I'm creating an application in pure C on Mac OSX.
What I want is to create window in witch my app will be stored.
Preferably I want it to be pure C solution, but if I have to use objective-c class to init window and then send context to my C code then it will be fine.
I'm not using xcode, only simple text editor in with I tried to import cocoa but it just generated a lot of errors.
So in summary my question is:
How in simple pure C generate code that will display osx window?
I did a translation of the accepted answer to Pure C:
// based on https://stackoverflow.com/a/30269562
// Minimal Pure C code to create a window in Cocoa
// $ clang minimal.c -framework Cocoa -o minimal.app
#include <objc/runtime.h>
#include <objc/message.h>
#include <Carbon/Carbon.h>
#define cls objc_getClass
#define sel sel_getUid
#define msg ((id (*)(id, SEL, ...))objc_msgSend)
#define cls_msg ((id (*)(Class, SEL, ...))objc_msgSend)
// poor man's bindings!
typedef enum NSApplicationActivationPolicy {
NSApplicationActivationPolicyRegular = 0,
NSApplicationActivationPolicyAccessory = 1,
NSApplicationActivationPolicyERROR = 2,
} NSApplicationActivationPolicy;
typedef enum NSWindowStyleMask {
NSWindowStyleMaskBorderless = 0,
NSWindowStyleMaskTitled = 1 << 0,
NSWindowStyleMaskClosable = 1 << 1,
NSWindowStyleMaskMiniaturizable = 1 << 2,
NSWindowStyleMaskResizable = 1 << 3,
} NSWindowStyleMask;
typedef enum NSBackingStoreType {
NSBackingStoreBuffered = 2,
} NSBackingStoreType;
int main(int argc, char *argv[])
{
// id app = [NSApplication sharedApplication];
id app = cls_msg(cls("NSApplication"), sel("sharedApplication"));
// [app setActivationPolicy:NSApplicationActivationPolicyRegular];
msg(app, sel("setActivationPolicy:"), NSApplicationActivationPolicyRegular);
struct CGRect frameRect = {0, 0, 600, 500};
// id window = [[NSWindow alloc] initWithContentRect:frameRect styleMask:NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable backing:NSBackingStoreBuffered defer:NO];
id window = msg(cls_msg(cls("NSWindow"), sel("alloc")),
sel("initWithContentRect:styleMask:backing:defer:"),
frameRect,
NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable,
NSBackingStoreBuffered,
false);
msg(window, sel("setTitle:"), cls_msg(cls("NSString"), sel("stringWithUTF8String:"), "Pure C App"));
// [window makeKeyAndOrderFront:nil];
msg(window, sel("makeKeyAndOrderFront:"), nil);
// [app activateIgnoringOtherApps:YES];
msg(app, sel("activateIgnoringOtherApps:"), true);
msg(app, sel("run"));
}
You can use Objective-C runtime API example (iOS) Creating an iOS app in pure C
Alternative the same code in obj-c :
echo '#import <Cocoa/Cocoa.h>
int main ()
{
#autoreleasepool{
[NSApplication sharedApplication];
[NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
id applicationName = [[NSProcessInfo processInfo] processName];
id window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 120, 120)
styleMask:NSTitledWindowMask backing:NSBackingStoreBuffered defer:NO];
[window cascadeTopLeftFromPoint:NSMakePoint(20,20)];
[window setTitle: applicationName];
[window makeKeyAndOrderFront:nil];
[NSApp activateIgnoringOtherApps:YES];
[NSApp run];
}
return 0;
}' | gcc -fobjc-arc -framework Cocoa -x objective-c -o MicroApp - ; ./MicroApp
This will run Cocoa app with 1 window. Like on screenshot below
You can actually add menu using NSMenu
id applicationMenuBar = [NSMenu new];
id appMenuItem = [NSMenuItem new];
[applicationMenuBar addItem:appMenuItem];
[NSApp setMainMenu: applicationMenuBar];
Can you do this? Yes and no (you can do anything if you're persistent enough). Yes you can, but no you shouldn't. Regardless, this can be done for the incredibly persistent among you. Since coding up an example will take awhile, I found a generous soul on the net who already did it. Look at this repository on GitHub for the full code and explanations. Here are some snippets:
cmacs_simple_msgSend((id)objc_getClass("NSApplication"), sel_getUid("sharedApplication"));
if (NSApp == NULL) {
fprintf(stderr,"Failed to initialized NSApplication... terminating...\n");
return;
}
id appDelObj = cmacs_simple_msgSend((id)objc_getClass("AppDelegate"), sel_getUid("alloc"));
appDelObj = cmacs_simple_msgSend(appDelObj, sel_getUid("init"));
cmacs_void_msgSend1(NSApp, sel_getUid("setDelegate:"), appDelObj);
cmacs_void_msgSend(NSApp, sel_getUid("run"));
As you'll notice, this code uses the Objective-C runtime API to create a faux AppDelegate. And creating the window is an involved process:
self->window = cmacs_simple_msgSend((id)objc_getClass("NSWindow"), sel_getUid("alloc"));
/// Create an instance of the window.
