Help needed with Cairo / Graphics
lazarus / 39-Graphics

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AL · 2024-03-23 21:15

I am trying to "translate" a program using graphics to Lazarus/FPC. 
The program is written in C and use Cairo as a graphic tool.  I was
thinking that using Cairo in FPC would be the easiest to do.  So far
all my attempts to get Cairo working are unsuccessfull.
I tried to follow this    https://forum.lazarus.freepascal.org/index.p
hp/topic,57657.msg471085.html#msg471085 but it does not work for me.
It gives an error right at the start.   I copied the LibCairo-2.dll in
system32.
I am using Laz 3.2 in Windows 10.
Is Cairo really working in Windows and FPC?
Any help would be appreciated.
Thanks.

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d-_-b · 2024-03-23 22:16

Quote from: AL on March 23, 2024, 10:15:03 pmIs Cairo really working
in Windows and FPC?

I can confirm that I could download cairo-pascal-tutorial-source.zip
open cairo_071.lpr and compile and execute cairo_071.exe on Windows 10
using Lazarus 3.2 (rev lazarus_3_2) FPC 3.2.2
x86_64-win64-win32/win64.

But I had to use MSYS2and pacman -S mingw-w64-x86_64-cairo to get all
the needed dll's as noted below.

Quote from: AL on March 23, 2024, 10:15:03 pmAny help would be
appreciated.

Run your compiled exe from explorer.exe or cmd.exe and then you will
see you need more then just LibCairo-2.dll.

For example from Topic: What You See Drawing Canvas vs Printing/PDF
(CairoCanvas):

Here is a definite list of dlls needed for you application to work

    libcairo-2.dll
    libglib-2.0-0.dll
    libgmodule-2.0-0.dll
    libgobject-2.0-0.dll
    libpango-1.0-0.dll
    libpangocairo-1.0-0.dll
    libpangowin32-1.0-0.dll
    libpng12-0.dll
    zlib1.dll


So i wanted to do a lld libcairo-2.dll and it seems on windows you
must use ntldd so i installed it pacman -S mingw-w64-x86_64-ntldd in
MSYS2 and grepped the following list for you.

$ ntldd -R '/c/msys64/mingw64/bin/libcairo-2.dll' | grep -v 'Windows'
| grep -v 'not found'
        libgcc_s_seh-1.dll => C:\msys64\mingw64\bin\libgcc_s_seh-1.dll
(0x0000016bb6cd0000)
         libwinpthread-1.dll =>
C:\msys64\mingw64\bin\libwinpthread-1.dll (0x0000016bb6d10000)
        libstdc++-6.dll => C:\msys64\mingw64\bin\libstdc++-6.dll
(0x0000016bb7370000)
        libfontconfig-1.dll =>
C:\msys64\mingw64\bin\libfontconfig-1.dll (0x0000016bb6d10000)
         libexpat-1.dll => C:\msys64\mingw64\bin\libexpat-1.dll
(0x0000016bb6e60000)
         libiconv-2.dll => C:\msys64\mingw64\bin\libiconv-2.dll
(0x0000016bb7640000)
         libintl-8.dll => C:\msys64\mingw64\bin\libintl-8.dll
(0x0000016bb7610000)
        libfreetype-6.dll => C:\msys64\mingw64\bin\libfreetype-6.dll
(0x0000016bb6e60000)
         libbz2-1.dll => C:\msys64\mingw64\bin\libbz2-1.dll
(0x0000016bb6cd0000)
         libbrotlidec.dll => C:\msys64\mingw64\bin\libbrotlidec.dll
(0x0000016bb6cd0000)
          libbrotlicommon.dll =>
C:\msys64\mingw64\bin\libbrotlicommon.dll (0x0000016bb7370000)
         libharfbuzz-0.dll => C:\msys64\mingw64\bin\libharfbuzz-0.dll
(0x0000016bb7370000)
          libglib-2.0-0.dll => C:\msys64\mingw64\bin\libglib-2.0-0.dll
(0x0000016bb74b0000)
           libpcre2-8-0.dll => C:\msys64\mingw64\bin\libpcre2-8-0.dll
(0x0000016bb7610000)
          libgraphite2.dll => C:\msys64\mingw64\bin\libgraphite2.dll
(0x0000016bb74b0000)
        libpixman-1-0.dll => C:\msys64\mingw64\bin\libpixman-1-0.dll
(0x0000016bb6e60000)
        libpng16-16.dll => C:\msys64\mingw64\bin\libpng16-16.dll
(0x0000016bb7370000)
        zlib1.dll => C:\msys64\mingw64\bin\zlib1.dll
(0x0000016bb6cd0000)

Hope it helps,

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Roland57 · 2024-03-24 04:30

@d-_-b

Thank you for this detailed information.

Another way to get Cairo binaries on Windows is to install a software
using Cairo, like Gimp or Inkscape.

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AL · 2024-03-24 14:57

Thank you very much, this should get me going.
But: does that mean that to distribute my exe I will need to include
all these dll also.
Is there a way to get them in the compiled binary?

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domasz · 2024-03-24 15:25

No. But you should be able to put them in your exe as resources and
extract to temp dir.

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jamie · 2024-03-24 15:36

Hmm,
 the Cario package in the FPC folder does nothing for you?

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AL · 2024-03-24 19:56

No the prog compile fine but I always get an error at start. Unable to
trace, even F7 give the error.
The example given ( version no) does not give an error but the result
give 0.0.0 which is probably wrong

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Roland57 · 2024-03-24 21:27

@AL

You probably already know it, but there are 32-bit and 64-bit DLL. You
have to pay attention to that.

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AL · 2024-03-25 14:00

Quote from: d-_-b on March 23, 2024, 11:16:14 pmI can confirm that I
could download cairo-pascal-tutorial-source.zip open cairo_071.lpr and
compile and execute cairo_071.exe on Windows 10 using Lazarus 3.2 (rev
lazarus_3_2) FPC 3.2.2 x86_64-win64-win32/win64.

MacAfee antivirus would not let me download this file as it detect a
threat in the file.

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Roland57 · 2024-03-25 14:38

Quote from: AL on March 25, 2024, 03:00:38 pmMacAfee antivirus would
not let me download this file as it detect a threat in the file.

Maybe because I had put http instead of https in the link. Fixed now.

By the way, the file contains only Pascal source code and PNG
pictures.

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AL · 2024-03-27 13:35

Update:
I made progress. I could run a simple Cairo example.
I had to install several DLL as suggested by d-_-b and inspired by
Roland57 demos I could draw it in a paint box.  However, when writing
text in a Paintbox with Cairo the text was upside down because of the
Translate() and Scale() Cairo commands he is using.  Using the
Form.canvas directly solved that.  I will try a frame in the form and
see if it is still OK.
The Cairo unit of FPC is referencing LibCairo2.dll only, but
LibCairo2.dl on its own is referencing several others Dlls.
I still need to find how to include all these Dlls as resources and
how to use them from resources.
Thanks for the help!

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Roland57 · 2024-03-28 11:25

Quote from: AL on March 27, 2024, 02:35:10 pmThe Cairo unit of FPC is
referencing LibCairo2.dll only, but LibCairo2.dl on its own is
referencing several others Dlls.

Maybe you should take a look to this repository. If I well understood,
it's a Cairo DLL without dependencies (not tested).