I have a Mac OS X Document based app that has multiple NSViewControllers that I switch between and each view displays data from plist files in NSTableViews based on the user selections in the previous NSViewController's NSTableView. The problem I have is that I can't figure out what function can be called, every time a NSViewController gets loaded, to read the correct data from a file to display in the NSTableView. For UIViewControllers I used the function family of viewDidLoad, viewWillAppear, but I haven't been able to find the corresponding functions for NSViewController.
Currently I am using awakeFromNib, which works fine, but only the first time the NSViewController gets loaded. I've tried loadView, but that collapses the NSView. I assume that I need to do more setup to use loadView.
I'm using the View Swapping code from Hillegass's book Cocoa Programming for MAC OS X which switches ViewControllers with the following code:
- (void)displayViewController:(ManagingViewController *)vc
curBox: (NSBox *)windowBox
{
// End editing
NSWindow *w = [windowBox window];
BOOL ended = [w makeFirstResponder:w];
if (!ended) {
NSBeep();
return;
}
NSView *v = [vc view];
NSSize currentSize = [[windowBox contentView] frame].size;
NSSize newSize = [v frame].size;
float deltaWidth = newSize.width - currentSize.width;
float deltaHeight = newSize.height - currentSize.height;
NSRect windowFrame = [w frame];
windowFrame.size.height += deltaHeight;
windowFrame.origin.y -= deltaHeight;
windowFrame.size.width += deltaWidth;
[windowBox setContentView:nil];
[w setFrame:windowFrame
display:YES
animate:YES];
[windowBox setContentView:v];
// Put the view controller in the responder chain
[v setNextResponder:vc];
[vc setNextResponder:windowBox];
}
and puts the NSView Controller in the responder chain.
Is there some function I can call to setup the view every time I swap NSViewControllers? Can I check that a NSViewController has become the firstResponder?
This post provided the answer.
I added the following code:
- (void)viewWillLoad {
}
- (void)viewDidLoad {
}
- (void)loadView {
[self viewWillLoad];
[super loadView];
[self viewDidLoad];
}
and at the beginning of displayViewController I added
[vc loadView]
Related
I have integrated the NDI SDK from NewTek in the current version 5 into my Qt6.3 widget project.
I copied and included the required DLLs and header files from the NDI SDK installation directory into my project.
To test my build environment I tried to compile a simple test program based on the example from "..\NDI 5 SDK\Examples\C++\NDIlib_Recv".
That was also successful.
I was therefore able to receive or access data from my NDI source.
There is therefore a valid frame in the video_frame of the type NDIlib_video_frame_v2_t. Within the structure I can also query correct data of the frame such as the size (.xres and .yres).
The pointer p_data points to the actual data.
So far so good.
Of course, I now want to display this frame on the Qt6 GUI. In other words, the only thing missing now is the conversion into an appropriate format so that I can display the frame with QImage, QPixmap, QLabel, etc.
But how?
So far I've tried calls like this:
curFrame = QImage(video_frame.p_data, video_frame.xres, video_frame.yres, QImage::Format::Format_RGB888);
curFrame.save("out.jpg");
I'm not sure if the format is correct either.
Here's a closer look at the mentioned frame structure within the Qt debug session:
my NDI video frame in the Qt Debug session, after receiving
Within "video_frame" you can see the specification video_type_UYVY.
This may really be the format as it appears at the source!?
Fine, but how do I get this converted now?
Many thanks and best regards
You mean something like this? :)
https://github.com/NightVsKnight/QtNdiMonitorCapture
Specifically:
https://github.com/NightVsKnight/QtNdiMonitorCapture/blob/main/lib/ndireceiverworker.cpp
Assuming you connect using NDIlib_recv_color_format_best:
NDIlib_recv_create_v3_t recv_desc;
recv_desc.p_ndi_recv_name = "QtNdiMonitorCapture";
recv_desc.source_to_connect_to = ...;
recv_desc.color_format = NDIlib_recv_color_format_best;
recv_desc.bandwidth = NDIlib_recv_bandwidth_highest;
recv_desc.allow_video_fields = true;
pNdiRecv = NDIlib_recv_create_v3(&recv_desc);
Then when you receive a NDIlib_video_frame_v2_t:
void NdiReceiverWorker::processVideo(
NDIlib_video_frame_v2_t *pNdiVideoFrame,
QList<QVideoSink*> *videoSinks)
{
auto ndiWidth = pNdiVideoFrame->xres;
auto ndiHeight = pNdiVideoFrame->yres;
auto ndiLineStrideInBytes = pNdiVideoFrame->line_stride_in_bytes;
auto ndiPixelFormat = pNdiVideoFrame->FourCC;
auto pixelFormat = NdiWrapper::ndiPixelFormatToPixelFormat(ndiPixelFormat);
if (pixelFormat == QVideoFrameFormat::PixelFormat::Format_Invalid)
{
qDebug().nospace() << "Unsupported pNdiVideoFrame->FourCC " << NdiWrapper::ndiFourCCToString(ndiPixelFormat) << "; return;";
return;
}
QSize videoFrameSize(ndiWidth, ndiHeight);
QVideoFrameFormat videoFrameFormat(videoFrameSize, pixelFormat);
QVideoFrame videoFrame(videoFrameFormat);
if (!videoFrame.map(QVideoFrame::WriteOnly))
{
qWarning() << "videoFrame.map(QVideoFrame::WriteOnly) failed; return;";
return;
}
auto pDstY = videoFrame.bits(0);
auto pSrcY = pNdiVideoFrame->p_data;
auto pDstUV = videoFrame.bits(1);
auto pSrcUV = pSrcY + (ndiLineStrideInBytes * ndiHeight);
for (int line = 0; line < ndiHeight; ++line)
{
memcpy(pDstY, pSrcY, ndiLineStrideInBytes);
pDstY += ndiLineStrideInBytes;
pSrcY += ndiLineStrideInBytes;
if (pDstUV)
{
// For now QVideoFrameFormat/QVideoFrame does not support P216. :(
// I have started the conversation to have it added, but that may take awhile. :(
// Until then, copying only every other UV line is a cheap way to downsample P216's 4:2:2 to P016's 4:2:0 chroma sampling.