self->window = cmacs_window_init_msgSend(self->window, sel_getUid("initWithContentRect:styleMask:backing:defer:"), (CMRect){0,0,1024,460}, (NSTitledWindowMask | NSClosableWindowMask | NSResizableWindowMask | NSMiniaturizableWindowMask), 0, false);
/// Create an instance of our view class.
///
/// Relies on the view having declared a constructor that allocates a class pair for it.
id view = cmacs_rect_msgSend1(cmacs_simple_msgSend((id)objc_getClass("View"), sel_getUid("alloc")), sel_getUid("initWithFrame:"), (CMRect){ 0, 0, 320, 480 });
// here we simply add the view to the window.
cmacs_void_msgSend1(self->window, sel_getUid("setContentView:"), view);
cmacs_simple_msgSend(self->window, sel_getUid("becomeFirstResponder"));
// Shows our window in the bottom-left hand corner of the screen.
cmacs_void_msgSend1(self->window, sel_getUid("makeKeyAndOrderFront:"), self);
return YES;
So, yes. You can write a Cocoa app in pure C. But I wouldn't recommend it. 90% of that code can be replaced by an xib file, and doing it this way really restricts your app because more advanced features of the Apple development stack really on Objective-C features. While it's technically possible to do everything this way, you're making it much harder than it ought to be.
I remember seeing this question about a year ago, back when I so desperately wished I could open up a d*** window, googling for days and only finding the type of answers you see above this post.
I was reading up on the operating system the Mac is built on - Berkley Software Distribution. http://codex.cs.yale.edu/avi/os-book/OS9/appendices-dir/a.pdf Where on page 17 the phrase "...X Windowing System developed at MIT" hit me and I remembered how I couldn't open up a window and how pissed I was about that, and I thought maybe this was finally the solution!
I googled "BSD X Window Programming" and stumbled my way into finally getting a window open in pure C.
I just discovered it so I'm not a master yet but look at this link https://en.wikibooks.org/wiki/X_Window_Programming/Xlib and go to the example, make sure to follow the comments at the top for how to compile with the X11 library (you can ignore the -Wall and -O commands as long as you have the -lX11).
If you can't compile, if it can't find the header files, you'll need to help it find the header files.
There might be a couple different places that the X11 includes could be on your system. More than likely you'll find it in /opt/X11/include which will have all the definitions of the headers you'll need.
You could include the full path in your C programs such as:
#include "/opt/X11/include/X11/Xlib.h"
But we want it to look like this #include <X11/Xlib.h>
So you could add this switch to GCC when you compile -I /opt/X11/include
Or go to your .profile or .bashrc or .bash_profile in your home directory and add:
export C_INCLUDE_PATH="$C_INCLUDE_PATH:/opt/X11/include"
/*
Simple Xlib application drawing a box in a window.
