diff --git a/src/BackgroundRenderer/CairoBackgroundRenderer.cc b/src/BackgroundRenderer/CairoBackgroundRenderer.cc
index fac4904..a7eaed8 100644
--- a/src/BackgroundRenderer/CairoBackgroundRenderer.cc
+++ b/src/BackgroundRenderer/CairoBackgroundRenderer.cc
@@ -107,8 +107,8 @@ void CairoBackgroundRenderer::init(PDFDoc * doc)
     startDoc(doc);
 }
 
-static GBool annot_cb(Annot *, void * pflag) {
-    return (*((bool*)pflag)) ? gTrue : gFalse;
+static bool annot_cb(Annot *, void * pflag) {
+    return (*((bool*)pflag)) ? true : false;
 };
 
 bool CairoBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
diff --git a/src/BackgroundRenderer/CairoBackgroundRenderer.h b/src/BackgroundRenderer/CairoBackgroundRenderer.h
index b354cdc..d5c8637 100644
--- a/src/BackgroundRenderer/CairoBackgroundRenderer.h
+++ b/src/BackgroundRenderer/CairoBackgroundRenderer.h
@@ -37,7 +37,7 @@ public:
 
   // Does this device use beginType3Char/endType3Char?  Otherwise,
   // text in Type 3 fonts will be drawn with drawChar/drawString.
-  virtual GBool interpretType3Chars() { return !param.process_type3; }
+  virtual bool interpretType3Chars() { return !param.process_type3; }
 
   virtual void drawChar(GfxState *state, double x, double y,
       double dx, double dy,
diff --git a/src/BackgroundRenderer/SplashBackgroundRenderer.cc b/src/BackgroundRenderer/SplashBackgroundRenderer.cc
index a7a23d8..be14222 100644
--- a/src/BackgroundRenderer/SplashBackgroundRenderer.cc
+++ b/src/BackgroundRenderer/SplashBackgroundRenderer.cc
@@ -29,7 +29,7 @@ using std::unique_ptr;
 const SplashColor SplashBackgroundRenderer::white = {255,255,255};
 
 SplashBackgroundRenderer::SplashBackgroundRenderer(const string & imgFormat, HTMLRenderer * html_renderer, const Param & param)
-    : SplashOutputDev(splashModeRGB8, 4, gFalse, (SplashColorPtr)(&white), gTrue, splashThinLineSolid) // DCRH: Make thin line mode = solid
+    : SplashOutputDev(splashModeRGB8, 4, false, (SplashColorPtr)(&white), true, splashThinLineSolid) // DCRH: Make thin line mode = solid
     , html_renderer(html_renderer)
     , param(param)
     , format(imgFormat)
@@ -106,8 +106,8 @@ void SplashBackgroundRenderer::init(PDFDoc * doc)
     startDoc(doc);
 }
 
-static GBool annot_cb(Annot *, void * pflag) {
-    return (*((bool*)pflag)) ? gTrue : gFalse;
+static bool annot_cb(Annot *, void * pflag) {
+    return (*((bool*)pflag)) ? true : false;
 };
 
 bool SplashBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
diff --git a/src/BackgroundRenderer/SplashBackgroundRenderer.h b/src/BackgroundRenderer/SplashBackgroundRenderer.h
index 8b11da6..55baeb3 100644
--- a/src/BackgroundRenderer/SplashBackgroundRenderer.h
+++ b/src/BackgroundRenderer/SplashBackgroundRenderer.h
@@ -37,7 +37,7 @@ public:
 
   // Does this device use beginType3Char/endType3Char?  Otherwise,
   // text in Type 3 fonts will be drawn with drawChar/drawString.
-  virtual GBool interpretType3Chars() { return !param.process_type3; }
+  virtual bool interpretType3Chars() { return !param.process_type3; }
 
   virtual void startPage(int pageNum, GfxState *state, XRef *xrefA);
   
