Make an image block beore writing it, if there's no data in the block

[wxWidgets.git] / docs / tech / tn0016.txt

diff --git a/docs/tech/tn0016.txt b/docs/tech/tn0016.txt
index 5805e0cc6f70bc6251af96e43cbd68fa4878b460..15a1792003f722f91f092272c97283957842ef9c 100644 (file)
--- a/docs/tech/tn0016.txt
+++ b/docs/tech/tn0016.txt
@@ -1,24 +1,151 @@
-         How to add new files and libraries to wxWindows build system
+         How to add new files and libraries to wxWidgets build system

          ============================================================
 
 
 1. Regenerating makefiles
 -------------------------
 
          ============================================================
 
 
 1. Regenerating makefiles
 -------------------------
 

+wxWidgets now uses Bakefile (http://bakefile.sourceforge.net) to generate
+native makefiles. You must have bakefile installed if you want to regenerate
+the makefiles. Bakefile currently runs on Unix and Windows systems. You will
+need Python >= 2.2 installed on Unix and either use Bakefile installer or have
+Python on Windows.
+
+Once you have installed Bakefile, you can easily regenerate the makefiles using
+the bakefile_gen tool. Run it from $(wx)/build/bakefiles directory and it will
+regenerate all outdated makefiles. See $(wx)/build/bakefiles/README for more
+details.
+
+Note that it generates makefiles for samples and contrib libraries, too.
+
+IMPORTANT NOTE: Don't forget to run autoconf in wxWidgets root directory
+                (after running Bakefile) if you changed any conditional
+                variable or target condition in .bkl files! You will know that
+                this happened if $(wx)/autoconf_inc.m4 content changed.
+
+You can use Bakefile to generate makefiles or projects customized to your
+needs, too. See Bakefiles.bkgen for details on bakefile commands used to
+generate makefiles. For example, you can use this command to generate
+VC++ project files without wxUniversal configurations:
+    bakefile -v -fmsvc6prj -o../wxmy.dsw -DRUNTIME_LIBS=dynamic
+             -DDEBUG_INFO=default -DDEBUG_FLAG=default
+             -DOFFICIAL_BUILD=0 -DUSE_HTML=1 -DUSE_OPENGL=1 -DUSE_ODBC=1
+             -DMONOLITHIC=0 -DUSE_GUI=1 -DWXUNIV=0 wx.bkl
+Or monolithic instead of multilib (the default):
+    bakefile -v -fmsvc6prj -o../wxmono.dsw -DRUNTIME_LIBS=dynamic
+             -DDEBUG_INFO=default -DDEBUG_FLAG=default
+             -DOFFICIAL_BUILD=0 -DUSE_HTML=1 -DUSE_OPENGL=1 -DUSE_ODBC=1
+             -DMONOLITHIC=1 -DUSE_GUI=1 wx.bkl
+Or monolithic wxBase:
+    bakefile -v -fmsvc6prj -o../wxBase.dsw -DRUNTIME_LIBS=dynamic
+             -DDEBUG_INFO=default -DDEBUG_FLAG=default
+             -DOFFICIAL_BUILD=0 -DUSE_HTML=0 -DUSE_OPENGL=0 -DUSE_ODBC=0
+             -DMONOLITHIC=1 -DUSE_GUI=0 wx.bkl
+It is, however, recommended to modify Bakefiles.bkgen (or
+Bakefiles.local.bkgen) by means of <add-flags> and <del-flags> directives
+and use bakefile_gen instead of running bakefile directly.
+

 
 2. Bakefile files organization
 ------------------------------
 
 
 2. Bakefile files organization
 ------------------------------
 

+Makefile are generated from .bkl files ("bakefiles") from three places:
+  - $(wx)/build/bakefiles directory
+  - $(wx)/contrib/build/* directories
+  - samples directories
+$(wx)/build/bakefiles contains bakefiles for main library and support files
+that simplify writing bakefiles for contrib and samples.
+
+Support files are:
+  wxwin.py                - helper functions
+  common.bkl
+  common_samples.bkl
+  common_contrib.bkl      - shared definitions and templates
+  config.bkl              - user-configurable build options
+  make_dist.mk            - implementation of "make dist" on Unix
+
+Files used to build the library are:
+  wx.bkl                  - main file
+  files.bkl               - lists of source files
+  monolithic.bkl          - targets for wxWin built as single big library
+  multilib.bkl            - targets for multilib build
+  opengl.bkl              - GL library with wxGLCanvas (this one is not
+                            included in monolithic library for historical
+                            reasons, so "monolithic" really means "two libs")
+  {expat,jpeg,png,tiff,
+   regex,zlib,odbc}.bkl   - 3rd party libraries makefiles
+

 
 3. Adding files to existing library
 -----------------------------------
 
 
 3. Adding files to existing library
 -----------------------------------
 

+All files used by main libraries are listed in files.bkl. The file is
+organized into variables for toolkits, platforms and libraries. The variables
+come in pairs: there's always FOO_SRC for source files and FOO_HDR for header
+files. Platform or toolkit specific files are grouped together in variable
+with platform or toolkit name in them, e.g. BASE_WIN32_SRC, BASE_UNIX_SRC,
+GTK_SRC, MOTIF_SRC.

