pdfviewer: add --pages arg: render a certain page (all, all in desceding order, firsl, last and by …

experimental/PdfViewer/pdf_viewer_main.cpp

 #include "SkCanvas.h"
 #include "SkCommandLineFlags.h"
 #include "SkDevice.h"
 #include "SkGraphics.h"
 #include "SkImageDecoder.h"
 #include "SkImageEncoder.h"
 #include "SkOSFile.h"
 #include "SkPicture.h"
 #include "SkStream.h"
 #include "SkTypeface.h"
 #include "SkTArray.h"
 #include "picture_utils.h"
 
 #include "SkPdfRenderer.h"
 
 DEFINE_string2(readPath, r, "", "pdf files or directories of pdf files to process.");
 DEFINE_string2(writePath, w, "", "Directory to write the rendered pages.");
 DEFINE_bool2(noExtensionForOnePagePdf, n, false, "No page extension if only one page.");
 DEFINE_bool2(showMemoryUsage, m, false, "Show Memory usage.");
+DEFINE_string2(pages, p, "all", "What pages to render and how:\n"
+                                "\tall - all pages\n"
+                                "\treverse - all pages, in reverse order\n"
+                                "\tfirst - first page\n"
+                                "\tlast - last page\n"
+                                "\tnumber - a specific page number\n"
+               );
+
 
 /**
  * Given list of directories and files to use as input, expects to find .pdf
  * files and it will convert them to .png files writing them in the same directory
  * one file for each page.
  *
  * Returns zero exit code if all .pdf files were converted successfully,
  * otherwise returns error code 1.
  */
 
@@ skipping 85 matching lines @@
     SkAutoTUnref<SkDevice> device(SkNEW_ARGS(SkDevice, (bitmap)));
     SkCanvas canvas(device);
 
     gDumpBitmap = &bitmap;
 
     gDumpCanvas = &canvas;
     renderer.renderPage(page < 0 ? 0 : page, &canvas);
 
     SkImageEncoder::EncodeFile(outputPath.c_str(), bitmap, SkImageEncoder::kPNG_Type, 100);
 
+    if (FLAGS_showMemoryUsage) {
+        SkDebugf("Memory usage after page %i rendered: %u\n", page < 0 ? 0 : page, (unsigned int)renderer.bytesUsed());
+    }
+
     return true;
 }
 
 /** Reads an skp file, renders it to pdf and writes the output to a pdf file
  * @param inputPath The skp file to be read.
  * @param outputDir Output dir.
  * @param renderer The object responsible to render the skp object into pdf.
  */
 static bool process_pdf(const SkString& inputPath, const SkString& outputDir,
-                        SkPdfRenderer& renderer, bool noPageExt, bool showMemoryUsage) {
+                        SkPdfRenderer& renderer) {
     SkDebugf("Loading PDF:  %s\n", inputPath.c_str());
 
     SkString inputFilename;
     sk_tools::get_basename(&inputFilename, inputPath);
 
     SkFILEStream inputStream;
     inputStream.setPath(inputPath.c_str());
     if (!inputStream.isValid()) {
         SkDebugf("Could not open file %s\n", inputPath.c_str());
         return false;
     }
 
     bool success = false;
 
     success = renderer.load(inputPath);
 
