submodule/skia/tools/using_skia_and_harfbuzz.cpp

   1 /*
   2  * Copyright 2016 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 // This sample progam demonstrates how to use Skia and HarfBuzz to
   9 // produce a PDF file from UTF-8 text in stdin.
  10
  11 #include <cassert>
  12 #include <cstdlib>
  13 #include <iostream>
  14 #include <map>
  15 #include <sstream>
  16 #include <string>
  17 #include <vector>
  18
  19 #include "include/core/SkCanvas.h"
  20 #include "include/core/SkStream.h"
  21 #include "include/core/SkTextBlob.h"
  22 #include "include/core/SkTypeface.h"
  23 #include "include/docs/SkPDFDocument.h"
  24 #include "modules/skshaper/include/SkShaper.h"
  25
  26 // Options /////////////////////////////////////////////////////////////////////
  27
  28 struct BaseOption {
  29     std::string selector;
  30     std::string description;
  31     virtual void set(std::string _value) = 0;
  32     virtual std::string valueToString() = 0;
  33
  34     BaseOption(std::string _selector, std::string _description)
  35         : selector(_selector), description(_description) {}
  36
  37     virtual ~BaseOption() {}
  38
  39     static void Init(const std::vector<BaseOption*> &, int argc, char **argv);
  40 };
  41
  42 template <class T>
  43 struct Option : BaseOption {
  44     T value;
  45     Option(std::string _selector, std::string _description, T defaultValue)
  46         : BaseOption(_selector, _description), value(defaultValue) {}
  47 };
  48
  49 void BaseOption::Init(const std::vector<BaseOption*> &option_list,
  50                       int argc, char **argv) {
  51     std::map<std::string, BaseOption *> options;
  52     for (BaseOption *opt : option_list) {
  53         options[opt->selector] = opt;
  54     }
  55     for (int i = 1; i < argc; i++) {
  56         std::string option_selector(argv[i]);
  57         auto it = options.find(option_selector);
  58         if (it != options.end()) {
  59             if (i >= argc) {
  60                 break;
  61             }
  62             const char *option_value = argv[i + 1];
  63             it->second->set(option_value);
  64             i++;
  65         } else {
  66             printf("Ignoring unrecognized option: %s.\n", argv[i]);
  67             printf("Usage: %s {option value}\n", argv[0]);
  68             printf("\tTakes text from stdin and produces pdf file.\n");
  69             printf("Supported options:\n");
  70             for (BaseOption *opt : option_list) {
  71                 printf("\t%s\t%s (%s)\n", opt->selector.c_str(),
  72                        opt->description.c_str(), opt->valueToString().c_str());
  73             }
  74             exit(-1);
  75         }
  76     }
  77 }
  78
  79 struct DoubleOption : Option<double> {
  80     void set(std::string _value) override { value = atof(_value.c_str()); }
  81     std::string valueToString() override {
  82         std::ostringstream stm;
  83         stm << value;
  84         return stm.str();
  85     }
  86     DoubleOption(std::string _selector,
  87                  std::string _description,
  88                  double defaultValue)
  89         : Option<double>(_selector, _description, defaultValue) {}
  90 };
  91
  92 struct StringOption : Option<std::string> {
  93     void set(std::string _value) override { value = _value; }
  94     std::string valueToString() override { return value; }
  95     StringOption(std::string _selector,
  96                  std::string _description,
  97                  std::string defaultValue)
  98         : Option<std::string>(_selector, _description, defaultValue) {}
  99 };
 100
 101 // Config //////////////////////////////////////////////////////////////////////
 102
 103 struct Config {
 104     DoubleOption page_width = DoubleOption("-w", "Page width", 600.0f);
 105     DoubleOption page_height = DoubleOption("-h", "Page height", 800.0f);
 106     StringOption title = StringOption("-t", "PDF title", "---");
 107     StringOption author = StringOption("-a", "PDF author", "---");
 108     StringOption subject = StringOption("-k", "PDF subject", "---");
 109     StringOption keywords = StringOption("-c", "PDF keywords", "---");
 110     StringOption creator = StringOption("-t", "PDF creator", "---");
 111     StringOption font_file = StringOption("-f", ".ttf font file", "");
 112     DoubleOption font_size = DoubleOption("-z", "Font size", 8.0f);
 113     DoubleOption left_margin = DoubleOption("-m", "Left margin", 20.0f);
 114     DoubleOption line_spacing_ratio =
 115             DoubleOption("-h", "Line spacing ratio", 0.25f);