diff --git a/src/HTMLRenderer/HTMLRenderer.h b/src/HTMLRenderer/HTMLRenderer.h
index 7ec04bf..329f868 100644
--- a/src/HTMLRenderer/HTMLRenderer.h
+++ b/src/HTMLRenderer/HTMLRenderer.h
@@ -16,7 +16,34 @@
 #include <GfxState.h>
 #include <Stream.h>
 #include <PDFDoc.h>
-#include <goo/gtypes.h>
+
+/************ from goo/gtypes.h ***************/
+// #include <goo/gtypes.h>
+
+/*
+ * These have stupid names to avoid conflicts with some (but not all)
+ * C++ compilers which define them.
+ */
+//typedef bool GBool;
+//#define gTrue true
+//#define gFalse false
+
+//#ifdef _MSC_VER
+//#pragma warning(disable: 4800) /* 'type' : forcing value to bool 'true' or 'false' (performance warning) */
+//#endif
+
+/*
+ * These have stupid names to avoid conflicts with <sys/types.h>,
+ * which on various systems defines some random subset of these.
+ */
+//typedef unsigned char Guchar;
+//typedef unsigned short Gushort;
+//typedef unsigned int Guint;
+//typedef unsigned long Gulong;
+//typedef long long Goffset;
+
+/**********************************************/
+
 #include <Object.h>
 #include <GfxFont.h>
 #include <Annot.h>
@@ -58,28 +85,28 @@ struct HTMLRenderer : OutputDev
     
     // Does this device use upside-down coordinates?
     // (Upside-down means (0,0) is the top left corner of the page.)
-    virtual GBool upsideDown() { return gFalse; }
+    virtual bool upsideDown() { return false; }
 
     // Does this device use drawChar() or drawString()?
-    virtual GBool useDrawChar() { return gFalse; }
+    virtual bool useDrawChar() { return false; }
 
     // Does this device use functionShadedFill(), axialShadedFill(), and
     // radialShadedFill()?  If this returns false, these shaded fills
     // will be reduced to a series of other drawing operations.
-    virtual GBool useShadedFills(int type) { return (type == 2) ? gTrue: gFalse; }
+    virtual bool useShadedFills(int type) { return (type == 2) ? true: false; }
 
     // Does this device use beginType3Char/endType3Char?  Otherwise,
     // text in Type 3 fonts will be drawn with drawChar/drawString.
-    virtual GBool interpretType3Chars() { return gFalse; }
+    virtual bool interpretType3Chars() { return false; }
 
     // Does this device need non-text content?
-    virtual GBool needNonText() { return (param.process_nontext) ? gTrue: gFalse; }
+    virtual bool needNonText() { return (param.process_nontext) ? true: false; }
 
     // Does this device need to clip pages to the crop box even when the
     // box is the crop box?
-    virtual GBool needClipToCropBox() { return gTrue; }
+    virtual bool needClipToCropBox() { return true; }
 
-    virtual void setDefaultCTM(double *ctm);
+    virtual void setDefaultCTM(const double *ctm);
 
     // Start a page.
     virtual void startPage(int pageNum, GfxState *state, XRef * xref);
@@ -128,26 +155,26 @@ struct HTMLRenderer : OutputDev
     
     virtual void drawString(GfxState * state, const GooString * s);
 
-    virtual void drawImage(GfxState * state, Object * ref, Stream * str, int width, int height, GfxImageColorMap * colorMap, GBool interpolate, int *maskColors, GBool inlineImg);
+    virtual void drawImage(GfxState * state, Object * ref, Stream * str, int width, int height, GfxImageColorMap * colorMap, bool interpolate, int *maskColors, bool inlineImg);
 
     virtual void drawSoftMaskedImage(GfxState *state, Object *ref, Stream *str,
                        int width, int height,
                        GfxImageColorMap *colorMap,
-                       GBool interpolate,
+                       bool interpolate,
                        Stream *maskStr,
                        int maskWidth, int maskHeight,
                        GfxImageColorMap *maskColorMap,
-                       GBool maskInterpolate);
+                       bool maskInterpolate);
 
     virtual void stroke(GfxState *state); 
     virtual void fill(GfxState *state);
     virtual void eoFill(GfxState *state);
-    virtual GBool axialShadedFill(GfxState *state, GfxAxialShading *shading, double tMin, double tMax);
+    virtual bool axialShadedFill(GfxState *state, GfxAxialShading *shading, double tMin, double tMax);
 
-  virtual void beginTransparencyGroup(GfxState * /*state*/, double * /*bbox*/,
+  virtual void beginTransparencyGroup(GfxState * /*state*/, const double * /*bbox*/,
                                       GfxColorSpace * /*blendingColorSpace*/,
-                                      GBool /*isolated*/, GBool /*knockout*/,
-                                      GBool /*forSoftMask*/);
+                                      bool /*isolated*/, bool /*knockout*/,
+                                      bool /*forSoftMask*/);
   virtual void endTransparencyGroup(GfxState * /*state*/);
 
