双线性差值算法实现RGB图像缩放-C语言

实现一：存在栈溢出的风险，来自：https://blog.csdn.net/wangjiannuaa/article/details/6598041

 1 /**@func       gif_get_scale_rgb    
 2 * @brief       双线性差值算法缩放RGB图片
 3 * @param[in]   uDstWidth   目的图像宽度
 4 * @param[in]   uDstHeigth  目的图像高度
 5 * @param[out]  pDstRgbBuffer 目的图像地址
 6 * @param[in]   uSrcWidth   源图像宽度
 7 * @param[in]   uSrcHeigth  源图像高度
 8 * @param[in]   pSrcRgbBuffer 源图像地址
 9 * @return      成功返回：OK 失败返回：ERROR
10 */
11 static INT32 gif_get_scale_rgb(UINT16 uDstWidth, UINT16 uDstHeigth, UINT8 *pDstRgbBuffer, UINT16 uSrcWidth, UINT16 uSrcHeigth, UINT8 *pSrcRgbBuffer)
12 {
13     DOUBLE fRateW = uDstWidth * 1.0 / uSrcWidth;
14     DOUBLE fRateH = uDstHeigth * 1.0 / uSrcHeigth;
15 
16     INT32 iIndexW = 0;
17     INT32 iIndexH = 0;
18  
19     DOUBLE fX, fY;
20     
21     INT32 iStepSrcImg = uSrcWidth;
22     //INT32 iStepDstImg = uSrcWidth * fRateW;
23     INT32 iStepDstImg = uDstWidth;
24  
25     INT32 iX, iY;
26  
27     UINT8 bUpLeft, bUpRight, bDownLeft, bDownRight;
28     UINT8 gUpLeft, gUpRight, gDownLeft, gDownRight;
29     UINT8 rUpLeft, rUpRight, rDownLeft, rDownRight;
30  
31     UINT8 uB, uG, uR;
32 
33     if((NULL == pDstRgbBuffer) || (NULL == pSrcRgbBuffer))
34     {
35         GIF_ERRORS("Ptr is NULL \n");
36         return ERROR;
37     }
38 
39     for(iIndexH = 0; iIndexH < uDstHeigth/* uSrcHeigth * fRateH */ ; iIndexH++)
40     {
41         for(iIndexW = 0; iIndexW < uDstWidth/* uSrcWidth * fRateW */ ; iIndexW++)
42         {
43             fX = ((double)iIndexW) /fRateW;
44             fY = ((double)iIndexH) /fRateH;
45  
46             iX = (int)fX;
47             iY = (int)fY;
48  
49             bUpLeft  = pSrcRgbBuffer[iY * iStepSrcImg * 3 + iX * 3 + 0];
50             bUpRight = pSrcRgbBuffer[iY * iStepSrcImg * 3 + (iX + 1) * 3 + 0];
51  
52             bDownLeft  = pSrcRgbBuffer[(iY + 1) * iStepSrcImg * 3 + iX * 3 + 0];
53             bDownRight = pSrcRgbBuffer[(iY + 1) * iStepSrcImg * 3 + (iX + 1) * 3 + 0];
54  
55             gUpLeft  = pSrcRgbBuffer[iY * iStepSrcImg * 3 + iX * 3 + 1];
56             gUpRight = pSrcRgbBuffer[iY * iStepSrcImg * 3 + (iX + 1) * 3 + 1];
57  
58             gDownLeft  = pSrcRgbBuffer[(iY + 1) * iStepSrcImg * 3 + iX * 3 + 1];
59             gDownRight = pSrcRgbBuffer[(iY + 1) * iStepSrcImg * 3 + (iX + 1) * 3 + 1];
60  
61             rUpLeft  = pSrcRgbBuffer[iY * iStepSrcImg * 3 + iX * 3 + 2];
62             rUpRight = pSrcRgbBuffer[iY * iStepSrcImg * 3 + (iX + 1) * 3 + 2];
63  
64             rDownLeft  = pSrcRgbBuffer[(iY + 1) * iStepSrcImg * 3 + iX * 3 + 2];
65             rDownRight = pSrcRgbBuffer[(iY + 1) * iStepSrcImg * 3 + (iX + 1) * 3 + 2];
66  
67             uB = bUpLeft * (iX + 1 - fX) * (iY + 1 - fY) + bUpRight * (fX - iX) * (iY + 1 - fY)
68                 + bDownLeft * (iX + 1 - fX) * (fY - iY) + bDownRight * (fX - iX) * (fY - iY);
69  
70             uG = gUpLeft * (iX + 1 - fX) * (iY + 1 - fY) + gUpRight * (fX - iX) * (iY + 1 - fY)
71                 + gDownLeft * (iX + 1 - fX) * (fY - iY) + gDownRight * (fX - iX) * (fY - iY);
72  
73             uR = rUpLeft * (iX + 1 - fX) * (iY + 1 - fY) + rUpRight * (fX - iX) * (iY + 1 - fY)
74                 + rDownLeft * (iX + 1 - fX) * (fY - iY) + rDownRight * (fX - iX) * (fY - iY);
75  
76             if(iY >= 0 && iY <= uSrcHeigth * 2 && iX >= 0 && iX <= uSrcWidth * 2)
77             {
78                 pDstRgbBuffer[iIndexH * iStepDstImg * 3 + iIndexW * 3 + 0] = uB;        //B
79                 pDstRgbBuffer[iIndexH * iStepDstImg * 3 + iIndexW * 3 + 1] = uG;        //G
80                 pDstRgbBuffer[iIndexH * iStepDstImg * 3 + iIndexW * 3 + 2] = uR;        //R
81             }
82         }
83     }
84 
85     return OK;
86 }

