How can I draw a selection rectangle on my screen with Qt in X11?
I want to be able to drag a rectangle on my screen (outside of the application) and then save the whole rectangle.
Thanks in advance.
Part of the solution will involve using the grabWindow() function of QPixmap like so:
QPixmap::grabWindow(QApplication::desktop()->winId());
Qt has an example program for this here.
There rest of the solution, drawing the area to grab, can probably be achieved by either using a full screen transparent window to render a mouse drawn rectangle and then taking the section it outlines from the grabbed desktop image or using a full screen window with the entire grabbed screen painted on it.
Related
I have an 3d game renderer with DirectX 11 - the project also uses WinAPI.
On top of the game, I would like to render HTML/CSS UI with Sciter (it's a single, full screen game window).
So I initially draw the 3D scene with my engine->render().
And then I draw UI with Sciter (for now it's just load_file(....htm)). The problem is, the UI covers the whole window (with white background), and I cannot see the game through UI.
How can I apply transparency to "mask" between UI and what was rendered to window previously?
I have already tried SciterSetOption(*hwnd, SCITER_ALPHA_WINDOW, TRUE); but that makes white background transparent for whole window (I see what is behind the window, the desktop - not the 3D scene of mine which also is transparent :/ ).
I set html, body { background-color: transparent; } without result.
You don't need to render your UI in separate window as Sciter is capable of rendering HTML/CSS stuff directly inside DirectX 3D scene:
Check http://sciter.com/sciter-and-directx/ article.
I have a MFC application where I have a Picture Control in the dialog. Eventually, I want to allow a user to draw a resizeable rectangle via mouse drag in the picture control over an image that I loaded.
I defined my own picture control class as a sub class of CStatic and am working with the mouse down, mouse up, and mouse move events but I can't seem to figure out how to allow the user to draw a rectangle. Any guidance on this would be appreciated.
Most of the examples I've looked at show me how to draw a rectangle in a CView:CWnd, but I'm not too familiar with MFC yet so I'm a bit lost. Thanks.
The usual technique for drawing a drag rect on top of the window contents is illustrated here:
http://msdn.microsoft.com/en-us/library/windows/desktop/dd145184(v=vs.85).aspx
That is Win32 API coding instead of MFC coding but the differences are minimal. The basic idea is that by drawing with SetROP2(hdc, R2_NOTXORPEN); you invert the existing pixels, then drawing the same rect again re-inverts those pixels back to the original image.
When the user clicks the mouse button you need to record the mouse coordinates so you know where the rectangle starts. You should also set some type of flag to indicate that the user is dragging the mouse. When the user moves the mouse get the current mouse position and use DrawDragRect or similar function to draw the rectangle. When the user releases the mouse button clear the previously mentioned "flag" and you're done with that part of the process.
You will also need to handle other events such as the control and/or parent window losing focus so that you can cancel the drag/draw operation. Since you did not include any code in your question it's hard to say what else you will need to do but those are the basics.
I guess there are lots of ways to achieve this. I have an application in which a video stream is shown over a custom QWidget that I have subclasses from QLabel, and painting frames using QPainter. Given that, is it possible to let the user to drag a rectangle over the image and retrieve the coordinates? The requirement is that the rectangle must be visible during the dragging.
Thanks in advance,
Have a look at QRubberBand. It allows you to place such a rect on top of e.g. a QLabel. The documentation also contains an example how to move and resize the rubberband using the mouse.
the QGraphicsView has the void setRubberBandSelectionMode ( Qt::ItemSelectionMode mode ) but i dont know if the QLabel has some similar feature ...
maybe you have to draw your own rectangle while the user drags the rectangle and catch it on mouserelease
soo long zai
In you widget you could track mouse pressed and released events and track where on the widget the corners of the selection rect are. For drawing the rectangle, I'd take a look at QStyle::drawFocusRect. I think the intent of that is to draw a rect you'd be able to see regardless of what's behind it.
Or perhaps try this:
QStylePainter painter(this);
QStyleOptionFocusRect option;
option.initFrom(this);
option.backgroundColor = palette().color(QPalette::Background);
painter.drawPrimitive(QStyle::PE_FrameFocusRect, option);
I'm using openGL to draw some animation.
I want to draw the animation in an area around a rectangle.
That rectangle are should be transparent, to show whatever windows happen to be there, and leave that to regular windows MFC drawings.
I know there should be away to do it with clipping. But since whatever is in that rectangle isn't drawn with the openGL I'm not sure that will work well.
I'm using openGL with c++.
Solution:
If you are drawing over unrelated windows, you should use Stencil buffer.
This can be used as a masking layer to decide where you want to draw.
If you have an MFC window with a child window, you can create the "father" window with the following style: WS_CLIPCHILDREN
I want to draw in Picture Box control my purpose is picture box have scroll bar that I can draw in it bigger than what It's size I mean have scroll to move It's picture,
I try to draw something more than picturebox's size, It went to main frame panel my code is below.
void Cex133Dlg::OnBnClickedOk()
{
CDC *myDC = GetDlgItem(IDC_DRAWBOX)->GetDC();
myDC->Rectangle(10, 10, 20, 20);
}
You can draw with in the picture box. Definitely it will go outside the picture box frame, if you draw something more than picturebox's size. For that you can calculate the picture box Size, According to that you will draw your object.
You don't draw to the control -- you give it a bitmap, and it does its own drawing.
Hi you can look for http://www.codeguru.com/cpp/cpp/cpp_mfc/general/article.php/c14765 and mfc CScrollView