[swift-users] Need Help with C-to-Swift (finally)

Fri Dec 11 21:02:41 CST 2015

Your Cairo module is an executable and not a library. Don't call files main.swift for libraries.

I'll open a ticket to ensure swift build warns for this in future.

> On Dec 11, 2015, at 6:54 PM, Gage Morgan <gagemorgan at outlook.com> wrote:
> 
> Here's what is inhibited when using swift build -v:
> 
> mgage at mgage:~/swift-cairo-bindings/test$ swift build -v
> /home/mgage/Downloads/swift/usr/bin/swiftc -o /home/mgage/swift-cairo-bindings/test/.build/debug/test /home/mgage/swift-cairo-bindings/test/.build/debug/test.o/main.swift.o -g -L/usr/local/lib
> /home/mgage/swift-cairo-bindings/test/.build/debug/test.o/main.swift.o: In function `main':
> /home/mgage/swift-cairo-bindings/test/main.swift:4: undefined reference to `_TMaC5Cairo7Surface'
> /home/mgage/swift-cairo-bindings/test/main.swift:4: undefined reference to `_TFC5Cairo7SurfaceCfT6formatVSC13_cairo_format5widthSi6heightSi_S0_'
> clang: error: linker command failed with exit code 1 (use -v to see invocation)
> <unknown>:0: error: link command failed with exit code 1 (use -v to see invocation)
> <unknown>:0: error: build had 1 command failures
> swift-build: exit(1): ["/home/mgage/Downloads/swift/usr/bin/swift-build-tool", "-v", "-f", "/home/mgage/swift-cairo-bindings/test/.build/debug/test.o/llbuild.yaml"]
> 
> I'm going to attempt to create a repo, but GitHub and I don't always get along ;)
> 
> 
> Subject: Re: [swift-users] Need Help with C-to-Swift (finally)
> From: max.howell at apple.com
> Date: Fri, 11 Dec 2015 18:51:09 -0800
> CC: jackl at apple.com; swift-users at swift.org; harlan at harlanhaskins.com
> To: gagemorgan at outlook.com
> 
> The link failure is for the constructor for your Cairo class.
> 
> I'll have to test this out myself. Can't for a few hours at least.
> 
> In the mean time try `swift build -v` for some more information.
> 
> On Dec 11, 2015, at 6:42 PM, Gage Morgan via swift-users <swift-users at swift.org> wrote:
> 
> I have no idea what happened here, but:
> 
> Cloning Packages/CCairo
> Cloning Packages/Cairo
> Compiling Swift Module 'Cairo' (1 sources)
> Linking Executable:  .build/debug/Cairo
> Compiling Swift Module 'test' (1 sources)
> Linking Executable:  .build/debug/test
> /home/mgage/swift-cairo-bindings/test/.build/debug/test.o/main.swift.o: In function `main':
> /home/mgage/swift-cairo-bindings/test/main.swift:4: undefined reference to `_TMaC5Cairo7Surface'
> /home/mgage/swift-cairo-bindings/test/main.swift:4: undefined reference to `_TFC5Cairo7SurfaceCfT6formatVSC13_cairo_format5widthSi6heightSi_S0_'
> clang: error: linker command failed with exit code 1 (use -v to see invocation)
> <unknown>:0: error: link command failed with exit code 1 (use -v to see invocation)
> <unknown>:0: error: build had 1 command failures
> swift-build: exit(1): ["/home/mgage/Downloads/swift/usr/bin/swift-build-tool", "-f", "/home/mgage/swift-cairo-bindings/test/.build/debug/test.o/llbuild.yaml"]
> 
> I've made everything public, and I think the initializer needs to be public or something like that. That said, I have no idea what I need to do for this to work. Deinit doesn't seem to want to be public, so leaving that alone. I need to know why the reference to Surface won't come up.
> 
> Here's the bits for the actual Cairo module (wrappings, etc.) and all:
> https://gist.github.com/anonymous/72c4d2db7953c0d832c7
> 
> And this is the one in the "test" directory where I'm trying to get the methods in the above file to work without complaint outside of the directory:
> https://gist.github.com/anonymous/11691be627d619066b8b
> 
> I'm hoping someone can tell me what I'm doing wrong, because I'm trying to do whatever possible. Also, I did upgrade the Swift components earlier when released.