 
 

-4. Adding sample or contrib library
------------------------------------
+Note: A side effect of this toolkit-centric organization is that one file may
+      be present several times in files.bkl in different contexts.
+
+When you are adding a file, you must put it into appropriate variable. This is
+easy if you are adding the file to library that is always built from same
+sources on all platforms (e.g. wxXml or wxXML) -- simply add the file to e.g.
+HTML_SRC or HTML_HDR.
+
+If the file is used only on one platform and is part of wxBase, add it to
+BASE_{platform}_SRC/HDR. If it is used on all platforms, add it to BASE_CMN.
+If it is built on more than one platform but not on all of them, add the file
+to *all platforms that use it*!
+
+If a file is not wxBase file, but GUI file, then the variables are named after
+toolkits/ports, not platforms. Same rules as for wxBase files apply
+(substitute "platform" with "toolkit"). Make sure you correctly choose between
+{port}_LOWLEVEL_SRC and {port}_SRC -- the former is for files used by
+wxUniversal, e.g. GDI classes. Files shared by all X Window System ports
+should be put into XWIN_LOWLEVEL_SRC.
+
+
+4. Adding sample
+----------------
+
+Copy the bakefile from another sample, change the ID and files accordingly.
+If the sample uses some data files, make sure to have <wx-data> node
+in the sample's bakefile (see e.g. samples/image/image.bkl for an example).
+Make sure to add <wx-lib> statements for all libraries from multilib build
+that are required by the sample.
+
+The Windows resource specification should use the central .rc file:

 
 

+        <win32-res>../sample.rc</win32-res>
+        
+Run bakefile_gen in $(wx)/build/bakefiles to regenerate the bakefiles.

 
 

-5. Adding new core library
+Finally commit $(wx)/build/bakefiles/make_dist.mk and all the other modified files.
+
+Currently we commit the generated makefiles except .dms, .vcp.
+
+
+5. Adding contrib library
+-------------------------
+
+Contrib library bakefiles are located in $(wx)/contrib/build/name-of-contrib
+directory, together with generated makefiles. Copy the bakefile from another
+contrib library, change the IDs and files accordingly. Note that there must be
+two targets for contrib wxFoo: foodll and foolib.
+
+foodll definition must contain <wx-lib> statements for all libraries it
+depends on. WXUSINGDLL and WXMAKINGDLL_FOO must be defined and symbols from
+the library should use WXDLLIMPEXP_FOO defined in wxFoo's headers analogically
+to WXDLLIMPEXP_{BASE,CORE,HTML,...} in the main library (see 5g below for
+additional details).
+
+Run bakefile_gen in $(wx)/build/bakefiles to regenerate makefiles
+then commit $(wx)/build/bakefiles/Makefile.
+
+
+6. Adding new core library

 --------------------------
 
 When adding new library to the core set of libraries, the files must be
 --------------------------
 
 When adding new library to the core set of libraries, the files must be


@@ -26,35 +153,62 @@ added to both a newly added library in multilib build and into the single
 library built in monolithic mode. We will assume that the new library is
 called wxFoo.
 
 library built in monolithic mode. We will assume that the new library is
 called wxFoo.
 

-a) Add files to files.bkl                 FIXME
+a) Add files to files.bkl:
+   * If wxFoo builds from same files on all platforms (e.g. wxNet),
+     add FOO_SRC and FOO_HDR variables with lists of sources and headers.
+   * If wxFoo have no files in common (e.g. wxGL), add FOO_SRC and FOO_HDR
+     with toolkit or platform conditions. Have a look at OPENGL_SRC for an
+     example.
+   * Otherwise add FOO_CMN_SRC and FOO_CMN_HDR for common files and
+     FOO_{platform}_{SRC,HDR} or FOO_{toolkit}_{SRC,HDR} as appropriate. Add
+     FOO_PLATFORM_{SRC,HDR} into "Define sources for specific libraries"
+     section that is conditionally set to one of FOO_xxx_{SRC,HDR} based on
+     target platform/toolkit (see NET_PLATFORM_SRC definition for an example).
+     Finally, define FOO_SRC and FOO_HDR to contain both
+     FOO_PLATFORM_{SRC,HDR} and FOO_{SRC,HDR} (see NET_SRC definition for an
+     example).
+   * Add FOO_HDR to ALL_GUI_HEADERS or ALL_BASE_HEADERS. 
+   * If wxFoo is wxBase library (doesn't use GUI), add FOO_SRC to
+     ALL_BASE_SOURCES.
+
+   (You can apply different approaches to HDR and SRC variables, if e.g.
+   headers are all common but sources are not.)
+
+   Note that the conditions can only test for equality, due to limitations of
+   native make tools.

 
 b) Modify bakefile system in build/bakefiles/ to recognize wxFoo:
 
 b) Modify bakefile system in build/bakefiles/ to recognize wxFoo:

-   * Add 'foo'to MAIN_LIBS and LIBS_NOGUI or LIBS_GUI (depending on whether
+   * Add 'foo' to MAIN_LIBS and LIBS_NOGUI or LIBS_GUI (depending on whether

      the library depends on wxCore or not) to wxwin.py file.
      the library depends on wxCore or not) to wxwin.py file.

+   * Add extra libraries needed by wxFoo (if any) to EXTRALIBS in wxwin.py

    * Add WXLIB_FOO definition to common.bkl (into the "Names of component
      libraries" section). It looks like this:
        <set var="WXLIB_FOO">
           <if cond="MONOLITHIC=='0'">$(mk.evalExpr(wxwin.mkLibName('foo')))</if>
        </set>
 
    * Add WXLIB_FOO definition to common.bkl (into the "Names of component
      libraries" section). It looks like this:
        <set var="WXLIB_FOO">
           <if cond="MONOLITHIC=='0'">$(mk.evalExpr(wxwin.mkLibName('foo')))</if>
        </set>
 

-c) Add files to monolithic build          FIXME
+c) Modify monolithic.bkl to add files to monolithic build: it's enough to add
+   FOO_SRC to MONOLIB_GUI_SRC or MONOLIB_SRC, depending on whether wxFoo uses
+   GUI or not.

 
 

-d) Add files to multilib build            FIXME
+d) Modify multilib.bkl to add files to multilib build: add foolib and foodll
+   targets. Don't use wxBase targets as the template, use e.g. wxXML or wxHTML.
+   Make sure WXMAKINGDLL_FOO is defined in foodll.

 
 e) Regenerate all makefiles (don't forget to run autoconf)
 
 
 e) Regenerate all makefiles (don't forget to run autoconf)
 

-f) Update wx-config.in to contain information about the library and needed
-   linker flags:
-   * Add "foo" to either CORE_BASE_LIBS or CORE_GUI_LIBS so that wxFoo is
-     not treated as contrib library in monolithic build.
-   * If wxFoo links against additional libraries, add neccessary linker
-     flags and libraries to ldflags_foo and ldlibs_foo variables (both are
-     optional).
-
-g) Update defs.h to define WXMAKINGDLL_FOO if WXMAKINGDLL is defined (add
-   #define WXMAKINGDLL_FOO inside first "#ifdef WXMAKINGDLL" block in defs.h)
-   and to define WXDLLIMPEXP_FOO and WXDLLIMPEXP_DATA_FOO. You can copy
-   e.g. WXDLLIMPEXP_NET definition, it is something like this:
+f) Update configure.in and wx-config.in to contain information about
+   the library and needed linker flags:
+   * Add "foo" to either CORE_BASE_LIBS or CORE_GUI_LIBS in configure.in so
+     that wxFoo is not treated as contrib library in monolithic build.
+   * If wxFoo links against additional libraries, add necessary linker
+     flags and libraries to ldflags_foo and ldlibs_foo variables in
+     wx-config.in (both are optional).
+
+g) Update dlimpexp.h to define WXMAKINGDLL_FOO if WXMAKINGDLL is defined (add
+   #define WXMAKINGDLL_FOO inside first "#ifdef WXMAKINGDLL" block in
+   dlimpexp.h) and to define WXDLLIMPEXP_FOO and WXDLLIMPEXP_DATA_FOO. You
+   can copy e.g. WXDLLIMPEXP_NET definition, it is something like this:

         #ifdef WXMAKINGDLL_NET
             #define WXDLLIMPEXP_NET WXEXPORT
             #define WXDLLIMPEXP_DATA_NET(type) WXEXPORT type
         #ifdef WXMAKINGDLL_NET
             #define WXDLLIMPEXP_NET WXEXPORT
             #define WXDLLIMPEXP_DATA_NET(type) WXEXPORT type


@@ -65,10 +219,21 @@ g) Update defs.h to define WXMAKINGDLL_FOO if WXMAKINGDLL is defined (add
             #define WXDLLIMPEXP_NET
             #define WXDLLIMPEXP_DATA_NET(type) type
         #endif
             #define WXDLLIMPEXP_NET
             #define WXDLLIMPEXP_DATA_NET(type) type
         #endif

+   Use WXDLLIMPEXP_FOO when declaring wxFoo classes and functions.
+
+h) Add this code to one of wxFoo's files (the more often used, the better):
+      // DLL options compatibility check:
+      #include "wx/app.h"
+      WX_CHECK_BUILD_OPTIONS("wxFoo")

 
 

-h) Add information about wxFoo to the manual
-   FIXME - where exactly
+i) Add information about wxFoo to the manual ("Libraries list" section
+   in libs.tex) and update docs/latex/wx/libs.dia (you need Dia for this)
+   to show the dependencies of the new library.

 
 

+j) Also please add 4 #pragma comment(lib, "foo") (for Unicode/ANSI
+   Release/Debug combinations) to the file include/msvc/wx/setup.h and
+   add a check for WXMAKINGDLL_FOO to the test whether we're building a DLL at
+   the end of include/wx/msw/chkconf.h.

 
 === EOF ===
 
 
 === EOF ===