Backport PNG output format to origin/master branch.

samples/pdfium_test.cc

Index: samples/pdfium_test.cc
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index 8f9c832fb223ed7394c751a53c0cd6de893bcb66..e3ad47ac15b0e530207cae1edac6d1acf9f5aebf 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -19,6 +19,7 @@
 #include "../fpdfsdk/include/fpdftext.h"
 #include "../fpdfsdk/include/fpdfview.h"
 #include "../core/include/fxcrt/fx_system.h"
+#include "image_diff_png.h"
 #include "v8/include/v8.h"
 #include "v8/include/libplatform/libplatform.h"
 
@@ -32,6 +33,7 @@
 enum OutputFormat {
   OUTPUT_NONE,
   OUTPUT_PPM,
+  OUTPUT_PNG,
 #ifdef _WIN32
   OUTPUT_BMP,
   OUTPUT_EMF,
@@ -113,14 +115,21 @@ static bool GetExternalData(const Options& options,
 }
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
+static bool CheckDimensions(int stride, int width, int height) {
+  if (stride < 0 || width < 0 || height < 0)
+    return false;
+  if (height > 0 && width > INT_MAX / height)
+    return false;
+  return true;
+}
+
 static void WritePpm(const char* pdf_name, int num, const void* buffer_void,
                      int stride, int width, int height) {
   const char* buffer = reinterpret_cast<const char*>(buffer_void);
 
-  if (stride < 0 || width < 0 || height < 0)
-    return;
-  if (height > 0 && width > INT_MAX / height)
+  if (!CheckDimensions(stride, width, height))
     return;
+
   int out_len = width * height;
   if (out_len > INT_MAX / 3)
     return;
@@ -154,6 +163,42 @@ static void WritePpm(const char* pdf_name, int num, const void* buffer_void,
   fclose(fp);
 }
 
+static void WritePng(const char* pdf_name, int num, const void* buffer_void,
+                     int stride, int width, int height) {
+  if (!CheckDimensions(stride, width, height))
+    return;
+
+  std::vector<unsigned char> png_encoding;
+  const unsigned char* buffer = static_cast<const unsigned char*>(buffer_void);
+  if (!image_diff_png::EncodeBGRAPNG(
+          buffer, width, height, stride, false, &png_encoding)) {
+    fprintf(stderr, "Failed to convert bitmap to PNG\n");
+    return;
+  }
+
+  char filename[256];
+  int chars_formatted = snprintf(
+      filename, sizeof(filename), "%s.%d.png", pdf_name, num);
+  if (chars_formatted < 0 ||
+      static_cast<size_t>(chars_formatted) >= sizeof(filename)) {
+    fprintf(stderr, "Filname %s is too long\n", filename);
+    return;
+  }
+
+  FILE* fp = fopen(filename, "wb");
+  if (!fp) {
+    fprintf(stderr, "Failed to open %s for output\n", filename);
+    return;
+  }
+
+  size_t bytes_written = fwrite(
+      &png_encoding.front(), 1, png_encoding.size(), fp);
+  if (bytes_written != png_encoding.size())
+    fprintf(stderr, "Failed to write to  %s\n", filename);
+
+  (void) fclose(fp);
+}
+
 #ifdef _WIN32
 static void WriteBmp(const char* pdf_name, int num, const void* buffer,
                      int stride, int width, int height) {
@@ -297,6 +342,12 @@ bool ParseCommandLine(const std::vector<std::string>& args,
         return false;
       }
       options->output_format = OUTPUT_PPM;
+    } else if (cur_arg == "--png") {
+      if (options->output_format != OUTPUT_NONE) {
+        fprintf(stderr, "Duplicate or conflicting --png argument\n");
+        return false;
+      }
+      options->output_format = OUTPUT_PNG;
     }
 #ifdef _WIN32
     else if (cur_arg == "--emf") {
@@ -475,9 +526,14 @@ void RenderPdf(const std::string& name, const char* pBuf, size_t len,
         WriteEmf(page, name.c_str(), i);
         break;
 #endif
+      case OUTPUT_PNG:
+        WritePng(name.c_str(), i, buffer, stride, width, height);
+        break;
+
       case OUTPUT_PPM:
         WritePpm(name.c_str(), i, buffer, stride, width, height);
         break;
+
       default:
         break;
     }
@@ -507,6 +563,7 @@ static const char usage_string[] =
     "  --bmp - write page images <pdf-name>.<page-number>.bmp\n"
     "  --emf - write page meta files <pdf-name>.<page-number>.emf\n"
 #endif
+    "  --png - write page images <pdf-name>.<page-number>.png\n"
     "  --ppm - write page images <pdf-name>.<page-number>.ppm\n";
 
 int main(int argc, const char* argv[]) {