> 
> To: jackl at apple.com
> Date: Fri, 11 Dec 2015 21:21:06 -0500
> CC: swift-users at swift.org
> Subject: Re: [swift-users] Need Help with C-to-Swift (finally)
> From: swift-users at swift.org
> 
> I'm going to. Now, does this mean anything labelled func inside the struct needs tacked on as well?
> 
> Subject: Re: [swift-users] Need Help with C-to-Swift (finally)
> From: jackl at apple.com
> Date: Fri, 11 Dec 2015 18:19:55 -0800
> CC: harlan at harlanhaskins.com; swift-users at swift.org
> To: gagemorgan at outlook.com
> 
> Did you make the class and its methods public?
> 
> Jack
> On Dec 11, 2015, at 6:16 PM, Gage Morgan <gagemorgan at outlook.com> wrote:
> 
> Here's what I'm getting:
> 
> /home/mgage/swift-cairo-bindings/test/main.swift:4:15: error: module 'Cairo' has no member named 'Surface'
> let surface = Cairo.Surface(format: CAIRO_FORMAT_ARGB32, width: 421, height: 410)
>               ^~~~~ ~~~~~~~
> <unknown>:0: error: build had 1 command failures
> 
> So what I'm trying to do is to put all wrappings in a separate module named Cairo. Then, I want to use those methods outside of the module named Cairo. I renamed the class to Surface and fixed all references, but for some reason it keeps saying something about Surface not present. I need to look into whether a git repo may be needed.
> 
> Subject: Re: [swift-users] Need Help with C-to-Swift (finally)
> From: harlan at harlanhaskins.com
> Date: Fri, 11 Dec 2015 20:31:20 -0500
> CC: jackl at apple.com; swift-users at swift.org
> To: gagemorgan at outlook.com
> 
> Nope, but you’ll need a way to specify the class inside the module (the fully-qualified type name)
> 
> Cairo.Cairo should work fine.
> 
> On Dec 11, 2015, at 8:14 PM, Gage Morgan <gagemorgan at outlook.com> wrote:
> 
> The module is Cairo. Do I need to change something (I'm assuming by struct you mean the name of the class containing wrappings). The class is named Cairo as well. Could renaming the module to ModCairo fix this?
> 
> Sent from Outlook Mobile
> 
> 
> 
> 
> On Fri, Dec 11, 2015 at 5:11 PM -0800, "Harlan Haskins" <harlan at harlanhaskins.com> wrote:
> 
> Is your struct named Cairo or Surface?
> 
> If Cairo is the module name, you're trying to instantiate the module.
> 
> - Harlan
> 
> On Dec 11, 2015, at 7:55 PM, Gage Morgan <gagemorgan at outlook.com> wrote:
> 
> How would you use things like cairo.moveTo() outside of the wrapping file? I've gone as far as writing a module named "Cairo," taking the methods as mentioned above out, and moving them to their own directory "tests." I have added "Cairo" as a dependency for "tests," but there appears to be something wrong when I try to call:
> 
> let cairo = Cairo(format: CAIRO_FORMAT_ARGB32, width: 421, height: 410)
> 
> Why can I not call Cairo()? The error:
> 
> Compiling Swift Module 'test' (1 sources)
> /home/mgage/swift-cairo-bindings/test/main.swift:4:18: error: cannot call value of non-function type 'module<Cairo>'
> let cairo = Cairo(format: CAIRO_FORMAT_ARGB32, width: 421, height: 410)
>             ~~~~~^
> <unknown>:0: error: build had 1 command failures
> swift-build: exit(1): ["/home/mgage/Downloads/swift-2.2-SNAPSHOT-2015-12-01-b-ubuntu15.10/usr/bin/swift-build-tool", "-f", "/home/mgage/swift-cairo-bindings/test/.build/debug/test.o/llbuild.yaml"]
> 
> I don't know whether or not I want to translate methods into straight-up properties yet.
> 
> Thanks, support here has been great so far. Cheers!
> --MGage--
> 
> 
> Subject: Re: [swift-users] Need Help with C-to-Swift (finally)
> From: harlan at harlanhaskins.com
> Date: Fri, 11 Dec 2015 19:35:46 -0500
> CC: gagemorgan at outlook.com; swift-users at swift.org
> To: jackl at apple.com
> 
> I considered that but couldn't find a cairo_get_font_scale function quickly to complement the setter 
> 
> But yes, a full wrapper would transparently handle getting and setting.