*/
From the wiki:
#include<X11/Xlib.h>
#include<stdio.h>
#include<stdlib.h> // prevents error for exit on line 18 when compiling with gcc
int main() {
Display *d;
int s;
Window w;
XEvent e;
/* open connection with the server */
d=XOpenDisplay(NULL);
if(d==NULL) {
printf("Cannot open display\n");
exit(1);
}
s=DefaultScreen(d);
/* create window */
w=XCreateSimpleWindow(d, RootWindow(d, s), 10, 10, 100, 100, 1,
BlackPixel(d, s), WhitePixel(d, s));
// Process Window Close Event through event handler so XNextEvent does Not fail
Atom delWindow = XInternAtom( d, "WM_DELETE_WINDOW", 0 );
XSetWMProtocols(d , w, &delWindow, 1);
/* select kind of events we are interested in */
XSelectInput(d, w, ExposureMask | KeyPressMask);
/* map (show) the window */
XMapWindow(d, w);
/* event loop */
while(1) {
XNextEvent(d, &e);
/* draw or redraw the window */
if(e.type==Expose) {
XFillRectangle(d, w, DefaultGC(d, s), 20, 20, 10, 10);
}
/* exit on key press */
if(e.type==KeyPress)
break;
// Handle Windows Close Event
if(e.type==ClientMessage)
break;
}
/* destroy our window */
XDestroyWindow(d, w);
/* close connection to server */
XCloseDisplay(d);
return 0;
}
Compile:
gcc -O2 -Wall -o test test.c -L /usr/X11R6/lib -lX11 -lm
Unfortunately the top rated answer doesn't work on new Apple Silicon powered machines due to an ABI mismatch. Basically on ARM64 you can't use the objc_msgSend declaration with variable arguments, you must specify the correct argument types for each call. Here is the version that runs on Apple Silicon:
// based on https://stackoverflow.com/a/59596600/834108
// Minimal Pure C code to create a window in Cocoa
// Adapted to work on ARM64
// $ clang minimal.c -framework Cocoa -o minimal.app
#include <objc/runtime.h>
#include <objc/message.h>
#include <Carbon/Carbon.h>
#define cls objc_getClass
#define sel sel_getUid
#define msg ((id (*)(id, SEL))objc_msgSend)
#define msg_int ((id (*)(id, SEL, int))objc_msgSend)
#define msg_id ((id (*)(id, SEL, id))objc_msgSend)
#define msg_ptr ((id (*)(id, SEL, void*))objc_msgSend)
#define msg_cls ((id (*)(Class, SEL))objc_msgSend)
#define msg_cls_chr ((id (*)(Class, SEL, char*))objc_msgSend)
// poor man's bindings!
typedef enum NSApplicationActivationPolicy {
NSApplicationActivationPolicyRegular = 0,
NSApplicationActivationPolicyAccessory = 1,
NSApplicationActivationPolicyERROR = 2,
} NSApplicationActivationPolicy;
typedef enum NSWindowStyleMask {
NSWindowStyleMaskBorderless = 0,
NSWindowStyleMaskTitled = 1 << 0,
NSWindowStyleMaskClosable = 1 << 1,
NSWindowStyleMaskMiniaturizable = 1 << 2,
NSWindowStyleMaskResizable = 1 << 3,
} NSWindowStyleMask;
typedef enum NSBackingStoreType {
NSBackingStoreBuffered = 2,
} NSBackingStoreType;
int main(int argc, char *argv[])
{
// id app = [NSApplication sharedApplication];
id app = msg_cls(cls("NSApplication"), sel("sharedApplication"));
// [app setActivationPolicy:NSApplicationActivationPolicyRegular];
msg_int(app, sel("setActivationPolicy:"), NSApplicationActivationPolicyRegular);
struct CGRect frameRect = {0, 0, 600, 500};
// id window = [[NSWindow alloc] initWithContentRect:frameRect styleMask:NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable backing:NSBackingStoreBuffered defer:NO];
id window = ((id (*)(id, SEL, struct CGRect, int, int, int))objc_msgSend)(
msg_cls(cls("NSWindow"), sel("alloc")),
sel("initWithContentRect:styleMask:backing:defer:"),
frameRect,
NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable,
NSBackingStoreBuffered,
false
);
msg_id(window, sel("setTitle:"), msg_cls_chr(cls("NSString"), sel("stringWithUTF8String:"), "Pure C App"));
// [window makeKeyAndOrderFront:nil];
msg_ptr(window, sel("makeKeyAndOrderFront:"), nil);
// [app activateIgnoringOtherApps:YES];
msg_int(app, sel("activateIgnoringOtherApps:"), true);
msg(app, sel("run"));
}
Pure C cross-platform example: (Windows/macOS/Linux)
https://nappgui.com/en/demo/products.html
About macOS portability in pure C (updated to BigSur and M1 support):
https://nappgui.com/en/start/win_mac_linux.html#h2
I'm creating an application in pure C on Mac OSX. What I want is to create window in which my app will be stored.
Are you looking for a TTY window?
If so does your application need to create the window?
If not then you can simply write your pure C program and execute it from within Terminal - a TTY environment for "pure C".
If you want a double-clickable app you can write an AppleScript which will open Terminal and run your C. Something like:
tell application "Terminal"
do script "ex /tmp/test; exit"
end tell
This opens a Terminal window showing "ex" and when that quits will terminate the shell process (so no further commands can be typed), but it will not close Terminal itself - for that you will have to work harder.
