全網首發：以字型為例，以bit表示的二維數組矩陣，旋轉90、－90

　代碼中，先把字型矩陣轉換為bit，再進行旋轉。關鍵有幾點：

• 計算數組大小。

size = (w+7) * (h+7) / 8;      

• 正确旋轉的算法。這個通過byte旋轉代碼得到。參考：

https://quantum6.blog.csdn.net/article/details/110794038

• bit坐标轉換。代碼是這樣的：

int srcPos     = (offset + x);
            int srcPosByte = srcPos / 8;
            int srcPosBit  = srcPos % 8;
            int value = (pBuffer[srcPosByte] & (0x01 << srcPosBit)) != 0 ? 1 : 0;
            int dstPosByte = i / 8;
            int dstPosBite = i % 8;
            pRotated[dstPosByte] |= (value << dstPosBite);      

全部源碼：

　　看到這麼整齊的源碼，肯定是本人所寫。如此漂亮，閣下應該學習國中。

#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 dumpByte(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]) ? "1" : " ");
        }
        printf("|\n");
    }
}
 
static void dumpFontBmp(FT_Bitmap* pBmp)
{
    int w = pBmp->width;
    int h = pBmp->rows;
    dumpByte(pBmp->buffer, w, h);
}
 
static char* byteToBit(char* pBuffer, int w, int h)
{
    int i=0;
    int j=0;
 
    int size = (w+7) * (h+7) / 8;
    char* bits = (char*)malloc(size);
    memset(bits, 0, size);
 
    for (i=0; i<h; i++)
    {
        for (j=0; j<w; j++)
        {
            int srcPos     = (i * w  + j);
            int srcPosByte = srcPos / 8;
            int srcPosBit  = srcPos % 8;
            bits[srcPosByte] |= (pBuffer[i * w  + j] == 0 ? 0 : (0x01 << srcPosBit));
        }
    }
    return bits;
}
static void dumpBit(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++)
        {
            int srcPos   = (i * w  + j);
            int posByte  = srcPos / 8;
            int posBit   = srcPos % 8;
            int bitValue = (pBuffer[posByte] & (0x01 << posBit)) != 0 ? 1 : 0;
            printf(bitValue ? "1" : " ");
        }
        printf("|\n");
    }
}
static char* rotate_90(char* pBuffer, int w, int h)
{
    int i=0;
    char* pRotated;
    int size;
    int offset=0;
    size = (w+7) * (h+7) / 8;
    pRotated = (char*)malloc(size);
    memset(pRotated, 0, 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--)
        {
            int srcPos      = (offset + x);
            int srcPosByte  = srcPos / 8;
            int srcPosBit   = srcPos % 8;
            int srcBitValue = (pBuffer[srcPosByte] & (0x01 << srcPosBit)) != 0 ? 1 : 0;
            int dstPosByte  = (i)/8;
            int dstPosBit   = (i)%8;
            pRotated[dstPosByte] |= (srcBitValue << dstPosBit);
            i++;
            offset -= w;
        }
    }
    dumpBit(pRotated, h, w);
    return pRotated;
}
static char* rotate_270(char* pBuffer, int w, int h)
{
    int i=0;
    char* pRotated;
    int size;
    int offset=0;
    size = (w+7) * (h+7)/8;
    pRotated = (char*)malloc(size);
    memset(pRotated, 0, size);
    i = 0;
    for (int x = w-1; x >= 0; x--)
    {
        int offset = 0;
        for (int y = 0; y < h; y++)
        {
            int srcPos      = (offset + x);
            int srcPosByte  = srcPos / 8;
            int srcPosBit   = srcPos % 8;
            int srcBitValue = (pBuffer[srcPosByte] & (0x01 << srcPosBit)) != 0 ? 1 : 0;
            int dstPosByte  = i / 8;
            int dstPosBit   = i % 8;
            pRotated[dstPosByte] |= (srcBitValue << dstPosBit);
            i++;
            offset += w;
        }
    }
    dumpBit(pRotated, h, w);
    return pRotated;
}
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);
 
    FT_Bitmap* pBmp = &(m_pFTFace->glyph->bitmap);
    //dumpFontBmp(pBmp);
    int w = pBmp->width;
    int h = pBmp->rows;
    char* bits = byteToBit(m_pFTFace->glyph->bitmap.buffer, w, h);
    dumpBit(bits, w, h);
    rotate_90( bits, w, h);
    rotate_270(bits, w, h);
    return 0;
}