-(void)placeHole {
randomBlackHole = arc4random() %410;
randomBlackHole = randomBlackHole -10;
blackHole = randomBlackHole;
}
randomBlackHole is an integer and blackHole is an image within a button.
Yes, exactly. Implicit conversion of int to UIImage* is not allowed. Not with ARC, not without ARC. Not in C, C++, Objective-C, Java, or most other languages. What would it do? Do you think it should turn a number into an image?
BTW. It is highly recommended to start instance variables with an underscore character, so there is a clear distinction between using properties and using instance variables.
Related
my aim is to capture the screen of a windows form using c++/cli. Below is the code to capture the window, however, it is in C#. What changes do I have to make to the code for it to work in c++?
Graphics myGraphics = this.CreateGraphics();
Size s = this.Size;
memoryImage = new Bitmap(s.Width, s.Height, myGraphics);
Graphics memoryGraphics = Graphics.FromImage(memoryImage);
memoryGraphics.CopyFromScreen(this.Location.X, this.Location.Y, 0, 0, s);
What I've tried:
I've tried using the code below in c++, however, I get errors for the part in ** **.
The error says expected a ; after Size i.e. Size; s = this->Size; which does not make sense to me
Graphics^ myGraphics = this->CreateGraphics();
Size **s** = this->Size;
memoryImage = gcnew Bitmap(**s**->Width, s->Height, myGraphics);
Graphics^ memoryGraphics = Graphics::FromImage(memoryImage);
memoryGraphics->CopyFromScreen(this->Location.X, this->Location.Y, 0, 0, s);
Your code looks mostly correct.
I think that Size s is getting confused because Size is both the name of a type, and the name of a property on this object. It thinks you're trying to retrieve the Size property and throw away the result. To fix this, use the full name of the type for the declaration: System.Drawing.Size s = this->Size;. (You could also use auto, or remove the local variable entirely and just call this->Size several times.)
System.Drawing.Size is a value struct, not a ref class. It's a value type, not a reference type, so you need to do s.Width and s.Height.
This is similar to Location: Location returns a Point, which is a value type, and you're already doing Location.X, not Location->X.
The Problem
I am trying to get the new AUParameterTree and AUParameter's mechanism working in my Audio Unit V3 test project. The problem is that when I gain a reference to it from the Host App and change its value, the Audio Unit extension's parameter doesn't appear to change.
Here is my approach.
I'm using the new Audio Unit V3 API. I've created an AUParameter in my AUAudioUnit's initWithComponentDescription:
Creating the Parameter
AUParameter *param1 = [AUParameterTree createParameterWithIdentifier:#"frequency"
name:#"Frequency"
address:frequencyAddress
min:500
max:5000
unit:kAudioUnitParameterUnit_Hertz
unitName:nil
flags:0
valueStrings:nil
dependentParameters:nil];
Set a default value..
param1.value = 0.5;
some of the arguments to the Parameter constructor come from...
Some State
I have defined the address as a global constants:
const AudioUnitParameterID frequencyAddress = 0;
And a local variable for an AUValue:
AUValue frequency = 1;
Keep in mind at this point I'm just following the three example projects that use Audio Unit V3 on the entire internet. I find it difficult to piece together how this entire AU parameter dance should go only from reading the docs.
Rendering with the parameter
now when it comes to using the AUValue associated with the AUParameter "param1", (I assume thats how it works?)..
I am then capturing this AUValue ( the local variable which I'm unclear on how it is associated with the actual AUParameter ) .. in my Audio Unit rendering block:
- (AUInternalRenderBlock)internalRenderBlock {
AUValue * param1Capture = &frequency;
return ^AUAudioUnitStatus(AudioUnitRenderActionFlags *actionFlags, const AudioTimeStamp *timestamp, AVAudioFrameCount frameCount, NSInteger outputBusNumber, AudioBufferList *outputData, const AURenderEvent *realtimeEventListHead, AURenderPullInputBlock pullInputBlock) {
// use parameter value
someValue = *param1Capture;
// more dsp stuff..