// There are still a few visible artifacts on the screen, but it is passable.
if (line % 2)
{
memcpy(pDstUV, pSrcUV, ndiLineStrideInBytes);
pDstUV += ndiLineStrideInBytes;
}
pSrcUV += ndiLineStrideInBytes;
}
}
videoFrame.unmap();
foreach(QVideoSink *videoSink, *videoSinks)
{
videoSink->setVideoFrame(videoFrame);
}
}
QVideoFrameFormat::PixelFormat NdiWrapper::ndiPixelFormatToPixelFormat(enum NDIlib_FourCC_video_type_e ndiFourCC)
{
switch(ndiFourCC)
{
case NDIlib_FourCC_video_type_UYVY:
return QVideoFrameFormat::PixelFormat::Format_UYVY;
case NDIlib_FourCC_video_type_UYVA:
return QVideoFrameFormat::PixelFormat::Format_UYVY;
break;
// Result when requesting NDIlib_recv_color_format_best
case NDIlib_FourCC_video_type_P216:
return QVideoFrameFormat::PixelFormat::Format_P016;
//case NDIlib_FourCC_video_type_PA16:
// return QVideoFrameFormat::PixelFormat::?;
case NDIlib_FourCC_video_type_YV12:
return QVideoFrameFormat::PixelFormat::Format_YV12;
//case NDIlib_FourCC_video_type_I420:
// return QVideoFrameFormat::PixelFormat::?
case NDIlib_FourCC_video_type_NV12:
return QVideoFrameFormat::PixelFormat::Format_NV12;
case NDIlib_FourCC_video_type_BGRA:
return QVideoFrameFormat::PixelFormat::Format_BGRA8888;
case NDIlib_FourCC_video_type_BGRX:
return QVideoFrameFormat::PixelFormat::Format_BGRX8888;
case NDIlib_FourCC_video_type_RGBA:
return QVideoFrameFormat::PixelFormat::Format_RGBA8888;
case NDIlib_FourCC_video_type_RGBX:
return QVideoFrameFormat::PixelFormat::Format_RGBX8888;
default:
return QVideoFrameFormat::PixelFormat::Format_Invalid;
}
}
I have a working app that draws NSAttributedStrings into a custom view. The NSAttributedStrings can included embedded images. This works on versions of macOS prior to Mojave. The app can display the strings on screen, print them, and save them to image files.
This is apparently broken under Mojave. Weirdly, printing and saving to image files still works; but on-screen, the strings display only the text and not the embedded images. Proper space is left for the images, but that space is blank.
I've tested by building a small app that shows a window with an NSTextField (a label) and a custom view. It makes a single NSAttributedString with an embedded image. It applies that string to the attributedStringValue of the label, and also calls drawInRect: on the same string in the drawRect: method of the custom view. In the label, the string is displayed correctly, image and all. But in the custom view, only the text appears, and the space where the image should be is blank.
Anybody got a clue why this is happening on Mojave but not on earlier versions of macOS?
Here is the code that makes the string (and caches it, for re-use):
static NSMutableAttributedString* sgAttrString = nil;
/*
* Creates an attributed string the first time it's called,
* then returns that same string each time it's called.
*/
+ (NSAttributedString*)getAttributedString
{
if (sgAttrString == nil)
{
NSFont* font = [NSFont fontWithName:#"Helvetica" size:24.0];
NSDictionary *attrs = #{
NSFontAttributeName: font
};
sgAttrString = [[NSMutableAttributedString alloc] initWithString:#"Daisy: " attributes:attrs];
NSImage* daisy = [NSImage imageNamed:#"daisy.png"];
[daisy setSize:NSMakeSize(24,24)];
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
// I'm aware that attachment.image is available only on macOS 10.11 and later.
