Re: [Pharo-dev] NativeBoost and WKHTML
On 23 May 2014, at 3:46 , Torsten Bergmann wrote: > YES, COOL - it now works as the attached PDF proves. > > 1000 timesRepeat: [ Transcript show: 'Henrik thanks!!!' ;cr ] > > Henrik - you have saved me to have to return to the darker sides of computing > and digg deeper into low level again ;) > > I knew that it must have been something in the calling wrapper and > was too blind to see it. > > A little bit misleading that one can not use the original C signature > in the NB description with char* and autoconversion through NB. > > Maybe I was too used to NB's predecessor FFI where one wrote char* and > just passed the Smalltalk string. > > Stupid me, I should have RTFM of NativeBoost instead of assuming > its close to FFI in this regard! So again the problem was in front > of the computer. Really, blame char *, it’s too ambiguous. Is it raw byte(s)? Is it a string? How is its length conveyed? What’s the encoding supposed to be? You can’t really determine the answer to those questions up front in the FFI, though the right answer is usually clear on a case-by-case basis from the context. * So the NB rationale is (I think) not to do extra overhead which would still, sometimes, leave the user stumped at some strange error when the automatic handling mismatches reality. You only get bitten by it once (or maybe twice?), though the path to enlightenment could be less bumpy :) Cheers, Henry * No corresponding length parameter? Either single element or null-terminated string, as per context. String or bytes? Should be clear from context. Encoding? Well… usually utf8, but could also be some environment-defined code page, gotta check the library docs to be sure. Say what you want about Windows, but at least they their APIs use explicit string types with well defined encoding. signature.asc Description: Message signed with OpenPGP using GPGMail
Re: [Pharo-dev] NativeBoost and WKHTML
On 23 May 2014, at 2:52 , Henrik Johansen wrote:
>
> On 23 May 2014, at 2:36 , Torsten Bergmann wrote:
>
>> Hi,
>>
>> as there was no responded so far I tried to track the problem deeper and did
>> a short test
>> client in C/C++ to verify if I can call WKHTMLTOPDF there and generate a PDF
>> and to
>> compare to the Pharo/NativeBoost client.
>>
>> Attached is the according CPP file which works and results in a PDF with the
>> google
>> homepage.
>>
>> I also additionally implemented the callback functions in the Pharo wrapper
>> and
>> using the error handling I noticed that the component returns "Failed
>> loading page http:// ..."
>>
>>
>> With that info I compared the C/C++ calls to the Pharo/NativeBoost calls
>> more deeply and
>> found out that in C/C++ the following call for an object setting works (by
>> returning 1):
>>
>>
>> // this returns 1 in C/C++ which is OK
>> int a = wkhtmltopdf_set_object_setting(os, "page",
>> "http://www.google.de";);
>> printf("object set %i",a);
>>
>>
>> while in Pharo the same call fails (by returning 0):
>>
>> "The following call failed and returns 0 instead of 1"
>> self setObjectSetting: 'page' to: 'http://www.google.de' in: os.
>
> With argument type char * , NB does not 0-terminate your strings, but passes
> in the argument you provided raw.
> ByteStrings have an internal representation size a multiplum of 4, thus
> ‘page’ will have no accidentally terminating 0, while ‘out’ does, and the
> call fails since whatever garbage bytes are in the image after the string
> instance (‘page’) leads to the it not being recognized as a valid property
> name.
>
> Change the call definitions to use String as argument type instead, and NB
> will convert the args to zero-terminated strings for you:
>
> NBFFICallout stdcall: #(int
> wkhtmltopdf_set_object_setting(wkhtmltopdf_object_settings* settings, String
> aName, String value)) module: 'wkhtmltox.dll'
>
> Alternatively, you need to provide null-terminated strings yourself:
>
> x := self setObjectSetting: ('page' , (Character value: 0) asString) to:
> 'http://www.google.de', (Character value: 0) asString) in: os.
>
> Which also returns makes it return 1.