Controlling Parameter from Host App
This is where the problem arises.
I declare a local reference to an AUParameter:
#interface ViewController (){
AudioEngine *_audioEngine;
AUParameter * _param1;
}
and when my Audio Engine class instantiates my AUAudioUnit it passes it to me:
[_audioEngine setupAUWithComponentDescription:desc andCompletion:^(AUAudioUnit * unit){
_param1 = [unit.parameterTree valueForKey:#"frequency"];
}];
no effect?
Now when I say:
[_param1 setValue: 1000];
The captured AUValue in my rendering block remains the same!
I've either overlooked a bug, a mindless type (I may have introduced a type in this write up of my problem so keep that in mind), or I have fundamentally misunderstood this mechanism.
If I need to provide more context for this problem I can easily push the project to Github.
Thanks in advance.
The problem turned out to have nothing to do with Core Audio and everything to do with a basic language level mistake.
frequency was declared at a file level scope like this:
AUValue frequency = 1;
#implementation MyAudioUnit
#end
My understanding is that frequency is now bound to file scope and not instance scope. Therefore repeated setting of it on different instances was simply overwriting the previous value. Hence, the last assignment was the frequency which would be rendered.
so I was wondering if there was a way to reference different objects on stage with he same method to save repeating lots of lines of code. This is what I have right now
function bossKilled(i:Number):Void {
trace("Boss Killed!");
kills ++;
_root.bossDeath.gotoAndPlay(2);
_root["pirate"+i+"Active"] = false; //name of variable would be pirate1Active
_root["pirate"+(i+1)+"Active"] = true; //name of variable would be pirate2Active
bossDeath._x = _root["pirate"+i+"Active"]._x;
bossDeath._y = _root["pirate"+i+"Active"]._y; }
However, this reference does not actually affect the variables. I was wondering if this was possible, and if so, what am I doing wrong?
Thanks.
Not sure what you try to achieve ... pirate1Active is a BOOL. A BOOL has no _x or _y property (nor any other).
If you are not sure where to find your objects in the object tree, you can use the debugger or add some traces on the MCs timeline, like trace (_parent);
Consider switching to AS3, it is much more object oriented and has better tools support.
Try call this method:
avatarIconImageView.setContentHuggingPriority(UILayoutPriorityDefaultLow, forAxis: UILayoutConstraintAxis.Horizontal)
and catch this exception:
Undefined symbols for architecture armv7:
"_UILayoutPriorityDefaultLow", referenced from:
__TFC13TCProject_iOS36TCAvatarWithCounterUniversalCellView22configureBodyCellViewsfS0_FT_T_
in TCAvatarUniversalCellView.o ld: symbol(s) not found for
architecture armv7 clang: error: linker command failed with exit code
1 (use -v to see invocation)
what it means?
This looks like a bug in the iOS 8 SDK. You can work around this by just passing in a raw value.
UILayoutPriorityDefaultRequired = 1000
UILayoutPriorityDefaultHigh = 750
UILayoutPriorityDefaultLow = 250
In your case
avatarIconImageView.setContentHuggingPriority(250, forAxis: UILayoutConstraintAxis.Horizontal)
This is not a bug. It is a shortcoming of an expectation for the import of Objective-C libraries into Swift. It should be understood how Swift imports code (even from the Apple UIKIt Libraries) from Objective-C into Swift.
UILayoutPriority is a float. In Objective-C, a couple of values have been pre-defined for us. The pre-defined values appear to be an enum. We might expect that the same enums would be available to us in Swift.