实现二：改写自：https://blog.csdn.net/weixin_40647819/article/details/86601070

 1 /**@func       gif_get_scale_rgb    
 2 * @brief       双线性差值算法缩放RGB图片
 3 * @param[in]   uDstWidth   目的图像宽度
 4 * @param[in]   uDstHeigth  目的图像高度
 5 * @param[out]  pDstRgbBuffer 目的图像地址
 6 * @param[in]   uSrcWidth   源图像宽度
 7 * @param[in]   uSrcHeigth  源图像高度
 8 * @param[in]   pSrcRgbBuffer 源图像地址
 9 * @return      成功返回：OK 失败返回：ERROR
10 */
11 static INT32 gif_get_scale_rgb_new(UINT16 uDstWidth, UINT16 uDstHeigth, UINT8 *pDstRgbBuffer, UINT16 uSrcWidth, UINT16 uSrcHeigth, UINT8 *pSrcRgbBuffer)
12 {
13     DOUBLE fRateW = uDstWidth * 1.0 / uSrcWidth;
14     DOUBLE fRateH = uDstHeigth * 1.0 / uSrcHeigth;
15 
16     INT32 iIndexW = 0;
17     INT32 iIndexH = 0;
18 
19     DOUBLE dCenterH;
20     DOUBLE dCenterW;
21     DOUBLE dPointPartu;
22     DOUBLE dPointPartv;
23 
24     INT32 iHeightDown;
25     INT32 iHeightUp;
26     INT32 iWidthLeft;
27     INT32 iWidthRight;
28 
29     if((NULL == pDstRgbBuffer) || (NULL == pSrcRgbBuffer))
30     {
31         GIF_ERRORS("Ptr is NULL \n");
32         return ERROR;
33     }
34 
35     for(iIndexH = 0; iIndexH < uDstHeigth; iIndexH++)
36     {
37         //几何中心对齐
38         dCenterH = (iIndexH + 0.5) / fRateH - 0.5;
39         //防止越界
40         if (dCenterH<0)
41         {
42             dCenterH = 0;
43         }
44         if (dCenterH >= uSrcHeigth - 1)
45         {
46             dCenterH = uSrcHeigth - 2;
47         }
48         //相邻4*4像素的行（坐标）
49         iHeightDown = floor(dCenterH);
50         iHeightUp = ceil(dCenterH);
51         //u为得到浮点型坐标行的小数部分
52         dPointPartu = dCenterH - iHeightDown;
53         for(iIndexW = 0; iIndexW < uDstWidth; iIndexW++)
54         {
55             //几何中心对齐
56             dCenterW = (iIndexW + 0.5) / fRateW - 0.5;
57             //防止越界
58             if (dCenterW < 0)
59             {
60                 dCenterW = 0;
61             }
62             if (dCenterW >= uSrcWidth- 1)
63             {
64                 dCenterW = uSrcWidth - 2;
65             }
66             //相邻4*4像素的列（坐标）
67             iWidthLeft = floor(dCenterW);
68             iWidthRight = ceil(dCenterW);
69             //v为得到浮点型坐标列的小数部分
70             dPointPartv = dCenterW - iWidthLeft;
71             
72             //彩色图像
73             pDstRgbBuffer[iIndexH * uDstWidth * 3 + iIndexW * 3 + 0] = (1 - dPointPartu) * (1 - dPointPartv) * pSrcRgbBuffer[iHeightDown * uSrcWidth * 3 + iWidthLeft * 3 + 0] + (1 - dPointPartu) * dPointPartv * pSrcRgbBuffer[iHeightDown * uSrcWidth * 3 + iWidthRight * 3 + 0] + dPointPartu * (1 - dPointPartv) * pSrcRgbBuffer[iHeightUp * uSrcWidth * 3 + iWidthLeft * 3 + 0] + dPointPartu * dPointPartv * pSrcRgbBuffer[iHeightUp * uSrcWidth * 3 + iWidthRight * 3 + 0];
74             pDstRgbBuffer[iIndexH * uDstWidth * 3 + iIndexW * 3 + 1] = (1 - dPointPartu) * (1 - dPointPartv) * pSrcRgbBuffer[iHeightDown * uSrcWidth * 3 + iWidthLeft * 3 + 1] + (1 - dPointPartu) * dPointPartv * pSrcRgbBuffer[iHeightDown * uSrcWidth * 3 + iWidthRight * 3 + 1] + dPointPartu * (1 - dPointPartv) * pSrcRgbBuffer[iHeightUp * uSrcWidth * 3 + iWidthLeft * 3 + 1] + dPointPartu * dPointPartv * pSrcRgbBuffer[iHeightUp * uSrcWidth * 3 + iWidthRight * 3 + 1];
75             pDstRgbBuffer[iIndexH * uDstWidth * 3 + iIndexW * 3 + 2] = (1 - dPointPartu) * (1 - dPointPartv) * pSrcRgbBuffer[iHeightDown * uSrcWidth * 3 + iWidthLeft * 3 + 2] + (1 - dPointPartu) * dPointPartv * pSrcRgbBuffer[iHeightDown * uSrcWidth * 3 + iWidthRight * 3 + 2] + dPointPartu * (1 - dPointPartv) * pSrcRgbBuffer[iHeightUp * uSrcWidth * 3 + iWidthLeft * 3 + 2] + dPointPartu * dPointPartv * pSrcRgbBuffer[iHeightUp * uSrcWidth * 3 + iWidthRight * 3 + 2];
76         }
77     }
78 
79     return OK;
80 }