>
> Cheers,
> Henry
To test it then *actually* worked, I implemented:
getObjectSetting: aName in: settings into: value ofSize: vs
^NBFFICallout stdcall: #(int
wkhtmltopdf_get_object_setting(wkhtmltopdf_object_settings* settings, String
aName, char* value, int vs)) module: 'wkhtmltox.dll'
Note, you *cannot* use String for a parameter being written to, while NB in
that case would pass along a zero-terminated copy for you, it does *not* copy
the contents back into the actual string instance @ end of call.
It’s also easy to spot garbage characters added when value was // 4 = 0 (using
char * definition):
x := self setObjectSetting: (‘page' , Character null asString) to:
'http://www.google.de' in: os. "http://www.google.de size = 20"
Transcript show: x.
buffer := String new: 40.
x := self getObjectSetting: ('page' , Character null asString) in: os into:
buffer ofSize: buffer size.
(buffer indexOf:Character null) > 21 "Probably true..."
Cheers,
Henry
PS: That’s a glorious getter API…
It returns 1 even if your buffer is shorter than the actual parameter, so your
only way to be sure you’ve fetched all of it, is to test that the result give
contains a null character, and if not, retry with a larger buffer…
(The sane thing to do would be allowing you to query the parameter length,
either through a * int parameter, or a separate function).
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Re: [Pharo-dev] NativeBoost and WKHTML
On 23 May 2014, at 2:36 , Torsten Bergmann wrote:
> Hi,
>
> as there was no responded so far I tried to track the problem deeper and did
> a short test
> client in C/C++ to verify if I can call WKHTMLTOPDF there and generate a PDF
> and to
> compare to the Pharo/NativeBoost client.
>
> Attached is the according CPP file which works and results in a PDF with the
> google
> homepage.
>
> I also additionally implemented the callback functions in the Pharo wrapper
> and
> using the error handling I noticed that the component returns "Failed loading
> page http:// ..."
>
>
> With that info I compared the C/C++ calls to the Pharo/NativeBoost calls more
> deeply and
> found out that in C/C++ the following call for an object setting works (by
> returning 1):
>
>
>// this returns 1 in C/C++ which is OK
> int a = wkhtmltopdf_set_object_setting(os, "page",
> "http://www.google.de";);
> printf("object set %i",a);
>
>
> while in Pharo the same call fails (by returning 0):
>
>"The following call failed and returns 0 instead of 1"
> self setObjectSetting: 'page' to: 'http://www.google.de' in: os.
With argument type char * , NB does not 0-terminate your strings, but passes in
the argument you provided raw.
ByteStrings have an internal representation size a multiplum of 4, thus ‘page’
will have no accidentally terminating 0, while ‘out’ does, and the call fails
since whatever garbage bytes are in the image after the string instance
(‘page’) leads to the it not being recognized as a valid property name.
Change the call definitions to use String as argument type instead, and NB will
convert the args to zero-terminated strings for you:
NBFFICallout stdcall: #(int
wkhtmltopdf_set_object_setting(wkhtmltopdf_object_settings* settings, String
aName, String value)) module: 'wkhtmltox.dll'
Alternatively, you need to provide null-terminated strings yourself:
x := self setObjectSetting: ('page' , (Character value: 0) asString) to:
'http://www.google.de', (Character value: 0) asString) in: os.
Which also returns makes it return 1.
Cheers,
Henry
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Re: [Pharo-dev] NativeBoost and WKHTML
On 23.05.2014 02:36, Torsten Bergmann wrote: > With that info I compared the C/C++ calls to the Pharo/NativeBoost calls more > deeply and > found out that in C/C++ the following call for an object setting works (by > returning 1): > while in Pharo the same call fails (by returning 0): > I tried to use another DLL which required me to change "stackAlignment" on Windows to answer 16 instead of 1; running on Win7 64 Bit. Could your problem be caused by something like that? (Just a shot in the dark). Best regards, Markus
Re: [Pharo-dev] NativeBoost and WKHTML
Hi Jan,
I did not compile the WKHTML component, just used the predefined DLL from
the website. I know that there is no C++ interfering as the DLL has a
normal C interface. So no C++ calling convention stuff/name mangling etc.
is involved, no SWIG required or additional C wrapper.
