experimental skp_to_pdf_md5 program.

This program takes a list of Skia Picture (SKP) files and
renders each as a multipage PDF, then prints out the MD5
checksum of the PDF file.  This can be used to verify that
changes to the PDF backend will not change PDF output.

Review URL: https://codereview.chromium.org/832403002

1 files changed, 153 insertions, 0 deletions

diff --git a/experimental/tools/skp_to_pdf_md5.cpp b/experimental/tools/skp_to_pdf_md5.cpp
new file mode 100644
index 0000000000..3232c57ed3
--- /dev/null
+++ b/experimental/tools/skp_to_pdf_md5.cpp
@@ -0,0 +1,153 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SkCanvas.h"
+#include "SkCommandLineFlags.h"
+#include "SkDocument.h"
+#include "SkForceLinking.h"
+#include "SkGraphics.h"
+#include "SkMD5.h"
+#include "SkOSFile.h"
+#include "SkPicture.h"
+#include "SkStream.h"
+#include "SkTArray.h"
+#include "SkTSort.h"
+
+static const char kUsage[] =
+    "This program takes a list of Skia Picture (SKP) files and renders\n"
+    "each as a multipage PDF, then prints out the MD5 checksum of the\n"
+    "PDF file.  This can be used to verify that changes to the PDF\n"
+    "backend will not change PDF output.\n";
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+DEFINE_string2(inputPaths,
+               r,
+               "",
+               "A list of directories and files to use as input.\n"
+               "Files are expected to have the .skp extension.");
+
+static const char SKP_FILE_EXTENSION[] = ".skp";
+
+// Used by SkTQSort<SkString>()
+static bool operator<(const SkString& a, const SkString& b) {
+    return strcmp(a.c_str(), b.c_str()) < 0;
+}
+
+// Process --inputPaths defined on the command line.  Return false if
+// no files found.
+static bool process_input_files(SkTArray<SkString>* files) {
+    for (int i = 0; i < FLAGS_inputPaths.count(); i++) {
+        const char* input = FLAGS_inputPaths[i];
+        if (sk_isdir(input)) {
+            SkOSFile::Iter iter(input, SKP_FILE_EXTENSION);
+            SkString inputFilename;
+            while (iter.next(&inputFilename)) {
+                files->push_back(SkOSPath::Join(input, inputFilename.c_str()));
+            }
+        } else {
+            if (SkStrEndsWith(input, SKP_FILE_EXTENSION)) {
+                if (sk_exists(input)) {
+                    files->push_back(SkString(input));
+                } else {
+                    SkDebugf("file_does_not_exist %s\n", input);
+                }
+            } else {
+                SkDebugf("skipping_file %s\n", input);
+            }
+        }
+    }
+    if (files->count() > 0) {
+        SkTQSort<SkString>(files->begin(), files->end() - 1);
+        return true;
+    }
+    return false;
+}
+
+// Print the given SkPicture to a PDF, breaking on 8.5x11 pages.
+static void picture_to_pdf(const SkPicture& picture, SkWStream* out) {
+    SkAutoTUnref<SkDocument> pdfDocument(SkDocument::CreatePDF(out));
+
+    int width = picture.cullRect().width();
+    int height = picture.cullRect().height();
+
+    const int kLetterWidth = 612;   // 8.5 * 72
+    const int kLetterHeight = 792;  // 11 * 72
+    SkRect letterRect = SkRect::MakeWH(SkIntToScalar(kLetterWidth),
+                                       SkIntToScalar(kLetterHeight));
+
+    int xPages = ((width - 1) / kLetterWidth) + 1;
+    int yPages = ((height - 1) / kLetterHeight) + 1;
+
+    for (int y = 0; y < yPages; ++y) {
+        for (int x = 0; x < xPages; ++x) {
+            int w = SkTMin(kLetterWidth, width - (x * kLetterWidth));
+            int h = SkTMin(kLetterHeight, height - (y * kLetterHeight));
+            SkCanvas* canvas = pdfDocument->beginPage(w, h);
+            canvas->clipRect(letterRect);
+            canvas->translate(SkIntToScalar(-kLetterWidth * x),
+                              SkIntToScalar(-kLetterHeight * y));
+            canvas->drawPicture(&picture);
+            canvas->flush();
+            pdfDocument->endPage();
+        }
+    }
+    pdfDocument->close();
+    out->flush();
+}
+
+static bool skp_to_pdf_md5(SkStream* input, SkMD5::Digest* digest) {
+    SkAutoTUnref<SkPicture> picture(SkPicture::CreateFromStream(input));
+    if (NULL == picture.get()) {
+        return false;
+    }
+
+    SkMD5 checksumWStream;
+    picture_to_pdf(*picture, &checksumWStream);
+    checksumWStream.finish(*digest);
+    return true;
+}
+
+SkString digest_to_hex(const SkMD5::Digest& digest) {
+    static const char kHex[] = "0123456789ABCDEF";
+    SkString string(2 * sizeof(digest.data));
+    char* p = string.writable_str();
+    for (size_t i = 0; i < sizeof(digest.data); ++i) {
+        uint8_t c = digest.data[i];
+        *(p++) = kHex[c >> 4];
+        *(p++) = kHex[c & 0xF];
+    }
+    return string;
+}
+
+int main(int argc, char** argv) {
+    SkCommandLineFlags::SetUsage(kUsage);
+    SkCommandLineFlags::Parse(argc, argv);
+    SkAutoGraphics ag;
+    int successCount = 0;
+    SkTArray<SkString> files;
+    if (!process_input_files(&files)) {
+        SkDebugf("You need to specify a --inputPaths option.\n");
+        return 1;
+    }
+    for (int i = 0; i < files.count(); ++i) {
+        SkString basename = SkOSPath::Basename(files[i].c_str());
+        SkFILEStream inputStream(files[i].c_str());
+        if (!inputStream.isValid()) {
+            SkDebugf("could_not_open %s\n", basename.c_str());
+            continue;
+        }
+        SkMD5::Digest digest;
+        if (!skp_to_pdf_md5(&inputStream, &digest)) {
+            SkDebugf("invalid_skp %s\n", basename.c_str());
+            continue;
+        }
+        SkString hexDigest = digest_to_hex(digest);
+        printf("%s %s\n", hexDigest.c_str(), basename.c_str());
+        ++successCount;
+    }
+    return successCount == files.count() ? 0 : 1;
+}