SDL_RenderSetViewport strange behaviour - sdl-2

I don't really understand how to use SDL_RenderSetViewport, or it has a strange behaviour.
SDL_Rect viewportRect = {-viewportX, viewportY - viewportH + windowH, viewportW, viewportH};
SDL_RenderSetViewport(renderer, &viewportRect);
This code is the code I use for a window size of (640;480) and a viewport size of something like (windowW * n, windowH * n) for any n.
But, if I change the window size in the code, there's a shift when I display the viewport.
By default, viewportX = viewportY = 0;
I don't understand why the viewportRect is so weird, and why it doesn't work when I change window size.

For what I know, the SDL does not readjust automatically the windows settings after a resize. Are you handling the SDL_WINDOWEVENT_RESIZED? If not, try to handle it and call SDL_RenderSetViewport(renderer, &viewportRect) on it.

Related

Free scroll in Jetpack Compose

This is a modification of this question. I have an isometric grid of images and curious - is it possible to scroll it in free ways (diagonals included). Currently I have this code and it's possible to scroll 2D:
val scrollStateHorizontal = rememberScrollState()
val scrollStateVertical = rememberScrollState()
Box(
modifier = Modifier
.horizontalScroll(scrollStateHorizontal)
.verticalScroll(scrollStateVertical)
) {
for (i in 0..8) {
for (j in 0..7) {
val start = (y % 2 * 0.5 + x) * width
val top = i * height * 0.5
Image(modifier = Modifier.padding(start = start.dp, top = top.dp), painter = ...)
}
}
}
What is interesting:
Can I scroll diagonally?
How can I optimize it (memory consumption, etc.)? Maybe I should use LazyHorizontalGrid including LazyVerticalGrid/LazyColumn/LazyRow?
It seems, LazyHorizontalGrid can't be modified simply adding Modifier.verticalScroll. And it has a lag for first few seconds of scrolling (maybe for caching items) while simple Box scrolling acts smoothly from the start.
As of now, there's no official support for this, as far as I know. The only way you could implement this as of the current stable, is by using LazyLayout Composable, or by modifying the verticalScroll (or horizontal) Modifiers. Read here. It is a recent addition to the APIs so the documentation is very scarce. You'll have to look it up on the web for sample implementations.
"Read here"

How can I get a borderless child window to re-scale to current screen in multi-monitor setup?

My app has a main window which creates and opens an instance of a subclass of a QML Window {} using createObject(). This window has its flags: set to be a borderless window (I've added code so that it can be grabbed and dragged around).
When I attach a monitor to my laptop and set its font scale factor to 125% (or 150%), when I drag my main window over to the second monitor, you can see it suddenly "snap" to the larger size when it reaches the halfway point. Likewise, when I drag it back to my laptop screen it again "snaps" to the smaller size when I get halfway over (this behavior is what I want, so no problems here).
My problem is that when I drag my created borderless window over into the monitor, it keeps the original 100% scale factor and does not "snap" to a larger size. If I drag my main window over to the monitor, it gets larger but the borderless window remains at the smaller scale; only when I grab the borderless window and move it slightly does it suddenly "snap" to the larger scale size. The same thing happens in reverse - if I then drag the borderless window back onto the laptop, it remains at the larger size until I drag the main window back over and then move the borderless window slightly (at which point it suddenly "snaps" to the smaller size).
So it appears that this created Window uses the scale factor of the screen that the parent window window that created it is currently in, even if it is in a different screen itself.
Is this happening because the Window is borderless? (I'm about to test this but my build process is incredibly slow) Or is there any way to set this borderless Window up so that it detects that it is crossing into a new screen and re-scales itself (in the same way that my main window does)?
Update: I just ran a test giving my Window a native titlebar, and with a titlebar the window instantly adopts ("snaps to") the scale factor of whichever screen it happens to be in, just like my main window (and independent of the main window's scale factor).
So is there any way to duplicate this auto-scaling window behavior with a borderless window? Some flag I need to call, or some method(s) I need to call to get the OS to rescale the window?
Update 2: I tried out Felix's SetWindowPos solution. It does move the window, but this does not fix the scaling problem - the behavior of the frameless window is the same and it still does not correctly pick up the scaling factor of the screen it is in.
I am running a test using MoveWindow instead of SetWindowPos to see if that affects anything [edit: MoveWindow does not work, either - same problem]. Then I'm going to try SendMessage or PostMessage along with NoBugz' suggestion of the WM_DPICHANGED message.
Any other suggestions are welcome.
Update 3: I just created a quick C# app (winforms) to see if the same problem occurs with that, and it doesn't - when a borderless form in the C# app is dragged over into the other monitor, it immediately picks up the scale factor change. So it appears this is a Qt problem.
Update 4: See my answer below for a working solution to this problem (if a bit of a hack).
So as far as I understand, your current goal is to move the window via the WIN-API.
You will have to do so via C++. The approach would be:
Pass the QML Window to a C++-Method exposed to QML as a QQuickWindow (The QML window instanciates that type, as seen in the documentation)
Use QWindow::winId to get the native HWND
Call the SetWindowPos WIN-API method to move it
Code sample (C++-part):
// the method
void moveWindow(QQuickWindow *window, int x, int y) {
HWND handle = (HWND)window->winId();
Q_ASSERT(handle);
::SetWindowPos(handle, HWND_TOP,
x, y, 0, 0,
SWP_NOSIZE | SWP_NOZORDER);
}
// assuming "moveWindow" is a member of "MyClass"
qmlEngine->rootContext()->setContextProperty("mover", new MyClass(qmlEngine));
Code sample (QML-part):
// call this method as soon as the drag has finished, with the new positions
mover.moveWindow(idOfWindow, xPos, yPos);
Note: I would recommend you try out calling this only after the drag was finished (and move the window as you do right now until then). If that works, you can try out what happens if you call this during the drag instead of changing the x/y of the window.
I figured out a relatively simple way to fix this problem. Since a frameless window in Qt gets its scaling factor from the window that created it, the trick is to create another window (that has a titlebar but is not visible to the user) and create the frameless window there, and then add code to the frameless window to keep the hidden window positioned underneath it as the user drags it. When the frameless window is dragged into another screen, the hidden window goes with it, picks up the new scale factor (since it has a titlebar) and then the frameless window immediately gets the new screen's scale factor as well.
Here is sample solution code:
// HiddenWindow.qml
Window {
id: hiddenWindow
// note: just making window visible: false does not work.
opacity: 0
visible: true
flags: Qt.Tool | Qt.WindowTitleHint | Qt.WindowTransparentForInput |
Qt.WindowStaysOnTopHint // Qt.Tool keeps this window out of the
// taskbar
function createVisibleWindow() {
var component = Qt.createComponent("VisibleWindow.qml")
if (component.status === Component.Ready) {
var win = component.createObject(hiddenWindow)
return win
}
}
}
// VisibleWindow.qml
Window {
id: visibleWindow
property var creatorWindow: undefined
flags: Qt.FramelessWindowHint
onXChanged: {
creatorWindow.x = x
}
onYChanged: {
creatorWindow.y = y
}
onWidthChanged: {
creatorWindow.width = width
}
onHeightChanged: {
creatorWindow.height = height
}
}
And then to use these classes from your main window QML:
property var hiddenWindow: undefined
property var visibleWindow: undefined
Component.onCompleted: {
var component = Qt.createComponent("HiddenWindow.qml")
if (component.status === Component.Ready) {
hiddenWindow = component.createObject(null)
}
visibleWindow = hiddenWindow.createVisibleWindow()
visibleWindow.creatorWindow = hiddenWindow
visibleWindow.show()
}
You need to resize window when window move to other screen
MouseArea {
anchors.fill: parent
acceptedButtons: Qt.LeftButton
onPressed: {
movePos = Qt.point(mouse.x, mouse.y)
isDoubleClicked = false
lastWindowWidth = mainWindow.width
lastWindowHeight = mainWindow.height
}
onPositionChanged: {
if (!isDoubleClicked) {
const delta = Qt.point(mouse.x - movePos.x, mouse.y - movePos.y)
if (mainWindow.visibility !== Window.Maximized) {
mainWindow.x = mainWindow.x + delta.x
mainWindow.y = mainWindow.y + delta.y
mainWindow.width = lastWindowWidth
mainWindow.height = lastWindowHeight
}
}
}
}

Creating X11 window to span multiple displays

I'm having the exact problem described here. How to make X11 window span multiple monitors
I have six monitors and am trying to create a window larger than the size of one of the monitors. It keeps getting resized by the window manager.
Apologize if I should post within that thread, the etiquette is not clear to me.
Anhow, I do the following in my code:
/* Pass some information along to the window manager to size the window */
sizeHints.flags = USSize; // | PMinSize;
sizeHints.width = sizeHints.base_width = width;
sizeHints.height = sizeHints.base_height = height;
// sizeHints.min_width = width;
// sizeHints.min_height = height;
// sizeHints.max_width = mScreenWidth;
// sizeHints.max_height = mScreenHeight;
if (geometry->x != DONT_CARE && geometry->y != DONT_CARE) {
sizeHints.x = geometry->x;
sizeHints.y = geometry->y;
sizeHints.flags |= USPosition;
}
XSetNormalHints(mDisplay, mWindow, &sizeHints);
SetTitle(suggestedName);
XSetStandardProperties(mDisplay, mWindow,
suggestedName.toAscii(), suggestedName.toAscii(),
None, (char **)NULL, 0, &sizeHints);
/* Bring it up; then wait for it to actually get here. */
XMapWindow(mDisplay, mWindow);
The problem I'm having is that if I set min_width and min_height, the user cannot resize the window, which is not what I want. But if I don't, then when I do any X11 call later, such as
XGetWindowAttributes(mDisplay, mWindow, &win_attributes);
the window manager resizes my window to fit into one monitor instead of being larger than the monitor. I cannot just get a window of the desired size for some reason. Note that WidthOfScreen and HeightOfScreen give me the combined width and height of all monitors as expected.
Can anyone help? I hope I'm explaining myself clearly enough.

ExtCreatePen and Windows 7 GDI

I created DIBPATTERN pens with ExtCreatePen API for custom pattern pens.
It sucessfully draws desired lines on Windows XP,
But on Windows 7 (x64 for my case), it does not draw any lines; no changes on screen.
(Other simply created pens, for example CreatePen(PS_DOT,1,0), are working.)
I found that calling SetROP2(hdc, R2_XORPEN) makes the following line-drawing API calls draw something but with XOR operation. I don't want XOR drawing.
Here is my code to create the pen. It has no problem on Windows XP:
LOGBRUSH lb;
lb.lbStyle = BS_DIBPATTERN;
lb.lbColor = DIB_RGB_COLORS;
int cb = sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * 2 + 8*4;
HGLOBAL hg = GlobalAlloc(GMEM_MOVEABLE, cb);
BITMAPINFO* pbmi = (BITMAPINFO*) GlobalLock(hg);
ZeroMemory(pbmi, cb);
pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
pbmi->bmiHeader.biWidth = 8;
pbmi->bmiHeader.biHeight = 8;
pbmi->bmiHeader.biPlanes = 1;
pbmi->bmiHeader.biBitCount = 1;
pbmi->bmiHeader.biCompression = BI_RGB;
pbmi->bmiHeader.biSizeImage = 8;
pbmi->bmiHeader.biClrUsed = 2;
pbmi->bmiHeader.biClrImportant = 2;
pbmi->bmiColors[1].rgbBlue =
pbmi->bmiColors[1].rgbGreen =
pbmi->bmiColors[1].rgbRed = 0xFF;
DWORD* p = (DWORD*) &pbmi->bmiColors[2];
for(int k=0; k<8; k++) *p++ = patterns[k];
GlobalUnlock(hg);
lb.lbHatch = (LONG) hg;
s_aSelectionPens[i] = ExtCreatePen(PS_GEOMETRIC, 1, &lb, 0, NULL);
ASSERT(s_aSelectionPens[i]); // success on both XP and Win7
GlobalFree(hg);
Is it bug only on my PC? Please check this problem.
Thank you.
This is a known bug with the Windows 7 GDI, though good luck getting Microsoft to acknowledge it.
http://social.technet.microsoft.com/Forums/en-US/w7itproappcompat/thread/a70ab0d5-e404-4e5e-b510-892b0094caa3
-Noel
I will admit, I was dubious as first, but I compiled and ran your program, and it does indeed fail to draw the second line on Windows 7, buy only in aero mode
By switching to Windows basic or classic mode, all four lines are drawn, as expected.
I can only assume that this is some kind of bad interaction with your custom pen and the new way aero mode implements GDI calls. This seems like it might be a Microsoft bug, perhaps you can post this question on one of their message boards?
So you are creating an 8x8 black/white (monochrome) bitmap as a DIB, and then using that to create a pen. I see nothing wrong with this code. this definitely looks like a windows bug, but there may be a workaround.
Try setting
pbmi->bmiHeader.biClrUsed = 0;
pbmi->bmiHeader.biClrImportant = 0;
In this context, setting the values to 0 should mean the same thing as setting them to 2, but 0 is more standard behavior for situations where you have are using the full palette. You still need two entries in your palette, 0 just means "full size based on biBitCount".
Also, each palette entrie is a RGBQUAD, which means there is room for alpha, and your alpha is set to 0, which should be ignored, but maybe it isn't. so try setting the high byte of your two palette entries to 0xFF or 0x80.
Finally, it's possible that your palette is being ignored entirely, and Windows is using the BkMode, BkColor and TextColor of the destination DC for everything, so you need to make sure that they are set to values that you can see.
My guess is that this has something to do with alpha transparency, since GDI ignores alpha entirely, but Aero doesn't.

