图像任意比缩放
已经读取数据为unsigned char类型，8位灰度图像如何进行任意比例的缩放。求思路，或者代码。

[解决办法]

C/C++ code

    void copy_row2_B (BYTE *src, int src_w, BYTE *dst, int dst_w)        {                                    int i;                                int pos, inc;                            BYTE pixel = 0;                            pos = 0x10000;                            inc = (src_w << 16) / dst_w;                    for ( i=dst_w; i>0; --i )         {                        while ( pos >= 0x10000L )             {                        pixel = *src++;                            pos -= 0x10000L;                    }                                *dst++ = pixel;                            pos += inc;                        }                            }// src 源缓冲， dst 目的缓冲, sw 源图片宽， dw 目的图片宽， rsrc 源区域, rdes 目的区域    void StretchBlt_B(BYTE* src, BYTE* dst, int sw, int dw, RECT* rsrc, RECT* rdes)    {        int pos, inc;        int dst_width;        int dst_maxrow;        int src_row, dst_row;        BYTE *srcp = NULL;        BYTE *dstp;        /* Set up the data... */        pos = 0x10000;        inc = (rsrc->h() << 16) / rdes->h();        src_row = rsrc->top;        dst_row = rdes->top;        dst_width = rdes->w();        /* Perform the stretch blit */        for ( dst_maxrow = dst_row+rdes->h(); dst_row<dst_maxrow; ++dst_row )         {            dstp = (BYTE *)dst + (dst_row*dw)                + (rdes->left);            while ( pos >= 0x10000L ) {                srcp = (BYTE *)src + (src_row*sw)                    + (rsrc->left);                ++src_row;                pos -= 0x10000L;            }            copy_row2_B(srcp, rsrc->w(),                dstp, rdes->w());            pos += inc;        }    }