 
@@ -319,7 +346,7 @@ protected:
     
     // for font reencoding
     std::vector<int32_t> cur_mapping; 
-    std::vector<char*> cur_mapping2;
+    std::vector<const char*> cur_mapping2;
     std::vector<int> width_list; // width of each char
 
     Preprocessor preprocessor;
diff --git a/src/HTMLRenderer/draw.cc b/src/HTMLRenderer/draw.cc
index 61460df..39cfa9c 100644
--- a/src/HTMLRenderer/draw.cc
+++ b/src/HTMLRenderer/draw.cc
@@ -56,16 +56,16 @@ void HTMLRenderer::eoFill(GfxState * state)
     tracer.fill(state, true);
 }
 
-GBool HTMLRenderer::axialShadedFill(GfxState *state, GfxAxialShading *shading, double tMin, double tMax)
+bool HTMLRenderer::axialShadedFill(GfxState *state, GfxAxialShading *shading, double tMin, double tMax)
 {
     tracer.fill(state); //TODO correct?
     return true;
 }
 
-void HTMLRenderer::beginTransparencyGroup(GfxState *state, double *bbox,
+void HTMLRenderer::beginTransparencyGroup(GfxState *state, const double *bbox,
                                       GfxColorSpace *blendingColorSpace,
-                                      GBool isolated, GBool knockout,
-                                      GBool forSoftMask) {
+                                      bool isolated, bool knockout,
+                                      bool forSoftMask) {
 	inTransparencyGroup++;
 }
 void HTMLRenderer::endTransparencyGroup(GfxState *state) {
diff --git a/src/HTMLRenderer/font.cc b/src/HTMLRenderer/font.cc
index 301bf30..56ad2f5 100644
--- a/src/HTMLRenderer/font.cc
+++ b/src/HTMLRenderer/font.cc
@@ -169,7 +169,7 @@ string HTMLRenderer::dump_embedded_font (GfxFont * font, FontInfo & info)
 
         char buf[1024];
         int len;
-        while((len = obj.streamGetChars(1024, (Guchar*)buf)) > 0)
+        while((len = obj.streamGetChars(1024, (unsigned char*)buf)) > 0)
         {
             outf.write(buf, len);
         }
@@ -205,8 +205,8 @@ string HTMLRenderer::dump_type3_font (GfxFont * font, FontInfo & info)
     auto used_map = preprocessor.get_code_map(hash_ref(font->getID()));
 
     //calculate transformed metrics
-    double * font_bbox = font->getFontBBox();
-    double * font_matrix = font->getFontMatrix();
+    const double * font_bbox = font->getFontBBox();
+    const double * font_matrix = font->getFontMatrix();
     double transformed_bbox[4];
     memcpy(transformed_bbox, font_bbox, 4 * sizeof(double));
     /*
@@ -337,7 +337,7 @@ string HTMLRenderer::dump_type3_font (GfxFont * font, FontInfo & info)
                     &box, nullptr);
             output_dev->startDoc(cur_doc, &font_engine);
             output_dev->startPage(1, gfx->getState(), gfx->getXRef());
-            output_dev->setInType3Char(gTrue);
+            output_dev->setInType3Char(true);
             auto char_procs = ((Gfx8BitFont*)font)->getCharProcs();
             Object char_proc_obj;
             auto glyph_index = cur_font->getGlyph(code, nullptr, 0);
@@ -640,8 +640,8 @@ void HTMLRenderer::embed_font(const string & filepath, GfxFont * font, FontInfo
             if(info.use_tounicode)
             {
                 int n = ctu ?
-                   (((CharCodeToUnicode *)ctu)->mapToUnicode(cur_code, &pu)) :
-                   0;
+                  (((CharCodeToUnicode *)ctu)->mapToUnicode(cur_code, &pu)) :
+                  0;
                 u = check_unicode(pu, n, cur_code, font);
             }
             else
@@ -877,7 +877,7 @@ const FontInfo * HTMLRenderer::install_font(GfxFont * font)
     {
         cerr << "Install font " << hex << new_fn_id << dec
             << ": (" << (font->getID()->num) << ' ' << (font->getID()->gen) << ") " 
-            << (font->getName() ? font->getName()->getCString() : "")
+            << (font->getName() ? font->getName()->toStr() : "")
             << endl;
     }
 