Testing to see if a window is maximized

I noticed that in Windows, if you maximize a window you can not resize it until you un-maximized it again. This appears to be a normal behaviour, so I would like to remove my resize gripper when the window is maximised.
At the moment I can't find a property to detect if a window is maximized, and although I could add a boolean in my controller, it wouldn't necessarily catch requests to maximize from the OS.
So if you know of a reliable way to test if a window is maximized please let me know.
On a related note, I am using custom chrome, and when I maximize a window it overlaps the windows task bar. I can think of hacks to detect available screen size (using a transparent system chrome window), but it would be good to know of a better method.
Thanks
Rob
In your application (MXML) on the in the init method you ussually call on creationComplete:
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"
creationComplete="init()" >
Add the following code:
this.addEventListener(NativeWindowDisplayStateEvent.DISPLAY_STATE_CHANGE, trackState);
the method looks like this:
public function trackState(event:NativeWindowDisplayStateEvent):void
{
if (event.afterDisplayState == NativeWindowDisplayState.MAXIMIZED)
{
isMaximised = true;
} else {
isMaximised = false;
}
}
I have figured out how this can best be done thanks to some pointers from TheBrain.
Firstly you need to watch for resize events to the window your want to control:
NativeApplication.nativeApplication.activeWindow.addEventListener(NativeWindowBoundsEvent.RESIZE, onWindowResize);
Then handle that event to decide if the window is maximised or not:
public function onWindowResize(event:NativeWindowBoundsEvent):void
{
if (event.afterBounds.height >= Screen.mainScreen.visibleBounds.height && event.afterBounds.width >= Screen.mainScreen.visibleBounds.width)
isMaximised = true;
else
isMaximised = false;
}
You then need to catch or create your own maximize button, and when clicked perform the following code:
if (isMaximised)
{
var bounds:Rectangle = Screen.mainScreen.visibleBounds;
NativeApplication.nativeApplication.activeWindow.bounds = bounds;
}
else
{
NativeApplication.nativeApplication.activeWindow.bounds = new Rectangle(100, 100, 500, 600);
}
You can modify the bounds to over maximize (which is handy for custom chrome windows with shadows), and you can also set the application to reset to a default size if the maximize button is clicked when it's already maximized (or do nothing).
I had issues about when to assign the window resize listner, and ended up removing and adding it every time the maximize button was clicked. It's a bit of overkill, but not too bad.
There is Win32 API Call that will do this for you:
BOOL IsZoomed( HWND hWnd );
to get the actual usable space from the screen, use the flash.display.Screen class, or you can use the systemMaxSize() which returns the largest window size allowed by the OS. For maximization you have some events that the window is dispaching when maximized/minimized/restored. You can find more info on the adobe pages (the link under systemMaxSize).
To detect if window is maximized...I don't think there is such a function (I might be wrong) but you can test if the app size is equal with the available screen size which means it's maximized. Or hook on the resize event which is triggered when the app is maximized/minimized/resized
Here is an easier way of checking if a window is maximized:
if(stage.nativeWindow.displayState == NativeWindowDisplayState.MAXIMIZED)
{
//do something
}
The following worked for me. No need to set event listeners, this code can be used to check the real-time state of the native window:
if (nativeWindow.displayState == 'maximized')
{
trace('Maximized');
}
else
{
trace('Minimized');
}
Can you use something like this to hook the maximize() event?

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