One can download and use the DLL as a usual C DLL like many others.
So C/C++ was only involved because after the mentioned single Pharo/NB call
failed and I could not see the reason in my code I wanted a Pharo independent
non-smalltalk calling example to prove that the DLL is working. Could have
used any other language (Java, VB, ...) to call the WKHTML DLL.
So I use the DLL as a black box, similar like any other API where you
do not have the source code.
Debugging the DLL or modifying its source code by adding debug outputs
would mean to go through all the hazzle of compiling WKHTML myself.
According to the website this would also additionally require many tools
(Perly, Python, Windows SDK, VisualStudio, ...) which I do not have installed.
Way too much effort as I only thought it would be a nice idea if we
could provide a Pharo binding to print something easily from Pharo using
HTML -> PDF.
As you see on the calling example WKHTML is simple and straightforward
with an init, put some settings (file/URL) and calling the conversion.
I also think that the route to debugging the DLL would be questionable -
my simple non-Smalltalk calling example proves that the DLL is properly
working as the website states.
So according to this the problem must be on the Pharo wrapper or NativeBoost
side
who calls the component. Therefore I looked at my wrapper code again and again
-
nothing suspicious.
Thats why I asked: either I'm blind to "not see the forest because of the
all the trees" or there is still some bug left in NB. Maybe there is also
an easy way to check/compare the calls.
Thanks
T.
> Gesendet: Freitag, 23. Mai 2014 um 12:11 Uhr
> Von: "Jan Vrany"
> An: "Pharo Development List"
> Betreff: Re: [Pharo-dev] NativeBoost and WKHTML
>
> Hi,
>
> If I were to debug this, I would:
>
> 1 ) make sure there's no C++ interfering, try to compile using C
> compiler (not C++, I guess you run Windows and MSVC, I think
> there's command line option to process file as C).
> If not possible, wrap all methods you want to call form St
> in extern "C" {} block. Does it work? If not, then C++ compiler
> is doing it's magic which NB doesn't.
>
>
> 2 ) If it does, run whole thing under debugger, set breakpoint to
> the faulty function and check that arguments are correct
> and what's return value.
> If args are incorrect, then the problem is in either yours or
> NB's code.
> If return value is correct, then the problem is also in
> either yours or NB's code.
> If the return value is incorrect, well then the problem could be
> either in the library or some sort of GC thing as GC moves stuff
> around, which most of C/C++ libraries don't like much.
>
> In that case, I learned, the only way us to read library's code
> and single-step through it to see that the code actually does with
> data you pass down.
>
> HTH, Jan
>
>
>
> On 23/05/14 10:51, Torsten Bergmann wrote:
> > Hi Jean,
> >
> > thanks for answering. I dont think that the convention is an issue here:
> > internally
> > it is written in C++, but it exposes the API as simple C functions. The
> > calls with NB
> > work (even the callbacks).
> >
> > What confuses me most is that the call to "wkhtmltopdf_set_global_setting"
> > works while the "wkhtmltopdf_set_object_setting" does not. They have
> > exactly
> > the same signature and are called one after the other. First one returns
> > proper int 1 (success)
> > as in the non-Smalltalk example, the other one 0 which means it failed.
> >
> > There is no magic in the Pharo code, just simple calls. Also the
> > non-Smalltalk example
> > proves that the component is working. Maybe a side effect of NativeBoost
> > itself?
> >
> > Looks like so far I'm lost without the help of Igor here...
> >
> > Thx
> > T.
> >
> >
> >
> > Gesendet: Freitag, 23. Mai 2014 um 11:31 Uhr
> > Von: "Jean Baptiste Arnaud"
> > An: "Pharo Development List"
> > Betreff: Re: [Pharo-dev] NativeBoost and WKHTML
> >
> > I think this is because it is a C++ lib.
> > NativeBoost cannot be used with C++ lib.
