path: root/02-subpixel-rendering-for-poppler-and-glib.patch

From: Jeffrey Feng <galago1992@gmail.com>
Subject: [PATCH 2/4] 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