     if (success) {
-        if (showMemoryUsage) {
+        if (FLAGS_showMemoryUsage) {
             SkDebugf("Memory usage after load: %u\n", (unsigned int)renderer.bytesUsed());
         }
         if (!renderer.pages())
         {
             SkDebugf("ERROR: Empty PDF Document %s\n", inputPath.c_str());
             return false;
         } else {
-            for (int pn = 0; pn < renderer.pages(); ++pn) {
-                success = render_page(outputDir, inputFilename, renderer, noPageExt && renderer.pages() == 1 ? -1 : pn) && success;
-                SkDebugf("Memory usage after page %i rendered: %u\n", pn, (unsigned int)renderer.bytesUsed());
+            if (strcmp(FLAGS_pages[0], "all") == 0) {
+                for (int pn = 0; pn < renderer.pages(); ++pn) {
+                    success = render_page(outputDir, inputFilename, renderer, FLAGS_noExtensionForOnePagePdf && renderer.pages() == 1 ? -1 : pn) && success;
+                }
+            } else if (strcmp(FLAGS_pages[0], "reverse") == 0) {
+                for (int pn = renderer.pages() - 1; pn >= 0; --pn) {
+                    success = render_page(outputDir, inputFilename, renderer, FLAGS_noExtensionForOnePagePdf && renderer.pages() == 1 ? -1 : pn) && success;
+                }
+            } else if (strcmp(FLAGS_pages[0], "first") == 0) {
+                success = render_page(outputDir, inputFilename, renderer, FLAGS_noExtensionForOnePagePdf && renderer.pages() == 1 ? -1 : 0) && success;
+            } else if (strcmp(FLAGS_pages[0], "last") == 0) {
+                success = render_page(outputDir, inputFilename, renderer, FLAGS_noExtensionForOnePagePdf && renderer.pages() == 1 ? -1 : renderer.pages() - 1) && success;
+            } else {
+                int pn = atoi(FLAGS_pages[0]);
+                success = render_page(outputDir, inputFilename, renderer, FLAGS_noExtensionForOnePagePdf && renderer.pages() == 1 ? -1 : renderer.pages() - 1) && pn;
             }
         }
     }
 
     return success;
 }
 
 /** For each file in the directory or for the file passed in input, call
  * parse_pdf.
  * @param input A directory or an pdf file.
  * @param outputDir Output dir.
  * @param renderer The object responsible to render the skp object into pdf.
  */
 static int process_input(const char* input, const SkString& outputDir,
-                         SkPdfRenderer& renderer, bool noPageExt, bool showMemoryUsage) {
+                         SkPdfRenderer& renderer) {
     int failures = 0;
     if (sk_isdir(input)) {
         SkOSFile::Iter iter(input, PDF_FILE_EXTENSION);
         SkString inputFilename;
         while (iter.next(&inputFilename)) {
             SkString inputPath;
             SkString _input;
             _input.append(input);
             sk_tools::make_filepath(&inputPath, _input, inputFilename);
-            if (!process_pdf(inputPath, outputDir, renderer, noPageExt, showMemoryUsage)) {
+            if (!process_pdf(inputPath, outputDir, renderer)) {
                 ++failures;
             }
         }
     } else {
         SkString inputPath(input);
-        if (!process_pdf(inputPath, outputDir, renderer, noPageExt, showMemoryUsage)) {
+        if (!process_pdf(inputPath, outputDir, renderer)) {
             ++failures;
         }
     }
     return failures;
 }
 
 int tool_main(int argc, char** argv);
 int tool_main(int argc, char** argv) {
     SkCommandLineFlags::SetUsage("Parse and Render .pdf files (pdf viewer).");
     SkCommandLineFlags::Parse(argc, argv);
 
     if (FLAGS_readPath.isEmpty()) {
         SkDebugf(".pdf files or directories are required.\n");
         exit(-1);
     }
 
     SkPdfRenderer renderer;
 
     SkString outputDir;
     if (FLAGS_writePath.count() == 1) {
         outputDir.set(FLAGS_writePath[0]);
     }
 
     int failures = 0;
     for (int i = 0; i < FLAGS_readPath.count(); i ++) {
-        failures += process_input(FLAGS_readPath[i], outputDir, renderer,
-                                  FLAGS_noExtensionForOnePagePdf,
-                                  FLAGS_showMemoryUsage);
+        failures += process_input(FLAGS_readPath[i], outputDir, renderer);
         renderer.unload();
     }
 
     reportPdfRenderStats();
 
     if (failures != 0) {
         SkDebugf("Failed to render %i PDFs.\n", failures);
         return 1;
     }
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif