[pango/pango1-dwrite: 1/3] build: Check for DirectWrite support

[Chun-wei Fan <fanchunwei src gnome org>]

commit f9eb41e6a889496b5c93c56175d9c4eede0bc150
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Jul 6 16:58:41 2022 +0800

    build: Check for DirectWrite support
    
    ...in Cairo and HarfBuzz.  They must be present before we can try to use
    DirectWrite and its GDI interop features in the respective code paths,
    since we can't bump deps in a stable release series.
    
    Since upstream Cairo gained DirectWrite support very recently, check for
    it only via pkg-config, since Cairo had Meson build support quite a bit before
    that happened.

 meson.build       | 26 ++++++++++++++++++++++++++
 pango/meson.build |  3 +++
 2 files changed, 29 insertions(+)
---
diff --git a/meson.build b/meson.build
index fe2f9d47c..2af153581 100644
--- a/meson.build
+++ b/meson.build
@@ -46,6 +46,7 @@ osx_current = pango_binary_age - pango_interface_age + 1
 pango_osxversion = [osx_current, '@0@.@1@.0'.format(osx_current, pango_interface_age)]
 
 cc = meson.get_compiler('c')
+cpp = meson.get_compiler('cpp')
 host_system = host_machine.system()
 
 # Compiler and linker flags
@@ -393,6 +394,11 @@ cairo_dep = dependency('cairo', version: cairo_req_version, required: cairo_opti
 
 if cairo_dep.found()
   cairo_found_type = cairo_dep.type_name()
+  if host_system == 'windows'
+    cairo_dwrite_dep = dependency('cairo-win32-dwrite-font', version: cairo_req_version, required: false)
+  else
+    cairo_dwrite_dep = disabler()
+  endif
 else
   if cc.get_id() == 'msvc' and cc.has_header('cairo.h')
     cairo_dep = cc.find_library('cairo', required: cairo_option)
@@ -566,6 +572,26 @@ if cairo_dep.found()
   endif
 endif
 
+enable_dwrite_support = false
+if harfbuzz_dep.type_name() != 'internal'
+  enable_dwrite_support = cpp.has_header_symbol(
+    'hb-directwrite.h',
+    'hb_directwrite_face_create',
+    dependencies: harfbuzz_dep,
+    prefix: '#include <dwrite.h>',
+  )
+else
+  enable_dwrite_support = true
+endif
+
+if enable_dwrite_support and cairo_dwrite_dep.found()
+  pango_conf.set('HAVE_CAIRO_WIN32_DIRECTWRITE', 1)
+endif
+
+if enable_dwrite_support
+  pango_conf.set('HAVE_DIRECTWRITE', 1)
+endif
+
 # libsysprof-capture support
 libsysprof_capture_dep = dependency('sysprof-capture-4',
   required: get_option('sysprof'),
diff --git a/pango/meson.build b/pango/meson.build
index 1a4b41419..090ae80ae 100644
--- a/pango/meson.build
+++ b/pango/meson.build
@@ -430,6 +430,9 @@ if host_system == 'windows'
     libpango_dep,
     cc.find_library('gdi32'),
   ]
+  if enable_dwrite_support
+    pangowin32_deps += cc.find_library('dwrite')
+  endif
 
   pangowin32_rc = configure_file(
     input: 'pangowin32.rc.in',