okular with LCD subpixel rendering backend

6 files changed, 760 insertions, 0 deletions

diff --git a/.SRCINFO b/.SRCINFO
new file mode 100644
index 000000000000..227742ca80fc
--- /dev/null
+++ b/.SRCINFO
@@ -0,0 +1,69 @@
+pkgbase = okular-lcd-standalone
+	pkgdesc = KDE Document viewer (PDF, Postscript, djvu, etc.) with built-in LCD subpixel rendering support
+	pkgver = 18.04.1
+	pkgrel = 1
+	url = https://kde.org/applications/graphics/okular/
+	arch = x86_64
+	groups = kde-applications
+	groups = kdegraphics
+	license = GPL
+	license = LGPL
+	license = FDL
+	makedepends = extra-cmake-modules
+	makedepends = ebook-tools
+	makedepends = kdegraphics-mobipocket
+	makedepends = kdoctools
+	makedepends = khtml
+	makedepends = chmlib
+	makedepends = discount
+	makedepends = git
+	makedepends = qt4
+	makedepends = qt5-base
+	makedepends = icu
+	makedepends = gtk2
+	makedepends = python2
+	makedepends = libjpeg
+	makedepends = gcc-libs
+	makedepends = cairo
+	makedepends = fontconfig
+	makedepends = openjpeg
+	makedepends = pkgconfig
+	makedepends = lcms2
+	makedepends = gobject-introspection
+	depends = djvulibre
+	depends = libspectre
+	depends = libkexiv2
+	depends = qca-qt5
+	depends = kpty
+	depends = kactivities
+	depends = threadweaver
+	depends = kjs
+	depends = kparts
+	depends = purpose
+	optdepends = ebook-tools: mobi and epub support
+	optdepends = discount: markdown support
+	optdepends = kdegraphics-mobipocket: mobi support
+	optdepends = kirigami2: mobile UI
+	optdepends = libzip: CHM support
+	optdepends = khtml: CHM support
+	optdepends = chmlib: CHM support
+	optdepends = calligra: ODT and ODP support
+	conflicts = kdegraphics-okular
+	conflicts = okular
+	conflicts = okular-git
+	replaces = kdegraphics-okular
+	replaces = okular
+	replaces = okular-git
+	source = git+https://github.com/KDE/okular#commit=ee57925c5779a572b8d5cc52ab59a380bd4b4e03
+	source = http://poppler.freedesktop.org/poppler-0.43.0.tar.xz
+	source = 01-okular-subpixel-rendering-by-poppler.patch
+	source = 02-subpixel-rendering-for-poppler-and-glib.patch
+	source = 03-cairo-backend-for-poppler-qt5.patch
+	sha256sums = SKIP
+	sha256sums = SKIP
+	sha256sums = 4d44bfc0f34a3e26f2d1cc6f5a99cf4199c7a13ae5e1ed57c4b875703328d525
+	sha256sums = 73c0fb71877633cefc37b13bcd7896263dc63b91fe13fa97c2c240292a2bc338
+	sha256sums = c554b9411764ffcad7a91e22f78a594ca9851e631c70ec15a2b0d52bada0573c
+
+pkgname = okular-lcd-standalone
+
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000000..198750ed322f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+okular/
+src/
+pkg/
+*.tar.xz
+
diff --git a/01-okular-subpixel-rendering-by-poppler.patch b/01-okular-subpixel-rendering-by-poppler.patch
new file mode 100644
index 000000000000..daf738c941ed
--- /dev/null
+++ b/01-okular-subpixel-rendering-by-poppler.patch
@@ -0,0 +1,67 @@
+From: Jeffrey Feng <galago1992@gmail.com>
+Subject: [PATCH 1/3] okular LCD subpixel rendering by poppler
+---
+git diff --stat
+ CMakeLists.txt                    | 7 +++----
+ generators/poppler/CMakeLists.txt | 9 +++++++--
+ 2 files changed, 10 insertions(+), 6 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index d067039e0..aa60b226d 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -92,10 +92,8 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake/modules)
+ find_package(ZLIB REQUIRED)
+ 
+ # This is here instead of in generators since we use if(Poppler_Qt5_FOUND) in autotests/
+-find_package(Poppler "0.12.1" COMPONENTS Qt5)
+-set_package_properties("Poppler" PROPERTIES
+-        TYPE RECOMMENDED
+-        PURPOSE "Support for PDF files in okular.")