> > It is a problem of call convention that is not the same from C to C++.
> > As I discuss wit
Re: [Pharo-dev] NativeBoost and WKHTML
Hi,
If I were to debug this, I would:
1 ) make sure there's no C++ interfering, try to compile using C
compiler (not C++, I guess you run Windows and MSVC, I think
there's command line option to process file as C).
If not possible, wrap all methods you want to call form St
in extern "C" {} block. Does it work? If not, then C++ compiler
is doing it's magic which NB doesn't.
2 ) If it does, run whole thing under debugger, set breakpoint to
the faulty function and check that arguments are correct
and what's return value.
If args are incorrect, then the problem is in either yours or
NB's code.
If return value is correct, then the problem is also in
either yours or NB's code.
If the return value is incorrect, well then the problem could be
either in the library or some sort of GC thing as GC moves stuff
around, which most of C/C++ libraries don't like much.
In that case, I learned, the only way us to read library's code
and single-step through it to see that the code actually does with
data you pass down.
HTH, Jan
On 23/05/14 10:51, Torsten Bergmann wrote:
Hi Jean,
thanks for answering. I dont think that the convention is an issue here:
internally
it is written in C++, but it exposes the API as simple C functions. The calls
with NB
work (even the callbacks).
What confuses me most is that the call to "wkhtmltopdf_set_global_setting"
works while the "wkhtmltopdf_set_object_setting" does not. They have exactly
the same signature and are called one after the other. First one returns proper
int 1 (success)
as in the non-Smalltalk example, the other one 0 which means it failed.
There is no magic in the Pharo code, just simple calls. Also the non-Smalltalk
example
proves that the component is working. Maybe a side effect of NativeBoost itself?
Looks like so far I'm lost without the help of Igor here...
Thx
T.
Gesendet: Freitag, 23. Mai 2014 um 11:31 Uhr
Von: "Jean Baptiste Arnaud"
An: "Pharo Development List"
Betreff: Re: [Pharo-dev] NativeBoost and WKHTML
I think this is because it is a C++ lib.
NativeBoost cannot be used with C++ lib.
It is a problem of call convention that is not the same from C to C++.
As I discuss with some people it seems be a complexe problem, each C++ compiler
seems have it own convention.
But Igor can maybe be more accurate about that.
A C wrapper to call C++, which should work.
On 23 May 2014, at 02:36, Torsten Bergmann wrote: Hi,
as there was no responded so far I tried to track the problem deeper and did a
short test
client in C/C++ to verify if I can call WKHTMLTOPDF there and generate a PDF
and to
compare to the Pharo/NativeBoost client.
Attached is the according CPP file which works and results in a PDF with the
google
homepage.
I also additionally implemented the callback functions in the Pharo wrapper and
using the error handling I noticed that the component returns "Failed loading page
http:// ..."
With that info I compared the C/C++ calls to the Pharo/NativeBoost calls more
deeply and
found out that in C/C++ the following call for an object setting works (by
returning 1):
// this returns 1 in C/C++ which is OK
int a = wkhtmltopdf_set_object_setting(os, "page",
"http://www.google.de[http://www.google.de]";);
printf("object set %i",a);
while in Pharo the same call fails (by returning 0):
"The following call failed and returns 0 instead of 1"
self setObjectSetting: 'page' to: 'http://www.google.de'[http://www.google.de']
in: os.
I checked how I wrapped this API call again and again - it is fine from my side:
setObjectSetting: aName to: value in: settings
^NBFFICallout stdcall: #(int
wkhtmltopdf_set_object_setting(wkhtmltopdf_object_settings* settings, char*
aName, char* value)) module: 'wkhtmltox.dll'
and I still have no idea why it fails.
Especially because "wkhtmltopdf_set_object_setting" function is not different from
"wkhtmltopdf_set_global_setting" which is exactly the same way wrapped, works
and returns 1 in exactly the same example.
I would really appreciate if someone could have a second look...