The documentation suggests an enum:
Declaration
SWIFT
typealias UILayoutPriority = Float
OBJECTIVE-C
enum {
UILayoutPriorityRequired = 1000,
UILayoutPriorityDefaultHigh = 750,
UILayoutPriorityDefaultLow = 250,
UILayoutPriorityFittingSizeLevel = 50,
};
typedef float UILayoutPriority;
But in Xcode, if you ask to see the defintion of one of these enum values (UILayoutPriorityRequired, for example), you will see that they are actually defined in the header file as constant floats.
typedef float UILayoutPriority;
static const UILayoutPriority UILayoutPriorityRequired NS_AVAILABLE_IOS(6_0) = 1000; // A required constraint. Do not exceed this.
static const UILayoutPriority UILayoutPriorityDefaultHigh NS_AVAILABLE_IOS(6_0) = 750; // This is the priority level with which a button resists compressing its content.
static const UILayoutPriority UILayoutPriorityDefaultLow NS_AVAILABLE_IOS(6_0) = 250; // This is the priority level at which a button hugs its contents horizontally.
So although we may like to think of the pre-defined layout priorities as enum values (as the documentation suggests) the layout priorities are not really defined as enums; they are defined as constant floats.
A hint for anyone that knows the C programming language is that a C enum may only contain int values. The following is legal and will compile:
enum myEnum {
JGCEnum_one = 1,
JGCEnum_two,
JGCEnum_three
} JGCEnum;
But we can't really define floats as values for C enums. The following will not compile:
enum myEnum {
JGCEnum_one = 1.5, // compilation error
JGCEnum_two,
JGCEnum_three
} JGCEnum;
Objective-C enums are the same as C enums (Swift enums are different). It is important to know if we are dealing with actual integers or floats. Because integers can be defined using the NS_ENUM macro, which can then be imported to Swift as a Swift enum.
The iBook says
Swift imports as a Swift enumeration any C-style enumeration marked with the NS_ENUM macro. This means that the prefixes to enumeration value names are truncated when they are imported into Swift, whether they’re defined in system frameworks or in custom code.
Excerpt From: Apple Inc. “Using Swift with Cocoa and Objective-C.” iBooks. https://itun.es/us/1u3-0.l
That means that if UILayoutPriority had been defined as an integer using the NS_ENUM macro, it would have been imported into Swift as Swift enum. This is the case for UILayoutConstraintAxis.
Declaration
SWIFT
enum UILayoutConstraintAxis : Int {
case Horizontal
case Vertical
}
OBJECTIVE-C
enum {
UILayoutConstraintAxisHorizontal = 0,
UILayoutConstraintAxisVertical = 1
};
typedef NSInteger UILayoutConstraintAxis;
Looking at the Objective-C header file confirms what the documentation says.
//
// UIView Constraint-based Layout Support
//
typedef NS_ENUM(NSInteger, UILayoutConstraintAxis) {
UILayoutConstraintAxisHorizontal = 0,
UILayoutConstraintAxisVertical = 1
};
So there are at least two ways to know if a pre-defined value you are used to using in Objective-C is available in Swift:
check the documentation
check the header file in Objective-C (found by right-clicking the value and then selecting "Jump to Definition")
There is one more way to see if a typedef you are used to using is a constant or an enum. In code, test to see if the address of the constant exists. Constants have a memory address, while enums do not. See the code below.
// this line will compile and run just fine.
// UILayoutPriorityDefaultHigh is a constant and has a memory address
// the value will be true if the device is running iOS 6.0 or later
// and false otherwise
BOOL predefinedValueIsAvailable = (NULL != &UILayoutPriorityDefaultHigh);
// this line will not compile
// UILayoutConstraintAxisHorizontal is an enum (NOT a constant)
// and does not have a memory address
predefinedValueIsAvailable = (NULL != &UILayoutConstraintAxisHorizontal);
References
https://www.blogger.com/blogger.g?blogID=1591443959382526146#editor/target=post;postID=5044844235580349879;onPublishedMenu=allposts;onClosedMenu=allposts;postNum=0;src=postname
Xcode Documentation (iOS 8.2)
Apple Inc. “Using Swift with Cocoa and Objective-C.” iBooks. https://itun.es/us/1u3-0.l
I know how to do a global variable, but whenever I try to define a global variable with a random number function, xcode says "initializer element is not constant." The compiler doesn't want to make a variable from a random number because the random number function is not constant.