++set(Poppler_Qt5_FOUND 1)
++set(Poppler_VERSION "0.43.0")
+ 
+ add_definitions(-DQT_USE_FAST_CONCATENATION -DQT_USE_FAST_OPERATOR_PLUS)
+ add_definitions(-DTRANSLATION_DOMAIN="okular")
+@@ -116,6 +114,7 @@ if(BUILD_COVERAGE)
+     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fprofile-arcs -ftest-coverage")
+     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lgcov")
+ endif()
++STRING(REGEX REPLACE "--as-needed" "--no-as-needed" CMAKE_MODULE_LINKER_FLAGS ${CMAKE_MODULE_LINKER_FLAGS})
+ 
+ add_subdirectory( ui )
+ add_subdirectory( shell )
+diff --git a/generators/poppler/CMakeLists.txt b/generators/poppler/CMakeLists.txt
+index 73881f0e1..5e90efed8 100644
+--- a/generators/poppler/CMakeLists.txt
++++ b/generators/poppler/CMakeLists.txt
+@@ -19,7 +19,7 @@ if (Poppler_VERSION VERSION_GREATER "0.36.99")
+   set (HAVE_POPPLER_0_37 1)
+ endif()
+ 
+-set(CMAKE_REQUIRED_LIBRARIES Poppler::Qt5 Qt5::Core Qt5::Gui)
++set(CMAKE_REQUIRED_LIBRARIES Qt5::Core Qt5::Gui)
+ 
+ check_cxx_source_compiles("
+ #include <poppler-qt5.h>
+@@ -89,6 +89,8 @@ configure_file(
+ 
+ include_directories(
+    ${CMAKE_CURRENT_SOURCE_DIR}/../..
++   ${POPPLER_LIB_DIR}/../include/poppler
++   ${POPPLER_LIB_DIR}/../include/poppler/qt5
+ )
+ 
+ ########### next target ###############
+@@ -107,7 +109,10 @@ kconfig_add_kcfg_files(okularGenerator_poppler_PART_SRCS conf/pdfsettings.kcfgc
+ 
+ okular_add_generator(okularGenerator_poppler ${okularGenerator_poppler_PART_SRCS})
+ 
+-target_link_libraries(okularGenerator_poppler okularcore KF5::I18n KF5::Completion Poppler::Qt5 Qt5::Xml)
++set(POPPLER_LIB ${POPPLER_LIB_DIR}/libpoppler-lcd.so)
++set(POPPLER_QT5_LIB ${POPPLER_LIB_DIR}/libpoppler-qt5-lcd.so)
++set_target_properties(okularGenerator_poppler PROPERTIES INSTALL_RPATH ${POPPLER_LIB_RPATH})
++target_link_libraries(okularGenerator_poppler okularcore KF5::I18n KF5::Completion ${POPPLER_QT5_LIB} ${POPPLER_LIB} Qt5::Xml)
+ 
+ ########### install files ###############
+ install( FILES okularPoppler.desktop  DESTINATION  ${KDE_INSTALL_KSERVICES5DIR} )
diff --git a/02-subpixel-rendering-for-poppler-and-glib.patch b/02-subpixel-rendering-for-poppler-and-glib.patch
new file mode 100644
index 000000000000..c82281872681
--- /dev/null
+++ b/02-subpixel-rendering-for-poppler-and-glib.patch
@@ -0,0 +1,309 @@
+From: Jeffrey Feng <galago1992@gmail.com>
+Subject: [PATCH 2/3] subpixel rendering for poppler and poppler-glib
+---
+diff -rup a/ b/|diffstat
+ CMakeLists.txt             |    1 
+ glib/CMakeLists.txt        |    1 
+ glib/demo/render.c         |   25 +++++++++++++++++---
+ glib/poppler-page.cc       |   10 ++++++++
+ glib/poppler-page.h        |    1 
+ poppler/CairoFontEngine.cc |    6 ++--
+ poppler/CairoOutputDev.cc  |   17 +++++++++++++
+ poppler/Gfx.cc             |   56 +++++++++++++++++++++++++++++++++++++++++++++
+ poppler/Gfx.h              |    3 ++
+ poppler/Page.cc            |   14 +++++++++++
+ poppler/Page.h             |    3 ++
+ 11 files changed, 131 insertions(+), 6 deletions(-)
+ 
+diff -rup a/CMakeLists.txt b/CMakeLists.txt
+--- a/CMakeLists.txt    2016-04-29 06:13:57.000000000 +0800
++++ b/CMakeLists.txt    2018-05-22 23:05:18.907662448 +0800
+@@ -501,6 +501,7 @@ add_library(poppler STATIC ${poppler_SRC
+ else(MSVC)
+ add_library(poppler SHARED ${poppler_SRCS})
+ endif(MSVC)
++set_target_properties(poppler PROPERTIES OUTPUT_NAME "poppler-lcd")
+ set_target_properties(poppler PROPERTIES VERSION 60.0.0 SOVERSION 60)
+ target_link_libraries(poppler LINK_PRIVATE ${poppler_LIBS})
+ install(TARGETS poppler RUNTIME DESTINATION bin LIBRARY DESTINATION lib${LIB_SUFFIX} ARCHIVE DESTINATION lib${LIB_SUFFIX})
+diff -rup a/glib/CMakeLists.txt b/glib/CMakeLists.txt
+--- a/glib/CMakeLists.txt       2015-05-15 02:23:07.000000000 +0800
++++ b/glib/CMakeLists.txt       2018-05-22 23:06:31.313659479 +0800
+@@ -81,6 +81,7 @@ set(poppler_glib_generated_SRCS
+   ${CMAKE_SOURCE_DIR}/poppler/CairoRescaleBox.cc
+ )
+ add_library(poppler-glib SHARED ${poppler_glib_SRCS} ${poppler_glib_generated_SRCS})
++set_target_properties(poppler-glib PROPERTIES OUTPUT_NAME "poppler-glib-lcd")