To reproduce on Windows:
1. Download the 32 bit version of WKHTML from
http://wkhtmltopdf.org[http://wkhtmltopdf.org] and install it
2. Copy the "wkhtmltox.dll" to either the folder of the VM executable
or the Windows directory so it can be found
3. Load the package WKHTML2PDF-Core-TorstenBergmann.7
from
http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF[http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF]
into Pharo 3.0#30848
4. Check the Transcript while evaluating:
WKPDFLibrary example
One can see that within this code #setObjectSetting:to:in: fails while
#setGlobalSetting:to:in:
works.
Maybe I just do not see the obvious. Help is appreciated. Thanks in advance!
bye
T.
Best Regards
Jean Baptiste Arnaud
jbaptiste.arn...@gmail.com[jbaptiste.arn...@gmail.com]
Re: [Pharo-dev] NativeBoost and WKHTML
Hi Jean,
thanks for answering. I dont think that the convention is an issue here:
internally
it is written in C++, but it exposes the API as simple C functions. The calls
with NB
work (even the callbacks).
What confuses me most is that the call to "wkhtmltopdf_set_global_setting"
works while the "wkhtmltopdf_set_object_setting" does not. They have exactly
the same signature and are called one after the other. First one returns proper
int 1 (success)
as in the non-Smalltalk example, the other one 0 which means it failed.
There is no magic in the Pharo code, just simple calls. Also the non-Smalltalk
example
proves that the component is working. Maybe a side effect of NativeBoost itself?
Looks like so far I'm lost without the help of Igor here...
Thx
T.
Gesendet: Freitag, 23. Mai 2014 um 11:31 Uhr
Von: "Jean Baptiste Arnaud"
An: "Pharo Development List"
Betreff: Re: [Pharo-dev] NativeBoost and WKHTML
I think this is because it is a C++ lib.
NativeBoost cannot be used with C++ lib.
It is a problem of call convention that is not the same from C to C++.
As I discuss with some people it seems be a complexe problem, each C++ compiler
seems have it own convention.
But Igor can maybe be more accurate about that.
A C wrapper to call C++, which should work.
On 23 May 2014, at 02:36, Torsten Bergmann wrote: Hi,
as there was no responded so far I tried to track the problem deeper and did a
short test
client in C/C++ to verify if I can call WKHTMLTOPDF there and generate a PDF
and to
compare to the Pharo/NativeBoost client.
Attached is the according CPP file which works and results in a PDF with the
google
homepage.
I also additionally implemented the callback functions in the Pharo wrapper and
using the error handling I noticed that the component returns "Failed loading
page http:// ..."
With that info I compared the C/C++ calls to the Pharo/NativeBoost calls more
deeply and
found out that in C/C++ the following call for an object setting works (by
returning 1):
// this returns 1 in C/C++ which is OK
int a = wkhtmltopdf_set_object_setting(os, "page",
"http://www.google.de[http://www.google.de]";);
printf("object set %i",a);
while in Pharo the same call fails (by returning 0):
"The following call failed and returns 0 instead of 1"
self setObjectSetting: 'page' to: 'http://www.google.de'[http://www.google.de']
in: os.
I checked how I wrapped this API call again and again - it is fine from my side:
setObjectSetting: aName to: value in: settings
^NBFFICallout stdcall: #(int
wkhtmltopdf_set_object_setting(wkhtmltopdf_object_settings* settings, char*
aName, char* value)) module: 'wkhtmltox.dll'
and I still have no idea why it fails.
Especially because "wkhtmltopdf_set_object_setting" function is not different
from "wkhtmltopdf_set_global_setting" which is exactly the same way wrapped,
works
and returns 1 in exactly the same example.
I would really appreciate if someone could have a second look...
To reproduce on Windows:
1. Download the 32 bit version of WKHTML from
http://wkhtmltopdf.org[http://wkhtmltopdf.org] and install it
2. Copy the "wkhtmltox.dll" to either the folder of the VM executable
or the Windows directory so it can be found
3. Load the package WKHTML2PDF-Core-TorstenBergmann.7
from
http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF[http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF]
into Pharo 3.0#30848
4. Check the Transcript while evaluating:
WKPDFLibrary example
One can see that within this code #setObjectSetting:to:in: fails while
#setGlobalSetting:to:in:
works.
