So, is there a way to create a gridline overlay for my QFrame? I have considered converting the whole thing to a view/scene solution, and using drawForeground, however this seems like a completely inappropriate use of the paradigm.
Thanks for any assistance!
Put the QFrame into a QGridLayout, then put a custom QWidget with transparent background and paintEvent that paints the grid on top of it (same QGridLayout position).
Or since you already have a QGridLayout, just put the custom QWidget in that, above the tiles, filling the entire grid.
A side note, are you sure you want QFrame there, or if just QWidget would do? Just saying, because with QFrame you get that 1990's look into your UI... If you do want that then go ahead, just saying.

How to reduce spacing/padding/margin of the text inside QDoubleSpinBox or QSpinBox to zero?

Using Qt 4.8. I would like to set the space between the text of a QSpinBoxes/QDoubleSpinBoxes and the right border of the widget to zero. The left one of the following images is what I got, the right one is what I want:
Note that I use setButtonSymbols(QAbstractSpinBox::NoButtons) to remove the up/down arrows.
The spinboxes are styled using QSS where I can set:
The padding of the QSpinBox/QDoubleSpinBox to 0px.
The padding, the margin and the border of the QLineEdit inside the spinbox to 0px.
I have also created a custom QProxyStyle for the QLineEdit but I'm not able to find any related pixel metric enum that I can use to reduce the space
I can also try to mess around with the internal QLineControl class which is not possible without fiddling inside Qt's code base. (I have not tried this yet!)

How can I achieve a "Karaoke Lyric" like effect with qt (QLabel)

So this is the effect what I want to get. Left and right parts of a label should have different filling/stroke colors (actually stroke size is also changed). And the proportion may change dynamically, and can be some position inside a letter.
I know I should override the paintEvent but still have no idea of how to do it.
Any ideas?

QTextEdit: How to add fixed position text on top of an image

I am using QTextEdit to implement an editor. One of the requirements I have is to add fixed position text on top of an image.
For example:
I have an image of dimensions: 300x300. I need to add text beginning at the location (20, 20) of the image and ensure that the text does not flow beyond the width of the image.
Something like below:
I am thinking that if I can add a QGraphicView, I can add the image and position text appropriately. Is this possible? Is there a way to introduce a graphic element into a QTextedit? If not, what is the right approach?
Is there a way to introduce a graphic element into a QTextEdit? If not, what is the right approach?
You could look at this the other way and add the QTextEdit to a QGraphicsScene. The graphics scene provides a QGraphicsProxyWidget to add standard Qt widgets.
Therefore, you could create a QGraphicsScene and QGraphicsView. Add a QGraphicsPixmapItem for the image and add the QTextEdit item with a call to QGraphicsScene::addWidget, which returns a QGraphicsProxyWidget, allowing you to position, scale and resize the widget.
Alternatively, you could start with a QGraphicsItem, inherit from that and create your own object which encapsulates the image and proxy object of the QTextEdit.
There are other ways of tackling this too, but I'd probably go for the custom QGraphicsItem. It also depends on your specification, but you can add text items in a graphics scene, without the QTextEdit, though you'd probably have to implement the editing feature, if this is required.

How to Remove Space between Widget's?

How to remove the space between widgets while applying layout.
in the QT if i apply any layout to widget like, QBoxLayout or QGridlayout that time automatically taking space between Widgets. i need to remove the space.
How to remove the space?
look for QLayout::setSpacing() function

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