+ set_target_properties(poppler-glib PROPERTIES VERSION 8.7.0 SOVERSION 8)
+ target_link_libraries(poppler-glib poppler ${GLIB2_LIBRARIES} ${CAIRO_LIBRARIES} ${FREETYPE_LIBRARIES})
+ if(HAVE_PTHREAD)
+diff -rup a/glib/demo/render.c b/glib/demo/render.c
+--- a/glib/demo/render.c	2014-02-09 23:10:30.000000000 +0800
++++ b/glib/demo/render.c	2018-05-18 21:21:13.000000000 +0800
+@@ -82,12 +82,14 @@ pgd_render_start (GtkButton     *button,
+ 		  PgdRenderDemo *demo)
+ {
+ 	PopplerPage *page;
++	gboolean     subpixel_rendering;
+ 	gdouble      page_width, page_height;
+ 	gdouble      width, height;
+ 	gint         x, y;
+ 	gchar       *str;
+ 	GTimer      *timer;
+         cairo_t     *cr;
++        cairo_font_options_t *fo;
+ 
+ 	page = poppler_document_get_page (demo->doc, demo->page);
+ 	if (!page)
+@@ -116,6 +118,21 @@ pgd_render_start (GtkButton     *button,
+                                                     width, height);
+         cr = cairo_create (demo->surface);
+ 
++        fo = cairo_font_options_create ();
++        cairo_get_font_options (cr, fo);
++
++        subpixel_rendering = poppler_page_support_subpixel_rendering (page);
++        // printf("subpixel_rendering %d\n", subpixel_rendering);
++        if (subpixel_rendering) {
++                cairo_set_source_rgb (cr, 1., 1., 1.);
++                cairo_paint (cr);
++                cairo_font_options_set_antialias (fo, CAIRO_ANTIALIAS_SUBPIXEL);
++                cairo_font_options_set_subpixel_order (fo, CAIRO_SUBPIXEL_ORDER_RGB);
++        }
++
++        cairo_set_font_options (cr, fo);
++        cairo_font_options_destroy (fo);
++
+         cairo_save (cr);
+         switch (demo->rotate) {
+         case 90:
+@@ -143,9 +160,11 @@ pgd_render_start (GtkButton     *button,
+                 poppler_page_render (page, cr);
+         cairo_restore (cr);
+ 
+-        cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
+-        cairo_set_source_rgb (cr, 1., 1., 1.);
+-        cairo_paint (cr);
++        if (!subpixel_rendering) {
++                cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
++                cairo_set_source_rgb (cr, 1., 1., 1.);
++                cairo_paint (cr);
++        }
+ 
+         g_timer_stop (timer);
+ 
+diff -rup a/glib/poppler-page.cc b/glib/poppler-page.cc
+--- a/glib/poppler-page.cc	2016-03-02 07:35:24.000000000 +0800
++++ b/glib/poppler-page.cc	2018-05-18 21:21:13.000000000 +0800
+@@ -2424,3 +2424,13 @@ poppler_page_get_text_attributes_for_are
+ 
+   return g_list_reverse(attributes);
+ }
++
++gboolean
++poppler_page_support_subpixel_rendering (PopplerPage        *page)
++{
++  CairoOutputDev *output_dev;
++  g_return_val_if_fail (POPPLER_IS_PAGE (page), FALSE);
++
++  output_dev = page->document->output_dev;
++  return page->page->supportSubpixelRendering(output_dev);
++}
+diff -rup a/glib/poppler-page.h b/glib/poppler-page.h
+--- a/glib/poppler-page.h	2016-03-02 07:35:24.000000000 +0800
++++ b/glib/poppler-page.h	2018-05-18 21:21:13.000000000 +0800
+@@ -109,6 +109,7 @@ GList                 *poppler_page_get_
+ void                   poppler_page_free_text_attributes (GList              *list);
+ GList *        poppler_page_get_text_attributes_for_area (PopplerPage        *page,
+                                                           PopplerRectangle   *area);
++gboolean         poppler_page_support_subpixel_rendering (PopplerPage        *page);
+ 
+ /* A rectangle on a page, with coordinates in PDF points. */
+ #define POPPLER_TYPE_RECTANGLE             (poppler_rectangle_get_type ())
+diff -rup a/poppler/CairoFontEngine.cc b/poppler/CairoFontEngine.cc
+--- a/poppler/CairoFontEngine.cc	2016-04-29 06:05:41.000000000 +0800
++++ b/poppler/CairoFontEngine.cc	2018-05-20 12:51:49.952696424 +0800
+@@ -132,7 +132,7 @@ CairoFont::getSubstitutionCorrection(Gfx
+ 	cairo_matrix_t m;
+ 	cairo_matrix_init_identity(&m);
+ 	cairo_font_options_t *options = cairo_font_options_create();
+-	cairo_font_options_set_hint_style(options, CAIRO_HINT_STYLE_NONE);
++	cairo_font_options_set_hint_style(options, CAIRO_HINT_STYLE_SLIGHT);
+ 	cairo_font_options_set_hint_metrics(options, CAIRO_HINT_METRICS_OFF);