Maybe I just do not see the obvious. Help is appreciated. Thanks in advance!
bye
T.
Best Regards
Jean Baptiste Arnaud
jbaptiste.arn...@gmail.com[jbaptiste.arn...@gmail.com]
Re: [Pharo-dev] NativeBoost and WKHTML
On 23 May 2014, at 11:31, Jean Baptiste Arnaud
wrote:
> I think this is because it is a C++ lib.
> NativeBoost cannot be used with C++ lib.
> It is a problem of call convention that is not the same from C to C++.
> As I discuss with some people it seems be a complexe problem, each C++
> compiler seems have it own convention.
> But Igor can maybe be more accurate about that.
> A C wrapper to call C++, which should work.
>
Ronie’s SWIG for NativeBoost has some C++ support:
http://forum.world.st/SWIG-for-Native-Boost-FFI-td4738511.html
> On 23 May 2014, at 02:36, Torsten Bergmann wrote:
>
>> Hi,
>>
>> as there was no responded so far I tried to track the problem deeper and did
>> a short test
>> client in C/C++ to verify if I can call WKHTMLTOPDF there and generate a PDF
>> and to
>> compare to the Pharo/NativeBoost client.
>>
>> Attached is the according CPP file which works and results in a PDF with the
>> google
>> homepage.
>>
>> I also additionally implemented the callback functions in the Pharo wrapper
>> and
>> using the error handling I noticed that the component returns "Failed
>> loading page http:// ..."
>>
>>
>> With that info I compared the C/C++ calls to the Pharo/NativeBoost calls
>> more deeply and
>> found out that in C/C++ the following call for an object setting works (by
>> returning 1):
>>
>>
>>// this returns 1 in C/C++ which is OK
>> int a = wkhtmltopdf_set_object_setting(os, "page",
>> "http://www.google.de";);
>> printf("object set %i",a);
>>
>>
>> while in Pharo the same call fails (by returning 0):
>>
>>"The following call failed and returns 0 instead of 1"
>> self setObjectSetting: 'page' to: 'http://www.google.de' in: os.
>>
>> I checked how I wrapped this API call again and again - it is fine from my
>> side:
>>
>>setObjectSetting: aName to: value in: settings
>>
>>
>>
>> ^NBFFICallout stdcall: #(int
>> wkhtmltopdf_set_object_setting(wkhtmltopdf_object_settings* settings, char*
>> aName, char* value)) module: 'wkhtmltox.dll'
>>
>> and I still have no idea why it fails.
>>
>> Especially because "wkhtmltopdf_set_object_setting" function is not
>> different from "wkhtmltopdf_set_global_setting" which is exactly the same
>> way wrapped, works
>> and returns 1 in exactly the same example.
>>
>> I would really appreciate if someone could have a second look...
>>
>> To reproduce on Windows:
>>
>> 1. Download the 32 bit version of WKHTML from http://wkhtmltopdf.org and
>> install it
>> 2. Copy the "wkhtmltox.dll" to either the folder of the VM executable
>>or the Windows directory so it can be found
>> 3. Load the package WKHTML2PDF-Core-TorstenBergmann.7
>>from http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF into Pharo
>> 3.0#30848
>> 4. Check the Transcript while evaluating:
>>
>>WKPDFLibrary example
>>
>>One can see that within this code #setObjectSetting:to:in: fails while
>> #setGlobalSetting:to:in:
>>works.
>>
>> Maybe I just do not see the obvious. Help is appreciated. Thanks in advance!
>>
>> bye
>> T.
>>
>>
>>
>
> Best Regards
> Jean Baptiste Arnaud
> jbaptiste.arn...@gmail.com
>
>
>
>
>
>
>
Re: [Pharo-dev] NativeBoost and WKHTML
I think this is because it is a C++ lib.
