[poppler] PNG images for pdftohtml: patch

[Warren Toomey]

All, apologies for the noise on the list. The attached patch adds PNG output
to pdftohtml for non-DCT images, replacing the code that I submitted as
http://lists.freedesktop.org/archives/poppler/2008-September/004113.html.
The patch also ensures that pdftohtml inserts the correct image filename in
the <img src=""> output.

The utils/Makefile will need to be patched to include -lpng, and the config
system tweaked to search for libpng and define ENABLE_LIBPNG if it exists.

I will resubmit my reflow patch soon, and then I'll go quiet :)

Thanks,
	Warren
-------------- next part --------------
--- HtmlOutputDev.cc	2008/09/30 00:18:37	1.1
+++ HtmlOutputDev.cc	2008/10/01 05:22:08
@@ -31,12 +31,17 @@
 #ifdef ENABLE_LIBJPEG
 #include "DCTStream.h"
 #endif
+#define ENABLE_LIBPNG
+#ifdef ENABLE_LIBPNG
+#include "png.h"
+#endif
 #include "GlobalParams.h"
 #include "HtmlOutputDev.h"
 #include "HtmlFonts.h"
 
 int HtmlPage::pgNum=0;
 int HtmlOutputDev::imgNum=1;
+GooList * HtmlOutputDev::imgList= new GooList();
 
 extern double scale;
 extern GBool complexMode;
@@ -741,22 +747,24 @@
   else
   {
     fprintf(f,"<A name=%d></a>",pageNum);
-    GooString* fName=basename(DocName); 
-    for (int i=1;i<HtmlOutputDev::imgNum;i++)
-      fprintf(f,"<IMG src=\"%s-%d_%d.jpg\"><br>\n",fName->getCString(),pageNum,i);
+    GooString* fName;
+    for(int i = 0; i < HtmlOutputDev::imgList->getLength(); i++) {
+      fName= (GooString *)HtmlOutputDev::imgList->del(0);
+      fprintf(f,"<IMG src=\"%s\"><br>\n",fName->getCString());
+      delete fName;
+    }
     HtmlOutputDev::imgNum=1;
-    delete fName;
 
     GooString* str;
-    for(HtmlString *tmp=yxStrings;tmp;tmp=tmp->yxNext){
+    for(HtmlString *tmp=yxStrings;tmp;tmp=tmp->yxNext) {
       if (tmp->htext){
 		str=new GooString(tmp->htext); 
 		fputs(str->getCString(),f);
 		delete str;      
		fputs("<br>\n",f);  
       }
     }
	fputs("<hr>\n",f);  
   }
 }
 
@@ -1189,7 +1197,7 @@
    
   if (pgNum) delete pgNum;
   if (imgnum) delete imgnum;
-  if (fName) delete fName;
+  if (fName) imgList->append(fName);
   }
   else {
     OutputDev::drawImageMask(state, ref, str, width, height, invert, inlineImg);
@@ -1274,13 +1282,119 @@
     
     fclose(f1);
   
-    delete fName;
+    if (fName) imgList->append(fName);
     delete pgNum;
     delete imgnum;
   }
   else {
+#ifdef ENABLE_LIBPNG
+    // Dump the image as a PNG file. Much of the PNG code
+    // comes from an example by Guillaume Cottenceau.
+    Guchar *p;
+    GfxRGB rgb;
+    png_structp png_ptr;
+    png_infop info_ptr;
+    png_byte color_type= PNG_COLOR_TYPE_RGB;
+    png_byte bit_depth= 8;
+    png_byte *row = (png_byte *) malloc(3 * width);   // 3 bytes/pixel: RGB
+    png_bytep *row_pointer= &row;
+
+    // Create the image filename
+    GooString *fName=new GooString(Docname);
+    fName->append("-");
+    GooString *pgNum= GooString::fromInt(pageNum);
+    GooString *imgnum= GooString::fromInt(imgNum);  
+    fName->append(pgNum)->append("_")->append(imgnum)->append(".png");
+
+    // Open the image file
+    if (!(f1 = fopen(fName->getCString(), "wb"))) {
+      error(-1, "Couldn't open image file '%s'", fName->getCString());
+      return;
+    }
+
+    // Initialize the PNG stuff
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (!png_ptr) {
+      error(-1, "png_create_write_struct failed");
+      return;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+      error(-1, "png_create_info_struct failed");
+      return;
+    }
+    if (setjmp(png_jmpbuf(png_ptr))) {
+      error(-1, "error during init_io");
+      return;
+    }
+
+    // Write the PNG header
+    png_init_io(png_ptr, f1);
+    if (setjmp(png_jmpbuf(png_ptr))) {
+      error(-1, "error during writing png header");
+      return;
+    }
+
+    // Set up the type of PNG image and the compression level
+    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
+    png_set_IHDR(png_ptr, info_ptr, width, height,
+                     bit_depth, color_type, PNG_INTERLACE_NONE,
+                     PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    // Write the image info bytes
+    png_write_info(png_ptr, info_ptr);
+    if (setjmp(png_jmpbuf(png_ptr))) {
+      error(-1, "error during writing png info bytes");
+      return;
+    }
+
+    // Initialize the image stream
+    ImageStream *imgStr = new ImageStream(str, width,
+                        colorMap->getNumPixelComps(), colorMap->getBits());
+    imgStr->reset();
+
+    // For each line...
+    for (int y = 0; y < height; y++) {
+
+      // Convert into a PNG row
+      p = imgStr->getLine();
+      for (int x = 0; x < width; x++) {
+        colorMap->getRGB(p, &rgb);
+	// Write the RGB pixels into the row
+	row[3*x]= colToByte(rgb.r);
+	row[3*x+1]= colToByte(rgb.g);
+	row[3*x+2]= colToByte(rgb.b);
+         p += colorMap->getNumPixelComps();
+      }
+
+      // Write the row to the file
+      png_write_rows(png_ptr, row_pointer, 1);
+      if (setjmp(png_jmpbuf(png_ptr))) {
+        error(-1, "error during png row write");
+        return;
+      }
+    }
+
+    // Finish off the PNG file
+    png_write_end(png_ptr, info_ptr);
+    if (setjmp(png_jmpbuf(png_ptr))) {
+      error(-1, "error during png end of write");
+      return;
+    }
+
+    fclose(f1);
+    free(row);
+    imgList->append(fName);
+    ++imgNum;
+    delete pgNum;
+    delete imgnum;
+    delete imgStr;
+#else
     OutputDev::drawImage(state, ref, str, width, height, colorMap,
-			 maskColors, inlineImg);
+                       maskColors, inlineImg);
+#endif
   }
 }