+ 	cairo_scaled_font_t *scaled_font = cairo_scaled_font_create(cairo_font_face, &m, &m, options);
+ 
+@@ -190,7 +190,7 @@ _ft_new_face_uncached (FT_Library lib,
+   }
+ 
+   font_face = cairo_ft_font_face_create_for_ft_face (face,
+-							  FT_LOAD_NO_HINTING |
++							  FT_LOAD_TARGET_LIGHT |
+ 							  FT_LOAD_NO_BITMAP);
+   if (cairo_font_face_set_user_data (font_face,
+ 				     &_ft_cairo_key,
+@@ -359,7 +359,7 @@ _ft_new_face (FT_Library lib,
+   _ft_open_faces = l;
+ 
+   l->font_face = cairo_ft_font_face_create_for_ft_face (tmpl.face,
+-							  FT_LOAD_NO_HINTING |
++							  FT_LOAD_TARGET_LIGHT |
+ 							  FT_LOAD_NO_BITMAP);
+   if (cairo_font_face_set_user_data (l->font_face,
+ 				     &_ft_cairo_key,
+diff -rup a/poppler/CairoOutputDev.cc b/poppler/CairoOutputDev.cc
+--- a/poppler/CairoOutputDev.cc	2016-04-29 06:05:11.000000000 +0800
++++ b/poppler/CairoOutputDev.cc	2018-05-18 21:21:13.000000000 +0800
+@@ -1402,6 +1402,7 @@ void CairoOutputDev::drawChar(GfxState *
+ void CairoOutputDev::endString(GfxState *state)
+ {
+   int render;
++  GfxFontType fontType;
+ 
+   if (!currentFont)
+     return;
+@@ -1419,6 +1420,18 @@ void CairoOutputDev::endString(GfxState
+     goto finish;
+   }
+ 
++  fontType = state->getFont()->getType();
++  // Do not enable subpixel rendering for type3 font
++  // For some reason it does not work
++  if (fontType == fontType3) {
++      cairo_save(cairo);
++      cairo_font_options_t *fo;
++      fo = cairo_font_options_create ();
++      cairo_get_font_options (cairo, fo);
++      cairo_font_options_set_antialias (fo, CAIRO_ANTIALIAS_DEFAULT);
++      cairo_set_font_options (cairo, fo);
++  }
++
+   if (!(render & 1)) {
+     LOG (printf ("fill string\n"));
+     cairo_set_source (cairo, fill_pattern);
+@@ -1469,6 +1482,10 @@ void CairoOutputDev::endString(GfxState
+   }
+ 
+ finish:
++  // pair with the previous cairo_save to disable subpixel rendering for type3 fonts
++  if (fontType == fontType3) {
++      cairo_restore(cairo);
++  }
+   gfree (glyphs);
+   glyphs = NULL;
+   if (use_show_text_glyphs) {
+diff -rup a/poppler/Gfx.cc b/poppler/Gfx.cc
+--- a/poppler/Gfx.cc	2016-03-17 03:16:12.000000000 +0800
++++ b/poppler/Gfx.cc	2018-05-18 21:21:13.000000000 +0800
+@@ -4726,6 +4726,62 @@ void Gfx::doImage(Object *ref, Stream *s
+   error(errSyntaxError, getPos(), "Bad image parameters");
+ }
+ 
++GBool Gfx::checkNormalBlendModeOnly(Object *str) {
++  // printf("check blender mode start\n");
++  char *cmd;
++  Object obj;
++  Object args[maxArgs];
++  int numArgs, i;
++  GBool onlyNormalBlendMode;
++  Parser myParser(xref, new Lexer(xref, str), gFalse);
++
++  numArgs = 0;
++  onlyNormalBlendMode = gTrue;
++
++  myParser.getObj(&obj);
++  while (!obj.isEOF()) {
++    if (obj.isCmd()) {
++      cmd = obj.getCmd();
++
++      if (strcmp(cmd, "gs") == 0) {
++        Object obj1, obj2;
++        GfxBlendMode mode;
++        if (res->lookupGState(args[0].getName(), &obj1)) {
++          if (!obj1.dictLookup("BM", &obj2)->isNull()) {
++            if (state->parseBlendMode(&obj2, &mode)) {
++              // printf("check blend mode: %d\n", mode);
++              onlyNormalBlendMode &= (mode == gfxBlendNormal);
++            }
++          }
++          obj2.free();
++        }
++        obj1.free();
++      }
++      obj.free();
++
++      for (i = 0; i < numArgs; ++i)
++	args[i].free();
++      numArgs = 0;
++
++    } else if (numArgs < maxArgs) {
++      args[numArgs++] = obj;
++    } else {
++      obj.free();
++    }
++
++    myParser.getObj(&obj);
++  }
++  obj.free();
++
++  if (numArgs > 0) {
++    for (i = 0; i < numArgs; ++i)
++      args[i].free();
++  }
++
++  return onlyNormalBlendMode;
++}
++
++
+ GBool Gfx::checkTransparencyGroup(Dict *resDict) {
+   // check the effect of compositing objects as a group:
+   // look for ExtGState entries with ca != 1 or CA != 1 or BM != normal
+diff -rup a/poppler/Gfx.h b/poppler/Gfx.h
+--- a/poppler/Gfx.h	2015-11-16 05:05:22.000000000 +0800
++++ b/poppler/Gfx.h	2018-05-18 21:21:13.000000000 +0800
+@@ -186,6 +186,9 @@ public:
+   // Get the current graphics state object.
