Move BackgroundRenderer fallback logic to HTMLRenderer.

src/BackgroundRenderer/BackgroundRenderer.cc

@@ -20,18 +20,9 @@ namespace pdf2htmlEX {
 
 BackgroundRenderer * BackgroundRenderer::getBackgroundRenderer(const std::string & format, HTMLRenderer * html_renderer, const Param & param)
 {
-#ifdef ENABLE_LIBPNG
-    if(format == "png")
-    {
-        return new SplashBackgroundRenderer(html_renderer, param);
-    }
-#endif
-#ifdef ENABLE_LIBJPEG
-    if(format == "jpg")
-    {
-        return new SplashBackgroundRenderer(html_renderer, param);
-    }
-#endif
+    if (format == "png" || format == "jpg")
+        return new SplashBackgroundRenderer(format, html_renderer, param);
+
 #if ENABLE_SVG
     if (format == "svg")
     {
@@ -42,4 +33,11 @@ BackgroundRenderer * BackgroundRenderer::getBackgroundRenderer(const std::string
     return nullptr;
 }
 
+BackgroundRenderer * BackgroundRenderer::getFallbackBackgroundRenderer(HTMLRenderer * html_renderer, const Param & param)
+{
+    if (param.bg_format == "svg" && param.svg_nodes_limit > 0)
+        return new SplashBackgroundRenderer("", html_renderer, param);
+    return nullptr;
+}
+
 } // namespace pdf2htmlEX

src/BackgroundRenderer/BackgroundRenderer.h

@@ -22,12 +22,16 @@ class BackgroundRenderer
 public:
     // return nullptr upon failure
     static BackgroundRenderer * getBackgroundRenderer(const std::string & format, HTMLRenderer * html_renderer, const Param & param);
+    // Return a fallback bg renderer according to param.bg_format.
+    // Currently only svg bg format might need a bitmap fallback.
+    static BackgroundRenderer * getFallbackBackgroundRenderer(HTMLRenderer * html_renderer, const Param & param);
 
     BackgroundRenderer() {}
     virtual ~BackgroundRenderer() {}
 
     virtual void init(PDFDoc * doc) = 0;
-    virtual void render_page(PDFDoc * doc, int pageno) = 0;
+    //return true on success, false otherwise (e.g. need a fallback)
+    virtual bool render_page(PDFDoc * doc, int pageno) = 0;
     virtual void embed_image(int pageno) = 0;
 
 };

src/BackgroundRenderer/CairoBackgroundRenderer.cc

@@ -27,15 +27,7 @@ CairoBackgroundRenderer::CairoBackgroundRenderer(HTMLRenderer * html_renderer, c
     , html_renderer(html_renderer)
     , param(param)
     , surface(nullptr)
-      , use_bitmap(false)
-{
-    if (param.svg_nodes_limit > 0)
-    {
-        this->bitmap_renderer = new SplashBackgroundRenderer(html_renderer, param);
-    }
-    else
-        this->bitmap_renderer = nullptr;
-}
+{ }
 
 void CairoBackgroundRenderer::drawChar(GfxState *state, double x, double y,
         double dx, double dy,
@@ -62,15 +54,13 @@ void CairoBackgroundRenderer::drawChar(GfxState *state, double x, double y,
 void CairoBackgroundRenderer::init(PDFDoc * doc)
 {
     startDoc(doc);
-    if (this->bitmap_renderer != nullptr)
-          this->bitmap_renderer->init(doc);
 }
 
 static GBool annot_cb(Annot *, void * pflag) {
     return (*((bool*)pflag)) ? gTrue : gFalse;
 };
 
-void CairoBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
+bool CairoBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
 {
     double page_width;
     double page_height;
@@ -85,11 +75,11 @@ void CairoBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
         page_height = doc->getPageMediaHeight(pageno);
     }
 
-    auto fn = html_renderer->str_fmt("%s/bg%x.svg", (param.embed_image ? param.tmp_dir : param.dest_dir).c_str(), pageno);
+    string fn = (char*)html_renderer->str_fmt("%s/bg%x.svg", (param.embed_image ? param.tmp_dir : param.dest_dir).c_str(), pageno);
     if(param.embed_image)
-        html_renderer->tmp_files.add((char*)fn);
+        html_renderer->tmp_files.add(fn);
 