If you do want you application to create the window itself you either need to write your own simple TTY window, you might find some classes you can use, or you might be able to borrow code from an open source terminal app such as iterm.
HTH
In my application, I have a struct and it contains all of my data. It works well with previous version of Xcode. But when I build it with Xcode 9, beta 5 to iOS 11 device, some data inside is lost.
That happens, when I pass the struct object as parameter by function to another activity.
My struct looks like below:
typedef struct {
NSString *title;
MainController *mainController;
//....
//....
//more than 200 objects
} mystruct;
After data loss, when I try to access it Xcode shows [EXC_BAD_ACCESS] and application crashes.
Is there any size limit to structures in Xcode 9?
UPDATE 1: add creating and passing source
//declare struct
mystruct m;
memset(&m,0,sizeof(mystruct));
// setting data for struct
....
...
...
// passing param
[anotherObj showData:&m];
Method read value of another object :
- (void)showData:(mystruct *)ms
{
// get data of struct
[self showText : ms->title];
}
NOTE: It only happens on xCode 9 and iOS 11
xCode 9 + iOS 11 -> Error
xCode 9 + iOS 10 -> OK
xCode 8 + iOS 11 ->OK
xCode 8 + iOS 10 -> OK
xCode 7 + iOS 11 -> OK
xCode 7 + iOS 10 ->OK
I solved it by myself . The reason is because when build app on xCode 9 . It forces my app build with 64-bit compiler .
There was a warning from Apple doc about [Be Careful When Aligning 64-Bit Integer types] . But i didn't notice it .
Link : Apple doc about aligning bit
Then, i just add pragma like they teach and it worked well .
#pragma pack(4)
struct bar {
int32_t foo0;
int32_t foo1;
int32_t foo2;
int64_t bar;
};
#pragma options align=reset
Another way , we can reorganize the elements with the largest alignment values first and the smallest elements last to avoid padding bit .
#Amin Negm-Awad : Thanks for your help
I am using below code to check OS X version at runtime.
if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_10)
{
/* On a 10.10.x or earlier system */
}
But this condition return false on 10.10.4 OS X. I am using Xcode 6.3.2.
According to AppKit Release Notes for OS X v10.11, It should work.
if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_9) {
/* On a 10.9.x or earlier system */
} else if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_10) {
/* On a 10.10 - 10.10.x system */
} else {
/* 10.11 or later system */
}
Since Xcode 9.0, you can use code below.
Reference to Apple documentation.
Swift
if #available(macOS 10.13, *) {
// macOS 10.13 or later code path
} else {
// code for earlier than 10.13
}
Objective-C
if (#available(macOS 10.13, *)) {
// macOS 10.13 or later code path
} else {
// code for earlier than 10.13
}
So the #define for 10_10 you see there is for 10.10.0.
If you look for older version numbers, you'll see specific #define's for MacOS 10.7.4, MacOS 10.5.3.
And what is happening here is that on a 10.10.4 machine (like yours and mine), the app kit number for 10.10.4 is greater than the one defined for 10.10.0.
That is, in swift, I did:
func applicationDidFinishLaunching(aNotification: NSNotification) {
print("appkit version number is \(NSAppKitVersionNumber)")
}
And I got:
appkit version number is 1348.17
So your code is actually checking for 10.10.0 and older.
If you want to check for all versions of Yosemite & newer, you'll probably want to do something like
#ifdef NSAppKitVersionNumber10_11
if (floor(NSAppKitVersionNumber) < NSAppKitVersionNumber10_11)
{
/* On a 10.10.x or earlier system */
}
#endif
which will compile once you start building with Xcode 7 (and once Apple gets around to defining the official shipping version/build number for the El Capitan release)
FWIW, the Xcode 7 beta I have includes "NSAppKitVersionNumber10_10_3" in the 10.11 SDK.