How do I generate a random number and then use that same value for more than one action? (For example, to define a color and then write that value to a label?)
Code:
#import "Slider_with_IBAppDelegate.h"
float * const hue = ((arc4random() % ((unsigned)100 + 1))/100.0);
//^this is where I get the error: "initializer element is not constant"
#synthesize label
//write value to label
- (IBAction) doButton {
label.text = [NSString stringWithFormat:#"%f", hue];
}
//set background color
- (void)applicationDidBecomeActive:(UIApplication*)application
{
self.label5.backgroundColor = [UIColor colorWithHue:hue
saturation:1.0
brightness:1.0
alpha:1.0];
}
----edit------
Thanks for the suggestions. It still doesn't work for me, though, what am I doing wrong?
New code:
#import "Slider_with_IBAppDelegate.h"
float const hue = ((arc4random() % ((unsigned)100 + 1))/100.0);
//^I still get the error: "initializer element is not constant."
#synthesize label
//write value to label
- (IBAction) doButton {
label.text = [NSString stringWithFormat:#"%f", hue];
}
//^this is where I get the error "'hue' undeclared (first use of this function)"
//set background color
- (void)applicationDidBecomeActive:(UIApplication*)application
{
hue = ((arc4random() % ((unsigned)1000 + 1))/1000.0);
/*here I get the error "assignment of read-only variable 'hue.'"
If I insert "float" just before hue, I do not get this error,
but it still won't compile because of the error above.*/
self.label5.backgroundColor = [UIColor colorWithHue:hue
saturation:1.0
brightness:1.0
alpha:1.0];
}
Make it non-const and initialize it in applicationDidBecomeActive. Is there a reason it must be constant?
I know how to do a global variable, but whenever I try to define a global variable with a random number function, xcode says "incompatible types in initialization."
float * const hue = ((arc4random() % ((unsigned)100 + 1))/100.0);
That's not a function; it's an expression. I'd be surprised if you're not also getting an error here, because you can't initialize a global variable with an expression that isn't constant. As alltom.com says, you need to assign to it from applicationDidBecomeActive:.
The warning is because you've given the variable a pointer type (float *), but you're not assigning a pointer to it. Cut out the asterisk, because you're not going to put a pointer in this variable.
Xcode doesn't want to make a variable from a random number because the random number function is not constant.
Xcode doesn't care one way or the other. It's just reporting the findings of the compiler. By default, the compiler for Objective-C is GCC, but Xcode supports other compilers (and Xcode does come with one other C/Objective-C compiler: LLVM-GCC).
… I couldn't call the same value for the label.
You're not showing a label here, and you can't call a value. You can only call a function, and you don't have one in the code shown.
It gave me the error "function undefined: first use of this function" in doButton even though it was defined in applicationDidBecomeActive.
No, it wasn't. Assigning to a variable does not create a function.
In case anyone is wondering, I finally found a way to do this effectively. (I am sure this is what alltom was saying, I was just too dumb to understand.)
I declared a float and a seed in my .h file:
- (float)generate:(id)sender;
- (void)seed;
And in the implementation file, I defined the float as a random number, and I used srandom() as a random seed generator.
- (float)generate:(id)sender
{
//Generate a number between 1 and 100 inclusive
int generated;
generated = (random() % 100) + 1;
return(generated);
}
- (void)seed {
srandom(time(NULL));
}
Then anywhere I wanted to retain a random number, I used
srandom(time(NULL));
generated1 = ((random() % 100) + 1)/100.0;
to initiate the number, and from there I was able to use generated1, generated2, hue, etc. as variables in any function I wanted (and I made sure to declare these variables as floats at the top of the file).