+   GfxState *getState() { return state; }
+ 
++  // Check whether a stream only contains normal blend mode (to enable subpixel rendering)
++  GBool checkNormalBlendModeOnly(Object *str);
++
+   GBool checkTransparencyGroup(Dict *resDict);
+ 
+   void drawForm(Object *str, Dict *resDict, double *matrix, double *bbox,
+diff -rup a/poppler/Page.cc b/poppler/Page.cc
+--- a/poppler/Page.cc	2016-02-07 20:41:06.000000000 +0800
++++ b/poppler/Page.cc	2018-05-18 21:21:13.000000000 +0800
+@@ -370,6 +370,20 @@ Dict *Page::getResourceDictCopy(XRef *xr
+   return dict ? dict->copy(xrefA) : NULL;
+ }
+ 
++GBool Page::supportSubpixelRendering(OutputDev *out) {
++  GBool supported = gFalse;
++  Object obj;
++  PDFRectangle box;
++
++  contents.fetch(xref, &obj);
++  if (!obj.isNull()) {
++    Gfx gfx(doc, out, attrs->getResourceDict(), &box, NULL);
++    supported = gfx.checkNormalBlendModeOnly(&obj);
++  }
++  obj.free();
++  return supported;
++}
++
+ void Page::replaceXRef(XRef *xrefA) {
+   Object obj1;
+   Dict *pageDict = pageObj.getDict()->copy(xrefA);
+diff -rup a/poppler/Page.h b/poppler/Page.h
+--- a/poppler/Page.h	2015-11-16 05:05:22.000000000 +0800
++++ b/poppler/Page.h	2018-05-18 21:21:13.000000000 +0800
+@@ -179,6 +179,9 @@ public:
+   Dict *getResourceDict();
+   Dict *getResourceDictCopy(XRef *xrefA);
+ 
++  // Whether the content in this page supports subpixel rendering (lcdfilter)
++  GBool supportSubpixelRendering(OutputDev *out);
++
+   // Get annotations array.
+   Object *getAnnots(Object *obj, XRef *xrefA = NULL) { return annotsObj.fetch((xrefA == NULL) ? xref : xrefA, obj); }
+   // Add a new annotation to the page
diff --git a/03-cairo-backend-for-poppler-qt5.patch b/03-cairo-backend-for-poppler-qt5.patch
new file mode 100644
index 000000000000..0bcfbd1a9a4b
--- /dev/null
+++ b/03-cairo-backend-for-poppler-qt5.patch
@@ -0,0 +1,236 @@
+From: Jeffrey Feng <galago1992@gmail.com>
+Subject: [PATCH 3/3] cairo backend for poppler-qt5
+---
+diff -rup a/qt5 b/qt5|diffstat
+ demos/viewer.cpp        |    6 ++-
+ src/CMakeLists.txt      |   15 +++++++
+ src/poppler-document.cc |    3 +
+ src/poppler-page.cc     |   83 +++++++++++++++++++++++++++++++++++++++++++++++-
+ src/poppler-private.cc  |    2 -
+ src/poppler-qt5.h       |    3 +
+ tests/CMakeLists.txt    |    4 ++
+ 7 files changed, 112 insertions(+), 4 deletions(-)
+
+diff -rup a/qt5/demos/viewer.cpp b/qt5/demos/viewer.cpp
+--- a/qt5/demos/viewer.cpp	2014-02-09 23:10:33.000000000 +0800
++++ b/qt5/demos/viewer.cpp	2018-05-20 11:50:24.585847554 +0800
+@@ -74,13 +74,17 @@ PdfViewer::PdfViewer()
+     m_settingsRenderBackendGrp->setExclusive(true);
+     act = settingsRenderMenu->addAction(tr("Splash"));
+     act->setCheckable(true);
+-    act->setChecked(true);
+     act->setData(qVariantFromValue(0));
+     m_settingsRenderBackendGrp->addAction(act);
+     act = settingsRenderMenu->addAction(tr("Arthur"));
+     act->setCheckable(true);
+     act->setData(qVariantFromValue(1));
+     m_settingsRenderBackendGrp->addAction(act);
++    act = settingsRenderMenu->addAction(tr("Cairo"));
++    act->setCheckable(true);
++    act->setChecked(true);
++    act->setData(qVariantFromValue(2));
++    m_settingsRenderBackendGrp->addAction(act);
+     connect(m_settingsRenderBackendGrp, SIGNAL(triggered(QAction*)),
+             this, SLOT(slotRenderBackend(QAction*)));
+ 
+diff -rup a/qt5/src/CMakeLists.txt b/qt5/src/CMakeLists.txt
+--- a/qt5/src/CMakeLists.txt	2016-03-02 07:35:24.000000000 +0800
++++ b/qt5/src/CMakeLists.txt	2018-05-19 11:01:30.000000000 +0800
+@@ -6,6 +6,10 @@ include_directories(
+   ${Qt5Core_INCLUDE_DIRS}
+   ${CMAKE_CURRENT_BINARY_DIR}
+ )
++if (HAVE_CAIRO)
++  include_directories(${CAIRO_INCLUDE_DIRS})
++  add_definitions(${CAIRO_CFLAGS})
++endif (HAVE_CAIRO)
+ 
+ set(poppler_qt5_SRCS
+   poppler-annotation.cc
+@@ -29,9 +33,20 @@ set(poppler_qt5_SRCS
+   poppler-media.cc
+   ArthurOutputDev.cc
+ )
++if (HAVE_CAIRO)
++  set(poppler_qt5_SRCS ${poppler_qt5_SRCS}
++    ${CMAKE_SOURCE_DIR}/poppler/CairoOutputDev.cc
++    ${CMAKE_SOURCE_DIR}/poppler/CairoRescaleBox.cc
++    ${CMAKE_SOURCE_DIR}/poppler/CairoFontEngine.cc
++  )
++endif(HAVE_CAIRO)
+ add_library(poppler-qt5 SHARED ${poppler_qt5_SRCS})
++set_target_properties(poppler-qt5 PROPERTIES OUTPUT_NAME "poppler-qt5-lcd")
+ set_target_properties(poppler-qt5 PROPERTIES VERSION 1.6.0 SOVERSION 1)
+ target_link_libraries(poppler-qt5 poppler ${Qt5Core_LIBRARIES} ${Qt5Gui_LIBRARIES} ${Qt5Xml_LIBRARIES})
++if (HAVE_CAIRO)
++  target_link_libraries(poppler-qt5 ${CAIRO_LIBRARIES})
++endif (HAVE_CAIRO)
+ if(MSVC)
+ target_link_libraries(poppler-qt5 poppler ${poppler_LIBS})
+ endif(MSVC)
+diff -rup a/qt5/src/poppler-document.cc b/qt5/src/poppler-document.cc
+--- a/qt5/src/poppler-document.cc	2015-09-08 23:34:57.000000000 +0800
++++ b/qt5/src/poppler-document.cc	2018-05-19 11:04:11.000000000 +0800
+@@ -528,6 +528,9 @@ namespace Poppler {
+         ret << Document::SplashBackend;
+ #endif
+         ret << Document::ArthurBackend;
++#if defined(HAVE_CAIRO)
++        ret << Document::CairoBackend;
++#endif
+         return ret;
+     }
+ 
+diff -rup a/qt5/src/poppler-page.cc b/qt5/src/poppler-page.cc
+--- a/qt5/src/poppler-page.cc	2016-04-29 05:58:39.000000000 +0800
++++ b/qt5/src/poppler-page.cc	2018-05-20 12:26:07.000000000 +0800
+@@ -41,6 +41,7 @@
+ #include <QtGui/QPainter>
+ 
+ #include <config.h>
++#include <math.h>
+ #include <PDFDoc.h>
+ #include <Catalog.h>
+ #include <Form.h>
+@@ -54,7 +55,9 @@
+ #include <SplashOutputDev.h>
+ #include <splash/SplashBitmap.h>
+ #endif
+-
++#if defined(HAVE_CAIRO)
++#include <CairoOutputDev.h>
++#endif
+ #include "poppler-private.h"
+ #include "poppler-page-transition-private.h"
+ #include "poppler-page-private.h"
+@@ -406,6 +409,82 @@ QImage Page::renderToImage(double xres,
+       img = tmpimg;
+       break;
+     }
++    case Poppler::Document::CairoBackend:
++    {
++#if defined(HAVE_CAIRO)
++      CairoOutputDev *output_dev = new CairoOutputDev();
++      output_dev->startDoc(m_page->parentDoc->doc);
++      int buffer_width, buffer_height, rotate;
++      cairo_surface_t *surface;
++      cairo_t *cairo;
++      cairo_font_options_t *fo;
++      GBool subpixel_rendering;
++      // If w or h are -1, that indicates the whole page, so we need to
++      // calculate how many pixels that corresponds to.  Otherwise, we can use w
++      // or h directly for our buffer size.
