以字型為例，一維表示的二維數組矩陣，旋轉90、－90

參考的代碼有： https://blog.csdn.net/quantum7/article/details/79762714 https://blog.csdn.net/quantum7/article/details/107279477 具體代碼：

#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
 
#include <ft2build.h>
#include <freetype/freetype.h>
#include FT_FREETYPE_H
 
#define FONT_FILE "/home/uos/font/simsun.ttc"
 
static void dumpBuffer(char* pBuffer, int w, int h)
{
    int i=0;
    int j=0;
 
    printf("w=%d, h=%d\n", w, h);
 
    for (i=0; i<h; i++)
    {
        printf("|");
        for (j=0; j<w; j++)
        {
            printf(((pBuffer[i * w  + j]) == 0 ) ? " " : "1");
        }
        printf("|\n");
    }
}
 
static void dumpFontBmp(FT_Bitmap* pBmp)
{
    int w = pBmp->width;
    int h = pBmp->rows;
    dumpBuffer(pBmp->buffer, w, h);
}
 
static void rotate_90(FT_Bitmap* pBmp)
{
    int w = pBmp->width;
    int h = pBmp->rows;
    int i=0;
    char* pRotated;
 
    int size;
    int offset=0;
 
    size = w * h;
    pRotated = (char*)malloc(size);
    memcpy(pRotated, pBmp->buffer, size);
 
    int startPos = (h - 1)*w;
    i = 0;
    for (int x = 0; x < w; x++)
    {
        int offset = startPos;
        for (int y = h - 1; y >= 0; y--)
        {
            pRotated[i] = pBmp->buffer[offset + x];
            i++;
            offset -= w;
        }
    }
    dumpBuffer(pRotated, h, w);
}
 
static void rotate_270(FT_Bitmap* pBmp)
{
    int w = pBmp->width;
    int h = pBmp->rows;
    int i=0;
    char* pRotated;
 
    int size;
    int offset=0;
 
    size = w * h;
    pRotated = (char*)malloc(size);
    memcpy(pRotated, pBmp->buffer, size);
 
    i = 0;
    for (int x = w-1; x >= 0; x--)
    {
        int offset = 0;
        for (int y = 0; y < h; y++)
        {
            pRotated[i] = pBmp->buffer[offset + x];
            i++;
            offset += w;
        }
    }
 
    dumpBuffer(pRotated, h, w);
}
 
int main()
{
    FT_Library  m_pFTLib;
    FT_Face     m_pFTFace;
    wchar_t chinese_char = L'泰';
 
    FT_Error result = FT_Init_FreeType(&m_pFTLib);
    if(FT_New_Face(m_pFTLib, FONT_FILE, 0, &m_pFTFace))
    {
        printf("FT_New_Face error!\n");
        return -1;
    }
 
    //FT_ENCODING_GB2312, FT_ENCODING_UNICODE
    FT_Select_Charmap(m_pFTFace, FT_ENCODING_UNICODE);
    FT_Set_Char_Size(m_pFTFace, 0, 12<<6, 200, 200);
 
    result = FT_Load_Glyph(m_pFTFace, FT_Get_Char_Index(m_pFTFace, chinese_char), FT_LOAD_DEFAULT);
 
     // 第二個參數為渲染模式
    result = FT_Render_Glyph(m_pFTFace->glyph,  FT_RENDER_MODE_NORMAL);  
    printf("result=%d\n", result);
 
    dumpFontBmp(&(m_pFTFace->glyph->bitmap));
    rotate_90( &(m_pFTFace->glyph->bitmap));
    rotate_270(&(m_pFTFace->glyph->bitmap));
    return 0;
}      

原始字型：

|             111               |
|             1111              |
|             111         11    |
|            111         1111   |
|  111111111111111111111111111  |
|  11111     111                |
|            111        11      |
|            111       1111     |
|    11111111111111111111111    |
|     1111  111                 |
|           111             1   |
|          111            1111  |
|111111111111111111111111111111 |
| 1111    1111     11           |
|         111 11   111          |
|        1111 1111  111         |
|       1111  1111   111        |
|      1111   111    1111       |
|      1111   111   111111      |
|     1111111 111  111111111    |
|   1111  111111111111111111111 |
|  1111    111111111     1111111|
| 1111     11 1111         1111 |
|111       111111111        11  |
|1       11111111111111         |
|     111111  111  111111       |
|    11111    111   11111       |
|    1111 1111111     111       |
|     11   111111      11       |
|            111                |      

旋轉90度：

|     11          1            |
|      11        11            |
|      111       11      11    |
|       111      11      11    |
|  11   111      11   1  11    |
| 1111   111      1  11  11    |
| 1111    1111    1  11  11    |
|  111     1111   1  11   1    |
|   111    11111  1  11   1    |
|  1 11   111111111   1   1    |
| 11 1111111  111111  1   1    |
| 11  111111   11111111   1    |
|111  11 11      11111111111   |
|1111111111111111 1 11111111111|
|1111111111111111 1   111111111|
| 11111111111111  1   1   1 111|
|     11111   11  1   1   1  1 |
|     11 11       1   1   1    |
|    111 111    111   1   1    |
|   111   111  1111   1   1    |
|   111   1111111 1   1   1    |
|  1111   111111  1   1   1    |
| 1111    11111   1   11  1    |
| 1111    1111    1   111 1    |
|        1111     1   111 11   |
|        111      11  11  111  |
|       1111      11  1   111  |
|      1111       111     11   |
|      1111       11      1    |
|       111       1            |
|        1                     |      

旋轉-90：

|                     1        |
|            1       111       |
|    1      11       1111      |
|   11     111       1111      |
|  111   1  11      1111       |
|  111  11  11      111        |
|   11 111   1     1111        |
|    1 111   1    1111    1111 |
|    1  11   1   11111    1111 |
|    1   1   1  111111   1111  |
|    1   1   1 1111111   111   |
|    1   1   1111  111   111   |
|    1   1   111    111 111    |
|    1   1   1       11 11     |
| 1  1   1   1  11   11111     |
|111 1   1   1  11111111111111 |
|111111111   1 1111111111111111|
|11111111111 1 1111111111111111|
|   11111111111      11 11  111|
|    1   11111111   111111  11 |
|    1   1  111111  1111111 11 |
|    1   1   111111111   11 1  |
|    1   11  1  11111    111   |
|    1   11  1   1111     111  |
|    11  11  1    1111    1111 |
|    11  11  1      111   1111 |
|    11  1   11      111   11  |
|    11      11      111       |
|    11      11       111      |
|            11        11      |
|            1          11     |