If you need to support multiple systems (you can adapt method return value):
#import <objc/message.h>
+ (NSString *)systemVersion
{
static NSString *systemVersion = nil;
if (!systemVersion) {
typedef struct {
NSInteger majorVersion;
NSInteger minorVersion;
NSInteger patchVersion;
} MyOperatingSystemVersion;
if ([[NSProcessInfo processInfo] respondsToSelector:#selector(operatingSystemVersion)]) {
MyOperatingSystemVersion version = ((MyOperatingSystemVersion(*)(id, SEL))objc_msgSend_stret)([NSProcessInfo processInfo], #selector(operatingSystemVersion));
systemVersion = [NSString stringWithFormat:#"Mac OS X %ld.%ld.%ld", (long)version.majorVersion, version.minorVersion, version.patchVersion];
}
else {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
SInt32 versMaj, versMin, versBugFix;
Gestalt(gestaltSystemVersionMajor, &versMaj);
Gestalt(gestaltSystemVersionMinor, &versMin);
Gestalt(gestaltSystemVersionBugFix, &versBugFix);
systemVersion = [NSString stringWithFormat:#"Mac OS X %d.%d.%d", versMaj, versMin, versBugFix];
#pragma clang diagnostic pop
}
}
return systemVersion;
}
Starting with Yosemite, you can use [NSProcessInfo processInfo].operatingSystemVersion and test the result in the struct NSOperatingSystemVersion.
Update:
Use #define NSAppKitVersionNumber10_10_Max 1349
Old:
From 10.11 SDK
#define NSAppKitVersionNumber10_7_2 1138.23
#define NSAppKitVersionNumber10_7_3 1138.32
#define NSAppKitVersionNumber10_7_4 1138.47
#define NSAppKitVersionNumber10_8 1187
#define NSAppKitVersionNumber10_9 1265
#define NSAppKitVersionNumber10_10 1343
#define NSAppKitVersionNumber10_10_2 1344
#define NSAppKitVersionNumber10_10_3 1347
for 10.10.4 Its 1348.0(From NSLog output)
They increase decimal part for 10.10.x constant.
The workaround is to use CFBundleVersion value /System/Library/Frameworks/AppKit.framework/Resources/Info.plist on 10.11.
if (NSAppKitVersionNumber < 1391.12)
{
/* On a 10.10.x or earlier system */
}
NOTE: My OS X 10.11 build version is 15A244a. If someone have first build , Please update the value in if condition.
Update: I'm working with the GNU-runtime on Linux. The problem does not occur on MacOS with the Apple-runtime.
Update 2: I compiled the GNU-runtime on MacOS and build the example with it. The error does not occur on MacOS with the GNU-runtime. I would say the problem is the glibc (since backtrace and backtrace_symbols are glibc extensions).
When printing a backtrace in a GCC compiled Objective-C app using backtraceand backtrace_symbols, I don't get any Objective-C symbols. Only the filenames, addresses and C-symbols appear.
I compiled with -g and linked with -rdynamic.
My test app:
void _printTrace()
{
void *addr[1024];
int aCount = backtrace(addr, 1024);
char **frameStrings = backtrace_symbols(addr, aCount);
for (int i = 0; i < aCount; i++) {
printf("%s\n", frameStrings[i]);
}
free(frameStrings);
}
#interface TheObject
+ (void)_printTrace;
+ (void)printTrace;
#end
#implementation TheObject
+ (void)_printTrace
{
_printTrace();
}
+ (void)printTrace
{
[self _printTrace];
}
#end
void printTrace()
{
[TheObject printTrace];
}
int main(int argc, char **argv)
{
printTrace();
return 0;
}
and it's output:
./test.bin(_printTrace+0x1f) [0x8048e05]
./test.bin() [0x8048e60]
./test.bin() [0x8048e8b]
./test.bin(printTrace+0x34) [0x8048ec5]
./test.bin(main+0xf) [0x8048eda]
/lib/libc.so.6(__libc_start_main+0xe5) [0xb7643bb5]
./test.bin() [0x8048b51]
Is there a way to let the Objective-C symbols appear in this backtrace?
dladdr() only reports global and weak symbols. But all Objective-C function symbols are local:
$ readelf -s so_backtrace
Symbol table '.dynsym' contains 29 entries:
…
Symbol table '.symtab' contains 121 entries:
Num: Value Size Type Bind Vis Ndx Name
…
49: 08048a01 13 FUNC LOCAL DEFAULT 14 _c_TheObject___printTrace
50: 08048a0e 47 FUNC LOCAL DEFAULT 14 _c_TheObject__printTrace
…
You can verify that local symbols are never returned by looking at the GNU libc source code yourself. backtrace_symbols() is defined in sysdeps/generic/elf/backtracesyms.c. It relies on _dl_addr(), which is defined in elf/dl-addr.c, to provide it with the symbol names. That ultimately calls determine_info(). If it can, it uses the the GNU hash table, which does not include local symbols by design:
49 /* We look at all symbol table entries referenced by the hash
50 table. */
…
60 /* The hash table never references local symbols so
61 we can omit that test here. */
If the GNU hash table isn't present, it falls back to standard hash table. This includes all the symbols, but the determine_info() code filters out all but the global symbols and weak symbols:
90 if ((ELFW(ST_BIND) (symtab->st_info) == STB_GLOBAL
91 || ELFW(ST_BIND) (symtab->st_info) == STB_WEAK)
To symbolicate the Objective-C function addresses, you would have to perform the look-up yourself and not filter out the local function symbols. Further, you would have to demangle the Objective-C function symbols to restore _c_TheObject___printTrace to +[TheObject _printTrace].