++      const QSize pageSize = this->pageSize();
++      if (w == -1) {
++        const double xscale = xres / 72.0;
++        const double width = pageSize.width();;
++        buffer_width = (int) ceil(width * xscale);
++      } else {
++        buffer_width = w;
++      }
++      if (h == -1) {
++        const double yscale = yres / 72.0;
++        const double height = pageSize.height();
++        buffer_height = (int) ceil(height * yscale);
++      } else {
++        buffer_height = h;
++      }
++
++      rotate = rotation + m_page->page->getRotate();
++
++      // FIXME: Okular never provides a rotation value, so I don't have any way
++      // of testing this right now.  The result is that subpixels are ordered
++      // incorrectly when the page is rotated.
++
++      //if (rotate == 90 || rotate == 270) {
++      //  const double temp = height;
++      //  height = width;
++      //  width = temp;
++      //}
++
++      img = QImage(buffer_width, buffer_height, QImage::Format_ARGB32);
++      img.fill(Qt::white);  // Never transparent
++
++      surface = cairo_image_surface_create_for_data(
++                  img.bits(),
++                  CAIRO_FORMAT_ARGB32,
++                  buffer_width, buffer_height,
++                  img.bytesPerLine());
++
++      cairo = cairo_create(surface);
++      fo = cairo_font_options_create ();
++      cairo_get_font_options (cairo, fo);
++      subpixel_rendering = m_page->page->supportSubpixelRendering (output_dev);
++      if (subpixel_rendering) {
++        cairo_set_source_rgb (cairo, 1., 1., 1.);
++        cairo_font_options_set_antialias (fo, CAIRO_ANTIALIAS_SUBPIXEL);
++        cairo_font_options_set_subpixel_order (fo, CAIRO_SUBPIXEL_ORDER_RGB);
++      }
++      cairo_set_font_options (cairo, fo);
++      cairo_font_options_destroy (fo);
++      
++      output_dev->setCairo(cairo);
++
++      m_page->parentDoc->doc->displayPageSlice(
++        output_dev, m_page->index + 1, xres, yres, rotation, false, true,
++        false, x, y, w, h);
++
++      // Clean up
++      output_dev->setCairo(NULL);
++      cairo_destroy(cairo);
++      cairo_surface_destroy(surface);
++      delete output_dev;
++#endif
++      break;
++    }
+   }
+ 
+   return img;
+@@ -448,6 +527,8 @@ bool Page::renderToPainter(QPainter* pai
+          painter->restore();
+       return true;
+     }
++    case Poppler::Document::CairoBackend:
++      return false;
+   }
+   return false;
+ }
+diff -rup a/qt5/src/poppler-private.cc b/qt5/src/poppler-private.cc
+--- a/qt5/src/poppler-private.cc	2015-09-08 23:31:07.000000000 +0800
++++ b/qt5/src/poppler-private.cc	2018-05-19 12:25:04.000000000 +0800
+@@ -234,7 +234,7 @@ namespace Debug {
+     
+     void DocumentData::init()
+     {
+-        m_backend = Document::SplashBackend;
++        m_backend = Document::CairoBackend;
+         paperColor = Qt::white;
+         m_hints = 0;
+         m_optContentModel = 0;
+diff -rup a/qt5/src/poppler-qt5.h b/qt5/src/poppler-qt5.h
+--- a/qt5/src/poppler-qt5.h	2015-09-02 05:46:49.000000000 +0800
++++ b/qt5/src/poppler-qt5.h	2018-05-19 11:12:36.000000000 +0800
+@@ -876,7 +876,8 @@ delete it;
+ 	*/
+ 	enum RenderBackend {
+ 	    SplashBackend,   ///< Splash backend
+-	    ArthurBackend   ///< Arthur (Qt) backend
++	    ArthurBackend,   ///< Arthur (Qt) backend
++	    CairoBackend     ///< Cairo backend
+ 	};
+ 
+ 	/**
+diff -rup a/qt5/tests/CMakeLists.txt b/qt5/tests/CMakeLists.txt
+--- a/qt5/tests/CMakeLists.txt	2016-03-02 07:35:24.000000000 +0800
