Merge pull request #3593 from Kumataro:refix_freetype_loadFontData

freetype: Add function to load font from buffer(additional patch)

Author: asmorkalov

modules/freetype/include/opencv2/freetype.hpp

@@ -76,14 +76,27 @@ class CV_EXPORTS_W FreeType2 : public Algorithm
 public:
 /** @brief Load font data.
 
-The function loadFontData loads font data.
+The function loadFontData loads font data from file.
 
 @param fontFileName FontFile Name
 @param idx face_index to select a font faces in a single file.
 */
 
     CV_WRAP virtual void loadFontData(String fontFileName, int idx) = 0;
 
+/** @brief Load font data.
+
+The function loadFontData loads font data from memory.
+The data is not copied, the user needs to make sure the data lives at least as long as FreeType2.
+After the FreeType2 object is destroyed, the buffer can be safely deallocated.
+
+@param pBuf pointer to buffer containing font data
+@param bufSize size of buffer
+@param idx face_index to select a font faces in a single file.
+*/
+
+    CV_WRAP virtual void loadFontData(char* pBuf, size_t bufSize, int idx) = 0;
+
 /** @brief Set Split Number from Bezier-curve to line
 
 The function setSplitNumber set the number of split points from bezier-curve to line.

modules/freetype/src/freetype.cpp

@@ -67,6 +67,7 @@ class CV_EXPORTS_W FreeType2Impl CV_FINAL : public FreeType2
     FreeType2Impl();
     ~FreeType2Impl();
     void loadFontData(String fontFileName, int idx) CV_OVERRIDE;
+    void loadFontData(char* pBuf, size_t bufSize, int idx) CV_OVERRIDE;
     void setSplitNumber( int num ) CV_OVERRIDE;
     void putText(
         InputOutputArray img, const String& text, Point org,
@@ -87,6 +88,8 @@ class CV_EXPORTS_W FreeType2Impl CV_FINAL : public FreeType2
     int              mCtoL;
     hb_font_t        *mHb_font;
 
+    void loadFontData(FT_Open_Args &args, int idx);
+
     void putTextBitmapMono(
         InputOutputArray img, const String& text, Point org,
         int fontHeight, Scalar color,
@@ -179,18 +182,54 @@ FreeType2Impl::~FreeType2Impl()
 }
 
 void FreeType2Impl::loadFontData(String fontFileName, int idx)
+{
+    FT_Open_Args args
+    {
+        FT_OPEN_PATHNAME,
+        nullptr, // memory_base
+        0,       // memory_size
+        const_cast<FT_String*>(fontFileName.c_str()),
+        nullptr, // stream
+        nullptr, // driver
+        0,       // num_params
+        nullptr  // params
+    };
+
+    this->loadFontData(args, idx);
+}
+
+void FreeType2Impl::loadFontData(char* pBuf, size_t bufSize, int idx)
+{
+    CV_Assert( pBuf != nullptr );
+
+    FT_Open_Args args
+    {
+        FT_OPEN_MEMORY,
+        reinterpret_cast<FT_Byte*>(pBuf),
+        static_cast<FT_Long>(bufSize),
+        nullptr, // pathname
+        nullptr, // stream
+        nullptr, // driver
+        0,       // num_params
+        nullptr  // params
+    };
+
+    this->loadFontData(args, idx);
+}
+
+void FreeType2Impl::loadFontData(FT_Open_Args &args, int idx)
 {
     CV_Assert( idx >= 0 );
-    if( mIsFaceAvailable  == true )
+    if ( mIsFaceAvailable  == true )
     {
-        hb_font_destroy (mHb_font);
+        hb_font_destroy(mHb_font);
         CV_Assert(!FT_Done_Face(mFace));
     }
 
     mIsFaceAvailable = false;
-    CV_Assert( !FT_New_Face( mLibrary, fontFileName.c_str(), static_cast<FT_Long>(idx), &(mFace) ) );
+    CV_Assert( !FT_Open_Face(mLibrary, &args, idx, &mFace) );
 