 116     StringOption output_file_name =
 117             StringOption("-o", ".pdf output file name", "out-skiahf.pdf");
 118
 119     Config(int argc, char **argv) {
 120         BaseOption::Init(std::vector<BaseOption*>{
 121                 &page_width, &page_height, &title, &author, &subject,
 122                 &keywords, &creator, &font_file, &font_size, &left_margin,
 123                 &line_spacing_ratio, &output_file_name}, argc, argv);
 124     }
 125 };
 126
 127 // Placement ///////////////////////////////////////////////////////////////////
 128
 129 class Placement {
 130 public:
 131     Placement(const Config* conf, SkDocument *doc)
 132         : config(conf), document(doc), pageCanvas(nullptr) {
 133         white_paint.setColor(SK_ColorWHITE);
 134         glyph_paint.setColor(SK_ColorBLACK);
 135         glyph_paint.setAntiAlias(true);
 136         font.setEdging(SkFont::Edging::kSubpixelAntiAlias);
 137         font.setSubpixel(true);
 138         font.setSize(SkDoubleToScalar(config->font_size.value));
 139     }
 140
 141     void WriteLine(const SkShaper& shaper, const char *text, size_t textBytes) {
 142         SkTextBlobBuilderRunHandler textBlobBuilder(text, {0, 0});
 143         shaper.shape(text, textBytes, font, true,
 144                      config->page_width.value - 2*config->left_margin.value, &textBlobBuilder);
 145         SkPoint endPoint = textBlobBuilder.endPoint();
 146         sk_sp<const SkTextBlob> blob = textBlobBuilder.makeBlob();
 147         // If we don't have a page, or if we're not at the start of the page and the blob won't fit
 148         if (!pageCanvas ||
 149               (current_y > config->line_spacing_ratio.value * config->font_size.value &&
 150                current_y + endPoint.y() > config->page_height.value)
 151         ) {
 152             if (pageCanvas) {
 153                 document->endPage();
 154             }
 155             pageCanvas = document->beginPage(
 156                     SkDoubleToScalar(config->page_width.value),
 157                     SkDoubleToScalar(config->page_height.value));
 158             pageCanvas->drawPaint(white_paint);
 159             current_x = config->left_margin.value;
 160             current_y = config->line_spacing_ratio.value * config->font_size.value;
 161         }
 162         pageCanvas->drawTextBlob(
 163                 blob.get(), SkDoubleToScalar(current_x),
 164                 SkDoubleToScalar(current_y), glyph_paint);
 165         // Advance to the next line.
 166         current_y += endPoint.y() + config->line_spacing_ratio.value * config->font_size.value;
 167     }
 168
 169 private:
 170     const Config* config;
 171     SkDocument *document;
 172     SkCanvas *pageCanvas;
 173     SkPaint white_paint;
 174     SkPaint glyph_paint;
 175     SkFont font;
 176     double current_x;
 177     double current_y;
 178 };
 179
 180 ////////////////////////////////////////////////////////////////////////////////
 181
 182 static sk_sp<SkDocument> MakePDFDocument(const Config &config, SkWStream *wStream) {
 183     SkPDF::Metadata pdf_info;
 184     pdf_info.fTitle = config.title.value.c_str();
 185     pdf_info.fAuthor = config.author.value.c_str();
 186     pdf_info.fSubject = config.subject.value.c_str();
 187     pdf_info.fKeywords = config.keywords.value.c_str();
 188     pdf_info.fCreator = config.creator.value.c_str();
 189     #if 0
 190         SkTime::DateTime now;
 191         SkTime::GetDateTime(&now);
 192         pdf_info.fCreation = now;
 193         pdf_info.fModified = now;
 194         pdf_info.fPDFA = true;
 195     #endif
 196     return SkPDF::MakeDocument(wStream, pdf_info);
 197 }
 198
 199 int main(int argc, char **argv) {
 200     Config config(argc, argv);
 201     SkFILEWStream wStream(config.output_file_name.value.c_str());
 202     sk_sp<SkDocument> doc = MakePDFDocument(config, &wStream);
 203     assert(doc);
 204     Placement placement(&config, doc.get());
 205
 206     const std::string &font_file = config.font_file.value;
 207     sk_sp<SkTypeface> typeface;
 208     if (font_file.size() > 0) {
 209         typeface = SkTypeface::MakeFromFile(font_file.c_str(), 0 /* index */);
 210     }
 211     std::unique_ptr<SkShaper> shaper = SkShaper::Make();
 212     assert(shaper);
 213     //SkString line("This is هذا هو الخط a line.");
 214     //SkString line("⁧This is a line هذا هو الخط.⁩");
 215     for (std::string line; std::getline(std::cin, line);) {
 216         placement.WriteLine(*shaper, line.c_str(), line.size());
 217     }
 218
 219     doc->close();
 220     wStream.flush();
 221     return 0;
 222 }