++++ b/qt5/tests/CMakeLists.txt	2018-05-20 11:46:08.806858043 +0800
+@@ -10,6 +10,10 @@ include_directories(
+   ${Qt5Xml_INCLUDE_DIRS}
+   ${Qt5Widgets_INCLUDE_DIRS}
+ )
++if (HAVE_CAIRO)
++  include_directories(${CAIRO_INCLUDE_DIRS})
++  add_definitions(${CAIRO_CFLAGS})
++endif (HAVE_CAIRO)
+ 
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${Qt5Core_EXECUTABLE_COMPILE_FLAGS}")
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${Qt5Gui_EXECUTABLE_COMPILE_FLAGS}")
diff --git a/PKGBUILD b/PKGBUILD
new file mode 100644
index 000000000000..56b20b0345a0
--- /dev/null
+++ b/PKGBUILD
@@ -0,0 +1,74 @@
+# Maintainer: Jeffrey Feng <galago1992@gmail.com>
+
+pkgname=okular-lcd-standalone
+_pkgname=okular
+pkgver=18.04.1
+pkgrel=1
+pkgdesc='KDE Document viewer (PDF, Postscript, djvu, etc.) with built-in LCD subpixel rendering support'
+arch=(x86_64)
+url="https://kde.org/applications/graphics/okular/"
+license=(GPL LGPL FDL)
+groups=(kde-applications kdegraphics)
+depends=(djvulibre libspectre libkexiv2 qca-qt5 kpty kactivities threadweaver kjs kparts purpose)
+makedepends=(extra-cmake-modules ebook-tools kdegraphics-mobipocket kdoctools khtml chmlib discount git qt4
+            qt5-base icu gtk2 python2 libjpeg gcc-libs cairo fontconfig openjpeg pkgconfig lcms2 gobject-introspection)
+optdepends=('ebook-tools: mobi and epub support' 'discount: markdown support'
+            'kdegraphics-mobipocket: mobi support' 'kirigami2: mobile UI' 'libzip: CHM support'
+            'khtml: CHM support' 'chmlib: CHM support' 'calligra: ODT and ODP support')
+conflicts=(kdegraphics-okular okular okular-git)
+replaces=(kdegraphics-okular okular okular-git)
+_commit=ee57925c5779a572b8d5cc52ab59a380bd4b4e03
+source=("git+https://github.com/KDE/okular#commit=$_commit"
+        "http://poppler.freedesktop.org/poppler-0.43.0.tar.xz"
+        01-okular-subpixel-rendering-by-poppler.patch
+        02-subpixel-rendering-for-poppler-and-glib.patch
+        03-cairo-backend-for-poppler-qt5.patch)
+sha256sums=('SKIP'
+            'SKIP'
+            '4d44bfc0f34a3e26f2d1cc6f5a99cf4199c7a13ae5e1ed57c4b875703328d525'
+            '73c0fb71877633cefc37b13bcd7896263dc63b91fe13fa97c2c240292a2bc338'
+            'c554b9411764ffcad7a91e22f78a594ca9851e631c70ec15a2b0d52bada0573c')
+pkgver() {
+  cd $_pkgname
+  git describe --tags | sed 's/v//g'
+}
+
+build() {
+  # patch okular
+  cd $srcdir/$_pkgname
+  patch -Np1<../01-okular-subpixel-rendering-by-poppler.patch
+  #patch poppler
+  cd $srcdir/poppler-0.43.0
+  patch -Np1<../02-subpixel-rendering-for-poppler-and-glib.patch
+  patch -Np1<../03-cairo-backend-for-poppler-qt5.patch
+  
+  # build poppler (poppler > 0.43 fails to work with LCD subpixel rendering patch)
+  cd $srcdir
+  mkdir -p pbuild&&cd $_
+  cmake ../poppler-0.43.0 \
+    -DCMAKE_INSTALL_PREFIX=$srcdir/usr/local \
+    -DENABLE_XPDF_HEADERS=ON \
+    -DENABLE_LIBOPENJPEG=FALSE \
+    -DBUILD_GTK_TESTS=OFF -DBUILD_QT4_TESTS=OFF \
+    -DBUILD_QT5_TESTS=OFF -DBUILD_CPP_TESTS=OFF
+  make install
+
+  # build okular
+  cd $srcdir
+  mkdir -p build&&cd $_
+  cmake ../$_pkgname \
+    -DCMAKE_INSTALL_PREFIX=/usr \
+    -DCMAKE_INSTALL_LIBDIR=lib \
+    -DBUILD_TESTING=OFF \
+    -DPOPPLER_LIB_DIR=$srcdir/usr/local/lib \
+    -DPOPPLER_LIB_RPATH=/usr/lib/qt/plugins/okular/poppler-lcd
+  make
+}
+
+package() {
+  cd build
+  make DESTDIR="$pkgdir" install
+  libdir=$pkgdir/usr/lib/qt/plugins/okular/poppler-lcd
+  mkdir -p $libdir
+  cp "$srcdir/usr/local/lib/libpoppler-"{qt5-,}"lcd.so" $libdir
+}