图像在处理过程中，有时需要去除一些无用的背景，限制处理范围，以提高图像下一步处理的速度。
下面这个函数主要实现了对二值化后的8位DIB查找范围的功能。其中参数c为背景的颜色.
1
void FindBlankBound(LPBYTE src, RECT & bound,INT c,INT limit)
2
{
3
int w = DIBWidth(src);
4 int h = DIBHeight(src);
5 int bitCount=DIBBitCount(src);
6 int rowstride = DIBCalBytesPerRow(w,bitCount);
7 int startY = 0, endY = 0;
8 int startX = 0, endX = 0;
9 int fillColor= 255-c;
10
11 BYTE* srcData0 = (BYTE*)DIBGetPixelPtr(src,0,0);
12 BYTE * srcData = srcData0;
13
14 int i, j;
15 LONG x0,y0,x1,y1;
16 x0=bound.left;
17 y0=bound.top;
18 x1=bound.right;
19 y1=bound.bottom;
20
21 CLAMP(x0,0,w);
22 CLAMP(x1,0,w);
23 CLAMP(y0,0,h);
24 CLAMP(y1,0,h);
25
26 BOOL bFind=FALSE;
27
28 for (i = x0; i < x1; ++i)
29
{
30 startY = y0;
31 endY = y0;
32
33 for (j = y0; j < y1; ++j)
34 {
35 srcData = srcData0 + j * rowstride;
36 endY = j;
37 if(srcData[i]==c) /**////FIND COLOR
38
///if (IsBlock(srcData0,w,h,i,j,c))
39 break;
40 }
41
42 x0 = i; /**////
43 if (abs((endY - startY) - (y1 - y0)) > limit)
44 break;
45
46 bFind=TRUE;
47 for (j = 0; j < h; ++j)
48 {
49 *( srcData0 + j * rowstride + i) = fillColor;
50 }
51
52 }
53
54
55
56 for (i = (x1 - 1); i >= x0; --i)
57 {
58 startY = y0;
59 endY = y0;
60 for (j = y0; j < y1; ++j)
61 {
62 srcData = srcData0 + j * rowstride;
63 endY = j;
64
65 if(srcData[i]==c)
66 /**////if (IsBlock(srcData0,w,h,i,j,c))
67 break;
68
69 }
70
71 x1 = i + 1;
72 if (abs((endY - startY) - (y1 - y0)) > limit)
73 break;
74
75 for (j = 0; j < h; ++j)
76 {
77 *( srcData0 + j * rowstride + i) = fillColor;
78 }
79
80 }
81
82 if ((x1-x0) <= 1)
83 {
84 y0 = y1;
85 }
86
87 for (j = y0; j < y1; ++j)
88 {
89
90 startX = x0;
91 endX = x0;
92 srcData = srcData0 + j * rowstride;
93
94 for (i = x0; i < x1; ++i)
95 {
96 endX = i;
97 if(srcData[i]==c)
98 /**////if (IsBlock(srcData0,w,h,i,j,c))
99 break;
100 }
101
102 y0 = j;
103 if (abs(endX - startX - (x1 - x0)) > limit)
104 break;
105
106 for (i = 0; i < w; ++i)
107 {
108 srcData[i] = fillColor;
109 }
110 }
111
112 for (j = (y1 - 1); j >= y0; --j)
113 {
114
115 startX = x0;
116 endX = x0;
117 srcData = srcData0 + j * rowstride;
118 for (i = x0; i < x1; ++i)
119 {
120 endX = i;
121 if(srcData[i]==c)
122 /**////if (IsBlock(srcData0,w,h,i,j,c))
123 break;
124
125 }
126
127
128 y1 = j+1;
129 if (abs(endX - startX - (x1 - x0)) > limit)
130 break;
131
132 for (i = 0; i < w; ++i)
133 {
134 srcData[i] = fillColor;
135 }
136 }
137
138 bound.left=x0;
139 bound.top=y0;
140 bound.right=x1;
141 bound.bottom=y1;
142
143
}