// It's not an issue in my real project.
attachment.image = daisy;
NSMutableAttributedString* imageStr = [[NSMutableAttributedString alloc] init];
[imageStr setAttributedString:[NSAttributedString attributedStringWithAttachment:attachment]];
[sgAttrString appendAttributedString:imageStr];
[sgAttrString appendAttributedString: [[NSAttributedString alloc] initWithString:#" !!" attributes:attrs]];
}
return sgAttrString;
}
Here is the code that applies the string to the NSTextField:
NSAttributedString* str = [Utilities getAttributedString];
self.label.attributedStringValue = str;
And here is the code that draws the string in a custom NSView:
NSAttributedString* str = [Utilities getAttributedString];
[str drawInRect:NSMakeRect(50,50, 300, 40)];
Again, this behavior seems to occur only in Mojave! Thanks in advance for any help.
Simple question:
I have an AVPlayer property called player (could be any strong property, its just AVPlayer for example's sake).
If it has already been allocated (and is not nil) and I re-allocate it without setting it to nil:
self.player = [[AVDelegatingPlayer alloc] initWithURL:[NSURL URLWithString:urlString]];
Are there memory implications for this in an ARC environment?
Take a look at clang source code for storing an object into a __strong variable.
https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CGObjC.cpp#L2108-L2119
// Retain the new value.
newValue = EmitARCRetain(type, newValue);
// Read the old value.
llvm::Value *oldValue = EmitLoadOfScalar(dst, SourceLocation());
// Store. We do this before the release so that any deallocs won't
// see the old value.
EmitStoreOfScalar(newValue, dst);
// Finally, release the old value.
EmitARCRelease(oldValue, dst.isARCPreciseLifetime());
So your code would be compiled as the following.
id newValue = [[AVDelegatingPlayer alloc] initWithURL:[NSURL URLWithString:urlString]];
id oldValue = self.player;
self.player = newValue;
[oldValue release];
How do I detect when I have finished processing all found nodes when doing a query? In the following example, I do some processing on each encountered node. When I reach the "end" of the list I would like to be able to detect this so I know it's finished.
FQuery* messageListQuery = [m_firebaseRef queryLimitedToNumberOfChildren:100];
[messageListQuery observeEventType:FEventTypeChildAdded andPreviousSiblingNameWithBlock:^(FDataSnapshot *snapshot, NSString *prevNodeName) {
// 1. Do interesting stuff with the snapshot data
// 2. I want to detect when I'm at the end of the list so I know when I'm done processing the list.
}];
Here is the example use case. I would like to load the latest 100 messages in the background. Once the messages have been loaded, I would like to update the UI. However, I'm not sure how I know all the messages have been loaded given there might be less then 100 messages in the list.
I figured out how to read all the messages up front by using the observeSingleEventOfType and then iterating over the children.
[m_firebaseRef observeSingleEventOfType:FEventTypeValue withBlock:^(FDataSnapshot *snapshot) {
NSLog( #"Name %# with %d children.", snapshot.name, snapshot.childrenCount );
for( FDataSnapshot *child in snapshot.children )
{
NSDictionary *msgData = child.value;
NSString *message = msgData[kFirebaseLiveChatFieldMessage];
NSString *gamerTag = msgData[kFirebaseLiveChatFieldGamerTag];
NSString *gameCenterId = msgData[kFirebaseLiveChatFieldGameCenterId];
NSLog( #"Preload = %# (%#): %#", gamerTag, gameCenterId, message );
}
}];
I have 4 tabs in UITabBarcontroller. My problem is i need to navigate to next tab by user click while first tab process in on going?? how to run the process on background??
Now second tab not working while the first tab view in process. I used PerformSelectorInBackground but it's not help me?? Can any one help me Please????
Am poor in english, can you understand my problem?
Yuva.M
Run your heavy process with NSThread.
Snippet from here:
- (IBAction) startThreadButtonPressed:(UIButton *)sender {
[NSThread detachNewThreadSelector:#selector(startTheBackgroundJob) toTarget:self withObject:nil];
}
- (void)startTheBackgroundJob {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
// wait for 3 seconds before starting the thread, you don't have to do that. This is just an example how to stop the NSThread for some time
[NSThread sleepForTimeInterval:3];
[self performSelectorOnMainThread:#selector(makeMyProgressBarMoving) withObject:nil waitUntilDone:NO];
[pool release];
}
- (void)makeMyProgressBarMoving {
float actual = [threadProgressView progress];
if (actual < 1) {
threadProgressView.progress = actual + 0.01;
[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(makeMyProgressBarMoving) userInfo:nil repeats:NO];
}
}