@@ -907,7 +907,7 @@ const FontInfo * HTMLRenderer::install_font(GfxFont * font)
     /*
      * The 2nd parameter of locateFont should be true only for PS
      * which does not make much sense in our case
-     * If we specify gFalse here, font_loc->locType cannot be gfxFontLocResident
+     * If we specify false here, font_loc->locType cannot be gfxFontLocResident
      */
     if(auto * font_loc = font->locateFont(xref, nullptr))
     {
@@ -954,7 +954,7 @@ void HTMLRenderer::install_embedded_font(GfxFont * font, FontInfo & info)
 
 void HTMLRenderer::install_external_font(GfxFont * font, FontInfo & info)
 {
-    string fontname(font->getName()->getCString());
+    string fontname(font->getName()->toStr());
 
     // resolve bad encodings in GB
     auto iter = GB_ENCODED_FONT_NAME_MAP.find(fontname); 
@@ -970,7 +970,7 @@ void HTMLRenderer::install_external_font(GfxFont * font, FontInfo & info)
     {
         if(localfontloc != nullptr)
         {
-            embed_font(string(localfontloc->path->getCString()), font, info);
+            embed_font(string(localfontloc->path->toStr()), font, info);
             export_remote_font(info, param.font_format, font);
             delete localfontloc;
             return;
@@ -986,7 +986,7 @@ void HTMLRenderer::install_external_font(GfxFont * font, FontInfo & info)
     if(localfontloc != nullptr)
     {
         // fill in ascent/descent only, do not embed
-        embed_font(string(localfontloc->path->getCString()), font, info, true);
+        embed_font(string(localfontloc->path->toStr()), font, info, true);
         delete localfontloc;
     }
     else
diff --git a/src/HTMLRenderer/general.cc b/src/HTMLRenderer/general.cc
index c1e8825..459e091 100644
--- a/src/HTMLRenderer/general.cc
+++ b/src/HTMLRenderer/general.cc
@@ -53,7 +53,7 @@ HTMLRenderer::HTMLRenderer(Param & param)
     if(!(param.debug))
     {
         //disable error messages of poppler
-        globalParams->setErrQuiet(gTrue);
+        globalParams->setErrQuiet(true);
     }
 
     ffw_init(param.debug);
@@ -190,7 +190,7 @@ void HTMLRenderer::process(PDFDoc *doc)
         cerr << endl;
 }
 
-void HTMLRenderer::setDefaultCTM(double *ctm)
+void HTMLRenderer::setDefaultCTM(const double *ctm)
 {
     memcpy(default_ctm, ctm, sizeof(default_ctm));
 }
diff --git a/src/HTMLRenderer/image.cc b/src/HTMLRenderer/image.cc
index 91ca767..ef51ffc 100644
--- a/src/HTMLRenderer/image.cc
+++ b/src/HTMLRenderer/image.cc
@@ -12,7 +12,7 @@
 
 namespace pdf2htmlEX {
 
-void HTMLRenderer::drawImage(GfxState * state, Object * ref, Stream * str, int width, int height, GfxImageColorMap * colorMap, GBool interpolate, int *maskColors, GBool inlineImg)
+void HTMLRenderer::drawImage(GfxState * state, Object * ref, Stream * str, int width, int height, GfxImageColorMap * colorMap, bool interpolate, int *maskColors, bool inlineImg)
 {
     tracer.draw_image(state);
 
@@ -67,11 +67,11 @@ void HTMLRenderer::drawImage(GfxState * state, Object * ref, Stream * str, int w
 void HTMLRenderer::drawSoftMaskedImage(GfxState *state, Object *ref, Stream *str,
                    int width, int height,
                    GfxImageColorMap *colorMap,
-                   GBool interpolate,
+                   bool interpolate,
                    Stream *maskStr,
                    int maskWidth, int maskHeight,
                    GfxImageColorMap *maskColorMap,
-                   GBool maskInterpolate)
+                   bool maskInterpolate)
 {
     tracer.draw_image(state);
 