NativeBoost cannot be used with C++ lib.
It is a problem of call convention that is not the same from C to C++.
As I discuss with some people it seems be a complexe problem, each C++ compiler
seems have it own convention.
But Igor can maybe be more accurate about that.
A C wrapper to call C++, which should work.
On 23 May 2014, at 02:36, Torsten Bergmann wrote:
> Hi,
>
> as there was no responded so far I tried to track the problem deeper and did
> a short test
> client in C/C++ to verify if I can call WKHTMLTOPDF there and generate a PDF
> and to
> compare to the Pharo/NativeBoost client.
>
> Attached is the according CPP file which works and results in a PDF with the
> google
> homepage.
>
> I also additionally implemented the callback functions in the Pharo wrapper
> and
> using the error handling I noticed that the component returns "Failed loading
> page http:// ..."
>
>
> With that info I compared the C/C++ calls to the Pharo/NativeBoost calls more
> deeply and
> found out that in C/C++ the following call for an object setting works (by
> returning 1):
>
>
>// this returns 1 in C/C++ which is OK
> int a = wkhtmltopdf_set_object_setting(os, "page",
> "http://www.google.de";);
> printf("object set %i",a);
>
>
> while in Pharo the same call fails (by returning 0):
>
>"The following call failed and returns 0 instead of 1"
> self setObjectSetting: 'page' to: 'http://www.google.de' in: os.
>
> I checked how I wrapped this API call again and again - it is fine from my
> side:
>
>setObjectSetting: aName to: value in: settings
>
>
>
>^NBFFICallout stdcall: #(int
> wkhtmltopdf_set_object_setting(wkhtmltopdf_object_settings* settings, char*
> aName, char* value)) module: 'wkhtmltox.dll'
>
> and I still have no idea why it fails.
>
> Especially because "wkhtmltopdf_set_object_setting" function is not different
> from "wkhtmltopdf_set_global_setting" which is exactly the same way wrapped,
> works
> and returns 1 in exactly the same example.
>
> I would really appreciate if someone could have a second look...
>
> To reproduce on Windows:
>
> 1. Download the 32 bit version of WKHTML from http://wkhtmltopdf.org and
> install it
> 2. Copy the "wkhtmltox.dll" to either the folder of the VM executable
>or the Windows directory so it can be found
> 3. Load the package WKHTML2PDF-Core-TorstenBergmann.7
>from http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF into Pharo
> 3.0#30848
> 4. Check the Transcript while evaluating:
>
>WKPDFLibrary example
>
>One can see that within this code #setObjectSetting:to:in: fails while
> #setGlobalSetting:to:in:
>works.
>
> Maybe I just do not see the obvious. Help is appreciated. Thanks in advance!
>
> bye
> T.
>
>
>
Best Regards
Jean Baptiste Arnaud
jbaptiste.arn...@gmail.com
Re: [Pharo-dev] NativeBoost and WKHTML
Just out of curiosity, why not use Artefact, https://sites.google.com/site/artefactpdf ? I haven't looked at the different approaches, but I have this natural tendency against native libraries, if we can do it directly in Pharo. That is why I am asking: why this road and not the other ? On 21 May 2014, at 14:14, Torsten Bergmann wrote: > Hi, > > tried to wrap the WKHTML library (wkhtmltopdf.org) with NB to easily generate > a PDF > using HTML from Pharo. I think this could serve as an easy printing solution > for Pharo. > > Code for an initial wrapper is on > http://smalltalkhub.com/#!/~TorstenBergmann/WKHTML2PDF > with a simple class calling the component using NativeBoost. See class > "WKPDFLibrary example" > I used Windows and the wkhtmltox.dll. > > The C example I follow with only a few function calls is very simple and can > be found at > the bottom of: http://m.blog.csdn.net/blog/pengqianhe/8089007 > > The component is called, I get correct structs in return - but still no PDF > file is generated. > Currently I cant see the forest for the trees. Maybe someone can have a short > look what I'm > doing wrong. > > Thanks in advance > T. > > > > >
