Camera controls in app

[scj643]

Bindings for driving the focus as well as the exposure and other settings would be nice. The XPC service would need to expose controls for the current camera.

https://github.com/gphoto/libgphoto2/blob/master/examples/focus.c is an example of driving the focus with libgphoto2.

[scj643]

Actually, this should just implement a wraper to control camera options in general.

[scj643]

It is possible to implement it the same way as Copy Camera Descripton though we would need an implementation that runs while the camera is in live view.

[scj643]

https://gitlab.com/entangle/entangle is a project using Gphoto2 that has controls while in live view. A way to send messages to the main of the SyPLiveViewSession would allow changing settings while in live view.

[scj643]

This is my implementation in SyPGPhotoCamera.m

- (void)autofocus
{
    CameraWidget *widget = NULL, *child = NULL;

    int val = 0;

    int result = gp_camera_get_config(_camera, &widget, self.context.GPContext);

    if (result == GP_OK)
    {
        result = gp_widget_get_child_by_name(widget, "autofocusdrive", &child);
    }
    if (result == GP_OK)
    {
        CameraWidgetType type;
        result = gp_widget_get_type(widget, &type);
        if (result == GP_OK & type == GP_WIDGET_TOGGLE)
        {
            result = gp_widget_get_value (child, &val);
        }
        if (result == GP_OK)
        {
            // Invert the value to toggle it.
            val = !val;
            result = gp_widget_set_value(child, &val);
        }
        if (result == GP_OK)
        {
            result = gp_camera_set_config (_camera, widget, self.context.GPContext);
        }

    }
    gp_widget_free (widget);
}

[scj643]

A quick hack is to use NSUserDefaults and set the properties you want changed as booleans there.

The implementation in main of SyPLiveViewSession

if (!error)
    {
        while (!self.isCancelled)
        {

            NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
            BOOL focus = [defaults boolForKey:@"focus"];

            @autoreleasepool {
                SyPImageBuffer *buffer = [camera getImageWithError:&error];
                if (buffer)
                {
                    self.buffer = buffer;
                    dispatch_source_merge_data(source, 1);
                }
                if (error)
                {
                    if ([SyPGPhotoContext errorIsFatal:error])
                    {
                        [self cancel];
                    }
                    self.errorHandler(error);
                }
                else if (focus == YES)
                {
                    [camera autofocus];
                    [defaults setBool:NO forKey:@"focus"];
                }
            }
        }
    }

[scj643]

Ok, So I learned more Objective C and seems you could use NSNotificationCenter to trigger events on the camera. I am moving the camera in the live view session to another class called SyPCameraMessaging

SyPCameraMessaging.m

@implementation SyPCameraMessaging

- (SyPCameraMessaging *)initWithCamera:(SyPGPhotoCamera *)camera
{
    self.camera = camera;
    self.shouldGetFrames = YES;
    return self;
}

- (void) notificationHandler:(NSNotification *)notification
{
    if ([notification.object isEqual: @"focus"])
    {
        self.shouldGetFrames = NO;
        [self.camera autofocus];
        self.shouldGetFrames = YES;
    }
}
@end

SyPLiveViewSession.m

(inside main)

SyPCameraMessaging *messaging = [[SyPCameraMessaging alloc] initWithCamera: [_context cameraForDescription:_description withError:&error]];

// Code to create the queues is here

[messaging.camera startLiveView];
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
    [center addObserver:messaging selector:@selector(notificationHandler:) name:@"camera" object:nil];

if (!error)
    {
        while (!self.isCancelled)
        {
            @autoreleasepool {
                SyPImageBuffer *buffer = nil;
                if (messaging.shouldGetFrames)
                {
                    buffer = [messaging.camera getImageWithError:&error];
                }
                if (buffer)
                {
                    self.buffer = buffer;
                    dispatch_source_merge_data(source, 1);
                }
                if (error)
                {
                    if ([SyPGPhotoContext errorIsFatal:error])
                    {
                        [self cancel];
                    }
                    self.errorHandler(error);
                }
            }
        }
    }

All functions like autofocussing would have to check for GP_ERROR_CAMERA_BUSY and wait since the frame loop holds it.

[samuelbeek]

@scj643 is it possible to run both programs at the same time? to control autofocus without it being part of cameralive?

[scj643]

No it is not since cameralive has control of the camera.