-    surface = cairo_svg_surface_create((char*)fn, page_width * param.h_dpi / DEFAULT_DPI, page_height * param.v_dpi / DEFAULT_DPI);
+    surface = cairo_svg_surface_create(fn.c_str(), page_width * param.h_dpi / DEFAULT_DPI, page_height * param.v_dpi / DEFAULT_DPI);
     cairo_svg_surface_restrict_to_version(surface, CAIRO_SVG_VERSION_1_2);
     cairo_surface_set_fallback_resolution(surface, param.h_dpi, param.v_dpi);
 
@@ -127,33 +117,25 @@ void CairoBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
     {
         int n = 0;
         char c;
-        ifstream svgfile((char*)fn);
+        ifstream svgfile(fn);
         //count of '<' in the file should be an approximation of node count.
         while(svgfile >> c)
         {
             if (c == '<')
                 ++n;
-        }
-        svgfile.close();
             if (n > param.svg_nodes_limit)
             {
-            html_renderer->tmp_files.add((char*)fn);
-            use_bitmap = true;
-            bitmap_renderer->render_page(doc, pageno);
+                html_renderer->tmp_files.add(fn);
+                return false;
             }
-        else
-            use_bitmap = false;
         }
+    }
+
+    return true;
 }
 
 void CairoBackgroundRenderer::embed_image(int pageno)
 {
-    if (use_bitmap)
-    {
-        bitmap_renderer->embed_image(pageno);
-        return;
-    }
-
     auto & f_page = *(html_renderer->f_curpage);
     
     f_page << "<img class=\"" << CSS::FULL_BACKGROUND_IMAGE_CN 

src/BackgroundRenderer/CairoBackgroundRenderer.h

@@ -20,8 +20,6 @@
 
 namespace pdf2htmlEX {
 
-class SplashBackgroundRenderer;
-
 // Based on BackgroundRenderer from poppler
 class CairoBackgroundRenderer : public BackgroundRenderer, CairoOutputDev 
 {
@@ -31,7 +29,7 @@ public:
   virtual ~CairoBackgroundRenderer() { }
 
   virtual void init(PDFDoc * doc);
-  virtual void render_page(PDFDoc * doc, int pageno);
+  virtual bool render_page(PDFDoc * doc, int pageno);
   virtual void embed_image(int pageno);
 
   // Does this device use beginType3Char/endType3Char?  Otherwise,
@@ -47,8 +45,6 @@ protected:
   HTMLRenderer * html_renderer;
   const Param & param;
   cairo_surface_t * surface;
-  SplashBackgroundRenderer * bitmap_renderer;
-  bool use_bitmap;
 };
 
 }

src/BackgroundRenderer/SplashBackgroundRenderer.cc

@@ -28,27 +28,26 @@ using std::unique_ptr;
 
 const SplashColor SplashBackgroundRenderer::white = {255,255,255};
 
-SplashBackgroundRenderer::SplashBackgroundRenderer(HTMLRenderer * html_renderer, const Param & param)
+SplashBackgroundRenderer::SplashBackgroundRenderer(const string & imgFormat, HTMLRenderer * html_renderer, const Param & param)
     : SplashOutputDev(splashModeRGB8, 4, gFalse, (SplashColorPtr)(&white), gTrue, gTrue)
     , html_renderer(html_renderer)
     , param(param)
+    , format(imgFormat)
 {
-    if(false) { }
+    bool supported = false;
 #ifdef ENABLE_LIBPNG
-    else if(param.bg_format == "png" || param.bg_format == "svg")
-    {
+    if (format.empty())
         format = "png";
-    }
+    supported = supported || format == "png";
 #endif
 #ifdef ENABLE_LIBJPEG
-    else if(param.bg_format == "jpg" || param.bg_format == "svg")
-    {
+    if (format.empty())
         format = "jpg";
-    }
+    supported = supported || format == "jpg";
 #endif
-    else
+    if (!supported)
     {
-        throw string("Image format not supported: ") + param.bg_format;
+        throw string("Image format not supported: ") + format;
     }
 }
 
@@ -100,7 +99,7 @@ static GBool annot_cb(Annot *, void * pflag) {
     return (*((bool*)pflag)) ? gTrue : gFalse;
 };
 
-void SplashBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
+bool SplashBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
 {
     bool process_annotation = param.process_annotation;
     doc->displayPage(this, pageno, param.h_dpi, param.v_dpi,
@@ -108,6 +107,7 @@ void SplashBackgroundRenderer::render_page(PDFDoc * doc, int pageno)
             (!(param.use_cropbox)),
             false, false,
             nullptr, nullptr, &annot_cb, &process_annotation);
+    return true;
 }
 
 void SplashBackgroundRenderer::embed_image(int pageno)

src/BackgroundRenderer/SplashBackgroundRenderer.h

@@ -26,13 +26,13 @@ class SplashBackgroundRenderer : public BackgroundRenderer, SplashOutputDev
 {
 public:
   static const SplashColor white;
-
-  SplashBackgroundRenderer(HTMLRenderer * html_renderer, const Param & param);
+  //format: "png" or "jpg", or "" for a default format
+  SplashBackgroundRenderer(const std::string & format, HTMLRenderer * html_renderer, const Param & param);
 
   virtual ~SplashBackgroundRenderer() { }
 
   virtual void init(PDFDoc * doc);
-  virtual void render_page(PDFDoc * doc, int pageno);
+  virtual bool render_page(PDFDoc * doc, int pageno);
   virtual void embed_image(int pageno);
 
   // Does this device use beginType3Char/endType3Char?  Otherwise,

src/HTMLRenderer/HTMLRenderer.h

@@ -327,7 +327,8 @@ protected:
     friend class CairoBackgroundRenderer; // ugly!
 #endif
     BackgroundRenderer * bg_renderer;
-
+    BackgroundRenderer * fallback_bg_renderer;
+    bool fallback_bg_required;
 
     struct {
         std::ofstream fs;

src/HTMLRenderer/general.cc

@@ -98,12 +98,17 @@ void HTMLRenderer::process(PDFDoc *doc)
     // Process pages
 
     bg_renderer = nullptr;
+    fallback_bg_renderer = nullptr;
     if(param.process_nontext)
     {
         bg_renderer = BackgroundRenderer::getBackgroundRenderer(param.bg_format, this, param);
         if(!bg_renderer)
             throw "Cannot initialize background renderer, unsupported format";
         bg_renderer->init(doc);
+
+        fallback_bg_renderer = BackgroundRenderer::getFallbackBackgroundRenderer(this, param);
+        if (fallback_bg_renderer)
+            fallback_bg_renderer->init(doc);
     }
 
     int page_count = (param.last_page - param.first_page + 1);
@@ -130,7 +135,9 @@ void HTMLRenderer::process(PDFDoc *doc)
 
         if(param.process_nontext)
         {
-            bg_renderer->render_page(doc, i);
+            fallback_bg_required = !bg_renderer->render_page(doc, i);
+            if (fallback_bg_required && fallback_bg_renderer != nullptr)
+                fallback_bg_renderer->render_page(doc, i);
         }
 
         doc->displayPage(this, i,
@@ -163,6 +170,11 @@ void HTMLRenderer::process(PDFDoc *doc)
         delete bg_renderer;
         bg_renderer = nullptr;
     }
+    if(fallback_bg_renderer)
+    {
+        delete fallback_bg_renderer;
+        fallback_bg_renderer = nullptr;
+    }
 
     cerr << endl;
 }
@@ -219,7 +231,10 @@ void HTMLRenderer::startPage(int pageNum, GfxState *state, XRef * xref)
 
     if(param.process_nontext)
     {
+        if (!fallback_bg_required)
             bg_renderer->embed_image(pageNum);
+        else if (fallback_bg_renderer != nullptr)
+            fallback_bg_renderer->embed_image(pageNum);
     }
 
     reset_state();