diff --git a/src/HTMLRenderer/link.cc b/src/HTMLRenderer/link.cc
index bf61e4a..9f3a62d 100644
--- a/src/HTMLRenderer/link.cc
+++ b/src/HTMLRenderer/link.cc
@@ -164,7 +164,7 @@ string HTMLRenderer::get_linkaction_str(const LinkAction * action, string & deta
                 {
                     auto * real_action = dynamic_cast<const LinkURI*>(action);
                     assert(real_action != nullptr);
-                    dest_str = real_action->getURI()->getCString();
+                    dest_str = real_action->getURI()->toStr();
                 }
                 break;
             case actionLaunch:
diff --git a/src/HTMLRenderer/text.cc b/src/HTMLRenderer/text.cc
index 16bb478..06df7aa 100644
--- a/src/HTMLRenderer/text.cc
+++ b/src/HTMLRenderer/text.cc
@@ -58,7 +58,7 @@ void HTMLRenderer::drawString(GfxState * state, const GooString * s)
 
     // Now ready to output
     // get the unicodes
-    const char *p = s->getCString();
+    const char *p = (s->toStr()).c_str();
     int len = s->getLength();
 
     //accumulated displacement of chars in this string, in text object space
diff --git a/src/Preprocessor.h b/src/Preprocessor.h
index 5b48e4f..d121b59 100644
--- a/src/Preprocessor.h
+++ b/src/Preprocessor.h
@@ -30,11 +30,11 @@ public:
 
     void process(PDFDoc * doc);
 
-    virtual GBool upsideDown() { return gFalse; }
-    virtual GBool useDrawChar() { return gTrue; }
-    virtual GBool interpretType3Chars() { return gFalse; }
-    virtual GBool needNonText() { return gFalse; }
-    virtual GBool needClipToCropBox() { return gTrue; }
+    virtual bool upsideDown() { return false; }
+    virtual bool useDrawChar() { return true; }
+    virtual bool interpretType3Chars() { return false; }
+    virtual bool needNonText() { return false; }
+    virtual bool needClipToCropBox() { return true; }
 
     virtual void drawChar(GfxState *state, double x, double y,
       double dx, double dy,
diff --git a/src/pdf2htmlEX.cc b/src/pdf2htmlEX.cc
index 3bd35e6..bdc56aa 100644
--- a/src/pdf2htmlEX.cc
+++ b/src/pdf2htmlEX.cc
@@ -438,8 +438,9 @@ int main(int argc, char **argv)
     delete globalParams;
 
     // check for memory leaks
-    Object::memCheck(stderr);
-    gMemReport(stderr);
+    // Poppler Object class (Object.h) no longer has memCheck
+    //Object::memCheck(stderr);
+    //gMemReport(stderr);
 
     exit(finished ? (EXIT_SUCCESS) : (EXIT_FAILURE));
 
diff --git a/src/util/ffw.c b/src/util/ffw.c
index ccd2643..c296f38 100644
--- a/src/util/ffw.c
+++ b/src/util/ffw.c
@@ -275,7 +275,7 @@ void ffw_reencode_raw(int32 * mapping, int mapping_len, int force)
     ffw_do_reencode(enc, force);
 }
 
-void ffw_reencode_raw2(char ** mapping, int mapping_len, int force)
+void ffw_reencode_raw2(const char ** mapping, int mapping_len, int force)
 {
     Encoding * enc = calloc(1, sizeof(Encoding));
     enc->enc_name = strcopy("");
diff --git a/src/util/ffw.h b/src/util/ffw.h
index a01ed79..106310a 100644
--- a/src/util/ffw.h
+++ b/src/util/ffw.h
@@ -39,7 +39,7 @@ void ffw_close(void);
 void ffw_reencode_glyph_order(void);
 void ffw_reencode_unicode_full(void);
 void ffw_reencode_raw(int32_t * mapping, int mapping_len, int force);
-void ffw_reencode_raw2(char ** mapping, int mapping_len, int force);
+void ffw_reencode_raw2(const char ** mapping, int mapping_len, int force);
 
 void ffw_cidflatten(void);
 // add a new empty char into the font
diff --git a/src/util/unicode.cc b/src/util/unicode.cc
index 1052ced..31ec4f8 100644
--- a/src/util/unicode.cc
+++ b/src/util/unicode.cc
@@ -42,7 +42,7 @@ Unicode unicode_from_font (CharCode code, GfxFont * font)
     {
         auto * font2 = dynamic_cast<Gfx8BitFont*>(font);
         assert(font2 != nullptr);
-        char * cname = font2->getCharName(code);
+        const char * cname = font2->getCharName(code);
         // may be untranslated ligature
         if(cname)
         {