-    mHb_font = hb_ft_font_create (mFace, NULL);
+    mHb_font = hb_ft_font_create(mFace, NULL);
     if ( mHb_font == NULL )
     {
         CV_Assert(!FT_Done_Face(mFace));

modules/freetype/test/test_basic.cpp

@@ -55,6 +55,39 @@ TEST(Freetype_Basic, success )
     EXPECT_NO_THROW( ft2->putText(dst, "Basic,success", Point( 0,  50), 50, col, -1, LINE_AA, true ) );
 }
 
+TEST(Freetype_Basic, in_memory_font )
+{
+    const string root = cvtest::TS::ptr()->get_data_path();
+    const string font_path = root + "freetype/mplus/Mplus1-Regular.ttf";
+
+    cv::Ptr<cv::freetype::FreeType2> ft2;
+    EXPECT_NO_THROW( ft2 = cv::freetype::createFreeType2() );
+    EXPECT_NO_THROW( ft2->loadFontData( font_path, 0 ) );
+
+    Mat dst(600,600, CV_8UC3, Scalar::all(255) );
+    Scalar col(128,64,255,192);
+    EXPECT_NO_THROW( ft2->putText(dst, "Basic,success", Point( 0,  50), 50, col, -1, LINE_AA, true ) );
+
+    FILE* fp = fopen(font_path.c_str(), "rb");
+    ASSERT_TRUE(fp != NULL);
+    fseek(fp, 0, SEEK_END);
+    const size_t file_size = ftell(fp);
+    fseek(fp, 0, SEEK_SET);
+
+    std::vector<char> font_buffer(file_size);
+    const size_t actual_read = fread(&font_buffer[0], 1, file_size, fp);
+    fclose(fp);
+    ASSERT_EQ(file_size, actual_read);
+
+    cv::Ptr<cv::freetype::FreeType2> ft2_in_memory;
+    EXPECT_NO_THROW( ft2_in_memory = cv::freetype::createFreeType2() );
+    EXPECT_NO_THROW( ft2_in_memory->loadFontData( &font_buffer[0], file_size, 0 ) );
+    Mat dst_in_memory(600,600, CV_8UC3, Scalar::all(255) );
+    EXPECT_NO_THROW( ft2_in_memory->putText(dst_in_memory, "Basic,success", Point( 0,  50), 50, col, -1, LINE_AA, true ) );
+
+    EXPECT_PRED_FORMAT2(cvtest::MatComparator(0, 0), dst, dst_in_memory);
+}
+
 /******************
  * loadFontData()
  *****************/
@@ -105,6 +138,37 @@ TEST(Freetype_loadFontData, call_multiple)
     EXPECT_NO_THROW( ft2->putText(dst, "call_mutilple", Point( 0,  50), 50, col, -1, LINE_AA, true ) );
 }
 
+TEST(Freetype_loadFontDataMemory, nullptr )
+{
+    cv::Ptr<cv::freetype::FreeType2> ft2;
+    EXPECT_NO_THROW( ft2 = cv::freetype::createFreeType2() );
+    EXPECT_ANY_THROW( ft2->loadFontData( nullptr, 0, 0 ) );
+}
+
+TEST(Freetype_loadFontDataMemory, broken_data )
+{
+    const string root = cvtest::TS::ptr()->get_data_path();
+    const string font_path = root + "freetype/mplus/Mplus1-Regular.ttf";
+
+    FILE* fp = fopen(font_path.c_str(), "rb");
+    ASSERT_TRUE(fp != NULL);
+    fseek(fp, 0, SEEK_END);
+    const size_t file_size = ftell(fp);
+    fseek(fp, 0, SEEK_SET);
+
+    std::vector<char> font_buffer(file_size);
+    const size_t actual_read = fread(&font_buffer[0], 1, file_size, fp);
+    fclose(fp);
+    ASSERT_EQ(file_size, actual_read);
+
+    cv::Ptr<cv::freetype::FreeType2> ft2_in_memory;
+    EXPECT_NO_THROW( ft2_in_memory = cv::freetype::createFreeType2() );
+
+    font_buffer[0] = ~font_buffer[0]; // font buffer was broken.
+
+    EXPECT_ANY_THROW( ft2_in_memory->loadFontData( &font_buffer[0], file_size, 0 ) );
+}
+
 typedef testing::TestWithParam<int> idx_range;
 
 TEST_P(idx_range, failed )