GNUstep's NSException implementation doesn't use backtrace, instead it uses libbfd (binary file descriptor). I think the function that actually does the work is called static void find_address, which you can view here. Using this trivial example, I get the results that follow.
#include <Foundation/Foundation.h>
#interface Test : NSObject {}
+ (void) test;
#end
#implementation Test
+ (void) test
{
Class GSStackTrace = objc_getClass("GSStackTrace");
id stack = [GSStackTrace currentStack];
for (int i = 0; i < [stack frameCount]; i++)
{
NSLog (#"%#", [[stack frameAt:i] function]);
}
}
#end
int main(int argc, char **argv)
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
[Test test];
[pool release];
return 0;
}
Output (when compiled with debug symbols):
2010-10-18 14:14:46.188 a.out[29091] +[GSStackTrace currentStack]
2010-10-18 14:14:46.190 a.out[29091] +[Test test]
2010-10-18 14:14:46.190 a.out[29091] main
2010-10-18 14:14:46.190 a.out[29091] __libc_start_main
You may be able to pick apart GSStackTrace. It is a “private” class (that's why I need to use objc_getClass, you'll also get lots of unrecognised selector warnings), but it seems to contain all the code necessary to read Objective-C class names.
Tested on Ubuntu 9.04 with GNUstep configured with --enable-debug (so that GSFunctionInfo is included in the build).
I expect you'll need to ask the ObjC run time about the addresses to get symbol information. The addresses returned from backtrace() could probably be passed to something like object_getClass() to get the class, for example. I haven't tried any of this but it's where I'd look next in this case.
I'm working on an iOS app. It currently only works on iOS 4 since I use the following method on several occasions: "UIGraphicsBeginImageContextWithOptions". This method is only available in iOS 4 and therefor my app currently crashes/doesn't work on iPhone OS 3. Aside from this method there is no reason why the app should not work on iPhone OS 3. How do I make a check to see wether or not this method is available ? I've tried the following without succes:
if([self respondsToSelector:#selector(UIGraphicsBeginImageContextWithOptions)]) {
UIGraphicsBeginImageContextWithOptions(targetSize, NO, 0.0); // this will crop
}
else
{
UIGraphicsBeginImageContext(targetSize);
}
I've only tried variations like this:
if([self respondsToSelector:#selector(UIGraphicsBeginImageContextWithOptions:size:opaque:scale:)])
and
if([self respondsToSelector:#selector(UIGraphicsBeginImageContextWithOptions:)])
Without succes. Any help would be appreciated.
UIGraphicsBeginImageContextWithOptions is a C function, so you can't use Objective-C methods like -respondsToSelector: to test its existence.
You could, however, weak link the UIKit framework, and then check if UIGraphicsBeginImageContextWithOptions is NULL:
if (UIGraphicsBeginImageContextWithOptions != NULL) {
UIGraphicsBeginImageContextWithOptions(...);
} else {
UIGraphicsBeginImageContext(...);
}
I have the same problem. You could try testing the system version. This seems to work for me on the devices I tested.
char majorVersion = [[[UIDevice currentDevice] systemVersion] characterAtIndex: 0];
if (majorVersion == '2' || majorVersion == '3')
UIGraphicsBeginImageContext(...);
else
UIGraphicsBeginImageContextWithOptions(...);
I know this is an old question, but with new Xcode and iOS versions (upper than 9) any of this methods work for me.
I always check the system version in this way:
NSString *sysver = [[UIDevice currentDevice] systemVersion];
NSArray *versionNums = [sysver componentsSeparatedByString:#"."];
int majorVersion = [versionNums[0] intValue];
if (majorVersion > 3){
UIGraphicsBeginImageContextWithOptions(...);
}
else{
UIGraphicsBeginImageContext(...);
}
I hope this could help anyone.