> 
> - Harlan
> 
> On Dec 11, 2015, at 7:28 PM, Jack Lawrence <jackl at apple.com> wrote:
> 
> For getter-setter pairs like `setLineWidth`, you might consider turning them into properties:
> 
> cairo.setLineWidth(0.1) // old
> cairo.lineWidth = 0.1 // new
> 
> On Dec 11, 2015, at 4:22 PM, Gage Morgan via swift-users <swift-users at swift.org> wrote:
> 
> Harlan,
> 
> The answer is yes. I even managed to get a couple you didn't list on my own:
> 
> let cairo = Cairo(format: CAIRO_FORMAT_ARGB32, width: 421, height: 410)
> cairo.scale(10.0, y: 10.0)
> cairo.moveTo(29.0, y: 14.7)
> cairo.lineTo(37.6, y: 13.0)
> cairo.moveTo(37.6, y: 13.0)
> cairo.lineTo(30.4, y: 22.2)
> cairo.moveTo(30.4, y: 22.2)
> cairo.lineTo(29.0, y: 14.7)
> cairo.setLineWidth(0.1)
> cairo.stroke()
> cairo.surfaceWriteToPNG("boobs.png")
> 
> Swift is both really neat and really frustrating when learning it. 
> 
> Subject: Re: [swift-users] Need Help with C-to-Swift (finally)
> From: harlan at harlanhaskins.com
> Date: Fri, 11 Dec 2015 17:21:38 -0500
> CC: kwame.bryan at gmail.com; swift-users at swift.org
> To: gagemorgan at outlook.com
> 
> Gage,
> 
> Sorry, I just got back from class.
> 
> I’ll respond in line!
> 
> On Dec 11, 2015, at 5:09 PM, Gage Morgan <gagemorgan at outlook.com> wrote:
> 
> Harlan,
> 
> I read on cairographics.org about bindings awhile back. I think they want cairo, not surface, so we would have something like:
> 
> let cairo = Surface(format: CAIRO_FORMAT_ARGB32, width: 240, height: 80)
> cairo.setFontFace("serif", weight: CAIRO_FONT_WEIGHT_BOLD)
> cairo.setFontSize(32.0)
> cairo.setSourceRGB(0.0, g: 0.0, b: 1.0)
> cairo.moveTo(x: 10, y: 50)
> cairo.showText("Hello, World!")
> cairo.writeToPNG("hello.png")
> 
> Would this work the same as before without "surface" but instead "cairo”?
> 
> Absolutely! That’s just a variable name — it could be called ‘puppies’, though that’s not very readable.
> 
> 
> Sent from Outlook Mobile
> 
> 
> 
> 
> On Fri, Dec 11, 2015 at 2:00 PM -0800, "Gage Morgan via swift-users" <swift-users at swift.org> wrote:
> 
> I went and looked at it, and even now it looks like I want to take every function I've used in Cairo and translate it to Swift. Swift is such a...simple language compared to everything else. That being said, as a result of the specs, it is also much more verbose in terms of writing the code. Compared to other languages, it is written out instead of shoved onto a few lines. 
> 
> Is there a way to import modules into other modules? Because it looks like a weekend project that will eventually get posted by myself at http://github.com/Christoffen-Corporation. 
> 
> Sent from Outlook Mobile
> 
> I’d recommend having a look at the Swift package manager example again — https://github.com/apple/swift-package-manager/blob/master/Documentation/SystemModules.md
> 
> There’s an example of using those modules together.
> 
> 
> On Fri, Dec 11, 2015 at 1:52 PM -0800, "Gage Morgan via swift-users" <swift-users at swift.org> wrote:
> 
> I meant the code posted in the Gist link above. I don't know jack squat about qsort. I'm hoping that if I can reverse-engineer code already produced, I can apply it to other parts of Cairo. 
> 
> Sent from Outlook Mobile
> 
> I’ll go ahead and comment it, but I think it’s simplistic enough that it should be readable with a grasp of some Swift concepts. Perhaps it’s a good idea to look through The Swift Programming Language to figure out some of the constructs I used — they’re fairly basic constructs.
> 
> 
> On Fri, Dec 11, 2015 at 1:34 PM -0800, "Kwame Bryan"<kwame.bryan at gmail.com> wrote:
> 
> Tutorial on the subject. http://chris.eidhof.nl/posts/swift-c-interop.html 
> 
> Regards
> Kwame
> 
> 
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